Six of 18 skin products bought from major online retailers contained clobetasol propionate, one of the most potent topical steroids available, without listing it on the label. The finding comes from a research letter in JAMA Network Open by researchers at Beth Israel Deaconess Medical Center and Harvard Medical School, published on 8 October 2026.
Clobetasol is a class I (superpotent) corticosteroid. In the United States it is available only on prescription, at a strength of 0.05%. Some of the products tested contained up to 9.2 times that concentration.
What the researchers did
The team selected 18 over-the-counter products that made claims about treating dermatitis, eczema, psoriasis or hyperpigmentation, listed no clinically proven active ingredient, and had at least 100 user reviews online. They bought the products between February and December 2025 and screened them for 28 corticosteroids and antifungal drugs using high-resolution liquid chromatography–mass spectrometry. When a product tested positive, they bought two more units to confirm.
What they found
6 of 18 products (33.3%) contained undeclared clobetasol propionate, and every unit of each positive product tested positive.
Three of the six were skin-brightening products sold as a gel, a cream and a serum under the same brand. Mean clobetasol levels in these ranged from 0.02% to 0.09%.
Three were sold for psoriasis, eczema or dermatitis. Mean levels ranged from 0.21% to 0.32%, with the highest single measurement at 0.46%.
Two products also contained undeclared antifungals: terbinafine in one and miconazole in another, the latter at a mean of 4.6% against a usual OTC strength of 2–4%.
The positive products had more than 10,000 combined customer reviews.
The authors report no conflicts of interest.
Why it matters for aesthetic patients
Superpotent steroids lighten skin and calm inflammation quickly, which may be why they appear in products sold for brightening and for itchy rashes. That quick effect is also the danger. Used for weeks without supervision, especially on the face, potent steroids can thin the skin, cause stretch marks and visible vessels, trigger steroid acne and perioral dermatitis, and cause patchy pigment changes. Near the eyes they can raise eye pressure. Over large areas, enough can be absorbed to suppress the body’s own cortisol production.
Stopping suddenly after long use can cause a rebound flare, which may lead patients to apply more of the same product. People seeking an even complexion or treating melasma are a group that may use brightening creams for months at a time.
The products are not confined to the US. Japanese coverage on 3 November noted that products with the same brand names are listed on Japanese retail sites, though it is not known whether those match the formulations tested. Health Canada warned about one of the brightening brands in 2023.
What practitioners can do
Aesthetic and dermatology clinics see the consequences: unexplained skin thinning, telangiectasia, acneiform eruptions or rebound redness in patients who report using only “natural” or “herbal” products. The study supports asking patients to bring in every product they use, including those bought online, and considering steroid exposure when facial skin changes do not fit the history.
Limitations
The researchers deliberately chose products likely to be adulterated, so the one-in-three figure is not an estimate of how common hidden steroids are across the market. The study tested product contents only; it did not measure exposure or harm in users. The method may have missed other chemical forms of steroids, so the true count could be higher. Only 18 products were tested.
The bottom line
A label is not a guarantee. Skin products bought online that promise rapid brightening or rapid relief of eczema or psoriasis without a named active ingredient deserve suspicion, and patients with unexplained facial skin changes should be asked about them.
Undeclared clobetasol, a prescription-only superpotent steroid, was found in 6 of 18 online skin products tested.
Concentrations reached up to 9.2 times the approved 0.05% strength; three positive products were sold for skin brightening.
The sample was targeted, so the 33% figure is not market prevalence, but the safety signal is clear.
Abilov Z, James MJ, Porter ML, Popov YV. Undeclared Pharmacologically Active Ingredients in Over-the-Counter Skin Products. JAMA Netw Open. 2026;9(10):e2638654. Published 8 Oct 2026. doi:10.1001/jamanetworkopen.2026.38654
Healio, 20 Oct 2026: news report
HIFUKO NEWS (Japanese), 3 Nov 2026: report
Original source: https://doi.org/10.1001/jamanetworkopen.2026.38654
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