Melanotan II vs MK-677 (Ibutamoren)
A detailed comparison to help you understand the differences and choose the right peptide for your research goals.
Melanotan II
Melanotan II is a synthetic peptide analog of α-MSH with broader receptor activity than Melanotan I. It produces tanning effects and has notable effects on sexual function and appetite suppression.
Full details →MK-677 (Ibutamoren)
MK-677, also known as Ibutamoren, is an orally active growth hormone secretagogue. Unlike peptides, it can be taken orally and has a long half-life, providing 24-hour GH elevation.
Full details →Side-by-Side Comparison
| Aspect | Melanotan II | MK-677 (Ibutamoren) |
|---|---|---|
| Dose Range | 250 mcg–1 mg | 10 mg–25 mg |
| Frequency | 1x daily | 1x daily |
| Cycle Length | 1–2 weeks | 8–24 weeks |
| Route | subcutaneous | oral |
| Mechanism | Non-selective melanocortin receptor agonist affecting MC1R (tanning), MC3R and MC4R (sexual function and appetite). This broader activity explains its multiple effects beyond tanning. | Acts as a potent, selective agonist of the ghrelin receptor (GHS-R1a). Increases GH and IGF-1 levels without affecting cortisol. Mimics ghrelin's GH-releasing effects. |
| Typical Dosage | Typical protocols: 0.25-0.5mg daily during loading phase for 1-2 weeks, then 0.5-1mg before UV exposure for maintenance. Start low to assess tolerance. | Typical dosing: 10-25mg taken orally once daily. Often taken at night due to sleep benefits and appetite increase. |
| Administration | Subcutaneous injection. Usually combined with UV exposure for tanning effects. Nasal spray formulations exist but have lower bioavailability. | Oral administration (capsule or liquid). Can be taken with or without food. Long half-life allows once-daily dosing. |
| Side Effects | Nausea (common initially), facial flushing, spontaneous erections, increased libido, appetite suppression, and mole darkening. | Increased appetite and water retention are most common. May cause lethargy, vivid dreams, and mild numbness. Can affect blood glucose and insulin sensitivity. |
| Best For |
What They Have in Common
Melanotan II, MK-677 (Ibutamoren) are both commonly used for:
Key Differences
Unique to Melanotan II:
Unique to MK-677 (Ibutamoren):
Which Has Stronger Evidence?
- Fat Loss: MK-677 (Ibutamoren) has stronger research support.
| Goal | Melanotan II | MK-677 (Ibutamoren) |
|---|---|---|
| Fat Loss | low | medium |
Key Studies
Melanotan II
- Melanotan II nasal spray: a possible risk factor for oral mucosal malignant melanoma?
International journal of oral and maxillofacial surgery, 2025
- Melanotan II User Experience: A Qualitative Study of Online Discussion Forums.
Dermatology (Basel, Switzerland), 2021
- Melanotan II, a melanocortin agonist, partially rescues the impaired thermogenic capacity of pituitary adenylate cyclase-activating polypeptide deficient mice.
Experimental physiology, 2021
MK-677 (Ibutamoren)
- Knowing the minimal detectable dose can facilitate the interpretation of a hair test result: II. Case example with ibutamoren (MK-677), a growth hormone secretagogue.
Clinica chimica acta; international journal of clinical chemistry, 2026
- Hepatotoxicity induced by MK-677.
BMJ case reports, 2025
- Investigating the P53-dependent anti-cancer effect of ibutamoren in human cancer cell lines.
Basic & clinical pharmacology & toxicology, 2025
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