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Collagen & Skin
Research Chemical

Acetyl Tetrapeptide-5

Also known as: Eyeseryl, Ac-bAla-His-Ser-His

Acetylated synthetic tetrapeptide sold as Eyeseryl for under-eye creams aimed at puffiness. A cosmetic ingredient, not an FDA-approved drug.

Last updated

Mechanism of Action

Acetyl tetrapeptide-5 (Ac-beta-Ala-His-Ser-His) is a short synthetic peptide developed by a cosmetic ingredient supplier for the eye area. The manufacturer's proposed mechanisms are inhibition of angiotensin-converting enzyme activity in skin, which is claimed to limit local fluid buildup, and reduced protein glycation, which is claimed to preserve collagen elasticity. These mechanisms come mainly from supplier in vitro data and have not been confirmed in independent, peer-reviewed human studies of the peptide on its own.

Half-life
Not well established
Administration Routes
Topical
Research Status
Research Chemical

Reported Benefits

  • Marketed to reduce the look of under-eye puffiness
  • Marketed to reduce the look of dark circles
  • Supplier in vitro data on anti-glycation activity
  • Independent clinical evidence for the peptide alone is lacking

Potential Side Effects

  • Mild stinging or redness near the eyes
  • Contact irritation from the overall formulation
  • Eye irritation if product gets into the eye

Common Dosing

There is no medical dose: acetyl tetrapeptide-5 is a cosmetic ingredient used at low concentrations in finished eye creams and serums, and the formulation is set by the product manufacturer. Follow the product label, and see a clinician for persistent or one-sided eye swelling, which can have medical causes.

The dosing information above is aggregated from research literature and anecdotal community reports for educational purposes only. It is not a recommendation, prescription, or medical advice. Peptides are sold as research chemicals only and are not intended for human use.

Contraindications

  • Known sensitivity to the product or its ingredients
  • Broken, infected or inflamed skin around the eye
  • Not for use in the eye itself

No documented stacking partners for Acetyl Tetrapeptide-5 yet.

No notable studies catalogued for Acetyl Tetrapeptide-5 yet.

No. As of 2026 it is a cosmetic ingredient, and US law does not require FDA premarket approval for cosmetics; it is not an approved drug for any condition. Products containing it may only make appearance claims, not claims to treat a disease.

Thin. Most of the data come from the ingredient supplier and laboratory tests, and we found no independent PubMed-indexed clinical trial of acetyl tetrapeptide-5 on its own, so this page lists no citations.

Under-eye bags often come from fat pad changes, fluid retention, allergies or genetics, which a topical peptide is unlikely to change much. Sudden or persistent swelling is worth raising with a clinician.

PeptideChat is for educational and research purposes only. Nothing on this site constitutes medical advice. Peptides are sold as research chemicals only and are not intended for human use. These statements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. PeptideChat is an independent educational resource — not a pharmacy, compounding, or 503A/503B outsourcing facility — and does not sell products or provide medical advice.