A four-amino-acid cosmetic peptide, acetyl tetrapeptide-5, sold in eye creams to reduce under-eye bags and puffiness.
Also called Acetyl tetrapeptide-5, Eyeseryl peptide, Eyeseryl peptide solution, Ac-beta-Ala-His-Ser-His-OH, Depuffin, Tetrapeptide-5 eye peptide
When Eyeseryl's status or evidence changes, it's in the next morning's email.
Eyeseryl is the trade name for acetyl tetrapeptide-5, a short lab-made peptide sold to skincare brands by the ingredient maker Lubrizol. It goes into eye creams and serums that promise smaller under-eye bags. It is one of the most common peptides in eye products, including widely sold serums such as The Ordinary's Multi-Peptide Eye Serum.
The supplier says it works three ways, all shown only in lab tests: it blocks angiotensin-converting enzyme (ACE), the blood-pressure enzyme, which is meant to improve circulation around the eye; it cuts leakage from small blood vessels, so less fluid pools under the eye; and it slows glycation, where sugars stiffen collagen. Under-eye bags also come from fat pads pushing forward with age, which no cream can move.
The only human data we could find is industry marketing data that was never peer-reviewed. It appears in a confidential ingredient brochure from ESPA, a French cosmetics company, posted online in 2017; the brochure labels its chart "eyeseryl" but does not say who ran the test: 20 women used a cream with 0.01% peptide twice a day for 60 days, and a dermatologist scored puffiness from photos. By day 60, 95% showed some improvement, but the test had no placebo group, and 30% of the women showed only a slight change. No independent controlled trial of acetyl tetrapeptide-5 has been published.
What it binds to, and what happens inside the body after that, step by step.
In supplier lab tests, acetyl tetrapeptide-5 inhibited angiotensin-converting enzyme in a dose-dependent way, cut leakage through a layer of cultured blood-vessel cells by 50% at 1 mg/mL, and protected the antioxidant enzyme superoxide dismutase from glycation. The idea is that less fluid leaks out of capillaries under the eye and collagen stays more flexible. None of these effects has been measured in human skin, and it is unknown how much of a 0.01% cream gets past the skin barrier.
Human results and animal results are kept apart below. A result in rats tells you a mechanism is plausible. It does not tell you what happens in a person.
The human evidence is one uncontrolled supplier test in 20 women that was never peer-reviewed. Everything else is lab work: ACE inhibition, reduced leakage in cultured blood-vessel cells, anti-glycation, and one fibroblast study of peptide mixtures. No independent, placebo-controlled trial exists.
20 women aged 18 to 65, no placebo group
With a 0.01% cream twice daily for 60 days, a dermatologist rated 95% as improved from baseline photos: 35% good, 30% fairly good and 30% slight. Industry marketing data that does not name who ran the test; not peer-reviewed.
Read the studyEnzyme assays and cultured endothelial cell monolayers
Inhibited ACE in a dose-dependent way and cut vascular permeability by 50% at 1 mg/mL; supplier data, not peer-reviewed.
Read the studyHuman skin fibroblasts in culture
Acetyl tetrapeptide-5 worked best at 100 micrograms per mL in an ACE assay, and a mix with carnosine, hexapeptide-11 and argireline reduced oxidative damage markers in stressed cells.
Read the studyWhen a new Eyeseryl study in people is published, the daily email covers it.
These are questions the published research has not answered.
No product containing Eyeseryl is approved as a medicine by the FDA.
Sold only as a cosmetic ingredient, which FDA does not review for efficacy before sale. It has never been developed as a drug. We found no published safety assessment of acetyl tetrapeptide-5 by the US Cosmetic Ingredient Review panel as of October 2026. In April 2026 Lubrizol launched a different ingredient, Eyeseryl All-In, which is a hexapeptide and not the same molecule as acetyl tetrapeptide-5. Not named on the WADA list.
When the FDA or WADA changes Eyeseryl's status, it's in the next morning's email.
No human half-life has been published for Eyeseryl, so we do not draw a clearance curve. Half-lives quoted online for it are usually estimates from animal data.
This table records the doses that trials and approved labels used, with the source for each row. It is a record of research, not a recommendation, and it is open to free members.
Which symptoms are expected and which mean stop and get help: side effects and red flags.
Tap a claim to see what the studies found.
The 95% figure is from a 20-woman supplier test with no placebo group, and it counts slight improvements. It was never peer-reviewed.
Bags from fat pushing forward under the eye are structural. The proposed mechanisms of acetyl tetrapeptide-5 target fluid and circulation, not fat.
Eyeseryl All-In, launched in 2026, is described by Lubrizol as a hexapeptide; the original Eyeseryl is the tetrapeptide acetyl tetrapeptide-5.
ACE inhibition was measured in a test tube at concentrations far above a cream. There is no evidence of any effect on blood pressure.
These pairings come up often. Almost none have been tested together in a trial, and the evidence note on each says so plainly.
Eye serums pair a depuffing peptide with an expression-line peptide and a collagen-signaling peptide to target bags, crow's feet and thin skin together.
EvidenceNo published trial has tested these blends; each ingredient's human evidence is thin.
Sold mainly as a pre-dissolved cosmetic ingredient; no drug-grade storage guidance exists.
Follow the cosmetic product's packaging and expiry date; no independent stability data are published.
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