The short answer
An eyelash or eyebrow serum is a cosmetic if it only conditions lashes or makes them look longer, fuller or darker. It is a drug if it claims to grow lashes or brows — and the only FDA-approved eyelash growth drug is a prescription product.
The bigger risk is the ingredient. Serums with prostaglandin analogs such as isopropyl cloprostenate have drawn FDA action: FDA said products with this synthetic prostaglandin analog and growth claims were unapproved new drugs, and it also treated some as adulterated cosmetics.
Claims: cosmetic or drug?
| Claim | Usually |
|---|---|
| “Conditions and nourishes lashes” | Cosmetic |
| “For the look of longer, fuller lashes” | Cosmetic |
| “Reduces lash breakage from mascara removal” | Cosmetic |
| “Grows longer lashes in 30 days”, “lengthens and thickens lashes” | Drug |
| “Regrows thin or sparse brows”, “stimulates follicles” | Drug |
| “Treats hypotrichosis” | Drug — disease claim |
Ingredient check
- Prostaglandin analogs (isopropyl cloprostenate, dechloro dihydroxy difluoro ethylcloprostenolamide and similar): this drug class is used in FDA-approved products for glaucoma and eyelash hypotrichosis. Avoid them in a cosmetic serum.
- Peptides, biotin, panthenol, castor oil, hyaluronic acid: common in cosmetic serums — but the claims still decide cosmetic vs drug. See hair growth serums.
- Colors in tinted brow serums or lash products used near the eye must be FDA-approved for the eye area. See color additive rules.
MoCRA steps for a cosmetic lash serum
- 1Register the factoryUnder MoCRA, with a U.S. Agent if foreign. Products that regularly come into contact with the mucous membrane of the eye are not covered by the small business exemption from registration and listing.
- 2List the productThe responsible person lists it with its ingredients.
- 3Keep safety substantiationIncluding eye irritation and microbiology data. See safety substantiation.
- 4Label for the U.S.Ingredients, net quantity, responsible company and a U.S. adverse event contact.
Example: a lash serum brand from South Korea
A Korean brand sells a lash serum at home with “grows lashes in 4 weeks”. For the U.S. it confirms the formula has no prostaglandin analog, changes the claim to “for the look of longer, fuller-looking lashes” and “conditions and strengthens against breakage”, removes before-and-after growth photos from its U.S. store, registers under MoCRA and lists the product.
Cosmetics label review with drug-claims check $250. Cosmetic facility registration with U.S. Agent from $300 (1 year) or $450 (2 years). Product listing $150 per product.
Frequently asked questions
Is an eyelash serum a cosmetic or a drug?
A cosmetic if it only conditions lashes or improves how they look. A drug if it claims to grow lashes.
Can a lash serum contain isopropyl cloprostenate?
FDA has taken action against eyelash and eyebrow products with this synthetic prostaglandin analog and growth claims, treating them as unapproved new drugs. It is a high-risk choice for a cosmetic.
Can I say “longer-looking lashes”?
Yes — appearance claims like this are generally cosmetic claims, as long as they are true.
Do lash serums qualify for the MoCRA small business exemption?
Usually not. Products that regularly come into contact with the mucous membrane of the eye under customary use are excluded from the small business exemption from registration and listing.
Sources
- Cosmetics & Toiletries — FDA warning letter on eyebrow and eyelash growth product claims (isopropyl cloprostenate)
- FDA — Is it a cosmetic, a drug, or both?
- FDA — Cosmetics labeling claims
Requirements checked on November 12, 2026. This article is general information, not legal advice.