Myristoyl Pentapeptide-9: 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: July 1, 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 Myristoyl Pentapeptide-9?

Myristoyl Pentapeptide-9 is a small lab-made molecule created by attaching myristic acid, a naturally occurring fatty acid found in coconut oil and nutmeg, to a chain of five specific amino acids known as Pentapeptide-9. The fatty acid portion helps the peptide slip through the outer layers of skin while the peptide portion delivers its targeted action once inside. Peptide technology took off in cosmetic science in the early 2000s when researchers discovered that short chains of amino acids could coax skin into looking firmer and smoother, and Myristoyl Pentapeptide-9 grew out of this movement as formulators looked for more stable, skin-friendly options. It is produced through solid-phase peptide synthesis, a precise method that builds the amino acid chain one unit at a time, followed by a controlled reaction that bonds the chain to myristic acid. After purification and safety testing, the ingredient arrives at cosmetic labs as a white to off-white powder ready to be mixed into finished formulas. You will typically find Myristoyl Pentapeptide-9 in age-defying serums, eye creams, sheet masks, moisturizing lotions, targeted firming treatments and even some high-performance primers where a light yet effective skin-conditioning boost is desired.

Myristoyl Pentapeptide-9’s Cosmetic Benefits/Uses

This ingredient is prized for one key function that directly enhances the feel and appearance of skin in topical products.

As a skin-conditioning agent, Myristoyl Pentapeptide-9 helps improve the overall softness, smoothness and suppleness of skin. By combining a lipid component that boosts penetration with a peptide sequence that supports a more refined surface, it can leave skin looking healthier and better hydrated, which in turn makes fine lines appear less noticeable and creates a smoother base for makeup.

Who Can Use Myristoyl Pentapeptide-9

Myristoyl Pentapeptide-9 is gentle enough for most skin types, including normal, dry, combination and mature skin. Its lightweight, non-greasy feel also makes it a good choice for oily or acne-prone complexions, as it conditions without adding heavy oils. Those with very sensitive or highly reactive skin should start slowly because any peptide can, in rare cases, cause mild irritation if the skin barrier is already compromised.

The ingredient is considered suitable for both vegans and vegetarians because it is made synthetically in the lab and does not rely on animal-derived raw materials or by-products.

Current safety data shows no specific concerns for women who are pregnant or breastfeeding when the ingredient is used topically and at the low levels found in cosmetic products. Still, this is not medical advice and anyone who is pregnant or nursing should review all skincare products with a qualified healthcare provider before use.

Myristoyl Pentapeptide-9 does not make skin more sensitive to the sun, so it is not classed as a photosensitiser. Standard daily sunscreen use is always recommended for overall skin health.

Potential Side Effects/Adverse Reactions

Side effects from topical Myristoyl Pentapeptide-9 vary from person to person. The following list covers potential reactions but these outcomes are uncommon when the ingredient is properly formulated and used as directed.

  • Mild redness or warmth at the application site
  • Transient itching or tingling, especially on very dry skin
  • Temporary stinging if applied to broken or compromised skin
  • Allergic contact dermatitis in individuals sensitive to peptides or fatty acids
  • Increased penetration of other active ingredients, which could heighten their side effects

If any unwanted reaction occurs stop using the product and seek advice from a healthcare professional or dermatologist.

Comedogenic Rating

Rating: 1 out of 5. While the molecule carries a myristic acid tail, it is used at very low levels and is chemically bound to a peptide, which makes it far less likely to clog pores than pure myristic acid. Most finished formulas that include Myristoyl Pentapeptide-9 are lightweight serums or lotions designed to feel non-greasy, so the overall risk of blocked pores is minimal. In practical terms this ingredient is generally considered suitable for those who are prone to acne or breakouts. The only time it might raise concern is in very rich cream bases that already contain several heavier oils.

Summary

Myristoyl Pentapeptide-9 is a lab-crafted peptide linked to a fatty acid that helps it slip into skin where it conditions, smooths and softens the surface. By boosting skin’s suppleness it can make fine lines look less obvious and create a better canvas for makeup. Although peptides are a hot topic in beauty circles this particular one is still a niche player, found mainly in higher-end serums and targeted eye products rather than in everyday moisturizers.

Current safety data is reassuring and adverse reactions are rare when products are used as directed. As with any new skincare ingredient it is wise to perform a quick patch test before full-face use to confirm personal compatibility.

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