Myristoyl Pentapeptide-17 (SymPeptide XLash)
Published · Researched 2026-09-21
Slug: myristoyl-pentapeptide-17 · Category: Skin, Hair & Cosmetic peptides · Research date: 2026-09-21
Overview
Myristoyl Pentapeptide-17 is the INCI name for the lash-serum peptide sold as SymPeptide XLash (Symrise) — marketed as a keratin-pathway stimulator for lashes and brows. It is the first-listed active in NULASTIN's lash serum and a core component of The Ordinary's Multi-Peptide Lash and Brow Serum, UKLASH, Toplash, and Japan's Rohto Lash Rich ("MP17"). Every review is of a formula, never the isolated peptide — a caveat the better sources state outright. Sequence and CAS not verified this round — UNVERIFIED.
Social standing
Platform pulse (observed 2026-09-21):
- Threads (brand-led): Kosas brand post (Aug 2025) promoting its "powerhouse pentapeptide" mascara/serum — brand content, useful for showing the ingredient's mainstream-beauty positioning, not independent validation. A junk chemistry-meme result (ruan.mei) was discarded.
- Beauty editors (independent): wildnpretty's UKLASH review (beauty editor): improved nourishment and plumpness reported before any length change — an honest sequencing of effects. abeautyedit's review of The Ordinary Multi-Peptide Lash and Brow Serum: surprise at results after six weeks, with the explicit caveat that the formula contains several active complexes so results cannot be assigned to MP-17 alone.
- Retailer reviews (polarized): Ulta's NULASTIN listing (myristoyl pentapeptide-17 as first ingredient) carries both growth praise and reports of no change or irritation — the most genuinely mixed dataset found. eyelashes.org's City Lash analysis describes polarized customer outcomes and notes weak isolated evidence for MP-17 versus combination use.
- Brand clinical framing: Toplash's dual-peptide complex is described as ophthalmically tested with 0% irritation across 64 participants over 90 days — a brand claim, not an independent trial.
- Facebook Groups: Post queries returned zero indexed hits (search-index limitation noted).
- Instagram: No independent owner content captured this round beyond brand assets.
Group consensus: Lash-serum reviewers are the most polarized in this track: visible improvement for some, nothing or irritation for others, with the honest middle (UKLASH-style: condition first, length maybe) being the most credible pattern. Isolated MP-17 evidence remains weak — combinations do the talking.
Viral moments: None observed. Steady product-review background noise.
Praise: Improved lash condition/plumpness; some users report visible growth; Rohto/Kosas give it mainstream-beauty legitimacy. Complaints: Polarized outcomes; irritation reports (Ulta/NULASTIN); effects inseparable from co-actives; brand "clinical" language overstates the evidence.
Social validation
Tier 3 — independent beauty-editor reviews plus polarized retailer datasets; Meta-platform signal is brand-only. Tier 2 is not claimed.
- wildnpretty UKLASH review (beauty editor): independent, honest effect sequencing (condition before length).
- abeautyedit The Ordinary lash/brow review: independent, explicit multi-active attribution caveat.
- Ulta NULASTIN reviews (polarized, incl. irritation): independent retail dataset, both directions represented.
- Kosas Threads brand post (Aug 2025): brand content — labeled, not counted as validation.
- Absence record: Facebook group queries returned zero indexed hits.
Key specs
| Attribute | Value | Status |
|---|---|---|
| Identity | Myristoyl Pentapeptide-17 (myristoylated pentapeptide) | Verified (INCI) |
| Trade name | SymPeptide XLash (Symrise) | Verified |
| Sequence / CAS | Not verified this round | UNVERIFIED |
| INCI name | Myristoyl Pentapeptide-17 | Verified |
| Typical cosmetic use | Lash/brow serums, usually combined with other peptide complexes (e.g., Widelash); applied to lash line / brows | Verified |
| Mechanism | Positioned as a keratin-pathway stimulator supporting lash appearance | Verified as claimed positioning; isolated in-vivo evidence weak (per eyelashes.org analysis) |
Pricing (observed 2026-09-21)
| Product | Price | Source |
|---|---|---|
| UKLASH lash serum | price not captured this round | wildnpretty review |
| NULASTIN Lash Follicle Fortifying Serum | price not captured this round | Ulta listing |
| The Ordinary Multi-Peptide Lash and Brow Serum | price not captured this round | abeautyedit review |
| Rohto Lash Rich (MP17) | price not captured this round | product packaging imagery |
| Toplash dual-peptide lash serum | price not captured this round | brand blog |
| FB Marketplace "lash serum" search | 3 listings, all unrelated (lash clusters, lip balm) — zero relevant | facebook-cli, 2026-09-21 |
Street reality: lash serums price on brand, not on the peptide — drugstore to prestige spreads are wide and the same INCI hides behind very different price tags. No meaningful used market.
What's included / what's needed
- Finished lash/brow serum only. Apply to lash line/brows per product directions; stop use if irritation occurs. No equipment needed. Cosmetic use only.
Support reality
- The Ordinary/DECIEM, Kosas: established retail support and returns.
- UKLASH, NULASTIN, Toplash: DTC brand support; NULASTIN irritation reports exist — patch-test and read return policies before committing.
- Rohto (Japan): domestic-market support; gray-import buyers get retailer-only recourse.
Community verdict
Myristoyl Pentapeptide-17 is the lash world's honest Rorschach test: the same INCI produces raves and shrugs, and the best reviewers admit they cannot separate it from the formulas it ships in. Condition-and-plumpness claims hold up better than length claims; irritation is real for a minority. Buy the formula with the return policy, not the peptide with the story.
Regulatory & safety status
Myristoyl Pentapeptide-17 is NOT an FDA-approved drug. It is a cosmetic ingredient. US cosmetics require no premarket FDA approval provided sellers avoid drug claims — lash-growth language sits in the industry's grayest marketing zone, and "appearance of fuller lashes" is the compliant framing. No therapeutic indication approved by any regulator. Discontinue use if irritation occurs.
Images
| View | File | Status |
|---|---|---|
| hero | img/myristoyl-pentapeptide-17-hero.jpg | ✓ Kosas GrowPotion mascara/serum product shot (pentapeptide-positioned brand) |
| side/profile | img/myristoyl-pentapeptide-17-side.jpg | ✓ Rohto Lash Rich tube + wand — original filename non-canonical, renamed |
| rear | img/myristoyl-pentapeptide-17-rear.jpg | ✓ REVIVE7 lash serum tube + box (alternate brand, front packaging — disclosed) |
| top/alternate-angle | img/myristoyl-pentapeptide-17-top.jpg | ✓ REVIVE7 white lash tube + wand (alternate brand) — original filename non-canonical, renamed |
| detail | img/myristoyl-pentapeptide-17-detail.jpg | ✓ UKLASH tube + wand close-up — original filename non-canonical, renamed |
| real-owner-in-use | img/myristoyl-pentapeptide-17-in-use.jpg | ✓ Woman applying mascara-style wand — real in-use photo |
| scale | — | ✗ Missing — no suitable image found; not faked |
| box/accessories | img/myristoyl-pentapeptide-17-box.jpg | ✓ Rohto Lash Rich "MP17" pack + tube — original filename non-canonical, renamed |
7 of 8 views gathered (2026-09-21). One pre-existing candidate was deleted after visual audit: a Kosas product shot duplicating the hero view (same product, alternate angle) — removed per the no-duplicate-views rule. All kept files are real product photos, verified, converted to JPEG. No AI imagery.
Not medical advice. This is a research summary of public social and web sources, not a recommendation to buy or use any product. Cosmetic peptides are not medicines; consult a qualified clinician for skin concerns.
Named sources
- Ulta/NULASTIN — *Complaints:** Polarized outcomes; irritation reports (Ulta/NULASTIN); effects inseparable from co-actives; brand "clinical" language overstates the evidence.
- Every review — Every review is of a formula, never the isolated peptide — a caveat the better sources state outright.
- UKLASH review — wildnpretty's UKLASH review (beauty editor): improved nourishment and plumpness reported before any length change — an honest sequencing of effects.
- Retailer review — Ulta's NULASTIN listing (myristoyl pentapeptide-17 as first ingredient) carries both growth praise and reports of no change or irritation — the most genuinely mixed dataset found.
- Lash-serum review — *Group consensus:** Lash-serum reviewers are the most polarized in this track: visible improvement for some, nothing or irritation for others, with the honest middle (UKLASH-style: condition first, length maybe) being the most credible pattern.
- Ulta NULASTIN review — **Ulta NULASTIN reviews (polarized, incl.
- Threads (brand-led) — Kosas brand post (Aug 2025) promoting its "powerhouse pentapeptide" mascara/serum — brand content, useful for showing the ingredient's mainstream-beauty positioning, not independent validation. (Aug 2025)
- Retailer reviews (polarized) — Ulta's NULASTIN listing (myristoyl pentapeptide-17 as first ingredient) carries both growth praise and reports of no change or irritation — the most genuinely mixed dataset found. eyelashes.org's City Lash analysis describes polarized customer outcomes and…
Source URLs were not recorded for these references.