Leuphasyl

INCI: Leuphasyl (Pentapeptide-18)
Category: Neuropeptide / Expression Line Active
Used in: Serums, eye creams, forehead and expression-line treatments
Typical Usage Level (Topical): 2%

What This Ingredient Does

Leuphasyl is a neuropeptide that works at the neuromuscular junction, the point where nerve signals trigger muscle contractions. It mimics enkephalin, an endogenous peptide that binds to opioid receptors at nerve endings and reduces the intensity of muscle contraction signals. The result is a partial, temporary relaxation of repetitive facial muscle activity that causes expression lines. Leuphasyl does not paralyse muscle function; it modulates signal intensity. It is specifically formulated to complement Argireline (Acetyl Hexapeptide-8), which uses a different receptor mechanism. Together, they address expression line formation from two separate pathways, producing a more complete effect than either alone.

Key Benefits

  • Reduces the intensity of facial muscle contractions that deepen expression lines

  • Works via enkephalin receptor modulation distinct from Argireline's SNARE-complex mechanism

  • Synergistic with Argireline for a combined neuropeptide approach to line relaxation

  • Non-invasive alternative to support areas prone to expression-driven lines

  • Well-tolerated; no downtime, no skin barrier disruption

Who It's Best For

  • Those with forehead lines, crow's feet, or frown lines driven by repetitive muscle movement

  • Users already using Argireline who want to enhance results through a complementary pathway

  • Those seeking a topical alternative to injectable treatments for expression lines

  • Not a replacement for medical-grade procedures; suitable as a maintenance or preventative approach

Clinical Note by Dr. Su

Leuphasyl on its own produces modest results. Its real value is as part of a neuropeptide combination paired with Argireline, it addresses the same problem through two different mechanisms, which is how you get a clinically meaningful effect from topical peptides. Look for products that contain both.

(These references explain the scientific context not proprietary product testing.)