Acetyl tetrapeptide-5

Eyeseryl (trade name), Ac-AHSH, acetyl-alanyl-histidyl-seryl-histidine

Skin & cosmetic

Awaiting medical reviewEN ES DE FR PT ZH+ Follow for updates

Summary

Class: Synthetic tetrapeptide (Ala-His-Ser-His) with an acetyl group on the N-terminus
Mechanism: Reported to inhibit angiotensin-converting enzyme (ACE) locally, improving microcirculation and fluid drainage under the eye, and to reduce glycation of collagen
Routes studied: Topical only (eye creams, gels, patches)
Dose range reported: Ingredient-manufacturer studies: 10% of the commercial solution in the finished product, equating to about 0.01% (100 ppm) peptide †; retail products use 1–10% of the solution
Half-life: Not applicable; no systemic data
Storage: Finished products: room temperature, protect from light. Raw material solution: refrigerate
Regulatory status: Permitted cosmetic ingredient worldwide; no medicinal approval

Doses are as reported in studies or by the community — never recommendations.

1What it is

Acetyl tetrapeptide-5 is a short synthetic peptide developed by a Spanish cosmetic-peptide company in the 2000s and sold as "Eyeseryl", positioned specifically for puffiness and bags under the eyes. The design logic borrows from blood-pressure medicine: ACE inhibitors (drugs such as captopril) relax blood vessels and influence fluid balance, and some short peptides from food proteins are weak ACE inhibitors. The idea was a peptide that would do this locally in the thin, fluid-prone skin under the eye.

It is a wholly synthetic cosmetic molecule.

2How it's thought to work

Local ACE inhibition. Angiotensin II constricts small vessels and promotes fluid retention. If the peptide inhibits ACE in the skin, less angiotensin II would mean better local drainage and less overnight fluid pooling — the main cause of morning puffiness.

Anti-glycation. The ingredient manufacturer also reports that the peptide reduces glycation (sugar cross-linking) of collagen and elastin, which stiffens the fine structure under the eye and worsens the appearance of bags.

Important limit. Under-eye "bags" in older people are usually fat-pad herniation and skin laxity, which no topical can reverse. The peptide's rationale applies to fluid-related puffiness.

Proposed: a cosmetic tetrapeptide reported to inhibit ACE locally and to hold capillary junctions shut, so less fluid collects in the tissue under the eye. The mechanism is plausible and the published evidence is small and largely from the manufacturers.Schematic — not to scale

3What the research shows

ACE inhibition and anti-glycation (in vitro)

Manufacturer data report ACE-inhibitory activity of the peptide in enzyme assays and reduced glycation of collagen . Not independently published.

Eye-bag volume and puffiness (topical)

The ingredient manufacturer's volunteer study, cited in trade press (Cosmetics & Toiletries news; manufacturer dossier), applied a cream containing 10% Eyeseryl solution twice daily for 60 days in about 20 volunteers and reported a reduction in eye-bag volume measured by profilometry, with the majority of participants (around 70%) showing improvement, and self-assessment of reduced puffiness; a smaller effect appeared within two weeks †. Placebo comparison, blinding and statistics are not fully reported in public material.

Graded B/—

Dark circles

Some product studies pair Eyeseryl with other actives and claim improvement in dark circles; the peptide's own mechanism gives no obvious reason to expect pigment change. Treat as unproven.

Independent trials

None found. It appears in reviews as a "carrier/signal peptide for the eye area" with manufacturer-only evidence (Schagen 2017; Errante 2020). [1][2]

4Reported side effects and interactions

Literature-reported

Manufacturer safety testing reports no irritation or sensitisation at use levels; eye-area products are additionally tested for ocular irritation. No independent data.

Community-reported

well tolerated; it is a frequent ingredient in "peptide eye creams" with few complaints beyond formula-related stinging near the eyes.

Theoretical. systemic ACE inhibition from a trace topical peptide is implausible; there is no evidence of blood-pressure or potassium effects, and none would be expected. People taking ACE-inhibitor medicines have no documented interaction.

Interactions. none established.

Markers researchers commonly monitor

No blood markers apply. Practical measures:

Marker	Why it's watched
Morning photographs under identical light	puffiness varies hugely by time of day, salt intake, sleep and alcohol, so compare like with like.
Profilometry of the lower-lid area	the trial endpoint; available at some aesthetic clinics.
A diary of sleep, sodium and alcohol	confounders that swamp any peptide effect if ignored.
Forearm patch test, then a small test near (not in) the orbital area

Free for everyone. Safety information is never behind a paywall.

5Formulation and handling

Supplied as a water/glycerin solution of the peptide; recommended use 1–10% of finished product. Water-soluble, heat-sensitive, added in the cool-down phase. Also used in hydrogel eye patches and gel sticks. Not by consumers. No calculator applies.

6Commonly studied alongside

Acetyl hexapeptide-8 (Argireline) and palmitoyl tetrapeptide-7 (#182) in eye formulas; caffeine (another cosmetic de-puffing agent); dipeptide-2 (another "eye-bag" peptide); hyaluronic acid.

Informational cross-links. Not stack recommendations.

7Regulatory status by region

Region	Status (checked —)
United States	Cosmetic ingredient; cosmetic claims only
European Union	CosIng-listed skin-conditioning agent; permitted
United Kingdom	Same as EU
Australia	Permitted cosmetic ingredient
South Africa	Permitted in cosmetics
Sport (WADA)	Not listed

8Open questions

Is there any placebo-controlled, peer-reviewed trial separating the peptide from the vehicle? None found.
Does the peptide inhibit ACE in living skin, or only in a test tube?
How does it compare with simple cold compression or caffeine for fluid puffiness? Untested.

9References

1Schagen SK (2017). Topical peptide treatments with effective anti-aging results. Cosmetics. DOI
2Errante F et al. (2020). Cosmeceutical peptides in the framework of sustainable wellness economy. Front Chem. PubMed · DOI
3Gorouhi F, Maibach HI (2009). Role of topical peptides in preventing or treating aged skin. Int J Cosmet Sci. PubMed · DOI
4Manufacturer dossier / trade report (undated). Eyeseryl: acetyl tetrapeptide-5 reduces eye puffiness. Cosmetics & Toiletries news item (not peer-reviewed). PubMed

References are being resolved to PubMed/DOI identifiers; links search PubMed for the citation until then.

† Being confirmed by our reviewers against current sources.

10Community

forum threads →

community protocols include this →

Threads and protocols are visible to members. Joining is free.

Self-reported side effects Phase 2

Not enough data yet. 0 of the 50 members needed have logged this compound for 4+ weeks. We don't show anything below 50, so no one can be identified.

11Page history

31 Oct 2026Profile published — awaiting medical review

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