Melanotan II (MT-II) is a synthetic, cyclic heptapeptide analogue of the naturally occurring α-melanocyte-stimulating hormone (α-MSH). It acts as a non-selective agonist of the body’s melanocortin receptors (primarily MC1R, MC3R, MC4R, and MC5R).
In scientific and preclinical research, MT-II is primarily studied for its potent influence on systemic pigmentation (melanogenesis) and its secondary effects on metabolic rate, appetite suppression, and sexual function.
Key Research Mechanisms & Benefits
1. Advanced Melanogenesis (Skin Pigmentation)
By binding directly to MC1R receptors on melanocytes, Melanotan II stimulates the production of eumelanin (the dark brown-to-black pigment responsible for skin color) rather than pheomelanin (yellow-to-red pigment).
UV-Independent Pigmentation: Research indicates it induces skin darkening even in the absence of direct ultraviolet radiation, though the process accelerates when paired with minimal UV exposure.
Photoprotective Studies: Because eumelanin physically scatters UV light and scavenges free radicals, MT-II is widely investigated for its potential to protect fair-skinned or phototype-vulnerable subjects from sunburn and UV-induced DNA damage.
2. Appetite Suppression and Metabolic Shifts
By interacting with MC4R receptors in the central nervous system, MT-II mimics the body’s natural satiety pathways. In animal models, this results in significant acute appetite suppression and an upregulation of lipid metabolism, aiding in fat tissue loss.
3. Modulation of Sexual Function
Activation of central melanocortin pathways (specifically MC3R and MC4R) has been shown to induce erectile responses and increase libido through mechanisms entirely independent of the vascular nitric oxide system.
Theoretical Dosing Protocols (Research Use Only)
Important Regulatory & Safety Disclaimer: Melanotan II is an experimental research compound. It is not approved for human consumption, diagnostic procedures, or therapeutic use by the FDA, SAHPRA, or any international regulatory authorities. This profile is compiled strictly for educational and laboratory research purposes.
Melanotan II possesses high systemic bioavailability and is typically administered via subcutaneous (SQ) injection into adipose tissue using a standard insulin syringe.
Protocols in literature are strictly divided into two phases to prevent sudden hyper-pigmentation or extreme side effects:
Phase 1: The Loading Phase (Acclimatization & Pigment Building)
The goal of the loading phase is to gradually introduce the peptide to build tolerance and steadily upregulate melanin production.
Standard Daily Dosage: 100 mcg to 250 mcg once per day.
Protocol Practice: Researchers frequently start at a micro-dose of 50 mcg to 100 mcg on Days 1–3 to evaluate systemic sensitivity before adjusting upward toward a standard 250 mcg dose.
Duration: Run daily for 7 to 14 days, or until the target pigment density is achieved.
Phase 2: The Maintenance Phase (Color Preservation)
Once the desired pigmentation level is achieved, daily administration ceases to avoid progressive over-darkening.
Standard Weekly Dosage: 500 mcg to 1,000 mcg (1 mg) total per week.
Frequency: Split evenly into 1 to 2 injections per week (e.g., 250 mcg to 500 mcg per injection).
Reconstitution Math & Syringe Calibration
Melanotan II is highly stable in its lyophilized (freeze-dried) state but breaks down quickly once liquid is introduced. It is typically distributed in 10 mg vials.
Reconstitution Formula
Adding 2 mL of Sterile Bacteriostatic Water to a 10 mg vial creates a concentration of 5 mg per 1 mL. On a standard U-100 insulin syringe, the breakdown correlates as follows:
10 Units (0.1 mL) = 500 mcg
5 Units (0.05 mL) = 250 mcg
2 Units (0.02 mL) = 100 mcg
Storage and Handling
Mixing: Slowly trickle the bacteriostatic water down the internal glass wall of the vial. Do not shake or agitate the vial aggressively to avoid fracturing the peptide structure.
Temperature: Keep unmixed vials frozen at -20°C. Once reconstituted, store exclusively in a dark refrigerator at 2°C to 8°C and utilize within 30 days.
Documented Side Effects & Considerations
Due to its non-selective binding across multiple melanocortin receptors, MT-II exhibits several acute side effects that researchers must carefully monitor:
Nausea & Appetite Loss: Mild to severe acute nausea frequently occurs within 20–30 minutes post-injection (often mitigated by administering the dose immediately before sleep).
Flushing & Spontaneous Yawning: Temporary facial flushing, increased heart rate, and involuntary stretching/yawning are common due to central nervous system activation.
Hyperpigmentation & Mole Darkening: Existing moles, freckles, and scar tissue will darken significantly faster than surrounding skin. New micro-hyperpigmentation spots (“melanotan freckles”) can temporarily appear.
Priapism: Prolonged or unwanted erections can occur, especially if loading doses exceed recommended thresholds.