What Is Myristoyl Pentapeptide-17? Uses, Structure and Cosmetic Applications

Quick Answer: What Is Myristoyl Pentapeptide-17?

Myristoyl Pentapeptide-17 is a synthetic cosmetic peptide: a myristic acid chain attached to the pentapeptide sequence Lys-Leu-Ala-Lys-Lys, commonly written as Myr-KLAKK-NH₂. It is used in leave-on eyelash and eyebrow conditioning products such as lash serums, brow serums and mascara primers. It is a cosmetic conditioning ingredient, not a drug and not a prostaglandin analogue. 

Myristoyl Pentapeptide-17 

How Is Myristoyl Pentapeptide-17 Structured?

The molecule has three parts worth understanding before sourcing:

• The myristoyl group. A 14-carbon saturated fatty chain (myristic acid / tetradecanoic acid) conjugated to the peptide N-terminus. This fatty-chain modification influences lipophilicity and the molecule's behavior in lipid-containing formula environments.
• The pentapeptide. The five-amino-acid sequence Lys-Leu-Ala-Lys-Lys (KLAKK). The two lysine residues contribute basic, positively charged side chains, which is relevant to solubility behavior in aqueous systems.
• The C-terminal amide. The sequence is listed as the amide form, Myr-Lys-Leu-Ala-Lys-Lys-NH₂. Terminal form is not a cosmetic detail: an amide, a free-acid version and a salt form such as acetate are different materials with different active bases and should be confirmed on the batch certificate before dosing.

Confirming these three elements is the first quality gate in sourcing. Two suppliers can both quote "Myristoyl Pentapeptide-17" while supplying different terminal forms, different salt stoichiometry or different peptide content, and a formula dosed by weight without checking the assay basis can deliver a very different active level than intended. Sequence confirmation (for example by MS) and terminal-form confirmation on the COA are therefore not optional paperwork; they are the basis for reproducible formulation.

What Does Myristoyl Pentapeptide-17 Do in Cosmetics?

Within the EU CosIng system, the recorded function of Myristoyl Pentapeptide-17 is skin conditioning. Its commercial positioning, however, has developed around lash and brow care: it is one of the most frequently listed peptides in eyelash and eyebrow serums, appearing in 20 of 44 products surveyed by the Danish Environmental Protection Agency in 2025.

Supplier-level research describes the peptide in relation to keratin - promoting keratin production and nutrient absorption in hair-follicle cells - with finished-product goals centered on the appearance of stronger, fuller-looking lashes and brows. These are supplier claims and formulation objectives, not independently established clinical endpoints. For a B2B buyer, the useful summary is: the ingredient is associated with conditioning and appearance-oriented lash and brow formulas, and the evidence boundary should be kept explicit in marketing claims.

Main Cosmetic Applications

• Eyelash conditioning serum
• Eyebrow serum
• Mascara primer
• Lash conditioning serum
• Peptide-based eye-area formulations

The shared pattern is an eye-area product with extended contact time, in which the peptide is typically combined with other conditioning ingredients such as panthenol, hyaluronic acid or additional peptides.

Is It an Eyelash-Growth Drug?

No. Myristoyl Pentapeptide-17 is a cosmetic ingredient, not a pharmaceutical. The only FDA-approved treatment specifically indicated for eyelash hypotrichosis remains bimatoprost 0.03%, a prescription prostaglandin analogue. Cosmetic peptides must not be positioned as replacements for prescription ingredients, and formulations should avoid claims such as "clinically proven to grow eyelashes" or "treats eyelash loss."

Myristoyl Pentapeptide-17 is used and named as a cosmetic ingredient, but ingredient listing or nomenclature should not be interpreted as product-level regulatory approval. Finished products must comply with the applicable cosmetic regulations and safety requirements in the target market.

Powder, Acetate and Premixed Solution-What Is the Difference?

The same INCI name can be supplied in materially different commercial forms:

• Raw powder. A concentrated dry material. The buyer controls the carrier and the dose, but must have accurate weighing capability and must dose on the confirmed peptide content.
• Acetate salt. Many basic peptide powders are isolated as acetate salts. The salt form changes the weight contribution of the non-peptide portion, so the peptide content basis must be read from the COA rather than assumed.
• Premixed solution. A water- or glycerin-based liquid in which the peptide is pre-dissolved, often at ppm-level or low-percentage concentration. Handling is easier, but the active peptide concentration is far lower per gram of supplied material.

A branded complex is yet another category: SymPeptide® Xlash, for example, is a liquid system whose INCI is listed as Glycerin, Water, Myristoyl Pentapeptide-17. None of these forms can be substituted by equal weight. Dosing should always be calculated on the active peptide basis stated in the batch documentation.

What Evidence Is Available?

The evidence base for Myristoyl Pentapeptide-17 can be separated into levels:

• Ingredient-level claims. Raw-material suppliers describe keratin-related mechanisms and nutrient-support effects on follicle cells. The Danish EPA report records these as company claims about the ingredient and about branded blends.
• Finished-product observations. Some lash and brow serums report appearance improvements, but these products typically contain multiple actives - peptides, panthenol, hyaluronic acid, plant extracts - so results cannot be attributed to a single peptide.
• Independent review. A 2024 comprehensive review of eyelash serums in the Journal of Cosmetic Dermatology notes that non-prostaglandin ingredients, including cosmetic peptides, have a much more limited formal evidence base, and that more studies are needed in eyelash serum use.

Measured use levels in commercial products are also informative. In the Danish EPA survey, chemical analysis by UPLC-MS2 of 19 purchased serums found peptides at low concentrations - the highest measured level for any peptide was approximately 60 µg/g (0.006%), with manufacturers self-reporting Myristoyl Pentapeptide-17 at or below 0.01%. This confirms that in finished products the peptide functions as a low-dose conditioning ingredient, which is why active-basis accuracy at the raw-material level matters more than nominal powder weight.

The practical conclusion for formulators and buyers: Myristoyl Pentapeptide-17 is a well-established conditioning peptide with real market presence, but its supportable claims belong to conditioning and appearance, not to drug-level efficacy.

How Should Buyers Evaluate Quality?

For a cosmetic peptide supplied to an eyelash or brow serum formula, the core documentation set should cover:

• HPLC purity and chromatographic data
• LC-MS or MS identity confirmation
• Peptide content / assay basis (not only HPLC area purity)
• Counter-ion content where applicable (e.g., acetate)

Water content

• Residual solvent information
• Microbiological specification
• Batch-specific COA and batch traceability

Buyers should also confirm the exact sequence, terminal form (amide), salt status and supplied form before comparing quotations across suppliers - two materials with the same INCI can differ substantially in active basis.

Suppliers should be able to provide a batch-specific COA per lot, supporting HPLC and MS data, and samples should be evaluated against the intended formula before scale-up. Batch-to-batch consistency, not just a single certificate, is what makes a lash or brow serum reproducible across production runs.

FAQ

What is the sequence of Myristoyl Pentapeptide-17?

The sequence is Myr-Lys-Leu-Ala-Lys-Lys-NH₂ (Myr-KLAKK-NH₂), a myristic acid chain conjugated to the pentapeptide Lys-Leu-Ala-Lys-Lys with an amide C-terminus.

What is its CAS number?

959610-30-1.

Is Myristoyl Pentapeptide-17 the same as Myristoyl Pentapeptide-17 acetate?

Not exactly. The target peptide structure is Myr-Lys-Leu-Ala-Lys-Lys-NH₂, while commercial peptide powders may be supplied with counter-ions such as acetate. Counter-ion content can affect the active peptide content per gram of supplied material. Buyers should therefore confirm peptide identity, assay basis and counter-ion content on the batch-specific COA.

Is it used for eyelashes or scalp hair?

Its commercial positioning is primarily eyelash and eyebrow conditioning. Scalp-hair products use different peptide systems; do not transfer lash-formula assumptions to scalp applications without formulation-specific evaluation.

Is it a cosmetic or pharmaceutical ingredient?

Cosmetic. It is not a drug and is not a substitute for prescription ingredients such as bimatoprost, the only FDA-approved treatment specifically indicated for eyelash hypotrichosis.

Looking for Myristoyl Pentapeptide-17 powder for cosmetic formulation research? HDM Biotech provides batch-specific COA, analytical documentation, sample support and bulk supply options according to the confirmed product specification. See also the 2026 market perspective: Why Is Myristoyl Pentapeptide-17 Gaining Attention in Lash and Brow Serums in 2026?

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References

1. Danish Environmental Protection Agency. Survey and risk assessment of eyelash and eyebrow serums. 2025. https://www2.mst.dk/Udgiv/publications/2025/05/978-87-7038-999-0a.pdf
2. Eyelash serums: A comprehensive review. Journal of Cosmetic Dermatology. 2024. https://onlinelibrary.wiley.com/doi/full/10.1111/jocd.16278
3. PubChem CID 127264611 - Myristoyl Pentapeptide-17. National Center for Biotechnology Information. https://pubchem.ncbi.nlm.nih.gov/compound/127264611