Guide
Which cosmetic ingredients are actually drugs
A table of the only ingredients in your bathroom whose strength the law requires to be stated, and the ranges they have to sit inside.
Part of Acne-prone skin · Eczema and atopic skin · Curly and coily hair
Almost nothing in a bathroom tells you how much of anything is in it. Cosmetic ingredient lists give an order and no quantities, which is set out in the guide to reading a cosmetics label.
There is one exception, and it is large enough to be worth a table. Some of what is on that shelf is legally a drug, and a drug has to name its active ingredient and its strength in a drug facts panel.
This is the list. If a product contains one of these for the stated purpose, it is a drug, and the number is on the box.
Drugs
States the active and its strength
Supplements
States amounts, above the line only
Cosmetics
States an order. No quantities at all
Acne
| Active | Permitted range |
|---|---|
| Benzoyl peroxide | 2.5 to 10 percent |
| Salicylic acid | 0.5 to 2 percent |
| Sulfur | 3 to 10 percent |
| Resorcinol | 2 percent, only combined with sulfur |
The useful thing here is not the ceiling but the floor. Benzoyl peroxide at 2.5 percent performs comparably to 10 percent in the clinical literature with markedly less irritation, so the range is not a quality ladder and buying the strongest available is not obviously right.
Dandruff, seborrheic dermatitis and psoriasis
| Active | Permitted range |
|---|---|
| Coal tar | 0.5 to 5 percent |
| Pyrithione zinc | 0.3 to 2 percent, washed off after brief exposure |
| Pyrithione zinc | 0.1 to 0.25 percent, left on the skin or scalp |
| Salicylic acid | 1.8 to 3 percent |
| Selenium sulfide | 1 percent, or 0.6 percent micronised |
| Sulfur | 2 to 5 percent |
Two things in that table are worth stopping on.
The same ingredient has two legal strengths depending on what the product claims. Salicylic acid is 0.5 to 2 percent for acne and 1.8 to 3 percent for dandruff. Identical molecule, different rule book, because the monograph is organised by what the product is for rather than by what is in it.
A wash-off product may be seven times stronger than a leave-on one. Pyrithione zinc runs to 2 percent when rinsed and stops at 0.25 percent when it stays. Contact time is doing the work, which is why the dermatology advice for medicated shampoo is to put it on the scalp and not leave it sitting.
Coal tar goes further than any other entry on this page: where a solution or fraction is used, the labelling must state the identity and concentration of that source and the concentration of coal tar in the finished product. Two numbers, both compulsory.
Skin protectants
This is the table most people find surprising, because the actives are ordinary moisturiser ingredients.
| Active | Permitted range |
|---|---|
| Petrolatum | 30 to 100 percent |
| Glycerin | 20 to 45 percent |
| Dimethicone | 1 to 30 percent |
| Zinc oxide | 1 to 25 percent |
| Lanolin | 12.5 to 50 percent |
| Allantoin | 0.5 to 2 percent |
| Colloidal oatmeal | 0.007 percent minimum |
| Calamine | 1 to 25 percent |
| Cocoa butter | 50 to 100 percent |
| Mineral oil | 50 to 100 percent |
| Topical starch | 10 to 98 percent |
A jar claiming to protect skin is a drug and states its active and its strength. A jar with the same contents claiming to moisturise is a cosmetic and states nothing. Same shelf, same ingredients, and only one of them tells you how much.
Colloidal oatmeal is the entry to note: a minimum of 0.007 percent, which is the lowest threshold in the list by a long way. A product leaning on oatmeal in its marketing has cleared a low bar.
Sunscreens
Every sunscreen sold in the United States is a drug. The actives and their limits are set by the sunscreen monograph, and it moved recently: on 10 June 2026 FDA added Bemotrizinol at concentrations up to 6 percent, the first new filter in a very long time.
That is why a sunscreen prints percentages on the back and a serum next to it prints nothing, which is the subject of its own question page.
The category that is the exception
Hair growth products are the one place where the regulation exists to say the opposite.
There is no monograph of permitted actives for over-the-counter topical hair growers. The regulation names the ingredients marketed for it, biotin and dexpanthenol among them, and concludes that “all labeling claims for OTC hair grower and hair loss prevention drug products for external use are either false, misleading, or unsupported by scientific data”.
Minoxidil is outside that because it was approved as a drug in its own right rather than under a monograph. So on that shelf, one product cleared approval and the rest are described by the regulator in those terms, and the packaging looks identical.
How to use this
Look for the drug facts panel first. It takes a second and it settles which world you are in.
A panel means an approved active, a defined range, and pre-cleared claims. No panel means a cosmetic: it may work perfectly well, and nothing about its claims was reviewed and no concentration is disclosed. The full argument is in the guide on which claims are regulated.
Sources
- 21 CFR 333.310: Acne active ingredients US Food and Drug Administration, via eCFR · ecfr.gov Benzoyl peroxide 2.5 to 10 percent, salicylic acid 0.5 to 2 percent, sulfur 3 to 10 percent, resorcinol 2 percent when combined with sulfur.
- 21 CFR 358.710: Active ingredients for the control of dandruff, seborrheic dermatitis, or psoriasis US Food and Drug Administration, via eCFR · ecfr.gov Coal tar 0.5 to 5 percent, pyrithione zinc 0.3 to 2 percent washed off or 0.1 to 0.25 percent left on, salicylic acid 1.8 to 3 percent, selenium sulfide 1 percent, sulfur 2 to 5 percent.
- 21 CFR 347.10: Skin protectant active ingredients US Food and Drug Administration, via eCFR · ecfr.gov Allantoin 0.5 to 2 percent, colloidal oatmeal 0.007 percent minimum, dimethicone 1 to 30 percent, glycerin 20 to 45 percent, lanolin 12.5 to 50 percent, petrolatum 30 to 100 percent, zinc oxide 1 to 25 percent.
- 21 CFR 310.527: Drug products containing active ingredients offered over-the-counter (OTC) for external use as hair growers or for hair loss prevention US Food and Drug Administration, via eCFR · ecfr.gov States that all labelling claims for over-the-counter topical hair grower and hair loss prevention products are either false, misleading, or unsupported by scientific data.
- Amending Over-the-Counter Monograph M020: Sunscreen Drug Products for Over-the-Counter Human Use US Food and Drug Administration, 10 June 2026, via the Federal Register · federalregister.gov Adds bemotrizinol at concentrations up to 6 percent as a sunscreen active ingredient.