Formaldehyde-releasers are commonly found in shampoos and cosmetics, despite decades of public concern. Is this concern backed by high-quality research, or a myth that hasn’t ever been busted? In this article we’ll review how to identify formaldehyde-releasers, why they are used in shampoos, and the potential risks.
What are formaldehyde-releasers?
Formaldehyde-releasing preservatives, more commonly referred to as ‘formaldehyde-releasers’, help to prevent microbial growth. They are routinely added to cosmetics to slowly release formaldehyde over time, preventing anything nasty from growing. There are over 40 formaldehyde-releasers, and countless branded derivatives, but the most common are :
- DMDM Hydantoin
- Ureas (imidazolidinyl, or diazolidinyl)
Unfortunately there is no quick way to identify them, as there is no universal naming system. Typically a formaldehyde-releaser will be one of the last ingredients on the label, as their concentrations are limited by regulatory bodies. The choice of which agent a cosmetic company decides to use is strongly dependent on the pH of the product, although factors such as the other ingredients are a consideration.
How do they work?
Not all formaldehyde-releasers work through the same mechanism, although there are two broad categories. Firstly, a formaldehyde-releaser can be synthesised directly from formaldehyde, and so still contain residues – an example of this would be some of the ureas. The second mechanism is a chemical that decomposes to produce formaldehyde over time – an example being quaternium-15, which decomposes in acidic conditions .
The exact mechanism isn’t particularly important (and the chemistry is outside the scope of this review!), but they all have one thing in common: they release formaldehyde at a constant rate. Formaldehyde or ‘methanal’ is a strong antimicrobial, and so helps to extend the shelf-life of shampoos .
Are there any risks?
Unlike many of the ingredients found in shampoos, there are numerous high-quality studies that highlight the risks of formaldehyde. In particular, formaldehyde is known to be carcinogenic and a strong irritant. The EU lists formaldehyde as a ‘category 1B carcinogen’, which means it’s a ‘substance presumed to have carcinogen potentials for humans’. It’s not banned in shampoos, because it’s used in extremely low concentrations and is not left on the skin.
When an allergy patch test is used to identify people with a formaldehyde irritant sensitivity, a prevalence of between 2 and 9% has been found [4, 5]. It can be difficult to avoid products with formaldehyde or formaldehyde-releasers, and so in those at risk an acute allergy can become chronic allergic dermatitis. Anyone with a history of sensitivity should avoid cosmetics with the label: ‘contains formaldehyde’.
What are the regulations?
Concern about the use of formaldehyde in cosmetics has been ongoing for decades, and the 1976 EU Directive ‘76/768/EC’ first stipulated that the final concentration of formaldehyde-releasers in a product must not be higher than 0.05%, or free formaldehyde of 2%. A number of amendments have since been added, and Directive ‘1223/2009’ imposed additional stipulations restricting its use in cosmetics [6, 7].
In the United States there are no legally enforceable regulations, but the Cosmetic Ingredient Review panel echoes EU advice . Several companies have voluntarily agreed to stop using formaldehyde-releasers, and among these is the pharmaceutical giant Johnson&Johnson, who manufacture many of the most popular brands .
Alternatives to formaldehyde-releases
There are surprisingly few antimicrobial alternatives to formaldehyde-releasers, which possess the necessary traits: low cost, odourless, stable, and effective. This is part of the reason why formaldehyde-releasers are still so prevalent, and the EU has continued to permit their use at low concentrations in cosmetics.
Finding like for like alternatives is difficult. For example, both sodium benzoate and potassium sorbate are potential alternatives to formaldehyde-releasers, but don’t have quite the same antimicrobial efficacy. Interestingly, a 2009 study showed that combining the two yielded stronger antimicrobial effects than either used as a single agent. The real downside is that both can still cause irritation. And there is an argument that two artificial ingredients are potentially worse than one .
Rather than looking for a like for like comparison, I’d recommend looking for other types of preservative altogether. For example, everyday ingredients such as salt, sugar and honey can help preserve shampoos. From a manufacturers perspective they aren’t sufficient as they shorten the shelf life of the shampoos dramatically. Personally I’d prefer a shorter shelf life if it meant avoiding putting formaldehyde on my skin every few days. That seems to be the approach of DHS who, in their coal tar shampoo, use just Sodium Chloride (salt) to preserve their shampoo. And I applaud them for it.
Other preservatives to look out for include Grapefruit Seed Extract, Antioxidants, Tea Tree Oil, Salicylic Acid, Vitamin E, Germaben II and Sodium Lactate. Manufacturers are also trying to develop new preservatives such as Rokonsal BSB-N made up of Benzyl Alcohol, Glycerin, Benzoic Acid, Sorbic Acid.
This is an area I believe we’ll see some major innovations in the coming years, due to the publics increasing appetite for safer chemicals in their cosmetics.
Where can I find formaldehyde-free shampoos?
The simplest way to find formaldehyde free shampoos is on this very site. Simply browse to our search tool, indicate that you wish to avoid Formaldehyde Releasers and press search.
The best formaldehyde-free dandruff shampoos
At the time of writing we have a ton of shampoos we’d recommend.
Here’s our top 10.
Pharmaceutical Specialties formed in 1974 to “start a company to make better products than were commercially available for people with sensitive skin”. And boy, have they achieved it with this Free and Clear shampoo.
What is perhaps surprising on a website dedicated to dandruff treatments is that this isn’t a dandruff shampoo at all.
It’s rather a "a non-medicated, mild shampoo for sensitive skin and scalp.”
That said, we can’t use a medicated shampoo all the time, and this is my go to shampoo for those “between” washes.
BIOM8 Skin Conditioning Oil is now part of my daily skin care routine. It’s as simple as that. I have lost count of the number of products I’ve reviewed over the years and I can count on one hand the number of products that have impacted me on this level.
If you suffer from dry skin, facial seb derm or rosacea I simply can’t recommend this product highly enough.
It even makes a good beard oil!
Designed to treat Dry Scalp
Maple Holistics Hydrate Shampoo has been superbly formulated to soothe and moisturize the scalp and hair. The ingredients have been carefully selected to decrease the chance that the product will irritate the skin. Using multiple low dose surfactants is a stroke of genius and only the fact the shampoo contains only one potential contact allergen says it all.
This is as close to perfection as you get in the commercial shampoo world.
I simply can't recommend this highly enough.
Designed to treat Dry Scalp
Nurture My Body Everyday Fragrance-Free Shampoo is an excellent gentle option for sufferers of a dry irritated scalp. The absence of any noteworthy irritants or allergens combined with the expert formulation of anti-inflammatory moisturizing ingredients makes an excellent change from the usual harsh surfactants and other toxins that lead to a vicious cycle of irritation and inflammation.
They've managed all of this in a shampoo that foams and washes well.
It's not particularly cheap, but this is simply one of the finest dry scalp shampoos out there.
Calling all sensitive scalp sufferers, if you haven’t yet found an anti-dandruff shampoo your scalp can tolerate, you haven’t yet found Sebclair shampoo. A piroctone olamine, Malassezia yeast quelling formula with extremely mild yet highly effective cleansers, accompanying scalp hydrators, flake fighters and natural anti-inflammatories. No fragrance, no essentials oils, no allergens. Sebclair shampoo really does stand out in our anti-dandruff crowd.
If your babe’s crusty cradle cap’s only getting worse, it’s time to try a leave on treatment – one which doesn’t leave your baby’s scalp looking like a grease ball. Enter Bioderma’s ABDderm Babysquam keratoregulating cream a 14 ingredient formula made from sensitive, hypoallergenic, moisturising, soothing and barrier building ingredients.
Useable 7 days a week with no fragrance or harsh preservatives Bioderma’s ABDderm Babysquam keratoregulating cream respects, repairs and conditions away crusty cradle cap.
Dead Sea Spa MAGIK Mineral Shampoo is a combination shampoo containing both salicylic acid and zinc pyrithione. The thinking behind this shampoo is that the salicylic acid will soften and exfoliate existing build up and the zinc pyrithione will help prevent new build up from forming.
I’m generally a big fan of combination shampoos and this is no exception. The shampoo feels great, has a nice light smell and leaves the hair feeling extremely soft. It only contains one known contact allergen too - cocamidopropyl betaine.
If you suffer from mild seb derm I can’t recommend this highly enough.
Designed to treat Seborrheic Dermatitis
One of the best and mildest shampoos out there for seb derm sufferers with sensitive skin.
Containing both Piroctone Olamine and Salicylic Acid as well as being SLS free, paraben free, artificial color free this shampoo has an absolutely outstanding choice of active and inactive ingredients.
There are still two or three chemicals in there that some may find irritating. Otherwise this would have been a five out of five performer.
Quite simply the best pure Salicylic Acid shampoo we’ve yet reviewed. The shampoo contains 3% Salicylic Acid combined with a fragrance free, sulfate free and virtually every other nasty ingredient free formulation. It does this and still feels luxurious when washing.
Neutrogena should be exceptionally proud of this top top class shampoo.
Designed to treat Dry Scalp
An impressive dry scalp treatment shampoo with an innovative formulation.
I have to applaud any company that can formulate a shampoo with so few allergens. The fact that it washes so well is marvelous. For those not sensitive to Cocamidopropyl Betaine, Phenoxyethanol or fragrances - this is an excellent shampoo.
Designed to treat Dry Scalp
This dry scalp treatment isn’t a shampoo at all, but rather a leave on moisturizer that you apply to your hair after washing.
The advantage of this approach is that, while shampoos are designed to clean (and all the sensitizing issues that come with that) this treatment is designed to moisturize and nothing else.
You’re free to use the shampoo of your choice and us this treatment in combination.
It’s an excellent approach that I hope other manufacturers take notice of.
Scalp 18 Coal Tar shampoo is a 2% coal tar formulation that has a number of added essential oils to further nourish and soothe the scalp.
These essential oils do contain fragrance but if you're not sensitive to fragrances then this is a superb shampoo.
It is extremely gentle and washes like a high end salon shampoo.
If you’re not sensitive to fragrances then I wouldn’t hesitate to recommend this shampoo.
Maple Holistics Tea Tree Shampoo is an outstanding Tea Tree shampoo for treating Dry Scalp or Seb Derm. It doesn’t contain any artificial coloring or fragrance, sulfates, parabens, or carcinogens. It contains only three potential contact allergens, with two of the three being tea tree and rosemary essential oils.
The combination of cleansing agents used are gentle, effective and innovative while the shampoo smells ace and washes even better.
If you're looking for a tea tree shampoo, I can't recommend this highly enough.
DHS Sal Shampoo is a 3% salicylic acid shampoo designed to treat Psoriasis and Seborrheic Dermatitis.
It’s an outstanding shampoo that washes well, contains relatively few ingredients, is gentle and won’t break the bank.
If you’re not sensitive to sulfates and are looking for a good salicylic acid shampoo, this is an excellent performer.
Yet again, DHS have produced a shampoo that we can't recommend highly enough.
Designed to treat Dry Scalp
Cleure Volumizing uses only a handful of skin conditioning agents and gentle cleansers to treat a dry scalp.
It contains only two potential irritants that should be considered low to moderate concerns, compared to other much harsher alternatives. This shampoo doesn’t use any sulfates, parabens, artificial fragrances, dyes, alcohol, salicylates, formaldehyde, or SLS, making it a good option for those with sensitive scalps who typically react to less gentle, conventional shampoo and other personal care products.
Unless you have severely sensitive skin and are highly reactive to any potential irritants, we suggest trying this shampoo from Cleure and seeing if it calms your sensitive skin, and helps to clear up any dryness and itchiness on your scalp.
Puracy Citrus Mint Natural Shampoo offers a great natural alternative to the many sulfate laden shampoos on the market today. Whether you are looking for an everyday use shampoo, or one that you can rotate your medicated dandruff shampoo with, we’d recommend trying the Natural Shampoo.
Because there are essential oils in the formula, we recommend caution to anyone who is sensitive to fragrances, or sensitive or allergic to any of the ingredients.
Otherwise, you’re looking at an expertly formulated shampoo that, for once, lives up to the manufacturer’s promises.
Sebclair Non-Steroidal Cream is an anti-fungal, piroctone olamine based treatment partnered with a trophy cabinet of natural anti-inflammatory actives. If you have a mild to moderate case of seb derm, hate steroids and love naturals Sebclair is for you. Best bit – there’s only two known allergens or irritants.
Designed to treat Seborrheic Dermatitis
Do you have an extremely sensitive scalp in need of anti-dandruff help? Do you suffer from mild to moderate seb derm? Meet your new best friend. Free & Clear’s Medicated Anti-Dandruff Shampoo contains zero allergens, zero irritants, zero sensitizers formula based on 2% zinc pyrithione. An active ingredient able to improve the health of dandruff affected skin while also helping pacify dandruff causing overgrowths of the Malassezia yeast.
I simply can't recommend this shampoo highly enough.
If you haven’t seen your favorite shampoo listed, chances are we’ve already reviewed it. Check out all our formaldehyde-releaser free dandruff shampoo reviews.
If you don’t see it listed, please let us know!
 De Groot, A. C., White, I. R., Flyvholm, M. A., Lensen, G., & Coenraads, P. J. (2010). Formaldehyde‐releasers in cosmetics: relationship to formaldehyde contact allergy. Contact Dermatitis, 62(1), 2-17.
 Becker, L. C., Bergfeld, W. F., Belsito, D. V., Klaassen, C. D., Hill, R., Leibler, D., & Andersen, F. A. (2010). Final report of the amended safety assessment of quaternium-15 as used in cosmetics. International Journal of Toxicology, 29(3 suppl), 98S-114S.
 Bolt, H. M. (1987). Experimental toxicology of formaldehyde. Journal of Cancer Research and Clinical Oncology, 113(4), 305-309.
 Wahlberg, J. E. (2001). Patch testing. In Textbook of contact dermatitis (pp. 435-468). Springer Berlin Heidelberg.
 Pratt, M. D., Belsito, D. V., DeLeo, V. A., Fowler Jr, J. F., Fransway, A. F., Maibach, H. I., & Sherertz, E. F. (2004). North American Contact Dermatitis Group patch-test results, 2001-2002 study period. Dermatitis, 15(4), 176-183.
 European Union. Directive: 76/768/EC. www.eur-lex.europa.eu [Accessed 22/10/16]
 European Union. Directive: 1223/2009. www.eur-lex.europa.eu [Accessed 22/10/16]
 Cosmetic Ingredient Review. Formaldehyde. www.cir-safety.org [Accessed 22/10/16]
 Johnson and Johnson. Ingredient Safety. www.jnj.com [Accessed 22/10/16]
 Stanojevic, D., Comic, L., Stefanovic, O., & Solujic-Sukdolak, S. (2009). Antimicrobial effects of sodium benzoate, sodium nitrite and potassium sorbate and their synergistic action in vitro. Bulg J Agric Sci J, 15(4), 307-11.