Myristoyl Pentapeptide-17 (MPP-17) is studied and used in cosmetic lash and brow products primarily as a conditioning peptide. The proposed mechanisms in supplier literature center on keratin-related gene expression and nutrient-support effects on follicle cells. What the ingredient is proposed to do and what can be claimed are two different questions, and this page separates the mechanism discussion from the evidence boundary.
Why Do Eyelashes Become Thin or Fragile?
Eyelashes have a short growth cycle compared with scalp hair, and several everyday factors can make them look thinner or more fragile:
- The natural lash cycle. Individual lashes grow, rest and shed on their own schedule. A certain amount of shedding is normal, and perceived thinning can simply reflect the cycle.
- Mechanical stress. Rubbing the eyes, sleeping on the face and habitual touching can bend or weaken lash shafts.
- Mascara removal. Repeated friction from makeup removal is one of the most common sources of lash breakage.
- Lash extensions. The added weight and removal process can stress natural lashes over time.
- Dryness and breakage. Like any keratin fiber, lashes can become more brittle when they are dry or over-processed.
- Individual differences. Genetics, age and health status influence lash density and thickness.
Thinning and fragility are not one single condition, so a single mechanism should not be used to explain every case - and no cosmetic ingredient should be positioned as treating all of them.
For a cosmetic product, the realistic target is therefore the condition of the lashes that are present - their flexibility, smoothness and overall appearance - rather than the number of follicles. This is the framing that keeps claims honest and testable.
What Role Does Keratin Play in Eyelashes?
The eyelash shaft is a keratin-based fiber: keratin is the structural protein that gives the lash its strength and resistance to breakage, in the same family of proteins that forms the hair shaft. When keratin fibers are weakened by mechanical or environmental stress, breakage becomes more visible.
It is important to keep two ideas separate. Reducing breakage in existing lash fibers is about preserving the appearance of a more complete lash line. Creating new follicles is a completely different biological claim - one that no cosmetic peptide should be used to support.
The lash fiber itself is organized in layers - an outer cuticle and an inner cortex - and both contribute to how light reflects off the lash and how resistant it is to splitting. Conditioning ingredients aim at these fiber properties rather than at follicle biology.
How Is Myristoyl Pentapeptide-17 Proposed to Work?
Raw-material suppliers describe Myristoyl Pentapeptide-17 in relation to keratin: promoting keratin production and nutrient absorption in hair-follicle cells, with the intended finished-product benefit of supporting stronger-looking, well-conditioned lashes and brows. The Danish Environmental Protection Agency records these as company claims in its 2025 survey of lash and brow serums.
In formulation terms, MPP-17 is a conditioning peptide used at low dose in leave-on eye-area products. The proposed contribution is to the condition and appearance of the lash and brow fibers, not a growth-promoting mechanism. In vitro or supplier-level mechanism data should not be rewritten as confirmed human effects.
Mechanism descriptions in this area typically come from supplier white papers and ingredient documentation rather than from independent, peer-reviewed human studies. That is why this page consistently describes them as proposed mechanisms: they explain why the ingredient was designed and where research is heading, not what has been clinically confirmed.
Conditioning Existing Lashes vs Stimulating New Growth
This distinction is the core of responsible lash-and-brow peptide communication:
| Direction | Reasonable Interpretation |
|---|---|
| Conditioning | Improving the flexibility, appearance and care state of existing lash fibers |
| Breakage reduction | Helping preserve a more complete lash-line appearance |
| Follicle growth | Requires stronger human clinical evidence |
| New follicles | Should not be promoted as a cosmetic raw-material claim |
Formulas can reasonably aim at the first two rows. The last two belong to a different regulatory and evidence category entirely.
What Do Finished-Product Studies Tell Us?
Finished-product studies are useful context, but they cannot isolate the contribution of a single peptide. Most commercial lash serums contain several actives - peptides, panthenol, hyaluronic acid, plant extracts and sometimes growth-factor blends - so a result observed in a finished formula cannot be attributed to Myristoyl Pentapeptide-17 alone.
One frequently cited example is the 2020 open-label study of an eyelash polygrowth factor serum, in which 29 of 30 participants completed a 90-day evaluation. Compared with baseline, the study reported improvements in length (10.52%), volume (9.3%), luster (11.43%), thickness (35%) and curl (50.83%). The tested product was a multi-ingredient polygrowth factor serum, not a single-peptide formula, and the authors themselves concluded that additional randomized, controlled studies with larger samples are needed to confirm the findings.
The practical reading for B2B buyers: finished-product numbers support interest in the category, but they do not license single-ingredient efficacy claims for a specific peptide powder.
Most studies in this category are open-label, relatively small and sometimes industry-funded, which further limits how much weight a single study can carry. Buyers should treat such results as directional context for the category, not as performance data for a specific peptide.
Is Myristoyl Pentapeptide-17 Prostaglandin-Free?
The raw material itself is not a prostaglandin or prostaglandin analogue - it is a synthetic myristoylated peptide. Whether a finished serum is truly "prostaglandin-free," however, must be verified against the complete formula. Surveys of online-purchased lash serums have found undeclared prostaglandin analogues in some products, so the presence of a peptide on the label does not by itself establish that the finished product contains no prostaglandin-related ingredient.
What Results Can Cosmetic Brands Reasonably Claim?
For a lash or brow serum containing Myristoyl Pentapeptide-17, claims that fit the evidence and the regulatory category include:
Helps support the appearance of fuller-looking lashes
Supports stronger-looking, well-conditioned lashes and brows
Conditioning formula for lash and brow care
Helps reduce the appearance of sparse lashes
Peptide-based care for healthier-looking lash and brow fibers
Claims to avoid include growing new eyelashes, replacing prescription products such as bimatoprost, and any guarantee of permanent change.
FAQ
Does Myristoyl Pentapeptide-17 grow new eyelashes?
No. It is positioned as a conditioning peptide for the appearance of existing lashes. Creating new lashes or follicles is a drug-level claim that cosmetic ingredients should not carry.
Does it increase keratin production?
Keratin-related effects are described in supplier-level research, but this is not an independently confirmed human clinical endpoint. It should be communicated as a research direction, not a proven effect.
How is it different from bimatoprost?
Bimatoprost 0.03% is a prescription prostaglandin analogue and the only FDA-approved treatment specifically indicated for eyelash hypotrichosis. Myristoyl Pentapeptide-17 is a cosmetic peptide with a much more limited formal evidence base.
Can it be used for eyebrows?
Yes, it appears in eyebrow serums as well as eyelash serums in commercial products, and the conditioning logic is the same. Finished formulas should still be evaluated separately for eye-area tolerance.
How strong is the clinical evidence?
Limited. The formal evidence base for non-prostaglandin lash ingredients is much smaller than for prescription alternatives, and finished-product results cannot be attributed to a single peptide.
References
- Sachdev M, Velugotla K, Revanker S, Somasekhar G. An Open-label, Single-center, Safety and Efficacy Study of Eyelash Polygrowth Factor Serum. J Clin Aesthet Dermatol. 2020;13(2):61-66. PMID 32308787.
- 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
- Eyelash serums: A comprehensive review. Journal of Cosmetic Dermatology. 2024. https://onlinelibrary.wiley.com/doi/full/10.1111/jocd.16278
- PubChem CID 127264611 - Myristoyl Pentapeptide-17. National Center for Biotechnology Information. https://pubchem.ncbi.nlm.nih.gov/compound/127264611