Myristoyl Pentapeptide-17
Hair / Lash GrowthAlso known as: Eyelash Growth Peptide
Mechanism
A peptide that promotes eyelash and eyebrow growth by stimulating keratin production in hair follicle cells. Unlike bimatoprost (Latisse), which uses a prostaglandin mechanism, this peptide works through keratin gene expression — a non-prostaglandin pathway with fewer side effects like iris color changes. Popular ingredient in lash and brow growth serums.
Technical detail
Myristoyl-conjugated pentapeptide that upregulates keratin gene expression (KRT85, KRT31, KRT34) in hair follicle keratinocytes. Myristic acid (C14:0) lipid conjugation enhances follicular penetration. Mechanism distinct from prostaglandin F2-alpha analogs (bimatoprost/latanoprost): does not activate prostanoid FP receptors, avoiding prostaglandin-associated side effects (iris hyperpigmentation, periorbital fat atrophy). In-vitro data: 155-175% increase in keratin expression. No effect on melanogenesis. Typically formulated at 1-5% in lash serums.
Effects
## Integumentary/Hair-Lash System [Tier 2 - In Vitro/Small Studies] - Pentapeptide conjugated with myristic acid (C14 fatty acid) for enhanced lipophilic penetration into the follicle - Upregulates keratin gene expression in hair follicle keratinocytes — the structural protein that gives hair shaft its strength, thickness, and integrity - Specifically increases expression of keratin 14 and keratin 17, which are abundant in the hair cortex - Originally developed and studied for eyelash growth but applicable to scalp hair as well - Promotes longer anagen phase in lash and eyebrow follicles ## Hair Shaft Quality [Tier 2 - In Vitro] - Increased keratin production results in thicker, more robust hair shafts - Improved cuticle integrity — the outer protective layer of the hair shaft is reinforced - May reduce hair breakage and split ends by strengthening the internal cortex structure - Effects are primarily on the SHAFT quality rather than follicle regeneration ## Follicle Stimulation [Tier 3 - Mechanistic] - Myristic acid conjugation improves cellular uptake through lipid bilayer penetration - The pentapeptide sequence interacts with keratinocyte receptors to upregulate protein synthesis - Unlike prostaglandin analogs (bimatoprost/latanoprost), does NOT work through the prostaglandin F2-alpha pathway - This means: no iris color change, no periorbital fat atrophy, no hyperemia — safe for periocular use
Practitioner Guide
## Clinical Positioning Myristoyl-pentapeptide-17 is the "lash and brow" peptide. While it works on scalp hair too, its primary niche is eyelash and eyebrow enhancement as a safer alternative to prostaglandin analogs (bimatoprost/Latisse). It builds shaft thickness through keratin upregulation rather than extending growth phase through prostaglandin signaling. ## Formulation Guide ### For Lash/Brow Growth Concentration: 100-200 ppm myristoyl-pentapeptide-17 in a lash serum base Lash serum formulation: - Myristoyl-pentapeptide-17: 200 ppm - Myristoyl-hexapeptide-16 (optional, companion peptide): 100 ppm - Biotinoyl-tripeptide-1: 100 ppm - Panthenol: 1% - Hydroxyethylcellulose: 0.5% (thickener for application precision) - Glycerin: 5% - Phenoxyethanol: 0.5% - Purified water: QS to 100% Application: apply thin line to upper lash line (like eyeliner) and/or eyebrow area once nightly using a fine brush or applicator wand. ### For Scalp Hair (Combined Serum) Include at 100-200 ppm in the comprehensive hair serum alongside other peptides: - Acetyl-tetrapeptide-3: anti-DHT, ECM - AHK-Cu: follicle stimulation, angiogenesis - Biotinoyl-tripeptide-1: anchoring, metabolism - Myristoyl-pentapeptide-17: keratin production, shaft quality - Total concentration of peptide actives in the serum is modest — these are synergistic, not individually high-dose ingredients ### Combining with Bimatoprost/Latisse - Can be used alongside bimatoprost for enhanced results - Bimatoprost extends anagen phase (longer growth); myristoyl-pentapeptide-17 increases keratin production (thicker shaft) - Different mechanisms mean genuine combination benefit - For patients who want to discontinue bimatoprost (due to side effects): transition to peptide lash serum may maintain some results, though growth-phase extension effect will be lost ## Realistic Expectations ### Lashes - Week 2-4: lashes may appear slightly more conditioned/fuller - Month 1-2: early thickening noticeable, especially if lashes were fine/sparse - Month 2-3: measurable increase in lash thickness and length (modest) - Results are LESS dramatic than bimatoprost but carry zero risk of iris color change or periorbital fat loss ### Scalp - Similar timeline to other topical peptides (3-6 months for noticeable effect) - Contributes to overall shaft quality rather than dramatic regrowth - Best as part of multi-peptide approach ## Safety - Excellent safety profile — no prostaglandin-related side effects - No iris color change - No periorbital fat atrophy (the "sunken eye" look from chronic Latisse use) - No conjunctival hyperemia - Suitable for all skin types and tones - Safe during pregnancy/breastfeeding (topical peptide, no systemic absorption)
Research Summary
## Tier 1 — Limited Human Data - Small manufacturer-sponsored studies showing increased lash length and thickness after 8-12 weeks of topical application - No independent large-scale clinical trials - Widely used in commercial lash serums with positive consumer-reported outcomes ## Tier 2 — In Vitro Data - Keratinocyte cultures: dose-dependent upregulation of keratin 14 and keratin 17 mRNA expression (2-3x increase at effective concentrations) - Hair follicle organ culture: increased hair shaft diameter and improved cortex density - Improved keratin crosslinking evidenced by increased mechanical tensile strength of treated hair fibers ## Tier 3 — Mechanistic - Myristoylation enables rapid membrane association and improved intracellular delivery - Pentapeptide sequence activates transcription factors involved in keratin gene clusters (KRT14, KRT17) - Does not interact with prostaglandin receptors — confirmed by receptor binding assays (key safety differentiator) ## Evidence Gaps - No independent clinical trials for any indication - Dose-response not characterized in humans - Head-to-head vs. bimatoprost not studied - Long-term use data not available - Specific mechanism of keratin gene activation not fully elucidated