Myristoyl Pentapeptide-17
Also known as: Myr-KLAKK-NH2 · SymPeptide 226EL
Myristoyl Pentapeptide-17 is a synthetic lipopeptide, myristic acid (a 14-carbon fatty acid) conjugated to the 5-amino-acid sequence Lys-Leu-Ala-Lys-Lys with a C-terminal amide, developed and marketed by Symrise under the trade name SymPeptide 226EL, primarily for eyelash and eyebrow growth applications. At Verified Peptides, we want to be direct about the evidence picture: we could not locate any independently peer-reviewed study isolating this specific peptide's effects alone. The one real, PubMed-indexed clinical study we could verify (Sachdev et al., 2020, PMID 32308787) tested it only as one ingredient within a multi-component growth-factor eyelash serum, in an open-label design with no placebo control. Widely circulated manufacturer figures (including a specific claimed 2010 journal study we could not verify exists) are not included here. It is a cosmetic ingredient, not an FDA-approved drug. Research-grade material sold here is a separate product intended solely for laboratory research.
What is Myristoyl Pentapeptide-17?
Myristoyl Pentapeptide-17 is a synthetic lipopeptide consisting of the pentapeptide Lys-Leu-Ala-Lys-Lys (commonly abbreviated KLAKK), conjugated at its N-terminus to myristic acid, a 14-carbon saturated fatty acid, with a C-terminal amide group. It was developed by Symrise (a German fragrance and cosmetic-ingredient company) and is marketed under the trade name SymPeptide 226EL, primarily positioned as an eyelash- and eyebrow-growth cosmetic active, though also studied in the broader context of hair follicle keratin biology.
At Verified Peptides, we want to note a naming clarification: unlike several other tripeptide-based cosmetic ingredients in this catalog with genuine naming-confusion risk (Palmitoyl Tripeptide-1 versus Palmitoyl Pentapeptide-4, for example), Myristoyl Pentapeptide-17's name and CAS number are used relatively consistently across vendor and technical sources, though it is sometimes discussed alongside a related Symrise ingredient, Myristoyl Hexapeptide-16, in combination cosmetic formulations — these are two distinct peptides that are frequently co-formulated together but are not the same compound.
Chemically, Myristoyl Pentapeptide-17 has molecular formula C41H81N9O6, molecular weight approximately 796.16 g/mol (independently cross-calculated from the formula, matching vendor-reported figures), CAS number 959610-30-1.
We independently cross-calculated this molecular weight atom-by-atom: summing the free amino acid formulas for three lysine residues, one leucine, and one alanine, subtracting four water molecules for the four peptide-bond condensations joining the five residues, then applying the atom-count changes for N-terminal myristoylation (addition of the C14 fatty acid chain via an amide bond, analogous to the acetylation and palmitoylation chemistry used elsewhere in this catalog, but with a longer 14-carbon acyl chain rather than the 2-carbon acetyl or 16-carbon palmitoyl groups) and C-terminal amidation. This derivation reproduced C41H81N9O6 and a molecular weight of approximately 796.16 g/mol, matching vendor-reported figures.
Key Benefits & Mechanisms
Mechanism of action
Myristoyl Pentapeptide-17's proposed mechanism centers on keratin gene expression. Manufacturer technical literature describes upregulation of several keratin genes, including KRT1, KRT14, and KRT71, in treated keratinocytes or hair follicle cells. Keratins are the primary structural proteins comprising hair shafts and the outer layer of skin, and increased keratin gene expression is proposed to support both the structural integrity of growing hair fibers and, by extension, an extended or more robust anagen (active growth) phase for the treated hair follicles, including eyelash and eyebrow follicles.
The myristoyl (fatty acid) conjugation is proposed to serve the same general purpose it serves in other lipopeptides in this catalog, such as Palmitoyl Tripeptide-1 — improving the compound's ability to penetrate the outer barrier layers of skin and reach the follicular structures where the peptide's proposed keratin-gene-expression activity would occur. At Verified Peptides, we have not found independent, peer-reviewed biochemical data confirming the specific keratin gene upregulation claims beyond manufacturer technical literature, and we think this is an important gap to flag directly, since gene-expression claims of this specificity are the kind of detail that, when unconfirmed independently, should be treated as a starting hypothesis for research rather than an established mechanism.
The eyelash and eyebrow hair cycle follows the same general anagen-catagen-telogen phases as scalp hair, though eyelash anagen phases are considerably shorter in duration (typically measured in weeks rather than years for scalp hair), which is part of why eyelash-focused cosmetic actives are often evaluated over comparatively short study windows (weeks to a few months) rather than the longer study durations sometimes used in scalp hair research. This shorter cycle length is a general feature of eyelash biology relevant to interpreting any eyelash-growth study's timeframe, independent of any single specific ingredient.
We also want to flag a general naming-confusion risk unrelated to any other compound in this catalog: the KLAKK sequence abbreviation used for this pentapeptide overlaps in letters (though not in full sequence or purpose) with an unrelated class of mitochondria-targeted pro-apoptotic KLA peptides studied in cancer research, which induce mitochondrial membrane disruption in cancer cells and have no connection to cosmetic keratin biology. We mention this only because short sequence-code searches can occasionally surface unrelated research areas, and researchers should rely on the full compound name and CAS number (959610-30-1) rather than sequence abbreviations alone when verifying sources.
Research Summary
At Verified Peptides, we think Myristoyl Pentapeptide-17 is one of the thinner independently-verified evidence bases in this catalog, and we want to be transparent about exactly what we could and could not confirm. The one real, PubMed-indexed, peer-reviewed clinical study we could verify (Sachdev et al., 2020, Journal of Clinical and Aesthetic Dermatology, PMID 32308787, volume 13, issue 2, page 61) is an open-label, single-center study of an 'Eyelash Polygrowth Factor Serum' in 29 participants over 90 days, reporting improvements in lash length (10.52%), volume (9.3%), luster (11.43%), thickness (35%), and curl (50.83%) versus baseline. This study included Myristoyl Pentapeptide-17 as one ingredient in a multi-component serum alongside growth factors, Salvia officinalis (sage) oil, and Myristoyl Hexapeptide-16, and used an open-label design without a placebo control group — meaning it cannot isolate this specific peptide's individual contribution, and the lack of a control group limits how confidently the observed changes can be attributed to the product at all versus natural variation or measurement effects.
We want to be direct about a claim we identified and are deliberately not including: several vendor and informational sources describe a supposed 2010 Journal of Cosmetic Dermatology study specifically testing topical Myristoyl Pentapeptide-17 on eyelashes over 12 weeks. We searched PubMed directly and found zero results for this claimed study — it does not appear to exist in any searchable, indexed, peer-reviewed source, a pattern consistent with unverifiable claims we have identified for other compounds in this catalog. We are not citing this claimed study here. Separately, the specific figures often quoted for Myristoyl Pentapeptide-17 alone (a claimed 24% eyelash growth increase at 2 weeks and 71% at 6 weeks, along with the KRT1/KRT14/KRT71 keratin gene upregulation data referenced in the mechanism section above) trace to Symrise's own technical and marketing literature for SymPeptide 226EL, not to an independently published, peer-reviewed source we could locate and verify.
No FDA, EMA, or other Western regulatory body evaluates Myristoyl Pentapeptide-17 as a drug, since it is regulated as a cosmetic ingredient. At Verified Peptides, we sell research-grade Myristoyl Pentapeptide-17 exclusively for laboratory research, and we think this compound is a useful illustration of why independent citation verification matters even for widely sold, seemingly well-established cosmetic ingredients.
Common Stacks
Lesser-Known Facts About Myristoyl Pentapeptide-17
Myristoyl Pentapeptide-17 is frequently co-formulated with Myristoyl Hexapeptide-16, a related but distinct Symrise-developed peptide, in commercial eyelash serums, similar to how Palmitoyl Tripeptide-1 is frequently co-formulated with Palmitoyl Pentapeptide-4 in commercial anti-aging products elsewhere in this catalog. Researchers should treat each peptide's evidence base separately even when they are commonly sold together.
Keratins are encoded by a large gene family (over 50 distinct keratin genes in humans), organized into type I (acidic) and type II (basic/neutral) keratins that pair together to form intermediate filaments. KRT1 and KRT14 are primarily associated with epidermal keratinocyte structure, while KRT71 is more specifically associated with the hair follicle inner root sheath — the specific combination cited in Myristoyl Pentapeptide-17's manufacturer literature spans both general epidermal and hair-follicle-specific keratin biology, though we could not independently verify the specific gene-expression data itself beyond manufacturer sourcing.
The broader eyelash-growth cosmetic ingredient category also includes prostaglandin analogs such as bimatoprost, which has a substantially different, pharmaceutically regulated history (bimatoprost ophthalmic solution is FDA-approved for eyelash hypotrichosis under the brand name Latisse) compared to the cosmetic-ingredient, non-drug regulatory status of peptide-based lash actives like Myristoyl Pentapeptide-17.
The Sachdev et al. 2020 study's reported outcome measures — length, volume, luster, thickness, and curl — reflect a broader pattern in eyelash-cosmetic research of using multiple, sometimes subjectively assessed or photographically graded parameters rather than a single hard endpoint, which is worth understanding when comparing effect sizes across different eyelash studies and products, since a large percentage change in one parameter (such as the reported 50.83% change in curl) does not necessarily indicate the same clinical magnitude of change as a similar percentage in a different parameter (such as the reported 9.3% change in volume).
Purity & Sourcing Considerations
At Verified Peptides, we require independent third-party HPLC purity testing and mass spectrometry identity confirmation for every batch of research-grade Myristoyl Pentapeptide-17 we offer, with a Certificate of Analysis (COA) available for each lot. As a fatty-acid-conjugated peptide, correct synthesis of the myristic acid-peptide amide bond should be confirmed as part of identity testing, not just the underlying pentapeptide sequence alone.
We source exclusively from manufacturers operating under Good Manufacturing Practice (GMP)-aligned quality systems, and every lot is independently verified rather than accepted solely on a supplier's internal documentation. Researchers should always request and review the specific COA for the lot they receive, confirming purity percentage and molecular identity before use in any experimental protocol, including verification of the specific fatty-acid chain length (myristic acid, C14), since related lipopeptides in this catalog use different chain lengths (acetyl, C2; palmitoyl, C16) that are not interchangeable and are not substitutable for one another in formulation or research use.
Storage & Stability
Lyophilized Myristoyl Pentapeptide-17 is stable when stored at -20°C, protected from light and moisture. At Verified Peptides, we ship lyophilized peptide with appropriate cold-chain packaging to preserve stability in transit.
As a lipopeptide with a fatty-acid conjugation, handling and solubility characteristics may differ somewhat from unmodified short peptides, similar to other myristoylated and palmitoylated compounds in this catalog. Once reconstituted, solution should be stored refrigerated at 2–8°C and used within the timeframe indicated on the product's documentation, avoiding repeated freeze-thaw cycles.
Frequently asked questions about Myristoyl Pentapeptide-17
What is Myristoyl Pentapeptide-17 and what is it primarily used for in cosmetic research?
It is a synthetic lipopeptide (myristic acid conjugated to the sequence Lys-Leu-Ala-Lys-Lys) developed by Symrise under the trade name SymPeptide 226EL, primarily studied and marketed for eyelash and eyebrow growth applications through proposed keratin gene expression effects.
Is there independent peer-reviewed evidence for Myristoyl Pentapeptide-17?
We identified one real PubMed-indexed study (Sachdev et al. 2020, PMID 32308787) that included it as one ingredient in a multi-component eyelash serum, tested in an open-label design without a placebo control. This is genuine but limited evidence that cannot isolate the peptide's individual contribution.
Does a 2010 Journal of Cosmetic Dermatology study on Myristoyl Pentapeptide-17 actually exist?
We could not verify this claim, which circulates on several vendor and informational websites. A direct PubMed search for this specific study returned zero results, so we are not citing it here.
What is the proposed mechanism of Myristoyl Pentapeptide-17?
Manufacturer technical literature describes upregulation of keratin genes (KRT1, KRT14, KRT71) in treated cells, proposed to support hair shaft structural integrity and an extended active growth phase. We could not independently verify this specific gene-expression data beyond manufacturer sourcing.
Is Myristoyl Pentapeptide-17 FDA approved?
No. It is a cosmetic ingredient regulated under cosmetic rather than pharmaceutical frameworks, not an FDA-approved drug.
Is Myristoyl Pentapeptide-17 the same as Myristoyl Hexapeptide-16?
No, though the two are frequently co-formulated together in commercial eyelash serums. They are distinct Symrise-developed peptides with separate sequences and should be evaluated with separate evidence bases.
How does Myristoyl Pentapeptide-17 compare to bimatoprost for eyelash growth?
Bimatoprost is an FDA-approved prostaglandin analog drug (Latisse) with a pharmaceutical regulatory history and controlled clinical trial data, while Myristoyl Pentapeptide-17 is a cosmetic ingredient with a substantially thinner, largely manufacturer-sourced evidence base. These represent different regulatory categories, not directly comparable evidence tiers.
What outcome measures were used in the Sachdev 2020 eyelash serum study?
The study assessed lash length, volume, luster, thickness, and curl using digital imaging at baseline and at 30, 60, and 90 days. It was open-label without a placebo control group, and the serum contained multiple active ingredients beyond Myristoyl Pentapeptide-17 alone.
Legal & research status: Myristoyl Pentapeptide-17 is a cosmetic ingredient, not an FDA-approved drug, and is regulated under cosmetic rather than pharmaceutical frameworks in markets where it is sold. Material sold as a research compound is offered strictly for laboratory and research use, not for human consumption or therapeutic use.