Myristoyl Pentapeptide-17

Identity and Structure

Myristoyl pentapeptide-17 is a lipidated cosmetic peptide built around a five-amino-acid sequence attached to a C14 myristic acid chain at the N-terminus. It was developed and commercialized by Sederma (Croda) in the mid-2000s and originally positioned as a keratin-gene activator — an ingredient whose target was not collagen, elastin, or melanin but the keratin machinery of hair follicles and the cells that build the hair shaft. The ingredient rose to broad consumer awareness as the active driver in over-the-counter eyelash serums, where it was marketed as a non-prescription alternative to the bimatoprost-based prescription product Latisse.

Intended Mechanism

The claimed mode of action is upregulation of keratin gene expression — specifically hair-type keratins — within the matrix cells of the hair bulb and, by extension, the cells that form the emerging hair shaft. Ingredient-manufacturer materials have cited stimulation of insulin-like growth factor receptor expression in dermal papilla cells as a secondary mechanism, which would in principle extend the anagen (growth) phase of the hair cycle. The myristoyl chain is a delivery modification: it promotes partitioning into the follicular lipid environment and is not itself biologically active.

The mechanistic case is plausible but largely ingredient-house data. Independent peer-reviewed human evidence dissecting the molecular pathway in treated follicles is thin, and most of the cited mechanism flows from in vitro follicle-organ-culture work and dermal papilla cell assays rather than from in vivo biopsy studies.

Clinical Evidence

The strongest marketing claims for myristoyl pentapeptide-17 concern eyelash length, thickness, and density over 4–8 weeks of nightly application. Manufacturer-sponsored studies have reported measurable increases in lash length in the 10–20% range and user-assessed improvements in fullness across several weeks of use. These studies are typically small (n<30), short (≤12 weeks), and not placebo-controlled in the rigorous sense of randomized dermatology trials. A smaller body of work addresses scalp-hair applications, where the evidence is weaker still.

Honest assessment: the ingredient is credibly associated with modest cosmetic improvements to eyelash appearance, most visible in people with baseline thin or short lashes. It is not in the same evidence tier as bimatoprost (Latisse), a prostaglandin F2α analogue with FDA approval for eyelash hypotrichosis supported by multi-site randomized trials. For scalp hair loss, the evidence does not support myristoyl pentapeptide-17 as a primary therapy; FDA-recognized agents (minoxidil, finasteride, low-level laser devices) remain the appropriate first line.

Formulation and Application

Myristoyl pentapeptide-17 is typically used at parts-per-million concentrations in aqueous lash serums, brow conditioners, and scalp-applied treatments. It is often paired with other hair-targeting peptides — most commonly biotinoyl tripeptide-1, which targets follicle anchoring rather than keratin synthesis — and with supporting ingredients such as panthenol, biotin, and follicle-penetration enhancers. Nighttime application is the convention, partly for practical contact-time reasons (no makeup, extended exposure) and partly because hair-follicle mitotic activity peaks during sleep.

The application-safety caveat specific to lash serums is ocular contact. Unlike bimatoprost — which has its own well-characterized side-effect profile of iris pigmentation change and periorbital fat atrophy — myristoyl pentapeptide-17 does not appear to drive those pharmacological effects, but ocular surface irritation from any serum reaching the eye is possible and is the most common adverse event reported.

Safety and Regulatory Status

Myristoyl pentapeptide-17 is a cosmetic ingredient with no drug approval for any indication. It has no controlled status in the US, EU, or other major markets and is freely used in leave-on hair and lash products. Its real-world safety record across more than a decade of widespread retail use is good, with adverse events limited to contact irritation and occasional allergic reaction. It is not orally active and is not on any doping-controlled list.

Bottom Line

Myristoyl pentapeptide-17 is a reasonable cosmetic ingredient for consumers seeking gradual improvement in lash or brow appearance without a prescription. Its evidence base is thinner and its effect size smaller than bimatoprost, and it is not a serious intervention for androgenetic alopecia or other medical hair-loss conditions. It earns a place in the toolkit as a non-prescription option with acceptable safety and modest documented benefit — nothing more, nothing less.