EWG’s searchable Skin Deep® database of personal care products, or PCPs, and ingredients was developed as a free resource for consumers.
Years later, it’s also turned out to be useful for scientific research – and may be able to answer questions about cosmetic product types, ingredient trends and potential health concerns.
What is Skin Deep?
EWG’s Skin Deep is a free, public database of over 130,000 personal care products and their ingredients.
Launched in 2004, it empowers and educates consumers on the safety of ingredients used in cosmetics and corresponding product ratings.
Equipped with information from manufacturers, online retailers and the public, EWG’s researchers rate products for safety and add them to the database.
Behind the ratings
To review ingredients, a team of EWG scientists synthesize available safety information from databases and publications from government agencies, academic researchers and other institutions. Each ingredient is assigned a score based on its available hazard information for 10 different human health endpoints and data on ecotoxicity. The scores also include information on impurities, absorption and data availability.
The way a product is used can also affect its score.
For example, ingredients that are linked to respiratory problems may score higher if they are used in a spray or powder product than if they’re used in a solid, non-inhalable form. The scale is from 1, the least hazardous ingredients and products, to 10, assigned to ingredients and products with the greatest concern.
Studying exposures and trends
When evaluating product use, exposure and ingredient prevalence, researchers turn to Skin Deep to better understand the market and PCP safety.
Skin Deep can be used to identify products or product types that contain certain ingredients, understand potential health concerns or rank specific products by hazard. Leveraging Skin Deep has helped scientists at EWG and elsewhere evaluate their research questions with standardized data.
How buying habits may affect hazardous product use
A 2025 paper from researchers at Rutgers and Columbia reported that Black women, middle-age adults and consumers with lower incomes are more likely to use PCPs with high hazard scores. Authors also reported other differences in PCP use by age, race and ethnicity, gender and marital status.
The paper, published in the Journal of Exposure Science and Environmental Epidemiology, examined the hazard level of PCPs in relation to consumers’ sociodemographics, PCP purchasing behavior, and perceptions about PCP regulation and safety.
The study participants – Rutgers students, faculty and staff – completed a questionnaire about their PCP use, and those products were matched to hazard scores for each product in the Skin Deep database. Participants ages 40 to 59 used beauty products with higher hazard scores than both older and younger groups. The youngest participants, 18 to 39, used cologne and perfume with the highest hazard scores.
This study did not include participants under 18, but another study recently reported that undisclosed fragrance was one of the most common ingredients in products found in viral TikTok “get ready with me” videos – although that study did not refer to Skin Deep.
The words “fragrance” or “parfum” on a label signal blends of ingredients companies are not required to disclose. Some may be safe, but the blends could also contain potentially harmful ingredients.
The study of the Rutgers community also reported that consumer perceptions of PCP safety and regulation were related to hazard scores, as were individual purchasing behaviors. Those who reported always or usually consulting health apps and websites used hair, skin and beauty products with lower average hazard scores than those who never or rarely did.
Perceptions of product safety also affected the likelihood of using safer products. Participants who strongly agreed with statements that PCPs influence health generally used products with lower average hazard scores.
Disparities in safe hair product availability
A 2023 study from Harvard University evaluated differences in the safety of hair products available across sociodemographically diverse neighborhoods in Boston.
In the study, published in Environmental Health Perspectives, the authors used the Skin Deep database to match hazard scores to products in stores from eight communities with varying racial and ethnic backgrounds and socioeconomic status. This allowed them to assess whether products with low hazard scores were equitably available throughout Boston neighborhoods.
They reported that communities with lower socioeconomic status and a greater percentage of people of color had more than twice the risk of finding products with high Skin Deep hazard scores as communities that were predominantly white and had a higher socioeconomic status.
The authors also reported that more expensive products were less likely to have a moderate or high hazard score, and these products were less likely to be found in lower socioeconomic status neighborhoods.
Presence of PCP chemicals in the body
A 2018 paper published by authors from multiple research institutions examined concentration distributions, time trends and predictors of urinary biomarkers of common ingredients of concern in PCPs among a cohort of pregnant women living in Puerto Rico.
At several points during pregnancy, researchers collected urine samples and questionnaire responses to see what types of products and brands participants’ were using. Using Skin Deep, along with other resources, the authors identified brands and products that contained key ingredients they found in urine samples.
To measure exposure to chemicals in PCPs, authors collected urine samples and measured for the presence of several chemicals of concern:
- Seven different phenols, such as benzophenone-3, a common sunscreen ingredient also known as oxybenzone
- Triclosan and triclocarban, common active ingredients in soap
- Four parabens, ingredients used as preservatives in many PCPs.
Metabolites of the chemicals measured in urine were associated with PCP use. The average concentration of benzophenone-3, triclosan and parabens was two to three times higher among women who reported recent use of hand or body lotion than among women who did not.
Recent use of sunscreen was associated with fivefold higher geometric mean concentrations of benzophenone-3. Benzophenone-3, or oxybenzone, has been linked to reproductive harms.
Use of perfume and nail polish was associated with an increased concentration of butylparaben in urine. Many of these ingredients, known as endocrine-disrupting compounds may disrupt the hormone system.
The authors reported that the concentrations of triclocarban and triclosan in urine increased as the concentration of these ingredients in participants soap increased. In addition, triclosan and triclocarban geometric mean concentrations were twofold and fourfold higher among women reporting the use of liquid soap and bar soap, respectively, compared to those who did not.
Researchers use Skin Deep for many reasons, including to understand how PCP safety is associated with concentrations of chemicals in the body. They also want to identify products that are relevant for future research.
Higher hazards in PCPs marketed to Black women
EWG’s scientists also regularly use the Skin Deep database to conduct research projects.
Leveraging product information available in Skin Deep, EWG scientists analyzed over 4,000 personal care products marketed to Black women and compared their hazard scores and most hazardous ingredients to products without specific demographic marketing.
The report showed only 21% of products marketed to Black women were rated low hazard, compared to 27% of products without demographic marketing – highlighting an inequity in safe product availability.
The use of many hazardous ingredients found in products marketed to Black women in EWG’s 2016 report has declined, with one exception: The use of undisclosed fragrance has risen by 6.4 percentage points. This equates to hundreds more products using blends without disclosing the specific ingredients used.
Certain product categories – especially hair relaxers, dyes and bleaches – remained among the most hazardous, often containing caustic ingredients and formaldehyde releasers.
Using data from Skin Deep, researchers demonstrate inequities in product safety based on whether products were marketed to Black women. These inequities have long been demonstrated in exposure and epidemiological studies where concentrations of harmful chemicals are higher in Black women compared to white women, as well as the rate of adverse health outcomes such as reproductive harm.
Ongoing beauty justice research emphasizes how racialized beauty standards contribute to these disparities.
Harmful chemicals in hair coloring products
EWG scientists analyzed 560 hair-coloring products from Skin Deep. Using the product and ingredient hazard scores, they identified common hazardous ingredients in hair coloring products.
The median hazard score was 6, indicating most hair dyes are moderately hazardous. Only 4% of products scored in the safest range, with a 1 or 2 rating, and most of those were temporary dyes.
Over 1,000 different ingredients were used in various combinations in product formulations, resulting in an infinite combination of mixtures of hazardous ingredients, which may interact together to cause worse health problems than each ingredient individually would. Some of the most common ingredients in hair dyes were aromatic amines, phenolics and isothiazolones, which have been associated with cancer and allergic reactions.
When possible, consumers should avoid these ingredients in their hair dyes:
- P-phenylenediamine and resorcinol, both of which are linked to skin irritation, allergic reactions and potential cancer risks
- Formaldehyde-releasing preservatives such as DMDM hydantoin, which can expose consumers to formaldehyde, a known carcinogen
- Isothiazolinones, like methylisothiazolinone, which are strong sensitizers.
Many of these products also contained undisclosed fragrance mixtures. These mixtures may be made with blends of hundreds of chemicals without any requirement that manufacturers disclose the ingredients.
How to use Skin Deep:
- Check out the User’s Guide to Skin Deep to find out more about product and ingredient safety.
- If a product you use is missing from our database, use the Build Your Own Report Tool. Or submit your product for review using our Healthy Living App or by sending it to [email protected]
- If you want to use Skin Deep as part of your research, email [email protected]
