Acetyl Hexapeptide-38: 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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All information on this page is verified using publicly available nomenclature standards and reference materials from The Personal Care Products Council (PCPC) and the European Commission's CosIng database. Our analyses are based on technical data from these sources to ensure accuracy and reliability.

What Is Acetyl Hexapeptide-38?

Acetyl Hexapeptide-38 is a lab made peptide built from six linked amino acids that is then acetylated, a simple chemical step that adds an acetyl group and helps the peptide stay stable on skin. Because it is synthesized rather than harvested from plants or animals it is considered a sustainable and consistent ingredient. Peptide research for skin care took off in the 1990s and early 2000s and formulators soon learned that tailoring small chains of amino acids could send skin friendly signals. Hexapeptide-38 was one such discovery, and once chemists acetylated it the result showed better performance in creams and serums, leading to its commercial debut in the last decade.

Production starts with solid phase peptide synthesis, where each amino acid is added in a controlled order on a resin base. After the six unit chain is built, it is cleaved from the resin, purified, then acetylated. The finished ingredient is usually supplied to cosmetic labs as a water soluble solution or powder.

You will most often see Acetyl Hexapeptide-38 in firming serums, anti aging moisturizers, sheet masks, eye creams, lip plumping treatments and leave-on night creams where its skin conditioning talent can shine.

Acetyl Hexapeptide-38’s Cosmetic Benefits/Uses

In topical formulas Acetyl Hexapeptide-38 serves a single, focused role: skin conditioning. By supporting the skin’s own moisture balance and signaling for a smoother surface, it can help products leave skin feeling softer, looking more elastic and appearing generally healthier.

Who Can Use Acetyl Hexapeptide-38

Because it is a mild skin conditioning peptide, Acetyl Hexapeptide-38 is generally suited to all skin types including normal, dry, oily and combination. Its lightweight, water based nature means it will not add heavy oils that could clog pores, so even acne-prone or sensitive users usually tolerate it well. People dealing with compromised or highly reactive skin should still proceed carefully if the finished formula contains strong additional actives such as acids or retinoids, as those ingredients, not the peptide itself, may trigger irritation.

The ingredient is produced entirely through synthetic chemistry with no animal byproducts, making it appropriate for vegans and vegetarians.

No specific warnings exist for topical use during pregnancy or while breastfeeding, but out of an abundance of caution anyone who is pregnant or nursing should confirm with a qualified healthcare professional before introducing new skincare products. This information is not medical advice.

Acetyl Hexapeptide-38 does not increase photosensitivity, so there is no special need to restrict daytime use. Standard daily sunscreen is still recommended for overall skin health.

Potential Side Effects/Adverse Reactions

Responses to any cosmetic ingredient can differ from one person to another. The points below outline potential but uncommon adverse effects when Acetyl Hexapeptide-38 is applied topically. When formulated correctly most users experience none of these issues.

  • Mild transient redness
  • Sensation of warmth or stinging immediately after application
  • Localized itching or dryness if layered with other potent actives
  • Allergic contact dermatitis in individuals sensitive to peptides or preservatives used alongside the peptide

If discomfort, irritation or any unexpected reaction occurs discontinue use and seek guidance from a healthcare professional.

Comedogenic Rating

Rating: 0 (non-comedogenic)

Acetyl Hexapeptide-38 is a small, water-soluble peptide with no fatty or occlusive parts that could block pores. It typically appears in formulas at low concentrations and does not leave any residue that might trap oil or debris, so it earns a solid zero on the comedogenic scale.

This makes it suitable for people who are prone to acne or breakouts. Any risk of clogged pores comes more from the overall product base, such as heavy oils or waxes, rather than from the peptide itself.

If a breakout occurs while using a product containing this peptide, look at the full ingredient list because the culprit is likely another component.

Summary

Acetyl Hexapeptide-38 is a lab crafted six-amino-acid peptide that conditions skin by supporting moisture balance and signaling for a smoother, more elastic surface. It is mainly added to serums, creams and masks that aim to firm or refresh the look of skin.

While not as famous as blockbuster peptides like Matrixyl or Argireline it has carved out a steady place in many mid to high tier formulations thanks to its stability and gentle profile.

Current data shows it is well tolerated across skin types with very low risk of irritation or clogged pores. As with any new cosmetic, do a small patch test before full use to make sure your skin agrees with the complete formula.

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