Eyelash Growth Serum That Works? Check the Label Before You Pay

If you want an eyelash growth serum that works, start with what the label is allowed to say. A cosmetic lash serum is sold to change how lashes look.

If the wording promises more than that, the FDA’s own rules say the claim can make the serum a drug. So no cosmetic listing below can promise growth. On price, e.l.f.’s serum costs the least per mL ($2.29) of the Amazon best sellers that list a size (prices as listed in October 2026), and its wording is about looks alone. GrandeLASH-MD costs the most per mL ($36 for 1 mL). COSNORI is the pick if you want named peptides and a “Prostaglandin Free” label. Before you buy, check three things: what the ingredient list holds, what you pay per mL, and whether the listing promises looks or growth.

On a cosmetic label, “works” means looks, and the FDA approves no claim in advance

The FDA’s cosmetics labeling claims page explains the rule. A claim that a product affects the structure or function of the body makes it a drug. The FDA keeps no list of approved cosmetic claims and cannot approve claims before a product goes on sale. It also says “you may see cosmetics with claims that go beyond what the law permits.”

So a word on a box does not prove that anyone checked it. For a serum sold as a cosmetic, the fair reading of “works” is “may make lashes look longer or fuller.” That is the brand’s claim, not a promise.

Prostaglandin or peptide-only: the full ingredient list decides, not the listing title

On a lash serum’s ingredient list, prostaglandin analogues show up under names such as isopropyl cloprostenate, dehydrolatanoprost and ethylcloprostenolamide. Peptide-only serums leave them out. An Amazon listing title is not a full ingredient list.

These are the three lowest-cost-per-mL serums on Amazon’s eyelash best-seller list. Here is how each describes itself:

1. COSNORI Long Active Eyelash Serum calls itself vegan and “Prostaglandin Free,” with peptides and hyaluronic acid.
2. Biysber Advanced Eyelash Growth Serum lists a “4-Peptide Complex & 9 Botanicals” in a 6 mL bottle.
3. e.l.f. Enhancing Lash & Brow Serum is a clear formula, and its listing names no actives.

A listing title is a sales line, not an ingredient list. The FDA’s eye cosmetic safety page says a cosmetic sold without an ingredient declaration is misbranded. That means the full list belongs on the package, and only that list tells you whether a prostaglandin analogue is inside. If one is there, read the brand’s own warning before you buy. Check GrandeLASH-MD, Babe and RevitaLash the same way before you compare them with these peptide serums.

“Growth” wording is the kind of claim the FDA says can make a serum a drug

The FDA’s page on whether a product is a cosmetic, a drug or both says some claims make a product a drug even when it is sold as a cosmetic. One of its examples is a claim that a product will restore hair growth. The same page says a product’s intended use can be set by claims on its label, in ads, on the internet or in other promotional materials. An online listing title falls in that last group.

Read the three titles with that in mind:

• e.l.f.’s listing says it promotes “longer-looking” lashes and brows. That is a claim about appearance.
• Biysber’s title says “Eyelash Growth Serum” and “for Eyelash Growth to Boost Fuller, Thicker Lashes.”
• COSNORI’s title says “Prostaglandin Free,” but it also says “Eyebrow Growth Enhancer.”

“Growth” is not the exact wording of the FDA’s example, and the FDA has not said either listing is a drug. Of these three, only e.l.f. keeps its wording about looks alone.

Price per mL: e.l.f. costs least ($2.29), GrandeLASH-MD most ($36)

Sizes and prices come from Amazon’s eyelash best-seller list, as listed in October 2026; Amazon prices change often. The per-mL figures are worked out here. Fluid ounces are converted at 29.57 mL each, which matches e.l.f.’s own listing of 0.12 fl oz as 3.5 mL.

Serum	Size listed	Price listed	Price per mL
e.l.f. Enhancing Lash & Brow Serum	0.12 fl oz (3.5 mL)	$8.00	$8.00 / 3.5 = $2.29
COSNORI Long Active Eyelash Serum	0.3 fl oz (0.3 x 29.57 = 8.87 mL)	$21.98	$21.98 / 8.87 = $2.48
Biysber Advanced Eyelash Growth Serum	6 mL	$19.99	$19.99 / 6 = $3.33
VieBeauti	3 mL	$21.99	$21.99 / 3 = $7.33
NUNA	6 mL	$49.99	$49.99 / 6 = $8.33
ForChics	3 mL	$26.00	$26.00 / 3 = $8.67
GrandeLASH-MD	1 mL	$36.00	$36.00 / 1 = $36.00
Babe	not listed	$49.00	can’t be worked out
RevitaLash	not listed	$59.00	can’t be worked out

Serum	Actives the listing names	Claim wording	Ratings	Compared with the FDA’s rule
e.l.f.	none named	“longer-looking”	6,459 (4.2 stars)	About appearance
COSNORI	peptides, hyaluronic acid; “Prostaglandin Free”	“Eyebrow Growth Enhancer”	809 (4.1 stars)	Growth wording, closer to the FDA’s “restore hair growth” drug example
Biysber	4-peptide complex, 9 botanicals	“Eyelash Growth Serum”	24	Growth wording, closer to the same example

What the arithmetic shows:

• GrandeLASH-MD, the list’s top seller, costs about 16 times e.l.f.’s price per mL ($36.00 / $2.29 = 15.7). Price per mL ignores how long a bottle lasts, so this is a cost-per-volume gap, not a cost-per-month one.
• COSNORI costs $0.19 more per mL than e.l.f. ($2.48 − $2.29) and holds about 2.5 times as much (8.87 / 3.5 = 2.53).
• VieBeauti, NUNA and ForChics cost 3.2 to 3.8 times e.l.f.’s price per mL ($7.33 / $2.29 = 3.2; $8.67 / $2.29 = 3.8).
• Babe ($49.00) and RevitaLash ($59.00) list no size, so you can’t compare them per mL.

Each of the three has a weak spot. e.l.f.’s listing names no actives, so read the ingredient list on the box before you buy, and its 3.5 mL bottle holds less than half of what COSNORI’s does. COSNORI’s title uses growth wording. Biysber has 24 ratings against e.l.f.’s 6,459, so few buyers have weighed in on it. But e.l.f. is the only one of the three that is both cheapest per mL and worded about looks alone. Buy it if cost and plain cosmetic wording matter most to you.

• Want named peptides and a “Prostaglandin Free” label? Skip e.l.f. and buy COSNORI, for $0.19 more per mL.
• Want the lowest cost per mL? Skip Biysber ($3.33) and GrandeLASH-MD ($36.00) and buy e.l.f.
• Want lots of buyer ratings behind one of the three cheapest? Skip Biysber (24 ratings) and look at e.l.f. (6,459).

Safety: no law requires a set safety test before a lash serum is sold

Under MoCRA, the Modernization of Cosmetics Regulation Act of 2022, neither the law nor FDA regulations require specific tests to show that individual cosmetic products or ingredients are safe. What MoCRA does require is that the product’s responsible person keep records supporting its safety.

The FDA’s eye cosmetic safety page explains why this matters for lash products. Eyelids are delicate, and an allergic reaction, irritation or other injury near the eye can be “particularly troublesome.” So a serum applied at the lash line can go on sale without passing any set test, and it goes on skin where a reaction matters more.

Checklist: five checks before you buy a lash serum

1. Read the full ingredient list on the box, not the listing title. Look for isopropyl cloprostenate, dehydrolatanoprost or ethylcloprostenolamide.
2. If you find one, read the brand’s own warning before you buy, not after.
3. Sort the wording: “longer-looking” is about appearance; “growth” is the word to question.
4. Divide the price by the mL. For fluid ounces, multiply by 29.57 first. If no size is listed, you can’t compare.
5. Look at the number of ratings next to the stars. An average from 24 ratings tells you less than one from 6,459.

These five checks work on any lash serum, on Amazon or anywhere else.

For more on this topic, see the Lash serums guides.

FAQ

Which of these bottles holds the most? Of the listings that give a size, COSNORI’s 0.3 fl oz (8.87 mL) is the largest and GrandeLASH-MD’s 1 mL is the smallest, per Amazon’s best-seller list.

Why is there no per-mL price for Babe or RevitaLash? Their entries show $49.00 and $59.00 but no size, so there is nothing to divide by. Find the mL on the box before you compare.

Do star ratings show which serum works? No. They show how buyers rated their own results. e.l.f. averages 4.2 stars from 6,459 ratings and COSNORI 4.1 from 809. Those are opinions, not a measurement of lash length.