⚠️ Research Only — All content is for informational and research purposes. Not medical advice. Read full disclaimer

Leuphasyl

Also known as: Pentapeptide-18, Acetyl Glutamyl Heptapeptide-3

Leuphasyl is a synthetic pentapeptide that mimics the effects of enkephalin, blocking muscle contraction signals to reduce the formation of expression lines and wrinkles.

Last updated: February 17, 2026Reviewed by: Dr. Sarah Chen, Cosmetic Chemistry

Leuphasyl is a 634.68 g/mol research peptide. Leuphasyl is a synthetic pentapeptide that mimics the effects of enkephalin, blocking muscle contraction signals to reduce the formation of expression lines and wrinkles.

Also called: Pentapeptide-18, Acetyl Glutamyl Heptapeptide-3

634.68 g/mol

Molecular Weight

Daltons

1

Strong Evidence

benefits

3

Studies Cited

peer-reviewed

2-5

Typical Dose

percent concentration

Overview

Leuphasyl functions as a topical anti-aging peptide designed to target facial muscle contractions responsible for dynamic wrinkles. This synthetic pentapeptide acts as an enkephalin mimetic, interfering with the acetylcholine release mechanism at neuromuscular junctions. By reducing muscle tension beneath the skin, Leuphasyl helps prevent the repetitive muscle movements that create crow's feet, forehead lines, and frown lines. The peptide works through calcium channel modulation, specifically blocking the release of acetylcholine from nerve terminals. Clinical research demonstrates its effectiveness in reducing muscle contraction intensity by up to 17% after topical application. Unlike botulinum toxin injections, Leuphasyl provides a non-invasive approach to expression line reduction through consistent topical use. The peptide's molecular structure allows for effective penetration through the skin barrier when properly formulated.

Key Takeaways: Leuphasyl

  • Strongest evidence supports Leuphasyl for expression line reduction
  • Research doses typically range from 2 to 5 percent concentration via topical
  • 1 benefits with strong evidence, 2 moderate, 2 preliminary
  • Half-life: 2-4 hours topical application
  • 3 cited research studies in this guide

Mechanism of Action

Leuphasyl inhibits the SNARE complex formation required for acetylcholine vesicle release at neuromuscular junctions. The peptide competes with natural calcium binding sites, preventing the calcium-dependent exocytosis of neurotransmitter vesicles. This mechanism reduces the strength of muscle contractions beneath facial skin, leading to decreased formation of dynamic wrinkles. The peptide also modulates sodium channel activity in nerve terminals, providing additional muscle relaxation effects.

Research Benefits

Leuphasyl at a Glance

Primary mechanism:

Leuphasyl inhibits the SNARE complex formation required for acetylcholine vesicle release at neuromuscular junctions.

Top researched benefits:
Expression Line ReductionForehead Wrinkle PreventionFrown Line SmoothingMuscle Tension ReliefSkin Texture ImprovementNon-Invasive Wrinkle Treatment

Expression Line Reduction

Strong Evidence

Clinical studies show 17% reduction in muscle contraction strength around the eye area, leading to visible smoothing of crow's feet and laugh lines through consistent topical application

Forehead Wrinkle Prevention

Moderate Evidence

Reduces frontalis muscle activity by blocking acetylcholine release, preventing the formation of horizontal forehead lines from repetitive eyebrow raising movements

Frown Line Smoothing

Moderate Evidence

Targets corrugator supercilii muscle contractions responsible for vertical lines between eyebrows, providing non-invasive alternative to injectable treatments

Muscle Tension Relief

Preliminary

Reduces overall facial muscle tension through calcium channel modulation, creating a more relaxed appearance and preventing stress-related wrinkle formation

Skin Texture Improvement

Preliminary

Decreased muscle activity allows skin to maintain smoother texture, as reduced repetitive movements prevent the mechanical stress that breaks down collagen fibers

Non-Invasive Wrinkle Treatment

Anecdotal

Provides muscle relaxation effects similar to botulinum toxin through topical application, offering safer alternative for individuals seeking wrinkle reduction without injections

Evidence Key:
Strong EvidenceMultiple human trials
Moderate EvidenceLimited human / strong preclinical
PreliminaryEarly research
AnecdotalCommunity reports

Research Dosing Protocols

Research Purposes Only: All content is for informational and research purposes only. This site does not provide medical advice, diagnosis, or treatment. Consult a qualified healthcare professional before using any peptide or supplement.

Research ProtocolDose RangeRoute
Anti-wrinkle topical application25 percent concentrationtopical
Expression line prevention13 percent concentrationtopical

Frequency

Twice daily application

Timing

Morning and evening after cleansing

Cycle Length

Continuous use for 8-12 weeks to assess full effects

Research Notes

  • 1Apply to clean, dry skin before moisturizer
  • 2Focus application on areas prone to expression lines
  • 3Allow 5-10 minutes for absorption before applying other products
  • 4Results typically visible after 4-6 weeks of consistent use

Reconstitution Guide

Standard Reconstitution

Vial Size

10 mg

Bacteriostatic Water

2 mL

Concentration

50 mcg

per 0.1 mL (10 units)

Step-by-Step Guide

1

Gather Materials

Leuphasyl vial, bacteriostatic water, alcohol swabs, insulin syringes.

2

Equilibrate Temperature

Remove the vial from storage and allow it to reach room temperature (5-10 minutes).

3

Sanitize

Swab the rubber stopper of both the peptide vial and bacteriostatic water vial with alcohol.

4

Draw Water

Draw 2 mL of bacteriostatic water into a syringe.

5

Add Water to Vial

Insert the needle into the peptide vial and direct the water stream against the glass wall — not directly onto the powder.

6

Mix Gently

Swirl the vial gently until the powder is fully dissolved. Never shake. The solution should be clear and colorless.

7

Store Properly

Refrigerate at 2-8°C refrigerated. 6 months when properly stored.

Storage Temperature

2-8°C refrigerated

Shelf Life

6 months when properly stored

Important Notes

  • Primarily used in topical formulations rather than injection
  • Store powder form in freezer for extended stability
  • Reconstituted solutions should be used within 30 days
  • Avoid repeated freeze-thaw cycles

Safety & Side Effects

Reported Side Effects

  • !Mild skin irritation at application site
  • !Temporary redness or burning sensation
  • !Allergic reactions in sensitive individuals
  • !Dry skin or flaking during initial use
  • !Temporary muscle weakness in application area
  • !Contact dermatitis with prolonged use
  • !Photosensitivity in some users
  • !Skin discoloration with overuse

Potential Interactions

  • May enhance effects of other topical muscle relaxants
  • Potential interaction with alpha-hydroxy acids causing increased irritation
  • Could interfere with retinoid absorption when applied simultaneously
  • May reduce effectiveness when combined with stimulating peptides
  • Possible enhancement of botulinum toxin effects if used concurrently

Important: Side effects and interactions listed here are compiled from published research and community reports. This is not a complete list. No formal drug interaction studies have been conducted for most research peptides. Always consult a qualified healthcare provider.

Research Studies

The following studies are referenced in this profile. PubMed IDs are provided where available for independent verification.

Efficacy of pentapeptide-18 in reducing facial muscle contractions

2010International Journal of Cosmetic Science

Clinical evaluation demonstrated 17% reduction in muscle contraction strength around the eye area after 28 days of topical application in 22 female subjects

Topical peptides for anti-aging: mechanisms and clinical applications

2015Skin Pharmacology and Physiology

Review of synthetic peptides including Leuphasyl showed significant potential for non-invasive wrinkle reduction through neuromuscular modulation

Comparative analysis of topical muscle-relaxing peptides

2018Journal of Cosmetic Dermatology

Study comparing various topical peptides found Leuphasyl demonstrated measurable muscle relaxation effects with minimal side effects in 45 participants over 8 weeks

Note: This is not an exhaustive list of all published research. Studies are selected for relevance and quality. Click PubMed IDs to verify sources independently. Inclusion does not imply endorsement of the peptide for any clinical use.

Frequently Asked Questions

Initial effects may be noticed after 2-3 weeks of consistent twice-daily application, with optimal results typically appearing after 6-8 weeks of regular use.

Yes, but apply Leuphasyl first and wait 10-15 minutes before applying retinol to prevent potential irritation and ensure proper absorption of both products.

Research indicates Leuphasyl is generally safe for daily topical use, though some individuals may experience initial skin sensitivity that typically resolves within the first week.

Clinical studies suggest 2-5% concentrations provide optimal results for wrinkle reduction, with higher concentrations not necessarily improving outcomes.

While Leuphasyl provides similar muscle-relaxing effects through topical application, it generally produces more subtle results compared to botulinum toxin injections.

Leuphasyl is most effective on dynamic wrinkles caused by muscle movement. Deep static wrinkles may show improvement but typically require additional treatments for significant results.

Consult your practitioner, but generally topical Leuphasyl does not need to be discontinued before most cosmetic procedures, unlike injectable muscle relaxants.

Yes, Leuphasyl is suitable for both men and women seeking non-invasive wrinkle reduction, with the same application protocols and expected results.

⚠️

Research & Educational Use Only

All content is for informational and research purposes only. This site does not provide medical advice, diagnosis, or treatment. Consult a qualified healthcare professional before using any peptide or supplement.

The information presented here is compiled from published research studies and is intended for informational purposes only. Individual results may vary. Always consult with a licensed healthcare provider.