Melanotan-2 vs Snap-8
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.
An advanced 8-amino-acid peptide that relaxes facial muscles from the outside in—think of it as 'Botox in a bottle' that you apply to your skin to smooth expression lines without needles or injections.
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Quick comparison
Dose range
Melanotan-2
0.5–0.5 mg
Snap-8
10–10 %
Frequency
Melanotan-2
Once daily
Snap-8
Once daily
Administration
Melanotan-2
Subcutaneous injection
Snap-8
Topical application
Cycle length
Melanotan-2
4-6 weeks
Snap-8
Ongoing/indefinite
Onset speed
Melanotan-2
Moderate (1-2 weeks)
Snap-8
Moderate (1-2 weeks)
Evidence level
Melanotan-2
Limited human trials
Snap-8
Moderate human trials (Phase 1-2)
Benefit ratings
Tanning Efficacy
Sexual Function
Tan Longevity
Wrinkle Reduction
Muscle Relaxation
Skin Smoothing
Compound specifications
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
Snap-8
Molecular formula
C41H70N16O16S
Molecular weight
1075.16 g/mol
Half-life
Topical activity persists 12-24 hours on skin
Bioavailability
Penetrates stratum corneum; reaches viable epidermis with appropriate formulation
CAS number
868844-74-0
Dosing compared
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Community-reported starting dose, not peer-reviewed.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Community-reported loading dose, not peer-reviewed.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].
Snap-8
Topical
3-5% of supplied peptide solution in formulation
Once to twice daily · 4 weeks initial trial
Source class: manufacturer recommendation, not peer-reviewed clinical data. Lipotec/Lubrizol recommends 3-10% of supplied peptide solution in formulations [1][2]. No peer-reviewed study has tested any specific concentration of Snap-8 alone in a topical formulation.
10% of supplied peptide solution in formulation
Twice daily · Ongoing use
Source class: manufacturer recommendation, not peer-reviewed clinical data. Lipotec/Lubrizol recommends up to 10% concentration [1][2]. The wrinkle-reduction percentages attributed to this concentration (such as 63%) originate from manufacturer datasheets, not peer-reviewed publications, and have not been independently verified.
Best suited for
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.
Snap-8
Expression Line Fighters
If you've noticed those lines that form when you smile, frown, or squint are starting to stick around even when your face is relaxed, Snap-8 is designed exactly for this. It works on the muscle-skin connection that creates these dynamic wrinkles.
Botox-Curious but Needle-Shy
Love the idea of smoother skin but not ready for injections? Snap-8 offers a topical alternative that works through a similar mechanism as Botox—just gentler and without the commitment. Perfect for testing the waters of muscle-relaxing anti-aging.
Prevention-Focused Millennials
Starting in your late 20s or early 30s with preventive skincare? Snap-8 can help keep expression lines from becoming permanent fixtures by calming the repetitive muscle movements that eventually etch wrinkles into your skin.
Sensitive Skin Types
Unlike some anti-aging actives that can be harsh, Snap-8 is remarkably well-tolerated. If retinoids make your skin angry or acids cause irritation, peptides like Snap-8 offer effective anti-aging without the drama.
Side effects
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
Snap-8
Common
- Mild tingling sensation
- Temporary redness
- Skin dryness
Uncommon
- Contact irritation
- Skin tightness
Serious
- Allergic reaction
Safety & evidence
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
Snap-8
Evidence level
Moderate human trials (Phase 1-2)
FDA status
Not FDA approved
Safety overview
No peer-reviewed study has tested Snap-8 (acetyl octapeptide-3) alone for safety or efficacy. The compound has been included in two published multi-component microneedle patch studies, both of which combined it with several other active ingredients. Avcil et al. (2020) tested a hyaluronic acid microneedle patch loaded with acetyl octapeptide-3 plus palmitoyl tripeptide-5, adenosine, and seaweed extracts in a 12-week monocentric trial on the eye area. None of the subjects reported any primary or cumulative skin reactions [1]. Shin et al. (2024) tested a dissolving microneedle patch containing acetyl octapeptide-3, L-ascorbic acid 2-glucoside, and sodium cyclic lysophosphatidic acid in 24 subjects over 28 days (patch vs placebo on opposite eyes). No adverse effects were reported [2]. In both studies, multiple active ingredients were present — adverse effects cannot be attributed to or excluded from Snap-8 specifically. An FDA in vitro study of the related compound acetyl hexapeptide-8 (Argireline, 6 amino acids vs Snap-8's 8) found that the peptide remains mostly in the stratum corneum (0.22% of applied dose in human skin) with none reaching the dermis, supporting low systemic exposure for topical SNARE-interfering peptides [4].
Contraindications
- Known allergy to peptide ingredients
- Active skin infections at application site
- Open wounds or severe skin irritation
- Pregnancy (as a precaution due to limited data)
Which is right for you?
Choose Melanotan-2 if...
- Achieving a natural-looking tan
- Reducing sun exposure time
- Enhancing libido and sexual function
- Appetite suppression
Choose Snap-8 if...
- Wrinkle reduction
- Expression line smoothing
- Preventive anti-aging
- Non-invasive cosmetic enhancement