Can This Product Hurt Me? Assessing Health Risk in Certain Personal Care Products

Personal care products include a wide range of items such as cosmetics, skin care products, hair care products, deodorants, and more. Two of the largest segments of these products are shampoo and hair dye. In 2022, there were more than 388 million units of regular shampoo and nearly 172 million units of hair coloring sold in the United States. Hair dye represents 22 percent of the overall worldwide cosmetic market, second only to skin care. These products are subject to various regulations to ensure they are safe for consumer use.

Health regulations typically focus on the ingredients used, labeling requirements, and the manufacturing processes. California and Maryland have passed legislation banning numerous intentionally added chemicals in personal care products. Enacted in 2021, California’s Toxic‑Free Cosmetics Act takes effect on January 1, 2025, and targets the removal of 24 chemicals from products. The State of Maryland followed shortly thereafter with similar mandates. In October 2023, the California legislature enacted regulations which added 26 chemicals to the list by January 2027. These state enforcement actions follow upon legislation implemented in the European Union which bans ingredients linked to certain human health risks. Understanding these regulations is crucial for manufacturers and distributors of personal care products to ensure compliance and maintain consumer trust.

Integral’s scientists work extensively in the personal care products space and recently Ernest Fung and his co-authors published research on potential health risks related to chemicals in shampoos and hair dyes.

Shampoo

Preservatives in shampoo are essential for preventing the growth of bacteria, mold, and yeast, ensuring the product remains safe and effective throughout its shelf life. However, some preservatives have raised health concerns due to their potential to cause skin irritation, allergic reactions, and other health issues.

Historically, formaldehyde was used as a preservative in personal care products to extend product shelf life; however, given its skin sensitization potential it has been phased out of use and replaced with alternative preservatives, some of which release formaldehyde such as dimethylol dimethyl hydantoin (DMDMH).

The team conducted a quantitative risk assessment (QRA) aimed to assess the risk of skin sensitization induction following use of shampoo products containing the maximum allowable concentrations of DMDMH in formulation (1% w/v), translating to a free formaldehyde concentration of 0.02%. To determine a margin of safety (MOS) for exposure to DMDMH from use of shampoo products, consumer exposure levels were estimated based on typical use scenarios and then benchmarked against an acceptable exposure level. The MOS values for a shampoo product containing 1% DMDMH (0.02% formaldehyde) indicated skin sensitization induction among healthy individuals is not expected. Thus, it can be concluded that shampoo products containing DMDMH at or below current allowable concentrations are not expected to increase the risk of skin sensitization.

For more details, check out the publication “Quantitative risk assessment of dermal sensitization potential following use of shampoo products containing the formaldehyde releasing preservative DMDM hydantoin.” (Link to paper)

Hair Dyes

Hair dye products include a range of chemicals, depending on the type and color. Under the Federal Food, Drug, and Cosmetic Act, color additives must be approved by U.S. Food and Drug Administration (FDA) for their intended use before they are used in FDA-regulated products, including cosmetics.

Para-phenylenediamine (PPD) is a chemical commonly used in hair dyes, textiles, and some cosmetic products. It is known for its potential to cause allergic reactions and other health issues related to dermal exposure. Due to these concerns, various regulatory bodies have established guidelines and restrictions on the use of PPD. 4-aminobiphenyl (4-ABP) has reportedly been found as a trace contaminant (presumably from PPD) in consumer permanent hair dye.

4-ABP is a well-documented carcinogen, with stringent regulations in place worldwide to minimize exposure and protect human health. While several regulatory agencies have designated 4-ABP as a human bladder carcinogen based on evidence in humans and experimental animals, only the California Office of Environmental Health Hazard Assessment has established a cancer risk value for 4-ABP of 0.03 μg/day based on liver tumors developed in mice.

Using methodologies consistent with risk assessment policies in California or the U.S., Integral scientist Ernest Fung and his co-authors developed a dermal QRA to evaluate the risk of bladder cancer from exposure to 4‑ABP from hair dye applied to the scalp. Previously published laboratory analyses characterizing 4-ABP concentrations in consumer hair dyes indicate the concentrations can range from below the limit of detection to 8,120 ppb. Precautionary estimates of human scalp surface area, maximum skin adherence, hair dye retention factor, and percent dermal absorption were used to estimate the daily systemic exposure dose from dermal application of hair dye. The results suggest that there is no indication of increased risk of bladder cancer in humans from exposure to 4-ABP in consumer hair dye, especially as it is extremely unlikely that a consumer would use permanent hair dye daily (as this assessment models).

For more details check out “Dermal exposure and hair dye: Assessing potential bladder cancer risk from permanent hair dye” (LINK TO ABSTRACT AND ARTICLE)

Conclusions

Shampoo and hair dye are two products categories which have been a focus of regulatory agencies. Manufacturers and retailers must follow the scientific principles in human health risk assessment to evaluate the chemicals they use in their products. Integral’s health scientists provide a robust understanding of a chemical’s potential toxicity, so clients can make informed decisions about chemical safety.