A search for the hashtag “skincare” on TikTok turns up more than 35 million videos, but most follow the same formula. “Get ready with me,” a beauty influencer coos before walking viewers through their routine, which often involves several steps and a slew of products. These videos are wildly popular, but new research suggests they may do more harm than good.

In the first study of the risks and benefits of social media skincare routines—published today in the journal Pediatrics—Northwestern University researchers analyzed the regimens of TikTok creators aged seven to 18. The findings revealed that these girls use an average of six different products on their faces, and some use more than a dozen. The typical routine costs roughly $168 per month and includes 11 different active ingredients, which are chemicals designed to address a specific skin concern such as acne or aging.

The creators of these videos are chasing flawless skin, and they want to help you find it too. But the reality is that layering this many active ingredients at once increases the risk of developing skin irritation, Sun sensitivity, and a skin allergy known as contact dermatitis, according to the researchers. Previous studies have shown that developing this allergy can limit the kinds of soaps, shampoos, and cosmetics you can use for the rest of your life. 

“That high risk of irritation came from both using multiple active ingredients at the same time, such as hydroxy acids, as well as applying the same active ingredient unknowingly over and over again when that active ingredient was found in three, four, five different products,” said lead author Molly Hales, a postdoctoral research fellow and dermatologist at Northwestern University Feinberg School of Medicine, according to a university statement.

For this study, Hales and a colleague each created a new TikTok account and reported themselves to be 13 years old. They gathered a sample of 100 unique skincare videos, then documented the demographics of the creators; the number and types of products used; and the total cost of each regimen. All but one of the 82 creators were girls with clear, light, blemish-free skin, according to the study. The researchers then created a list of each product’s active and inactive ingredients and identified which were most likely to cause contact dermatitis.

The 100 videos featured 260 distinct products. Among the 25 top-viewed videos, 76% contained at least one potential contact allergen—typically fragrance. But the most common ingredients were chemical exfoliants called alpha-hydroxy acids (AHAs). The top videos contained three AHAs per regimen on average, with some featuring up to seven of these exfoliants. The most popular active ingredient, citric acid, was found in 29% of all products. 

AHAs can cause skin irritation and increase Sun sensitivity, according to the Food and Drug Administration. Because of this, it’s important to use these ingredients in moderation and follow them with SPF to prevent sunburn and reduce the risk of developing skin cancer. Despite this, only 26% of videos about daytime skincare routines included sunscreen.

“The overall low rate of sunscreen use in the videos represents a significant missed opportunity, particularly for the youngest creators and users who do not yet need acne treatments, antiaging ingredients, or even topical emollients but would benefit from diligent sun protection,” the authors state. In one video, a 10-year-old with red hair and fair, freckled skin—which are markers of melanoma risk—applied eight different products, none of which contained SPF.

Gizmodo reached out to TikTok for comment, but the company did not respond by the time of publication. A TikTok spokesperson told The Guardian, “this type of content is common across all media, and the authors admit they did not assess its impact on teen wellbeing. However, they did find actual benefits to teen self-expression, parent-teen bonding, and building a supportive community on TikTok.”

Still, the researchers concluded that these videos “offer little to no benefit for the pediatric populations they are targeting.” The regimens are overly complicated, time consuming, expensive, and increase children’s exposure to irritation, allergy, and sun damage, they say. 

What’s more, the proliferation of skincare content has increased the stigma around acne, eczema, aging, and other skin conditions, Tess McPherson of the British Association of Dermatologists—who was not involved in the study—told The Guardian.

“Younger and younger children are seeking skincare products when they don’t need them, they’re not helpful,” she said. “This is a very concerning statement on society and how we view how skin should look.”