Hidden Prescription Steroid Found in a Third of Tested Online Skin Products, Including 'Brightening' Serums

A short study published in JAMA Network Open on 8 October 2026 is a useful reminder that what a skin product lists on its label is not always what is in the tube.

Researchers bought 18 over-the-counter skin products from large online marketplaces between February and December 2025. They deliberately picked products that promised results for eczema, psoriasis, dermatitis or dark patches, did not list any ingredient known to treat those problems, and had at least 100 customer reviews. Some were chosen because similar products had previously been flagged. Each was screened in a laboratory for 28 corticosteroids and antifungal drugs using high-resolution mass spectrometry, and any positive result was repeated on two more units bought separately.

Six of the 18 products, a third, contained clobetasol propionate, one of the strongest prescription steroids available, which none of them declared. Every unit tested from those six was positive. Measured strengths ranged from roughly 0.01% to 0.46%; the highest was about nine times the 0.05% strength a doctor would prescribe. Two products also contained an undeclared antifungal drug. Together the positive products carried more than 10,000 customer reviews, and some were listed as category best-sellers.

Three of the six were from one line sold for brightening or lightening the skin: a gel, a cream and a serum. Two of those list vitamin C among their ingredients. Nothing suggests vitamin C itself was the problem; the point is that a familiar brightening ingredient on the label offered no protection against a hidden drug.

The authors warn that unsupervised, long-term use of such a strong steroid on the face and around the eyes can thin the skin, trigger steroid acne, raise eye pressure and, with heavy use, suppress the body's own hormone production.

The study has clear limits. The sample was small and was chosen to find contaminated products, so the one-in-three figure describes this targeted search, not the share of all skin products on sale. It also screened only for steroids and antifungals, not for substances such as hydroquinone or mercury, and the products were sold in the US. Still, the pattern it describes, fast-acting creams that quietly contain prescription steroids, is a long-standing concern for Indian dermatologists too. Products from established brands with full ingredient lists and a traceable manufacturer are a safer starting point than unbranded online listings promising rapid results.