Leuphasyl
A cosmetic-ingredient pentapeptide modeled on leucine-enkephalin — marketed by Lipotec as a post-synaptic adjunct to Argireline-class pre-synaptic peptides for expression-line reduction.
A synthetic enkephalin analog (Tyr-D-Ala-Gly-Phe-Leu) developed by Lipotec as a cosmetic ingredient, proposed to reduce acetylcholine release at the neuromuscular junction through a δ-opioid receptor-mediated pathway on motor neurons.
Mechanism of action
Proposed to act at δ-opioid receptors on motor neuron terminals to reduce acetylcholine release. Manufacturer claims are that the mechanism is complementary to Argireline's SNAP-25 competitive inhibition, and that the combination produces additive expression-line reduction.
Primary uses
- Topical cosmetic anti-aging formulations (expression-line reduction)
Typical dosing
The concentrations in circulation come from the ingredient's supplier, and a seller's figure is not a source on this site; no study in the sources read sets one.
Educational information, not medical advice. The doses on this page come from approved labels, published studies and, where no study exists, amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
Regulatory status
Cosmetic ingredient; not a drug.
Status as of this entry's last review, October 4, 2026. Approvals, compounding rules and sport rules change; the regulatory tracker is checked more often.
What we checked
Leuphasyl is indexed on PubMed under its INCI name, pentapeptide-18, but only in laboratory and formulation work; there is no human trial. This section records what can be checked.
Identity, computed
| Sequence | Tyr-Ala-Gly-Phe-Leu (Tyr-D-Ala-Gly-Phe-Leu) |
| Formula | C29H39N5O7 |
| Average mass | 569.66 g/mol |
| Monoisotopic mass | 569.2849 Da |
| Isoelectric point | 6.09 (net charge -0.02 at pH 7) |
PubChem record 10099522 lists Leuphasyl as this D-alanine-containing pentapeptide, formula C29H39N5O7 at 569.6 g/mol, which the calculator reproduces. An earlier version of this entry gave C30H41N5O7 and 583.68; both were corrected on October 4, 2026. The sequence is leucine-enkephalin with D-alanine in place of glycine at position 2.
Regulatory status, read October 5, 2026
Drugs@FDA: 0 records for “leuphasyl”. EMA medicines list: 0 records for “leuphasyl”. Run for semaglutide, the same queries return 6 and 5 records (and the registry search 84 trials), so a zero here is an absence, not a broken search. Not named on the WADA 2026 and 2027 Prohibited Lists. As a substance with no current approval for human therapeutic use, it falls under section S0 (non-approved substances), which is prohibited at all times; the lists were read on September 27, 2026.
What the maker or sellers claim
Claim, from its supplier: Leuphasyl softens expression lines by acting on enkephalin receptors to quiet nerve signalling, and works best with Argireline. No published human trial tests either claim.
What the searches turned up
The three papers in the study cards below are cell, spectroscopy or modelling work. A fourth 2026 paper from the same group modelled Leuphasyl and the venom-derived pentapeptide Vialox against cancer targets and tested both on cancer cells in culture (Akhan et al., 2026). None of the four tested an effect on wrinkles in people.
What we looked for and did not find
No human study, no animal study and no registry record. As a cosmetic ingredient it needs no FDA approval in the US; cosmetics are not reviewed for effectiveness before sale.
| Source | Query | Results, October 5, 2026 | What it was |
|---|---|---|---|
| PubMed | pentapeptide-18 | 4 | modelling and formulation studies |
| PubMed | leuphasyl | 3 | |
| ClinicalTrials.gov | pentapeptide-18 | 0 | |
| Drugs@FDA (openFDA) | leuphasyl | 0 | |
| EMA medicines list | leuphasyl | 0 |
What the studies show
Leuphasyl is the cosmetic ingredient pentapeptide-18. Its published work is laboratory and computational; no clinical trial of it is in PubMed, and a manufacturer's figures are not treated as evidence here.
Analysis · 2026
Structure and modelling
Spectroscopic characterisation and molecular modelling of pentapeptide-18, with predicted interactions with skin-ageing signalling pathways (MAPK, PI3K/AKT, NF-κB) and computed absorption and toxicity properties.
In Vitro · 2026
With Vialox, in skin cells
An in silico and laboratory study of Leuphasyl and Vialox reported no toxicity to HaCaT skin cells at concentrations up to 1 mg/mL; the authors present both as possible anti-ageing ingredients.
In Vitro · 2024
A delivery formulation
Solid lipid nanoparticles carrying retinol and pentapeptide-18 were optimised and characterised (particle size about 135 nm, stable over four weeks at 25 °C) as a cosmetic raw material.
References
- [pubmed] Akhan D, et al. "Pentapeptide-18 as an anti-aging candidate: Spectroscopic characterization and molecular interaction analysis." Comput Biol Chem, 2026;123:108952. PMID: 41722287.
- [pubmed] Akhan D, et al. "Integrative In Silico and In Vitro Evaluation of Vialox and Leuphasyl Pentapeptides for Antiaging Applications." Chem Biodivers, 2026;23(5):e02546. PMID: 42116636.
- [pubmed] Pawłowska M, et al. "Solid Lipid Nanoparticles Incorporated with Retinol and Pentapeptide-18-Optimization, Characterization, and Cosmetic Application." Int J Mol Sci, 2024;25(18). PMID: 39337562.
- [pubmed] Akhan D, et al. "In Vitro and In Silico Assessment of Anticancer Activity of Venom-Derived and Biomimetic Neurotransmitter Inhibitor Pentapeptides." Cell Biochem Biophys, 2026;84(3):3909-3950. PMID: 42412310.
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This entry is for educational purposes only and does not constitute medical advice. Dosing information reflects published regulatory or research data and is not a recommendation. Many compounds described here are not approved for human use in the United States. Consult a licensed medical professional before considering any peptide therapy.