What is Leuphasyl?
Leuphasyl is a synthetic pentapeptide (Tyr-D-Ala-Gly-Phe-Leu) developed by Lipotec (now part of Lubrizol). Its sequence is structurally related to enkephalin, an endogenous neuropeptide that acts on opioid receptors. The palmitoylated commercial form improves stratum corneum penetration.
Important: Leuphasyl is a cosmetic ingredient, not a pharmaceutical. The information on this page is offered for educational and cosmetic formulation reference purposes. It is not medical advice.
Proposed mechanism of action
Leuphasyl targets opioid receptors at the presynaptic membrane of sensory neurons in the dermis. By activating these receptors, it is proposed to:
- Reduce intracellular cAMP levels in nerve terminals
- Decrease calcium influx at the presynaptic membrane
- Lower the probability of neurotransmitter vesicle release
This upstream neuronal modulation complements the downstream SNARE-complex inhibition produced by Argireline. Together, they target the neuromuscular-contraction cascade at two different points, which is the rationale for combining them in the same formulation.
What the research says
Available evidence is predominantly from in-vitro cell models and industry-sponsored studies. Lipotec’s published data reports a ~26% reduction in wrinkle depth when Leuphasyl (4%) is combined with Argireline (5%) versus baseline, compared to ~16% for Argireline alone. Independent replication in peer-reviewed journals with large sample sizes is limited.
The opioid-receptor mechanism is biologically plausible given the structural analogy to enkephalin, but receptor selectivity and actual skin-tissue concentrations at achievable topical doses have not been fully characterized.
Typical use in formulations
- Concentration range: 3–5% in finished product
- Optimal pH: 5.0–6.5
- Solubility: Water-soluble; supplied as an aqueous solution by most ingredient suppliers
- Target area: Dynamic expression lines, particularly forehead and periorbital regions
- Incompatibilities: No widely documented incompatibilities; avoid aggressive acidic or basic environments outside formulation pH range.
- Synergies: The combination with Argireline (5% + 5%) is the most-studied pairing. Adding SNAP-8 creates a triple-action “neurocosmetic” targeting three points in the muscle-contraction pathway.
Cosmetic vs. pharmaceutical context
Leuphasyl is listed in the EU CosIng database and accepted by major cosmetic regulatory frameworks as a cosmetic ingredient. Claims must reference appearance outcomes (expression line depth, skin texture) rather than pharmacological actions (nerve inhibition, muscle relaxation). The opioid-receptor mechanism is a proposed mode of action for formulator education, not a claim for product labeling.
Reported protocol (research reference)
| Reported dose | Typically used at 3–5% concentration in topical formulations, most effectively in combination with Argireline at comparable concentrations. |
|---|---|
| FDA status | Not FDA approved |