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Pentapeptide-18 · expression-line active
Overview
On the INCI deck this active reads as Pentapeptide-18 — the five-residue peptide commercialised as Leuphasyl. The sequence Tyr-D-Ala-Gly-Phe-Leu is studied around the enkephalin pathway, a proposed mechanism for modulating neurotransmitter release that is distinct from, and complementary to, the SNARE/SNAP-25 route the acetyl-hexapeptide family (Argireline, SNAP-8) engages. For a finished-product brand the value is a second mechanistic lever on the same dynamic-line story — forehead, glabellar, periocular — which is why the marketed positioning often pairs it with Argireline as a combination expression-line system. Pepoderma writes the Leuphasyl spec for cosmetic chemists building expression-line serums, eye creams, and pre-makeup primers that want a multi-pathway claim rather than a single-peptide one. The active goes into the water phase cool and late on copper-clean process water; near-neutral carriers (pH 5.5–7.0) on polyglyceryl, lecithin, or sucrose-ester emulsifiers behave well, and pre-dissolving the powder in a small glycerin or propanediol slurry keeps it dispersing cleanly. Because Leuphasyl engages a different proposed pathway from the acetyl-hexapeptides, a brief can layer the two in one aqueous phase for a complementary-mechanism narrative; keep the preservation system robust, since neither peptide self-preserves. Sample fills of 10 mg and 100 mg cover bench iterations and pilot work; kilo-scale runs on the standard OEM cycle once a carrier is locked. Leuphasyl stacks with SNAP-8 and Argireline on the expression-line arm and with Matrixyl or GHK-Cu when a brief wants a signal or carrier arm alongside. INCI and CAS appear on the SDS for CPNP and equivalent cosmetic notifications, with an allergen and trace-impurity sheet per lot.
Who buys this, and why
Anti-aging peptide actives — Copper Tripeptide-1 (GHK-Cu), Acetyl Octapeptide-3 (SNAP-8), Palmitoyl Pentapeptide-4 (Matrixyl) — ship primarily to indie beauty brand founders building retail serums, established skincare R&D chemists extending an existing anti-wrinkle line, and med-aesthetic brand OEMs developing back-bar retail products. The defining formulation considerations are use-level optimisation (lower is often better at the working pH), carrier selection (aqueous vs. lipid-encapsulated), and chelator-free preservative systems. The data packet ships with guidance on all three on the lot report.
Primary buyer fit: med-aesthetic brand R&D + back-bar retail OEM and regional cosmetic-active distributors serving brand programmes.
Applications & formulation fit
A neurotransmitter-inhibiting peptide: Pentapeptide-18 is an enkephalin-pathway active that modulates acetylcholine release through a different receptor than the SNAP-25 peptides — which is why it is often paired with Argireline for a layered expression-line story.
Use levels, pH window, and carrier compatibility are covered in the Journal — verify them against your own base:
Specifications
Documentation available on request
Regulatory note
Supplied as a cosmetic-grade peptide active under the EU EC 1223/2009 cosmetic regulation, NMPA cosmetic ingredient framework, FDA OTC monograph framework (where applicable), and equivalent regimes elsewhere. NOT a finished cosmetic product. Brand registration, finished-product safety substantiation, claim documentation, and notification (CPNP for EU, equivalent registries elsewhere) remain the responsibility of the brand owner. INCI naming and CAS are supplied with the SDS that ships with every lot.
Frequently asked questions
Leuphasyl (Pentapeptide-18) is studied around the enkephalin pathway, while Argireline (Acetyl Hexapeptide-8) and SNAP-8 are studied around the SNARE/SNAP-25 route — two different proposed levers on neurotransmitter release. Because the proposed mechanisms are complementary rather than identical, the category often positions Leuphasyl and Argireline as a combination expression-line system so a brand can tell a multi-pathway story on pack. For a formulator the practical upshot is that both are water-soluble peptides that co-formulate in the same aqueous phase; the decision to combine is a claim-and-cost call, framed at the 'studied / designed to support' level rather than as an efficacy promise.
Add it to the water phase cool and late on copper-clean process water at a near-neutral pH (5.5–7.0), in anionic or non-ionic emulsions or a hydrogel; pre-dissolving the powder in a small glycerin or propanediol slurry avoids clumping. As with any cosmetic peptide it does not self-preserve, so the preservation system must hold the whole formula — and when it is combined with Argireline the total peptide load deserves a sense-check against the retail price point. Use-level and pH specifics are best verified against your own base; our wrinkle-peptide comparison guide covers the formulation detail rather than us restating a single number here.
Sample fills are 10 mg for first-pass bench iterations and 100 mg once a carrier is selected and stability work begins; brand programmes scale to kilo lots on the standard OEM cycle. Every shipment carries the INCI name (Pentapeptide-18), the CAS, an allergen and trace-impurity statement for CPNP and equivalent cosmetic notifications, and a formulation-notes card. We supply the cosmetic-grade ingredient and its ingredient-level documentation; finished-product registration and claims substantiation remain the brand owner's responsibility.
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