Skip to content
preclinicalSkin & Cosmetic

Leuphasyl

Also known as: Pentapeptide-18, Tyr-D-Ala-Gly-Phe-Leu, Enkephalin Mimetic Pentapeptide, YAGFL

Leuphasyl is a synthetic pentapeptide that mimics the activity of enkephalins, the body's natural opioid neuropeptides. It binds to enkephalin receptors on nerve cells to reduce the release of acetylcholine at the neuromuscular junction, thereby decreasing muscle contraction intensity and smoothing expression lines. It is frequently combined with Argireline for synergistic anti-wrinkle effects, as the two peptides inhibit neurotransmitter release through complementary upstream mechanisms.

3 cited references·4 researched benefits

Quick Answer

Leuphasyl (Pentapeptide-18) is a synthetic pentapeptide that mimics endogenous enkephalins to reduce expression wrinkles. By binding to enkephalin receptors on motor neurons, it inhibits calcium influx and reduces acetylcholine release, decreasing muscle contraction intensity. Studies suggest it enhances Argireline efficacy by up to 25% when used in combination. It targets the upstream signaling cascade rather than the SNARE complex directly.

Key Facts

Mechanism
Leuphasyl mimics the sequence of met-enkephalin (Tyr-Gly-Gly-Phe-Met) with a D-alanine substitution at position 2 for improved stability. It binds to opioid/enkephalin receptors on the presynaptic motor neuron membrane. Receptor activation inhibits adenylate cyclase, reduces intracellular cAMP levels, and decreases calcium channel opening. With less calcium influx into the nerve terminal, fewer neurotransmitter vesicles fuse with the presynaptic membrane, resulting in reduced acetylcholine release. This indirectly diminishes muscle contraction at the neuromuscular junction. Because Leuphasyl acts upstream of Argireline (which targets the SNARE complex), combining both peptides produces additive inhibition of the neuromuscular signaling cascade.
Research Status
preclinical
Half-Life
N/A (topical cosmeceutical — not systemically absorbed)
Molecular Formula
C₂₈H₃₇N₅O₇
Primary Use
Skin & Cosmetic
Table of Contents

Benefits

  • Reduces expression wrinkle depth through enkephalin receptor-mediated inhibition of neurotransmitter releasepreliminary
  • Synergistic wrinkle reduction when combined with Argireline — studies suggest up to 25% enhanced efficacy versus Argireline alonepreliminary
  • Acts through a unique upstream mechanism (cAMP/calcium pathway) not shared by other cosmetic peptidespreliminary
  • Excellent safety profile with no reports of irritation or sensitization at cosmetic concentrationsmoderate

Dosage Protocols

RouteDosage RangeFrequencyNotes
Topical serum2–5% Leuphasyl solution2x dailyApply to clean skin before moisturizer, focusing on expression wrinkle areas (forehead, crow's feet, glabella). Most effective when layered with or combined in a formula alongside Argireline for dual-mechanism wrinkle reduction.
Topical cream (combination formula)2–5% Leuphasyl with 5–10% Argireline2x daily (morning and evening)The Leuphasyl + Argireline combination targets two distinct steps in the neuromuscular signaling cascade. Apply consistently for 4–8 weeks before evaluating efficacy.

Medical disclaimer

Dosage information is provided for educational reference only. Always follow your prescriber's instructions and consult a qualified healthcare provider before starting any peptide protocol.

Side Effects

  • Mild transient skin tingling at the application siterare
  • No significant irritation or sensitization reported in patch testing at cosmetic concentrationsrare
  • No systemic opioid effects at topical cosmetic concentrations due to minimal absorptionrare

Frequently Asked Questions

How does Leuphasyl work with Argireline?
Leuphasyl and Argireline target different steps of the same neuromuscular signaling pathway. Leuphasyl acts upstream by binding enkephalin receptors, reducing calcium influx, and decreasing the amount of acetylcholine released. Argireline acts downstream by inhibiting the SNARE complex that enables vesicle fusion. Together, they create a more complete blockade of neurotransmitter release than either peptide alone, producing enhanced wrinkle reduction.
Is Leuphasyl an opioid? Will it cause opioid effects?
While Leuphasyl mimics the enkephalin peptide structure and binds to enkephalin receptors, it is applied topically at very low concentrations and is not systemically absorbed. There are no reports of opioid-like effects (sedation, analgesia, dependence) from topical cosmetic use. The peptide acts locally on nerve terminals near the skin surface and does not reach the central nervous system.
Is Leuphasyl effective on its own, or only in combination?
Leuphasyl has independent muscle-relaxing activity, but available data suggests its effects are more modest when used alone compared to combination with Argireline. Most commercial formulations include Leuphasyl as a synergistic booster rather than a standalone active. If using a single anti-wrinkle peptide, Argireline or Syn-Ake typically offer more pronounced results than Leuphasyl alone.

References

  1. 1
    Pentapeptide-18 (Leuphasyl): an enkephalin-mimetic peptide for expression wrinkle reduction in cosmeceutical applications(2010)
  2. 2
    Synergistic anti-wrinkle effects of Pentapeptide-18 and Acetyl Hexapeptide-8 in a combination topical formulation(2012)
  3. 3
    A comprehensive review of peptides in cosmeceuticals: from science to consumer applications(2020)PubMed ↗

Latest Research

Last updated: 2026-02-19