A review of topical peptides notes pentapeptide-18 (leuphasyl) as one of the 'less invasive topical equivalents' of botulinum toxin, based on laboratory evidence of reduced muscle contraction.
Pentapeptide-18 (Leuphasyl)
Neurotransmitter-inhibiting peptide (Leuphasyl) for expression line reduction

Overview
Last reviewed: 2026-08-18
Identity & Aliases
Also known as
Full composition (formula, molecular weight, sequence) in Quick Facts →
Research Areas
Available Evidence
Laboratory and ex-vivo assays using muscle tissue models indicate leuphasyl reduces contraction of muscle fibers via an enkephalin-mimetic effect, which underpins its marketed 'Botox-like' wrinkle-smoothing mechanism. These are laboratory assays, not clinical proof of cosmetic efficacy.
Claims of wrinkle reduction comparable to botulinum toxin are not supported by published clinical trials; cosmetic efficacy claims rest largely on manufacturer-provided data and reviews of topical peptide studies.
Key Studies & Findings
Benefits & Effects
Side Effects & Safety
Limitations & Open Questions
Pharmacology
Reported Research Dosing
Reported values from research literature and community protocols. Educational reference only — not a dosing recommendation or medical advice.
dosage not established
Frequently Asked Questions
What is pentapeptide-18?
A pentapeptide cosmetic ingredient (INCI name), also known as Leuphasyl, marketed as an enkephalin-like peptide that reduces muscle contraction for 'Botox-like' wrinkle-smoothing effects.
Does pentapeptide-18 work like Botox?
Not in a clinical sense. Its mechanism is proposed to be muscle-relaxing in laboratory assays, but no published clinical trials demonstrate efficacy comparable to botulinum toxin.
Is pentapeptide-18 approved as a drug?
No. It is a cosmetic ingredient, not a drug; cosmetic efficacy claims are not subject to FDA drug approval.
Research Citations
Pawłowska M, Marzec M, Jankowiak W, Nowak I (2024)
Park J, Jung H, Jang B, Song HK, Han IO, Oh ES (2020)
Pawłowska M, Marzec M, Jankowiak W, Nowak I (2024)
Mu Receptors.
Herman TF, Cascella M, Muzio MR (2025)
Cy5.5-Knottin 2.5F.
Chopra A (2004)
+ 21 more citations
Related Resources
Quick Facts
Formula
C29H39N5O7
Molecular Weight
569.0
Mechanism
Neurotransmitter inhibitor for expression wrinkle reduction
Safety Information
Generally safe for cosmetic topical use. Enkephalin analog for skin applications.
Citations
26Pawłowska M, Marzec M, Jankowiak W, Nowak I (2024)
Park J, Jung H, Jang B, Song HK, Han IO, Oh ES (2020)
Pawłowska M, Marzec M, Jankowiak W, Nowak I (2024)
4.Mu Receptors.
Herman TF, Cascella M, Muzio MR (2025)
5.Cy5.5-Knottin 2.5F.
Chopra A (2004)
+ 21 more citations