Anti-aging
Leuphasyl
A stabilized enkephalin fragment marketed as a topical, needle-free alternative to neuromuscular-blocking wrinkle treatments — the mechanism is plausible, the human wrinkle-reduction evidence is thin.
Research chemical Anti-aging
- Full name
- Pentapeptide-18
- Also known as
- Pentapeptide-18, Leu-DAP, SNAP-8 alternative, Enkephalin-analog pentapeptide
- Regulatory status
- Unregulated cosmetic ingredient (not a drug); sold in serums/creams, not injectables. No FDA or EMA drug approval process applies because it isn't marketed as a therapeutic.
Origin
Leuphasyl is a synthetic pentapeptide (Tyr-D-Ala-Gly-Phe-Leu) derived from the endogenous opioid peptide Leu-enkephalin, with a D-amino acid substitution at position 2 to resist enzymatic degradation and extend stability in topical formulations. It is a cosmetic-industry ingredient, not a pharmaceutical.
Mechanism
Proposed to act at the neuromuscular junction interface in skin by binding opioid-receptor-like sites and dampening catecholamine and acetylcholine release, theoretically reducing the frequency and force of the micro-contractions in facial muscles that contribute to expression-line formation. This is distinct from Botox's mechanism (SNARE-protein cleavage) and from Argireline's (SNARE-complex assembly inhibition); Leuphasyl is generally pitched as complementary to both.
Research summary
Evidence
Published data are almost entirely in vitro and in silico: molecular docking/dynamics and spectroscopic studies show Leuphasyl binding to inflammation- and matrix-remodeling targets (MMP-13, TGF-β, TNF-α pathways) and formulation studies confirm it is stable and non-cytotoxic to skin cell lines when delivered in lipid nanocarriers. No randomized, placebo-controlled human trial of Leuphasyl alone measuring wrinkle depth has been located on PubMed; manufacturer-reported efficacy claims are not independently peer-reviewed. By contrast, its usual co-formulant Argireline (acetyl hexapeptide-3) does have a small published RCT showing modest anti-wrinkle effects.
Evidence tier: Research chemical — see the methodology note for how this is assessed.
Citations
- Pentapeptide-18 as an anti-aging candidate: Spectroscopic characterization and molecular interaction analysis — Akhan et al., 2026
- Integrative In Silico and In Vitro Evaluation of Vialox and Leuphasyl Pentapeptides for Antiaging Applications — Akhan et al., 2026
- Solid Lipid Nanoparticles Incorporated with Retinol and Pentapeptide-18—Optimization, Characterization, and Cosmetic Application — Pawłowska et al., 2024
- D-tyrosine adds an anti-melanogenic effect to cosmetic peptides — Park et al., 2020
- The anti-wrinkle efficacy of argireline, a synthetic hexapeptide, in Chinese subjects: a randomized, placebo-controlled study — Wang et al., 2013
Reported benefits
- Reported softening of expression lines (crow's feet, forehead lines) with regular topical use, per manufacturer and formulation literature
- Marketed as a synergistic partner to Argireline for combined 'triple mechanism' wrinkle serums
- Non-injectable, no downtime, compatible with routine skincare layering
Dosing protocols reported in the literature & community
These are protocols reported by compounding pharmacies, published trials, or self-experimentation communities — not a prescription. Start low, especially for anything new.
| Route | Reported protocol |
|---|---|
| topical | Typically formulated at 5-10% of a peptide-complex solution, itself included in a finished serum/cream at low single-digit percentages; applied once or twice daily to clean, dry skin, often in combination products with Argireline and/or Matrixyl-type peptides |
Side effects
- Mild irritation or contact sensitivity in a minority of users, as with most concentrated peptide serums
- No systemic side effects reported given negligible dermal penetration at typical topical concentrations
Safety notes
Community & reddit notes (anecdotal — not clinical evidence)
Discussed mainly in skincare/DIY-formulation circles as a budget, non-invasive component of 'peptide facial serums,' almost always stacked with Argireline; users report subtle, gradual softening rather than Botox-like results, and skepticism about marketing claims is common even among enthusiasts.