Acetyl Tetrapeptide-5: What Is It, Cosmetic Uses, Benefits & Side Effects

Curious about this ingredient? In this article we're explaining exactly what it is and why it's used within cosmetic formulations.
Updated on: June 23, 2025
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We verify all information on this page using publicly available nomenclature standards from The Personal Care Products Council (PCPC), the European Commission's CosIng database and documentation provided directly by ingredient manufacturers. Our analysis is based on technical data from these sources to ensure accuracy and reliability.

What Is Acetyl Tetrapeptide-5?

Acetyl Tetrapeptide-5 is a lab crafted peptide made by adding an acetyl group to Tetrapeptide-5, a short chain of four amino acids. The acetylation step helps the peptide stay stable and penetrate the skin surface more easily. First introduced by peptide research companies in the early 2000s, it quickly caught the eye of cosmetic chemists looking for gentle ingredients that target puffiness and dryness around the eyes.

The manufacturing process starts with solid-phase peptide synthesis, where each amino acid is added one by one to build Tetrapeptide-5. The finished chain is then acetylated, purified and blended into a water-based solution that can be mixed into creams or serums.

Because of its water-binding talent and mild nature, Acetyl Tetrapeptide-5 shows up most often in eye creams, sheet masks, leave-on gels, anti aging serums and other moisturizers designed to soften fine lines and reduce a tired look.

Acetyl Tetrapeptide-5’s Cosmetic Benefits/Uses

In skin care formulas Acetyl Tetrapeptide-5 serves one main role.

Humectant: It attracts and holds moisture from the surrounding air and the deeper layers of the skin, helping the formula keep the surface hydrated for longer. This extra moisture makes the skin look plumper, eases the look of fine lines and gives a smoother feel.

Who Can Use Acetyl Tetrapeptide-5

Acetyl Tetrapeptide-5 is gentle and water based which makes it appropriate for almost every skin type including dry, oily, combination and sensitive. Because it helps pull in moisture without adding oil it can calm dryness while staying light enough for skin that is prone to shine. There are no specific issues that make it unfit for acne prone skin.

The peptide is made by synthetic methods and contains no animal derived material so it is suitable for both vegetarians and vegans.

No research shows that topical Acetyl Tetrapeptide-5 is unsafe for women who are pregnant or breastfeeding. Still this is not medical advice and anyone who is expecting or nursing should ask a doctor before starting new skincare just to be certain.

The ingredient does not make skin more sensitive to sunlight and can be used both day and night without raising the risk of sunburn. It also plays well with most common actives like niacinamide, hyaluronic acid and mild plant extracts so layering is rarely a problem.

Potential Side Effects/Adverse Reactions

Side effects from using Acetyl Tetrapeptide-5 can vary from person to person. The points below describe potential reactions but most users will not notice any problems when the peptide is formulated and applied as intended.

  • Mild redness or warmth at the application site
  • Temporary stinging, especially on very dry or compromised skin
  • Itchiness that settles once the product is rinsed off
  • Allergic contact dermatitis in people sensitive to peptides or other formula components

If any of these reactions occur stop use and seek advice from a healthcare professional.

Comedogenic Rating

Rating: 0 (non-comedogenic)

Acetyl Tetrapeptide-5 is a small, water-soluble peptide that does not leave an occlusive film or add extra oil to the skin, so it has virtually no tendency to clog pores. It is therefore considered safe for people who are prone to acne or breakouts.

Because the peptide is typically used at low concentrations and is easily removed with normal cleansing, it poses minimal risk of residue buildup that could otherwise trap sebum or debris.

Summary

Acetyl Tetrapeptide-5 is mainly valued as a humectant that attracts and locks in water, which helps the skin look smoother, plumper and less puffy. It does this by binding moisture to the upper layers of the skin, supporting the skin’s natural barrier and improving surface hydration.

The peptide enjoys moderate popularity, showing up most often in eye creams and lightweight serums rather than in every moisturizer on the shelf, yet formulators appreciate its gentle touch and targeted benefits.

Overall it is considered a very safe ingredient with a low chance of irritation or pore blockage, but as with any new skincare product it is wise to perform a quick patch test to rule out personal sensitivity.

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