Acetyl Hexapeptide-3 (Argireline) vs Melanotan-2
SNARE complex inhibitor that reduces expression wrinkles through topical neuromuscular modulation — the 'Botox in a bottle' peptide.
A synthetic copy of the hormone that switches on tanning. Small human trials found it darkened skin without sun exposure and triggered erections in men with erectile dysfunction. It has never been approved by any regulator.
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Quick comparison
Dose range
Acetyl Hexapeptide-3 (Argireline)
5–10 %
Melanotan-2
0.5–0.5 mg
Frequency
Acetyl Hexapeptide-3 (Argireline)
Once daily
Melanotan-2
Once daily
Administration
Acetyl Hexapeptide-3 (Argireline)
Topical
Melanotan-2
Subcutaneous injection
Cycle length
Acetyl Hexapeptide-3 (Argireline)
Ongoing/indefinite
Melanotan-2
4-6 weeks
Onset speed
Acetyl Hexapeptide-3 (Argireline)
Moderate (1-2 weeks)
Melanotan-2
Moderate (1-2 weeks)
Evidence level
Acetyl Hexapeptide-3 (Argireline)
Limited human trials
Melanotan-2
Limited human trials
Benefit ratings
Expression Wrinkle Reduction
Non-Invasive Treatment
Safety Profile
Tanning Efficacy
Sexual Function
Tan Longevity
Compound specifications
Acetyl Hexapeptide-3 (Argireline)
Molecular formula
C35H62N14O11S
Molecular weight
887.0 Da
Half-life
Topical stability dependent on formulation; methionine residue susceptible to oxidation; stable at pH 5.5-7.7
Bioavailability
Limited skin penetration (0.22-0.54%); primarily acts at stratum corneum and superficial epidermis; O/W emulsions enhance delivery
CAS number
616204-22-9
Melanotan-2
Molecular formula
C50H69N15O9
Molecular weight
1024.18 g/mol
Half-life
No human value published. In mice, plasma clearance after injection was rapid; no human pharmacokinetic study located.
Bioavailability
Completely absorbed by subcutaneous injection in humans for the related peptide melanotan-I; not separately measured for melanotan-II in humans
CAS number
121062-08-6
Dosing compared
Acetyl Hexapeptide-3 (Argireline)
Topical
5-10% concentration (cream or serum)
Twice daily (morning and evening) · Minimum 28-30 days; ongoing use to maintain effect
Used as a leave-on skin cream or serum. In studies, a 10% formula applied twice a day around the eyes reduced wrinkle depth by about 17% after 15 days and up to 27-30% after 30 days. It works on the skin surface only and is not injected. [1][2]
Melanotan-2
Subcutaneous
0.25 mg (250 mcg)
Once daily · First 3-5 days (loading)
Community-reported starting dose, not peer-reviewed. No clinical trial used a flat 0.25 mg dose. The published human trials dosed by body weight at 0.01-0.03 mg/kg subcutaneously in 3 healthy men [1]. Mild nausea was reported at most dose levels in that trial, which is what starting low is commonly described as managing [1].
0.5 mg (500 mcg)
Once daily · Continue loading 7-14 days until desired pigmentation
Community-reported loading dose, not peer-reviewed. The dose used in every published human trial was 0.025 mg/kg subcutaneously, about 1.75 mg for a 70 kg adult, given to 3 healthy men [1] and to 20 men with erectile dysfunction [4][6][7]. Subcutaneous is the only route with human trial evidence [1]. In the phase-I trial, 0.03 mg/kg produced grade II drowsiness and fatigue in 1 of 2 men who reached that dose, which is why 0.025 mg/kg was the dose carried forward [1].
0.5 mg (500 mcg)
2-3 times per week · Ongoing maintenance
Community-reported maintenance schedule, not peer-reviewed. No published trial tested a maintenance phase; the longest published human dosing was 10 subcutaneous doses over 2 weeks in 3 healthy men [1]. A systemic-toxicity case followed a 6 mg self-injection, roughly three times the 0.025 mg/kg dose used in trials [9].
Best suited for
Acetyl Hexapeptide-3 (Argireline)
Individuals seeking non-invasive reduction of expression lines and dynamic wrinkles
Acetyl Hexapeptide-3 (Argireline) is particularly well-suited for individuals focused on individuals seeking non-invasive reduction of expression lines and dynamic wrinkles. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach [1][4].
Those with needle phobia who want botulinum toxin-like effects without injections
Acetyl Hexapeptide-3 (Argireline) is particularly well-suited for individuals focused on those with needle phobia who want botulinum toxin-like effects without injections. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach [4].
People targeting crow's feet, forehead lines, and glabellar creases
Acetyl Hexapeptide-3 (Argireline) is particularly well-suited for individuals focused on people targeting crow's feet, forehead lines, and glabellar creases. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Individuals looking for preventive anti-wrinkle treatment to slow expression line formation
Acetyl Hexapeptide-3 (Argireline) is particularly well-suited for individuals focused on individuals looking for preventive anti-wrinkle treatment to slow expression line formation. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Melanotan-2
Fair-Skinned Individuals Who Struggle to Tan
If you're the type who burns before you bronze, MT-2 can be a game-changer. It works by telling your skin cells to produce more melanin—the pigment that creates a tan. [13][17] People who normally can't tan often see the most dramatic results.
Those Wanting to Reduce Sun Exposure
MT-2 means you need far less UV exposure to develop and maintain a tan. A few minutes of sun or a brief tanning bed session goes much further. This could potentially reduce your cumulative UV damage over time.
Year-Round Tan Maintenance
Unlike a natural tan that fades quickly, MT-2 tans last longer and can be maintained year-round with minimal upkeep. Many users find they can keep their summer color through winter with just weekly maintenance doses.
Those Experiencing Low Libido
MT-2 has significant effects on sexual arousal and function in both men and women. [18][13] While PT-141 is more targeted for this purpose, [10] some users appreciate getting tanning and libido benefits from one peptide.
Side effects
Acetyl Hexapeptide-3 (Argireline)
Common
- Mild Skin Irritation
- Transient Redness
- Slight Dryness
- Stinging on Compromised Skin
Uncommon
- Contact Dermatitis
Serious
- Allergic Contact Dermatitis
Melanotan-2
Common
- Facial flushing
- Nausea
- Darkening of moles and freckles
- Spontaneous erections (men)
- Drowsiness and fatigue
Uncommon
- New mole formation
- Headaches
Serious
- Priapism (prolonged erection)
- Concerning mole changes
Safety & evidence
Acetyl Hexapeptide-3 (Argireline)
Evidence level
Limited human trials
FDA status
Research compound
Safety overview
Acetyl Hexapeptide-3 demonstrates an excellent safety profile for topical cosmetic use with no serious adverse events reported in clinical studies. At the 10% concentrations used in cosmetic formulations, systemic absorption is minimal and no neurotoxicity has been observed despite its mechanism of action on the neuromuscular junction. In cell-culture testing, significant cytotoxicity appeared only at concentrations 18 to 10,000 times higher than the reference drug doxorubicin [5]. Primary concerns are limited to local skin irritation in sensitive individuals, such as mild erythema, transient stinging, or contact dermatitis in those with peptide hypersensitivity.
Contraindications
- Known hypersensitivity to acetyl hexapeptide-3 or formulation components
- Active skin infections or open wounds at the application site
- No known systemic contraindications at cosmetic concentrations
- Use with caution in individuals with neuromuscular disorders (theoretical concern)
Melanotan-2
Evidence level
Limited human trials
FDA status
Not FDA approved
Safety overview
Human safety data for melanotan-2 comes from small trials totalling about 23 men, plus a handful of published case reports. In the phase-I study of 3 healthy men, mild nausea was reported at most dose levels, and the 0.03 mg/kg dose caused grade II drowsiness and fatigue in 1 of the 2 men who reached it — which is why 0.025 mg/kg was the dose carried forward [1]. Across 20 men with erectile dysfunction given 0.025 mg/kg, severe nausea occurred in about 1 in 8 (12.9%) [4]. In the psychogenic erectile-dysfunction trial, nausea, stretching and yawning, and reduced appetite were each more common on melanotan-2 than on placebo, though none required treatment [6]. Beyond the trials, single case reports describe rhabdomyolysis (muscle breakdown that can injure the kidneys) after a 6 mg injection [9], ischaemic priapism needing surgery [10], melanoma in a 20-year-old woman who used it alongside sunbeds [8], and mucosal melanoma in a 22-year-old woman who used a nasal spray version [11]. A case report shows that something happened in one person; it cannot show how often it happens.
Contraindications
- History of melanoma or skin cancer
- Family history of melanoma
- Large number of atypical moles
- Pregnancy or breastfeeding
- Severe cardiovascular disease
Which is right for you?
Choose Acetyl Hexapeptide-3 (Argireline) if...
- Individuals seeking non-invasive reduction of expression lines and dynamic wrinkles
- Those with needle phobia who want botulinum toxin-like effects without injections
- People targeting crow's feet, forehead lines, and glabellar creases
- Individuals looking for preventive anti-wrinkle treatment to slow expression line formation
Choose Melanotan-2 if...
- Achieving a natural-looking tan
- Reducing sun exposure time
- Enhancing libido and sexual function
- Appetite suppression