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  • Writer's picturePau Rocas, PhD

Retinol and BHT. A fling that is coming to an end (for the best!).

Maybe you haven't heard about BHT, yet. That's fine. You are in the right place to learn why to better do your research before using it in the formulation of your cosmetics.

Now just a little bit of chemistry.

BHT structure

BHT (butylated hydroxytoluene) is a lipophilic synthetic antioxidant that works as preservative in lipsticks and moisturizers, retinol stabilizer in anti-aging and anti-acne formulas, among other cosmetics.

In nature, it's been proved that some organisms in phytoplankton are able to produce BHT in a natural manner (1).

Many cosmetics and personal care suppliers and manufacturers use BHT to prevent retinol early oxidation during storage or even at users home once opened.

So, clarifying, BHT may be used in three stages of cosmetic products production: 1) during retinoids manufacturing (BASF, the biggest manufacturer, use it in all their retinoids to avoid early degradation), 2) during retinol encapsulation or stabilization (many suppliers use it to enhance retinol stability) and 3) during cosmetics formulation (many cosmetics and personal care companies use it as extra aid to ensure retinol antioxidant activity during skin application).

So, why so much noise? Why every single day we receive more enquiries of our BHT-free Capsuretinol UHC? The truth is that CRO and CMO's come to us saying that their client has banned BHT either for safety concerns, to modernize their old formula or to create a cream for sensitive-skin, etc.

It is a fact that every day more and more cosmetic companies seek to innovate and create more modern and safer products to differentiate themselves from the crowd.

As alternative to BHT, at Ecopol Tech we have developed the most advanced polymer microcapsules, capable to protect retinoids from oxidation very efficiently, while using the minimum amount of polymer to ensure a natural non-greedy feeling after skin application.

Moreover, we are able of reaching 13% retinol concentration (highest in market) in a super easy to formulate waterborne dispersion, ensuring that cosmetic chemists get the maximal retinol concentration with the minimal content of inactive ingredients to create the most efficacious formulas.

In terms of health and safety concerns, BHT has been the subject of many studies, which have been contradictory in their findings. The result is that some are left with confusion over whether consuming and applying products containing BHT is safe. This confusion is nothing new, as we can see from the following excerpt from Business Week magazine back in 1995.

If we look to what David Suzuki Foundation experts say, BHA (BHT's sister antioxidant) and BHT can induce allergic reactions in the skin (1). The International Agency for Research on Cancer classifies BHA as a possible human carcinogen (2). The European Commission on Endocrine Disruption has also listed BHA as a Category 1 priority substance, based on evidence that it interferes with hormone function (3).

Long-term exposure to high doses of BHT is toxic in mice and rats, causing liver, thyroid and kidney problems and affecting lung function and blood coagulation (4). BHT can act as a tumour promoter in certain situations (5). Limited evidence suggests that high doses of BHT may mimic estrogen (6), the primary female sex hormone, and prevent expression of male sex hormones (7), resulting in adverse reproductive affects.

Under the Convention for the Protection of the Marine Environment of the North-East Atlantic, BHA is listed as a chemical of potential concern, noting its toxicity to aquatic organisms and potential to bioaccumulate (8). Likewise, a United Nations Environment Program assessment noted that BHT had a moderate to high potential for bioaccumulation in aquatic species (though the assessment deemed BHT safe for humans) (9).

In terms of regulatory status, the use of BHA and BHT in cosmetics is unrestricted in Canada, although Health Canada has categorized BHA as a “high human health priority” on the basis of carcinogenicity and BHT as a “moderate human health priority”. Both chemicals have been flagged for future assessment under the government’s Chemicals Management Plan.

International regulations are stronger. The European Union prohibits the use of BHA as fragrance ingredient in cosmetics. The State of California requires warning labels on products containing BHA, notifying consumers that this ingredient may cause cancer.

Hoping this helps to bring some light into the matter...

Stay safe and innovate!

0. Babu B, Wu JT (December 2008). "Production of Natural Butylated Hydroxytoluene as an Antioxidant by Freshwater Phytoplankton" (PDF). Journal of Phycology. 44 (6): 1447–1454. doi:10.1111/j.1529-8817.2008.00596.x. PMID 27039859.

1. U.S. National Library of Medicine, in Haz-Map: Occupational Exposure to Hazardous Agents, 2010, 2. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans vol. 17 (Paris: International Agency for Research on Cancer), vol. 40 (1986). 3. Study on Enhancing the Endocrine Disrupter Priority List with a Focus on Low Production Volume Chemicals, Revised Report to DG Environment (Hersholm, Denmark: DHI Water and Environment, 2007), 4. UNEP and OECD, 2,6-di-tert-butyl-p-cresol (BHT) Screening Information Data Set: Initial Assessment Report (Paris: OECD, 2002), 5. Baur, A.K. et al., “The lung tumor promoter, butylated hydroxytoluene (BHT), causes chronic inflammation in promotion-sensitive BALB/cByJ mice but not in promotion-resistant CXB4 mice,” Toxicology 169, no. 1 (December 2001): 1-15. 6. Wada, H. et al., “In vitro estrogenicity of resin composites,” Journal of Dental Research 83, no. 3 (March 2004): 222-6. 7. Schrader, TJ and GM Cooke, “Examination of selected food additives and organochlorine food contaminants for androgenic activity in vitro,” Toxicological Sciences 53, no. 2 (February 2000): 278-88. 8. “OSPAR List of Substances of Possible Concern. Fact sheet for Butylhydroxyanisol.” (OSPAR, April 15, 2002), 9. UNEP and OECD, 2,6-di-tert-butyl-p-cresol (BHT) Screening Information Data Set: Initial Assessment Report.

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