Personal Care Product Preservatives, And The Truth (Part I)

What Are Some Of These Ingredients?

I would love to find preservatives for my products that are non-toxic, and do the job effectively. So far, that has been a challenge, and given that I myself find my skin reacts to most of the so called “natural preservatives,” I don’t dare suggest for someone else to wear them.

I’m involved in many lotion crafter and soap making online groups, and I generally stay away from topics of preservatives, and whether or not they are harmful. I have found that it only devolves into arguments over who is “right”.

Note: This article was written by both Tober and Rob, so if this article switches between “I” and “we” that is the reason.

I will chime in and point out that some people do indeed have allergic and/or sensitivity reactions to these ingredients, as I am vocal and passionate about this topic due to my personal skin reactions. But other than pointing out that these preservatives are not for everybody, I generally stay quiet, mainly because sensitivities to such chemicals are not taken seriously.

Actually, I have found that allergies in general are not taken seriously by those who neither experience allergies nor have a loved one who does. Many don’t realize the lethality behind some allergies, especially food allergies. And I hate to say it, but it seems the major manufacturers of personal care products could care less about the percentage of the population that have sensitivities/allergies to many of the ingredients they use.

I have anecdotally read that about 3% of the population is sensitive to such chemicals. I was curious as to what scientific research has been conducted regarding what percentage of the population actually has adverse reactions to such chemicals. I found the following study on the prevalence of contact dermatitis to several of these chemicals.1 Based on this research it seems that the percentage of the population that is sensitive to at least one of the chemicals that were tested could be as high as 11.6%. Some chemicals tested were more likely to cause reactions than others, and this study did not test all chemicals used in personal care products – only some of them. But that is still a lot of people!

But even if you’re not allergic or have sensitivities to any of these additives, there might be other reasons to stay away from these ingredients. It is also possible that you could be among the percentage who is sensitive to some degree and not be aware of the effects these chemicals are having on you. Ultimately, the choice is yours, but in my opinion, what you put on your body, is just as important (or at least almost as important) as what you put in your body.

In case you are not familiar, hidden in many of your personal care products, including soap, lotions, shaving creams, and even specialty delicate anti-wrinkle creams, there are some very nasty chemicals. These chemicals are often sold under shiny new names to fool the public. Although there is a great deal of scientific research and studies to show that these chemicals indeed do have detrimental effects on human health, even in minuscule amounts. It is ironic that the exact argument often used to defend the use of these chemicals in products – that they are used in such small amounts – is irrelevant if harm is shown even in those small amounts.

If these ingredients kill bacteria, fungus, and mold, then why would they not also harm the cells of your skin? Your skin cells are very small in comparison to your entire body. At the same time, if you’re using these products daily, or twice daily, or even more often if you use a combination of products, then these small amounts of ingredients will slowly accumulate into rather large amounts over time – particularly if they are lipid (fat) soluble, which many of them are. So you don’t really know how much you are exposing yourself on a regular basis when you use them.

Therefore the argument that such minuscule amounts are harmless is very misleading, and doesn’t take into consideration accumulation over time when we use more than one product that has these added chemicals. None of us, in one day, use just soap, or just lotion, or just hand sanitizer, or whatever. We often use a combination of personal care products several times a day.

My spouse and I have done endless hours of research on these chemicals, and have had many late night dates reading peer reviewed science journals on such research. We also looked to see who funded each study (to make sure there is no skewed data due to conflict of interest – though that information is sometimes more difficult to find), and how the study was actually conducted. Were controls included? Was a descent population size used? Did the study design actually make sense and test what they claim? Do the conclusions actually represent the results provided? Etc. These are all very time consuming tasks, and often require a degree in the sciences of some sort, which my spouse and I both worked hard to achieve. Now we offer you a simplified version of the results. Although science based, we tried to write this article to be approachable by the lay person, with references for those who like to fact check.

We used several resources to research this article. One of the sources we used was PubMed which is an online database funded by the National Institute of Health (NIH) that contains most peer reviewed published biomedical research. Another resource we used in our research was the Material Safety Data Sheet (MSDS) which is another database that lists facts and safety information about a wide variety of chemicals. Unfortunately, many of the ingredients found in personal care products are not found in the MSDS database, or the database has very limited information. Therefore it is necessary to dig further into the toxicology research science. We also sometimes used Wikipedia and Google to find basic information and as starting points for more detailed investigation. I mention these resources for the naysayers of this article because if they are going to continue to purchase and use conventional chemical-based personal care products, they will need these resources to figure out all the potentially harmful synthetics they are putting on their bodies (and the potential side effects that may follow).

The general rule of thumb I give to people is, if you have no idea what an ingredient is, or can’t even pronounce it, then you probably shouldn’t buy it or use it.

Following is a list of commonly used ingredients used in personal care products, and some quite concerning scientific evidence about them. This list is not all inclusive, and part II of this article will cover the newer versions of these chemicals that are sold under fancy new names.


There are several kinds: Propylparaben, Methylparaben, Ethylparaben, Isobutylparaben, and Butylparaben. Notice they all end with “paraben”? So you don’t really have to remember all of these when checking ingredients, just look for words that end with paraben.

I lumped them all together because they are all structurally related, and when it comes to toxicity, they are also related.

So what’s wrong with parabens? Well, there is growing evidence that exposure to parabens can lead to cancer. Here is a study showing that exposure to methyparaben, propylparaben, and butylparaben can increase phosphorylation in certain cell lines,2 in other words, it can alter the protein activity or structure. This same study3 also states that propylparaben can inhibit apoptosis in cancer cells. Apoptosis is the body’s natural way to fight cancer by basically telling the cells of our body that have mutated to commit suicide, preventing the mutated cells from dividing themselves and resulting in more mutated cells, i.e. cancer. If you stop the process of apoptosis, then the mutated cells proliferate which can then lead to cancer. Here is a study to show that just about all parabens can lead to breast cancer.4 Here is another study supporting further evidence that parabens can lead to breast cancer.5

Here is a quote from my hubby about his scientifically based opinion of parabens: “Parabens are dangerous endocrine disruptors. That is only good if you want to cause infertility in adults or have fetuses and children that have developmental abnormalities.” No, he wasn’t exaggerating. He was referring to the following reproductive toxicology studies of parabans: “ Effects of n-butylparaben on steroidogenesis and spermatogenesis through changed E₂ levels in male rat offspring6, “Butyl paraben-induced changes in DNA methylation in rat epididymal spermatozoa.7 and “Effects of butyl paraben on the male reproductive system in mice.”8




Come on people, we put this in/on dead people to preserve their bodies! Why in the world would you want to put this on your skin when you’re still alive?

OK, perhaps a bit more explanation and evidence is required. To start, according to the Centers for Disease Control (CDC) “ingestion of 30 mL (1 oz) of a solution containing 37% formaldehyde has been reported to cause death in an adult human,” and “formaldehyde is a potent sensitizer and a probable human carcinogen,” and “formaldehyde is absorbed through intact skin and may cause irritation or allergic dermatitis”, however “rapid metabolism makes systemic effects unlikely following dermal exposure”.9 [emphasis mine].

Furthermore, the following review paper concluded that formaldehyde is a likely contributing cause of leukemia.10

The National Cancer Institute as well as the EPA, and the World Health Organization (WHO) all classify formaldehyde as a probable human carcinogen.11

In addition here are just a few of the dozens of studies with supporting evidence that formaldehyde poses significant concerns of both carcinogenicity and general toxicity:
“Endogenous Formaldehyde Is a Hematopoietic Stem Cell Genotoxin and Metabolic Carcinogen.”12

“Epigenetic alterations induced by genotoxic occupational and environmental human chemical carcinogens: A systematic literature review.”13

Contrasting directions and directives on hazard identification for formaldehyde carcinogenicity.14

Carcinogenic Air Toxics Exposure and Their Cancer-Related Health Impacts in the United States.15


Human health risks of formaldehyde indoor levels: An issue of concern.16

Formaldehyde is very toxic to all cell types via oxidative stress, DNA cross linking, and other cell dysfunction, as noted in this study.17 Finally, formaldehyde and formaldehyde releasing compounds (“releasers”) are common causes of contact dermatitis as the research shows here.18

Formaldehyde is just plain unhealthy and potentially dangerous stuff to be putting on or in your body. Period.

Diazolydinyl urea

Diazolidinyl urea along with imidazolidinyl urea, are significant formaldehyde releasers.19 In other words, they are compounds that slowly releases formaldehyde. And when does it release formaldehyde? Well, that’s dependent on the matrix according to this study.20 So have the cosmetic makers tested if formaldehyde is released in their combination of oils and waters? I have not found any evidence that they have done so.

So if formaldehyde is harmful to your body, why would you want to put something on that releases formaldehyde onto and into your body?

Imidazolidinyl Urea

See dizaolydinyl urea above. Both are chemically related.

DMDM Hydantoin

DMDM Hydantoin is primarily found in shampoos and conditioners, and is another formaldehyde releaser21 which has been linked to contact dermatitis in people who are allergic to formaldehyde.22 The research also shows that DMDM hydantoin is also a common cause of contact dermatitis even in people not sensitive to formaldehyde.23

It seems many of these preservatives act as preservatives simply by being formaldehyde releasers, which results in an unfavorable environment for bacteria. However, if you have sensitivity to formaldehyde, then you are likely to be sensitive to all of these common ingredients. And even if you are not immediately sensitive to formaldehyde, you are putting yourself at risk of toxic effects of exposure, including cancer.

For all of the above reasons it is a good idea to avoid this ingredient.

Ingredients 8


Glydant is the trade name for DMDM Hydantoim, which as stated above, is a formaldehyde releaser.


AKA hexamethylenetetramine chloroallyl chloride, is another formaldehyde releaser.24

Triethanolamine (TEA, TEOA)

“Triethanolamine is produced from the reaction of ethylene oxide with aqueous ammonia, also produced are ethanolamine and diethanolamine. The ratio of the products can be controlled by changing the stoichiometry of the reactants.”25 In trying to find all the scientific facts about this, there was not a great deal of research available regarding safety in humans or animals. One rat study involving topical application found: “Clinical observations included irritation, scaliness, and crustiness of the skin at the site of application for males and females. Males also had discoloration, and males administered 2,000 mg/kg had ulceration at the site of application. […] Microscopic lesions attributed to triethanolamine administration included acanthosis and inflammation at the site of application, nephropathy in females, and hypertrophy of the pituitary gland in males and females. These lesions generally occurred with dose-related increases in incidence and severity in males and females.”26 A study in mice found similar results. (Ibid) In other words, it caused skin damage and may have caused kidney and pituitary gland damage. So if this chemical causes skin damage, why are people using it on their skin? There was a recent review of the use of these ingredients in cosmetics, which didn’t include any new studies, and clearly states that it is effective as a conditioning agent, and with the exception of one formulation, not as a preservative.27 So if it’s not effective as a preservative, why are people using it as such?

Here is a study showing that triethanolamine resulted in damaged outer and inner ear cells in chinchillas when used as a earwax softener, one animal even experienced facial paralysis.28

According to this patch test study, 1.1% of the participants tested positive for allergic reactions to triethanolamine.29 And this study shows a 3.5% prevalence of reactivity.30 You’re probably thinking 1.1% and 3.5% is such a small number of people that it’s no big deal, but it is a big deal when you’re part of those groups.

Simply put, if it doesn’t work as a preservative, it is a skin irritant, and there are not enough studies done to show not only the safety but also efficacy of the ingredient, why are companies rushing to shove this chemical into our products?

Iodopropynyl Butylcarbamate (IPBC)

In researching this preservative I was surprised to find a large number of studies in regards to contact dermatitis. It is a culprit of such indeed. Iodoprpynyl butylcarbamate is actually a carbamate family of biocides,31 meaning it is a family of chemicals used as insecticides that function by inactivating the enzyme Acetylcholinesterase. Basically they act as a nerve agents to kill insects. However, I must point out that insects are not the only species that require that enzyme. Humans utilize that enzyme too, especially in brain and muscle tissue.32 Ok, at this point, I don’t think I need any toxicity studies to tell me that I don’t want this in my skin creams. But I read on and researched anyway.

The Environmental Working group has a good summary which I have quoted below:

Per — “Iodopropynyl Butylcarbamate does show ‘Limited evidence of gastrointestinal or liver toxicity’ per the US EPA; that there is strong evidence of ‘Human toxicant or allergen’ affects, by Cosmetic Ingredient Review Assessments; that it is ‘Suspected to be an environmental toxin’ from Environment Canada Domestic Substance List, and that at least ’50 studies in PubMed Science Library may include information on the toxicity of this chemical,’ NLM PubMed.”33

So… I’m thinking no thank you. I’ll look for something else.


A glycol ether used as a preservative in cosmetics and medications. Also known as ethelyne glycol phenyl ether.

The authors of one published study concluded that phenoxyethanol “has been shown to induce hepatotoxicity, renal toxicity, and hemolysis at dosages ≥ 400 mg/kg/day in subchronic and chronic studies in multiple species.”34 While this amount is more than would be absorbed by any single topical use of a personal care product, it may be possible that long term use may accumulate to this degree. No one knows, because it has never been studied. So why take the chance? If there is evidence that this chemical is liver toxic, kidney toxic and causes anemia, why would anyone take the chance of using it? Crazy.

In addition, the Food and Drug Administration has warned that the chemical is toxic to infants via ingestion, and “can depress the central nervous system and may cause vomiting and diarrhea. Combined with chlorphenesin, these two chemicals can cause respiratory depression in infants. Since these chemicals are often present in cosmetics and lotions applied to the hands and are easily ingested, caution should be exercised.”35

Phenoxyethanol is part of a family of chemically related compounds known as ethelene glycol ethers. There is much more research on the toxicology of these compounds than on Phenoxyethanol itself, and the research on the health implications of that family of compounds is rather disturbing. Below are merely a few examples we found.

This study shows that phenoxyethanol caused neuronal (brain) cell death through apoptosis (cell suicide) in the portion of the brain responsible for forming memories (hippocampus). In addition, this study shows that phenoxyethanol disrupted brain glucose metabolism which would likely cause a generalized disruption of brain function.36

Here is a study showing that oxidative stress is induced in rat brains via ethylene glycols.37

Additional studies showed ethylene glycols induce testicular lesions in rats38 and neuronal cell damage in human cell lines.39 There was so much more damning evidence on this family of chemicals – too much for one article alone.

Ingredients image 3

Polysorbate 20

A polyoxyethylene (not to be confused with phenoxyethanol – different compounds), is formed by the ethoxylation of sorbitan, prior to adding lauric acid. What’s left over from the chemical reaction process is a chain of polyethelene glycol.40 Polysorbate 20 at first appears non-toxic, as it is technically inert, meaning that it causes no reaction in a biological level. But is it really so innocent?

When you investigate more carefully, and specifically look for research on polyethelene glycol, often referred to just as PEG, there is published research showing it as a common allergen, sometimes severely so. Recently published research shows increasingly common allergic reactions to PEG.41

It is also worth pointing out that in pharmaceutical toxicology research and in clinical cases, human antibodies have been observed to PEG, meaning that human allergies to PEG have been observed in real world clinical settings. “[A]n emerging body of literature highlights the presence of antibodies produced by the immune system that specifically recognize and bind to PEG (anti-PEG Abs), including both pre-existing and treatment-induced Abs. More importantly, the existence of anti-PEG Abs has been correlated with […] increase in adverse effects in several clinical reports examining different PEGylated therapeutics.”42 In other words, medical professionals have been finding that humans can produce antibodies to PEG, thus causing an immune reaction to it. In some cases these antibodies were already present before exposure to PEG, and in other cases people developed the antibodies to PEG only after treatment with compounds that use PEG as a carrier. The key point here is that there is very much a concern that humans can develop allergies to products containing PEG.

So this chemical may be inert for many people, but for others it can cause serious allergic reactions. And those allergies can also develop over time with use. So caution is advised.

Ingredients image 4


This ingredient is not as popular as it used to be due to the formation of nitrosamines during it’s decomposition.43 Not only will it release nitrosamines, but also formaldehyde. And I recently learned thatNitrosamines form a large group of genotoxic chemical carcinogens which occur in the human diet and other environmental media.44 In addition, this chemical contains bromine, and it is common for brominated compounds to cause human toxicity. It also turns out that bronopol, under certain conditions, such as when diluted in liquid, at certain pH, or at higher temperatures, will release formaldehyde.45 So exposure should certainly be avoided as much as possible, for several reasons.

Another name for this is 2-Bromo-2-Nitropropane.

I would just like to take a moment here and point out that at one point, this was a very popular preservative, because we just didn’t know the consequences of using it as a preservative. It’s been used for decades, and it took a long time to realize the dangers of using it. Which is another reason when new chemicals are introduced, I prefer to wait and see what kind of toxicity studies have been done or will be done before I decide to use them.


This is a chemical compound with an IUPAC name of 5-bromo-5-nitro-1,3-dioxane,46 which is not only an anti-microbial, but is also corrosive to metals.47 Sounds lovely to put on your face eh?

There was limited data to find on bronidox, but did learn that it has a similar method of action as bronopol (and also contains bromine).48 Fortunately more information was available on bronopol. As I mentioned above, bronopol also releases formaldehyde, and I already discussed earlier why formaldehyde exposure is harmful.

In addition, you may notice that the IUPAC name of this has “dioxane” at the end of it because its chemical structure is related to dioxane. According to the EPA, dioxane is a probable human carcinogen, and exposure causes a host of other adverse effects.49 The State of California also includes it on their Proposition 65 list of “Chemicals known to the state to cause cancer or reproductive toxicity”. That list is actually useful to keep around your home to refer to when working around chemicals because it provides information that is often not included in MSDS (Material Safety Data Sheets). You can find the current list in PDF or Excel here.50

Benzalkonium chloride

This is also known as BZK, BKC, BAC, ADBAC, and known by many other abbreviations. It is used in a variety of products including medicines. In eye drops, it has to be used in concentrations of less than 0.01% otherwise it’s caustic to the cornea. Added to nasal sprays, it has been linked to asthma. Even the FDA admits it has been unable to classify it as safe due to lack of data regarding human and animal pharmacokinetics, dermal carcinogenicity, reproductive toxicity, and hormonal effects.51

According to several sources cited via Wikipedia, “benzalkonium chloride is a human skin and severe eye irritant. It is a suspected respiratory toxicant, immunotoxicant, gastrointestinal toxicant and neurotoxicant. Concentrated solutions are toxic to humans, causing corrosion/irritation to the skin and mucosa, and death if taken internally in sufficient volumes. 0.1% is the maximum concentration of benzalkonium chloride that does not produce primary irritation on intact skin or act as a sensitizer.”52 References, via Wikipedia:

There are also a number of published studies showing that this chemical is not on your safe list and should probably be completely avoided.

Zinc pyrithione

This comes from zinc, so it must be safe right? This one is commonly found in dandruff shampoo, and many anti-fungal creams. It is also an ingredient added to paint to make it stable in outdoor applications where it helps to prevent bacterial and fungal growth. Sounds not too bad so far right? Until you ask by what method of action does it act as a anti-bacterial/anti-fungal. This study shows that exposure to zinc pyrithione causes oxidative stress, DNA damage, and apoptosis in skin cells in a dose dependent manner.53 This means that if you use more than the right dose amount, it may lead to cell apoptosis (cell death), or cell senescence (the cause of skin aging).

Those results would certainly not be in line with anyone’s skin care goals.



This is another anti-mircobial/anti-fungal agent. Triclosan is a chemical derived from another chemical through a several step reaction process. I tried to figure out how I could simply explain the chemical synthesis process for the purpose of making it easy to understand, but really, I just couldn’t.

Triclosan has been a very popular chemical in the hospitals specifically, but also in personal care products, including liquid soap and toothpaste. Triclosan sounds innocent enough by targeting the process of production of fatty acids in bacteria, which does not work the same way in human cells.

There is question as to whether or not triclosan is a culprit as a thyroid hormone disruptor. In our search for research studies, we found one review paper that implied that it may not be a thyroid hormone disruptor, but couldn’t fully rule it out either.54 One finding that is concerning to me from the preceding meta-study is that triclosan binds to both androgen and estrogen receptors in vitro with low affinity and evokes diverse responses. While the authors of the paper brush this off, I do not. Any disruption of sex hormone function (female or male) is a big deal, and binding to androgen and estrogen receptors could do exactly that. The authors admit we don’t know what this is doing, so it needs more research.

Regardless, there are no studies that show that using triclosan has any more real world antibacterial affect than just washing your hands with soap and water. In other words, there does not appear to be any advantage over soap by using triclosan.

So why are we using a questionable chemical instead of soap when there is no known added benefit? Especially when there is potential harm to both human health and the environment?

Butylated Hydroxytoluene (BHT)

BHT, derived from phenol, is often found as a preservative in many cakes, chips, and cereals, and is also used in personal care products to help prevent oxidation. A very good antioxidant indeed for keeping skin creams sitting on store shelves for years until someone decides to buy them.

I’ll be honest, I have a personal vendetta against BHT, because it is used in so many products, including food, and yet, it is so far from healthy or natural (unlike antioxidants like Vitamins C or E). Think about it: this is basically taking a petroleum derivative and eating it or putting it on your face and body! It is actually prohibited as a food additive in some countries (hmmm… do they know something we don’t?).

Actually we know a good deal about it, as many studies have been conducted and written about, and the jury should not be out on this one. While BHT is fine as an industrial anti-oxidant, it should not be in food or personal care products.

Some older studies found here and here, show a possible link between BHT and carcinomas (cancer).55

A very recent study shows that BHT acts as an anti-androgen,56 meaning it blocks the action of male hormones like testosterone. This raises a number of health concerns, including male infertility.

Another study showed that BHT consumption caused pathological liver morphology (size and shape) and pathological liver chemistry panels. In other words, it caused harmful liver enlargement and adverse effects in liver function.57

So do not assume that just because you see this ingredient in your breakfast cereal that it is healthy or harmless; it is anything but.



This is a very popular antibacterial used since the 1970’s. This is actually a skin irritant that can also result in chemical burns if used in pure concentrations, not to mention that many people have severe allergic reactions to this chemical.58 Apparently it is also a commonly unrecognized cause in pediatric dermatitis.59 This chemical has also been shown to cause a higher prevalence of sensitivity than some of the other chemicals. Let’s dump it in all our personal care products, shall we?


See Methylchloroisothiazolinone above.


Sodium Dehydroacetate

This compound is not your typical one, and is dangerous in an uncommon but equally concerning way. This one prevents vitamin K activity, similarly but more potently than the pharmaceutical warfarin (you know, rat poison), which can result in bleeding disorders such as organ hemorrhage.60


This name can be confusing. Benzoin that is synthesized from benzodelhyde61 is different from benzoic acid that is derived from gum benzoin62 and refined into benzoic acid.63 Unfortunately, many companies are unclear in their labeling as to the source or type of the benzoin or benzoic acid used in their product. Sodium Benzoate is the salt of benzoic acid. This makes it difficult to know what exactly you are actually using. Regardless, if you are using products that contain such synthetic chemicals, make sure you are reading the ingredients carefully to try to discern which it contains.

I found quite a few research studies on this compound due to concerns over mutagenicity or carcinogenicity of the compound. However, none of those studies found evidence to support these concerns. According to the MSDS and the CDC, what is a concern is that there is evidence that benzoin is a significant cause of contact dermatitis.64 The research literature supports this as well:

“Benzoin Spray: Cause of Allergic Contact Dermatitis due to Its Rosin Content.”65

“Allergic contact dermatitis from tincture of benzoin with multiple concomitant reactions.”66

Severe allergic contact dermatitis resulting from occupational exposure to tincture of benzoin aerosol spray in an anesthesiologist.67

Benzoin sensitivity.68

Obviously not everyone is necessarily sensitive to this ingredient, but from the research we found, many people are, including myself. So either avoid it or use with caution if you must.

Ingredients image 1

Iron Oxide

I find this one to be of extreme interest because it is used as a coloring agent in so many of our natural make up formulations. I have been researching this specific ingredient in the last months because I do plan on coming out with my own line of makeup that is truly healthy, not just claimed as such. After much research, I have made the decision that my cosmetics will not contain iron oxide.

So what’s wrong with iron oxide? It’s just iron and oxygen right? Well, it can cause oxidative damage to your skin, which leads to premature aging. And now with nano particle iron oxide hitting the mainstream, there are numerous studies showing additional reason for concern, particularly regarding liver toxicity. Below are just a few of the concerning studies:

Hepatotoxicity evaluation of dextran stabilized iron oxide nanoparticles in Wistar rats.”69

Biodistribution of polyacrylic acid-coated iron oxide nanoparticles is associated with proinflammatory activation and liver toxicity.70

Iron overload by Superparamagnetic Iron Oxide Nanoparticles is a High Risk Factor in Cirrhosis by a Systems Toxicology Assessment.71

Repeated exposure to iron oxide nanoparticles causes testicular toxicity in mice.72

Sodium Carbomer

According to the website, Sodium Carebomer is not really a preservative. The referenced site says to include a preservative system because it’s not effective as one itself.73 It is actually added as a thickener, so if you were making a gel, this is something you could add. However, according to the MSDS, sodium carbomer is another word for sodium polyacrylate.74 Polyacrylate is apparently what they make artificial snow and diapers out of.75 Now I honestly couldn’t find anything toxic about this salt, and I searched rather extensively. But it’s not a preservative. It’s a water absorber, which turns the cream into a thicker concoction. So it’s really an unnecessary ingredient if a product is formulated correctly. But it is not useful as a preservative.


Oh, the softness this wonderful compound provides to products. Many products benefit from having dimethicone added, from lotions, to creams, to body oils and personal lubricants. It provides a wonderful feeling indeed. But what is it?

Dimethicone is really Polydimethylsiloxane which is an inert (meaning it doesn’t react) form of silicone. Many things are made out of silicones, including caulk, sealants, and adhesives.76

One study I found showed that polydimethylsiloxane binds with collagen, although this seemed to have little detrimental effect,77 collagen is an essential component of skin. I found a study showing that dimethicone is actually quite safe, and didn’t show any adverse effects in rats even at 10% concentration.78 However, as per Murphy’s law, it figures that this is one of the few chemical ingredients to which my hubby is sensitive.

What I found interesting is that it can be used as a treatment for lice,79 and fleas!80

However safe it may be, this chemical does not function as a preservative, so it can be used to get that soft feeling (if needed), but not to prevent bacterial or fungal growth in personal care products.

Ammonium Sulphate/Persulfate

This ingredient, made by treating ammonia with sulfuric acid, is most commonly used as fertilizer but is also used as a food additive,81 and of course in personal care products. But just because something is used in foods, doesn’t mean that it is safe. Here is a study showing that a percentage of pizza makers developed contact dermatitis, and one of the culprits was ammonium persulfate.82 Ammonium persulfate is similarly made via electrolysis of ammonium sulfate in sulfuric acid.83 Ammonium persulfate is actually commonly used by chemists to initiate (pro-)oxidant reactions. Roughly speaking you can think of contact with it as the opposite of taking beneficial anti-oxidants like Vitamins C or E. Don’t eat pizza? Here are several studies showing that hairdressers commonly develop contact dermatitis and asthma as a result of exposure to ammonium persulfate (and also other hair chemicals):

Occupational allergic “march”. Rapid evolution of contact dermatitis to ammonium persulfate into airborne contact dermatitis with rhinitis and asthma in a hairdresser.84

Patch-testing with hairdressing chemicals.85

Occupational contact dermatitis in hairdressers.86

If the point of a product is skin care, it makes no sense at all to use any of these chemicals (such as this one) that have repeatedly been shown to cause contact dermatitis upon skin contact.

Conclusion of Part 1

While this list of preservatives and chemicals is certainly not all inclusive (I wish it could be – but it’s already a very long list), it does contain many of the ingredients very commonly used in personal care products. I also didn’t go into very much detail for each one; I merely provided a basic explanation and why it might not be good for you. Ultimately, the decision of what you put on your body is completely up to you, but I personally like to be able to understand the items that are being put on my body, and know they are safe. Being able to pronounce them is also a bonus.

Additional Considerations

There is more to these toxic chemicals mislabeled as “natural preservatives” that we should consider. It isn’t always just about us. Our planet is the only one we have right now. There are some considerations we should at least think about. For instance, what effects do mass production and disposal of these chemical ingredients have on our planet? If putting these chemicals on your skin isn’t bad enough, few people are thinking of the long term effects on our environment of such chemicals. Not only production of the ingredients, but what goes down the drain, and so on. If you don’t care what goes on your skin, maybe just consider for a few moments how this affects our water supply (where many of these chemicals end up), and other people’s drinking that water.

Numerous studies have shown that many of these concerning chemicals end up in our drinking water, and therefore in people who don’t even use any products containing them. Here is a quote from a study showing that some of the compounds mentioned in this article are showing up in the water supply: “Personal care products and plasticizers have the potential to enter the water supply though treated and untreated sewage. Many of these compounds are suspected xenoestrogens.”87 (Note that xenoestrogens can cause both breast cancer in females, and infertility in males.) And according to this study our sewage water may already be contaminated beyond safe levels.88

Here is an interesting study of Swedish mothers and their children, whose lifestyles were considered and the levels of common chemicals tested in their urine. Results showed that indeed exposure to these chemicals increases the concentration of these ingredients in the urine.89

A second topic I would like for everyone to think about is what does the use of these potentially harmful chemicals in personal care products tell you about the companies that produce them? To me, it either means that these companies are incompetent and ignorant and are not aware of the potential harm, or alternately, they are aware but they don’t care about the harm they may be doing to their customers health, for the convenience and profit of their businesses. If the latter is true, they must also think that consumers are too stupid or ignorant to research and learn about the risks of these chemicals on their own. In either case – incompetence or ethical failure – those are companies that I would not want to support.

Lastly, I want to point out that some of these chemical ingredients have their place in the world. Some medications are better administered with the help of some of these compounds (e.g. PEGylated drugs), and some industrial processes are improved with the use of some of these compounds (e.g. BHT) over even more toxic ones. But just as you don’t want to take antibiotics daily (or ingest poison at all), similarly you don’t want to put these chemicals on your skin daily (or at all) either. Everything in moderation, and everything for its proper purpose. And the proper purpose of these chemicals is NOT in personal care products.

Look for part two coming soon, which will list some of latest supposedly “safe” preservatives, and part three listing some alternative truly natural ingredients that can be used as safer alternative preservatives.

Click for Part II

For Health,


*These statements have not been evaluated by the FDA.

References Cited:

1Kręcisz B, Chomiczewska-skóra D, Kieć-Świerczyńska M. [Preservatives as important etiologic factors of allergic contact dermatitis]. Med Pr.2015;66(3):327-32.

2Wróbel AM, Gregoraszczuk EŁ. Action of methyl-, propyl- and butylparaben on GPR30 gene and protein expression, cAMP levels and activation of ERK1/2 and PI3K/Akt signaling pathways in MCF-7 breast cancer cells and MCF-10A non-transformed breast epithelial cells. Toxicol Lett. 2015;238(2):110-6.

3Wróbel AM, Gregoraszczuk EŁ. Action of methyl-, propyl- and butylparaben on GPR30 gene and protein expression, cAMP levels and activation of ERK1/2 and PI3K/Akt signaling pathways in MCF-7 breast cancer cells and MCF-10A non-transformed breast epithelial cells. Toxicol Lett. 2015;238(2):110-6.

4Wróbel AM, Gregoraszczuk EŁ. Actions of methyl-, propyl- and butylparaben on estrogen receptor-α and -β and the progesterone receptor in MCF-7 cancer cells and non-cancerous MCF-10A cells. Toxicol Lett. 2014;230(3):375-81.

5Khanna S, Dash PR, Darbre PD. Exposure to parabens at the concentration of maximal proliferative response increases migratory and invasive activity of human breast cancer cells in vitro. J Appl Toxicol. 2014;34(9):1051-9.

6Zhang L, Dong L, Ding S, et al. Effects of n-butylparaben on steroidogenesis and spermatogenesis through changed E₂ levels in male rat offspring. Environ Toxicol Pharmacol. 2014;37(2):705-17.

7Park CJ, Nah WH, Lee JE, Oh YS, Gye MC. Butyl paraben-induced changes in DNA methylation in rat epididymal spermatozoa. Andrologia. 2012;44 Suppl 1:187-93.

8Oishi S. Effects of butyl paraben on the male reproductive system in mice. Arch Toxicol. 2002;76(7):423-9.

9Available at: Accessed July 19, 2016.

10Zhang L, Freeman LE, Nakamura J, et al. Formaldehyde and leukemia: epidemiology, potential mechanisms, and implications for risk assessment. Environ Mol Mutagen. 2010;51(3):181-91.

11Available at:, ( Accessed July 19, 2016.

12Pontel LB, Rosado IV, Burgos-barragan G, et al. Endogenous Formaldehyde Is a Hematopoietic Stem Cell Genotoxin and Metabolic Carcinogen. Mol Cell. 2015;60(1):177-88.

13Chappell G, Pogribny IP, Guyton KZ, Rusyn I. Epigenetic alterations induced by genotoxic occupational and environmental human chemical carcinogens: A systematic literature review. Mutat Res Rev Mutat Res. 2016;768:27-45.

14Rhomberg LR. Contrasting directions and directives on hazard identification for formaldehyde carcinogenicity. Regul Toxicol Pharmacol. 2015;73(3):829-33.

15Zhou Y, Li C, Huijbregts MA, Mumtaz MM. Carcinogenic Air Toxics Exposure and Their Cancer-Related Health Impacts in the United States. PLoS ONE. 2015;10(10):e0140013.

16Rovira J, Roig N, Nadal M, Schuhmacher M, Domingo JL. Human health risks of formaldehyde indoor levels: An issue of concern. J Environ Sci Health A Tox Hazard Subst Environ Eng. 2016;51(4):357-63.

17Zerin T, Kim JS, Gil HW, Song HY, Hong SY. Effects of formaldehyde on mitochondrial dysfunction and apoptosis in SK-N-SH neuroblastoma cells. Cell Biol Toxicol. 2015;31(6):261-72.

18Latorre N, Borrego L, Fernández-redondo V, et al. Patch testing with formaldehyde and formaldehyde-releasers: multicentre study in Spain (2005-2009). Contact Derm. 2011;65(5):286-92.

19Wikipedia, the free encyclopedia. Diazolidinyl urea. Available at: Accessed July 19, 2016].

20Lv C, Hou J, Xie W, Cheng H. Investigation on formaldehyde release from preservatives in cosmetics. Int J Cosmet Sci. 2015;37(5):474-8.

21Kireche M, Peiffer JL, Antonios D, et al. Evidence for chemical and cellular reactivities of the formaldehyde releaser bronopol, independent of formaldehyde release. Chem Res Toxicol. 2011;24(12):2115-28.

22Wikipedia, the free encyclopedia. DMDM hydantoin. Available at: Accessed July 19, 2016].

23Shaughnessy CN, Malajian D, Belsito DV. Cutaneous delayed-type hypersensitivity in patients with atopic dermatitis: reactivity to topical preservatives. J Am Acad Dermatol. 2014;70(1):102-7.

24Wikipedia, the free encyclopedia. Quaternium-15. Available at: Accessed July 19, 2016].

25Wikipedia, the free encyclopedia. Triethanolamine. Available at: Accessed July 19, 2016].

26NTP Toxicology and Carcinogenesis Studies of Triethanolamine (CAS No. 102-71-6) in F344 Rats and B6C3F1 Mice (Dermal Studies). Natl Toxicol Program Tech Rep Ser. 1999;449:1-298.

27Fiume MM, Heldreth B, Bergfeld WF, et al. Safety assessment of triethanolamine and triethanolamine-containing ingredients as used in cosmetics. Int J Toxicol. 2013;32(3 Suppl):59S-83S.

28Daniel SJ, Sahmkow SI, Munguia R, Schloss M, Akache F. Ototoxicity of triethanolamine polypeptide (cerumenex) in the chinchilla. Laryngoscope. 2008;118(3):478-82.

29Geier J, Lessmann H, Dickel H, et al. Patch test results with the metalworking fluid series of the German Contact Dermatitis Research Group (DKG). Contact Derm. 2004;51(3):118-30.

30Kieć-swierczyńska M, Krecisz B, Swierczyńska-machura D. [Contact allergy to preservatives contained in cosmetics]. Med Pr. 2006;57(3):245-9.

31Wikipedia, the free encyclopedia. Iodopropynyl butylcarbamate. Available at: Accessed July 19, 2016].

32Wikipedia, the free encyclopedia. Acetylcholinesterase. Available at: Accessed July 20, 2016].

33Available at: Accessed July 20, 2016.

34Troutman JA, Rick DL, Stuard SB, Fisher J, Bartels MJ. Development of a physiologically-based pharmacokinetic model of 2-phenoxyethanol and its metabolite phenoxyacetic acid in rats and humans to address toxicokinetic uncertainty in risk assessment. Regul Toxicol Pharmacol. 2015;73(2):530-43.

35Available at: Accessed March 10, 2020.

36Pomierny B, Krzyżanowska W, Niedzielska E, Broniowska Ż, Budziszewska B. Ethylene glycol ethers induce apoptosis and disturb glucose metabolism in the rat brain. Pharmacol Rep. 2016;68(1):162-71.

37Pomierny B, Krzyżanowska W, Smaga I, Pomierny-chamioło L, Stankowicz P, Budziszewska B. Ethylene glycol ethers induce oxidative stress in the rat brain. Neurotox Res. 2014;26(4):422-9.

38Fukushima T, Taki K, Ise R, Horii I, Yoshida T. MicroRNAs expression in the ethylene glycol monomethyl ether-induced testicular lesion. J Toxicol Sci. 2011;36(5):601-11.

39Regulska M, Pomierny B, Basta-kaim A, et al. Effects of ethylene glycol ethers on cell viability in the human neuroblastoma SH-SY5Y cell line. Pharmacol Rep. 2010;62(6):1243-9.

40Wikipedia, the free encyclopedia. Polysorbate 20. Available at: Accessed July 20, 2016].

41Wenande E, Garvey LH. Immediate-type hypersensitivity to polyethylene glycols: a review. Clin Exp Allergy. 2016;46(7):907-22.

42Zhang P, Sun F, Liu S, Jiang S. Anti-PEG antibodies in the clinic: Current issues and beyond PEGylation. J Control Release. 2016;

43Wikipedia, the free encyclopedia. Bronopol. Available at: Accessed July 20, 2016].

44Tricker AR, Preussmann R. Carcinogenic N-nitrosamines in the diet: occurrence, formation, mechanisms and carcinogenic potential. Mutat Res. 1991;259(3-4):277-89.

45Trivisano M, Carapelle E, Martino T, Specchio LM. Bilateral putaminal necrosis and bronopol toxicity. BMJ Case Rep. 2015;2015

46Wikipedia, the free encyclopedia. Chemical nomenclature. Available at: Accessed July 20, 2016].

47Wikipedia, the free encyclopedia. Bronidox. Available at: Accessed July 20, 2016].

48Ghannoum M, Thomson M, Bowman W, Al-khalil S. Mode of action of the antimicrobial compound 5-bromo-5-nitro-1,3-dioxane (bronidox). Folia Microbiol (Praha). 1986;31(1):19-31.

49Available at: Accessed July 20, 2016.

50Available at: Accessed July 20, 2016.

51Available at: Accessed July 20, 2016.

52Wikipedia, the free encyclopedia. Benzalkonium chloride. Available at: Accessed July 20, 2016].

53Rudolf E, Cervinka M. Stress responses of human dermal fibroblasts exposed to zinc pyrithione. Toxicol Lett. 2011;204(2-3):164-73.

54Witorsch RJ. Critical analysis of endocrine disruptive activity of triclosan and its relevance to human exposure through the use of personal care products. Crit Rev Toxicol. 2014;44(6):535-55.

55Franklin RA. Butylated hydroxytoluene in sarcoma-prone dogs. Lancet. 1976;1(7972):1296. And Butylated hydroxytoluene (BHT). IARC Monogr Eval Carcinog Risk Chem Hum. 1986;40:161-206.

56Pop A, Drugan T, Gutleb AC, et al. Individual and combined in vitro (anti)androgenic effects of certain food additives and cosmetic preservatives. Toxicol In Vitro. 2016;32:269-77.

57Mcfarlane M, Price SC, Cottrell S, et al. Hepatic and associated response of rats to pregnancy, lactation and simultaneous treatment with butylated hydroxytoluene. Food Chem Toxicol. 1997;35(8):753-67. Accessed July 20, 2016].

59Yu J, Treat J, Chaney K, Brod B. Potential Allergens in Disposable Diaper Wipes, Topical Diaper Preparations, and Disposable Diapers: Under-recognized Etiology of Pediatric Perineal Dermatitis. Dermatitis. 2016;27(3):110-8.

60Sakaguchi Y, Suga S, Oshida K, Miyamoto-kuramitsu K, Ueda K, Miyamoto Y. Anticoagulant effect of sodium dehydroacetate (DHA-S) in rats. J Appl Toxicol. 2008;28(4):524-9.

61Wikipedia, the free encyclopedia. Benzoin. Available at: Accessed July 20, 2016].

62Wikipedia, the free encyclopedia. Benzoin resin. Available at: Accessed July 20, 2016].

63Wikipedia, the free encyclopedia. Benzoic acid. Available at: Accessed July 20, 2016].

64Available at: Accessed July 20, 2016.

65Han JS, Jung JM, Lee WJ, et al. Benzoin Spray: Cause of Allergic Contact Dermatitis due to Its Rosin Content. Ann Dermatol. 2014;26(4):524-5.

66Sasseville D, Saber M, Lessard L. Allergic contact dermatitis from tincture of benzoin with multiple concomitant reactions. Contact Derm. 2009;61(6):358-60.

67Klein TG, Woehlck HJ, Pagel PS. Severe allergic contact dermatitis resulting from occupational exposure to tincture of benzoin aerosol spray in an anesthesiologist. J Anesth. 2009;23(2):292-4.

68Mann RJ. Benzoin sensitivity. Contact Derm. 1982;8(4):263.

69Easo SL, Mohanan PV. Hepatotoxicity evaluation of dextran stabilized iron oxide nanoparticles in Wistar rats. Int J Pharm. 2016;509(1-2):28-34.

70Couto D, Freitas M, Costa VM, et al. Biodistribution of polyacrylic acid-coated iron oxide nanoparticles is associated with proinflammatory activation and liver toxicity. J Appl Toxicol. 2016;

71Wei Y, Zhao M, Yang F, Mao Y, Xie H, Zhou Q. Iron overload by Superparamagnetic Iron Oxide Nanoparticles is a High Risk Factor in Cirrhosis by a Systems Toxicology Assessment. Sci Rep. 2016;6:29110.

72Sundarraj K, Manickam V, Raghunath A, Periyasamy M, Viswanathan MP, Perumal E. Repeated exposure to iron oxide nanoparticles causes testicular toxicity in mice. Environ Toxicol. 2016;

73Available at: Accessed July 20, 2016.

74Available at: Accessed July 20, 2016.

75Wikipedia, the free encyclopedia. Sodium polyacrylate. Available at: Accessed July 20, 2016].

76Wikipedia, the free encyclopedia. Polydimethylsiloxane. Available at: Accessed July 20, 2016].

77Kadziński L, Prokopowicz M, Jakóbkiewicz-banecka J, Gabig-cimińska M, Łukasiak J, Banecki B. Effect of silicone on the collagen fibrillogenesis and stability. J Pharm Sci. 2015;104(4):1275-81.

78Nair B. Final report on the safety assessment of stearoxy dimethicone, dimethicone, methicone, amino bispropyl dimethicone, aminopropyl dimethicone, amodimethicone, amodimethicone hydroxystearate, behenoxy dimethicone, C24-28 alkyl methicone, C30-45 alkyl methicone, C30-45 alkyl dimethicone, cetearyl methicone, cetyl dimethicone, dimethoxysilyl ethylenediaminopropyl dimethicone, hexyl methicone, hydroxypropyldimethicone, stearamidopropyl dimethicone, stearyl dimethicone, stearyl methicone, and vinyldimethicone. Int J Toxicol. 2003;22 Suppl 2:11-35.

79Head lice. Dimeticone is the pediculicide of choice. Prescrire Int. 2014;23(151):187-90.

80Jones IM, Brunton ER, Burgess IF. 0.4% dimeticone spray, a novel physically acting household treatment for control of cat fleas. Vet Parasitol. 2014;199(1-2):99-106.

81Wikipedia, the free encyclopedia. Ammonium sulfate. Available at: Accessed July 20, 2016].

82Lembo S, Lembo C, Patruno C, Balato A, Balato N, Ayala F. Pizza makers’ contact dermatitis. Dermatitis. 2014;25(4):191-4.

83Wikipedia, the free encyclopedia. Ammonium persulfate. Available at: Accessed July 20, 2016].

84Poltronieri A, Patrini L, Pigatto P, et al. [Occupational allergic “march”. Rapid evolution of contact dermatitis to ammonium persulfate into airborne contact dermatitis with rhinitis and asthma in a hairdresser]. Med Lav. 2010;101(6):403-8.

85Wang MZ, Farmer SA, Richardson DM, Davis MD. Patch-testing with hairdressing chemicals. Dermatitis. 2011;22(1):16-26.

86Kieć-swierczyńska M, Krycisz B, Chomiczewska D. [Occupational contact dermatitis in hairdressers]. Med Pr. 2009;60(5):377-82.

87Renz L, Volz C, Michanowicz D, et al. A study of parabens and bisphenol A in surface water and fish brain tissue from the Greater Pittsburgh Area. Ecotoxicology. 2013;22(4):632-41.

88Carbajo JB, Perdigón-melón JA, Petre AL, Rosal R, Letón P, García-calvo E. Personal care product preservatives: risk assessment and mixture toxicities with an industrial wastewater. Water Res. 2015;72:174-85.

89Larsson K, Ljung björklund K, Palm B, et al. Exposure determinants of phthalates, parabens, bisphenol A and triclosan in Swedish mothers and their children. Environ Int. 2014;73:323-33.



Nature's Complement is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program. If you purchase products on Amazon through any of our affiliate links, we get a small percentage of the transaction, at no extra cost to you. We spend a lot of time writing the articles on this site, and all this information is provided free of charge. When you use our affiliate links, you support the writing you enjoy without necessarily buying our products. (However we would appreciate if you would do that too!) Thank you for helping to support our work, however you choose to do so.

These statements have not been evaluated by the Food and Drug Administration. This information and/or products are not intended to diagnose, treat, cure or prevent any disease.

3 thoughts on “Personal Care Product Preservatives, And The Truth (Part I)

  1. […] Wow! That is a lot of stuff we put on our bodies on a daily basis! So what’s in many of these products? This is the second part of a series of articles. You can read part I here. […]

  2. […] in some depth in our articles “Personal Care Product Preservatives, And The Truth” Part 1 and Part 2. However there are still many more chemical ingredients we still need to write about, […]

  3. […] browser tabs our articles on some of the other ingredients you might not want in your products. Part 1, and Part […]

Comments are closed.