Acetyl Pentapeptide-55 Amide: 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 The Personal Care Products Council's (PCPC) INCI database. Our ingredient analyses are based exclusively on PCPC's technical data to ensure accuracy and reliability.

What Is Acetyl Pentapeptide-55 Amide?

Acetyl Pentapeptide-55 Amide is a lab made chain of five amino acids that has been capped with an acetyl group at one end and an amide group at the other. This small tweak helps protect the peptide from breaking down too quickly on the skin so it can do its job longer. The peptide itself is built through a method called solid-phase peptide synthesis, where each amino acid is added one by one to form the exact sequence. After the chain is complete it is acetylated, purified, dried and then blended into cosmetic formulas.

Peptides became popular in skin care during the early 2000s when scientists saw how certain short chains of amino acids could signal the skin to look and act younger. Acetyl Pentapeptide-55 Amide is one of the newer entries in this family, designed to be gentle yet effective at improving how the skin feels and looks. Because it is synthetic, there is no animal or plant harvesting involved which makes it a reliable option for brands that want consistent quality in every batch.

You will most often find Acetyl Pentapeptide-55 Amide in leave-on products such as anti-aging serums, eye creams, firming masks, concentrated ampoules, moisturizers and after-sun soothing treatments. These formulas take advantage of the peptide’s ability to sit on the skin and condition it over time.

Acetyl Pentapeptide-55 Amide’s Cosmetic Benefits/Uses

This ingredient is valued for its skin conditioning role in topical products.

As a skin conditioning agent, Acetyl Pentapeptide-55 Amide helps the surface of the skin feel softer and smoother while supporting a healthy look. By providing targeted amino acid signals it can encourage the skin’s own renewal processes, which may reduce the appearance of fine lines and uneven texture. The result is skin that appears more supple, well hydrated and comfortable, making the overall formula feel more luxurious and effective.

Who Can Use Acetyl Pentapeptide-55 Amide

Because this peptide is gentle and free of known irritants it is generally suitable for all skin types including dry, oily, combination and sensitive skin. Most people will notice only a softening feel with no lingering residue. The only group that may need extra caution is anyone with a history of allergic reactions to cosmetic peptides since a prior sensitivity could carry over.

Acetyl Pentapeptide-55 Amide is synthesized in a lab with no animal derived starting materials so it fits vegan and vegetarian lifestyles. Brands that follow cruelty free standards can also choose this ingredient without compromising their policies.

Current safety data shows no issues for women who are pregnant or breastfeeding when the peptide is used in normal topical amounts. Still, this is not medical advice and expectant or nursing mothers should let their healthcare provider review any product that becomes part of their routine just to be safe.

The ingredient does not trigger photosensitivity and can be applied morning or night. Pairing it with daily sunscreen is still smart skincare but no extra sun precautions are needed beyond the usual SPF habit.

Potential Side Effects/Adverse Reactions

Reactions to topical Acetyl Pentapeptide-55 Amide differ from person to person. The points below list potential side effects only and they are unlikely to affect most users when the product is formulated and used correctly.

  • Mild redness or warmth shortly after application
  • Transient itching or tingling as the product settles
  • Dry patches if used in a very high concentration without sufficient moisturizer
  • Swelling or puffiness around the eyes when an eye product is over applied
  • Allergic contact dermatitis in individuals already sensitive to peptides or preservatives in the same formula
  • Increased irritation if layered with strong acids or retinoids at the same time

If any of these effects persist or worsen stop using the product and consult a healthcare professional.

Comedogenic Rating

Rating: 0 / 5

Acetyl Pentapeptide-55 Amide is a small water-soluble molecule that does not leave an oily film or clog pores which places it at the very bottom of the comedogenic scale. The peptide is usually used in low amounts inside lightweight serums and creams so it has little chance to trap dead skin cells or excess sebum.

Because of this low clogging risk it is generally suitable for people who are prone to acne or breakouts.

As with any leave-on ingredient, the overall formula matters; if the product also contains heavy oils or waxes that could still lead to congestion even though the peptide itself is non-comedogenic.

Summary

Acetyl Pentapeptide-55 Amide is a lab crafted five-amino-acid peptide that conditions skin by signaling it to stay smooth and hydrated. By strengthening the skin’s surface and encouraging its natural renewal process it can soften fine lines, improve texture and boost overall comfort.

The ingredient is part of the newer wave of peptides so it is not as famous as classics like Matrixyl, yet brands looking for gentle performance boosters are beginning to add it to anti-aging serums eye creams and soothing gels.

Current safety data shows it is well tolerated across skin types with a very low risk of irritation or pore clogging. Even so it is smart to do a quick patch test when trying any new product to make sure your skin agrees with the full formula.

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