Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.
| Melanotan II | TB-500 (Thymosin Beta-4) | |
|---|---|---|
| Category | Peptides | Peptides |
| Standard Dose | Research indicates 250-500 mcg daily via subcutaneous injection during loading, reducing to 250 mcg 2-3 times weekly for maintenance. | Research indicates 2-2.5 mg administered twice weekly via subcutaneous injection. |
| Timing | Administer 4-6 hours before UV exposure for optimal tanning synergy. Can be taken at any time of day. | No strict timing requirements. Can be administered at any time of day. Systemic action means injection location is not critical. |
| Cycle Duration | Loading phase 1-2 weeks, then maintenance as long as desired. Pigmentation fades gradually upon discontinuation. | Loading phase: 4-6 weeks. Total cycle: 8-16 weeks. |
| Evidence Level | moderate_human | animal_plus_anecdotal |
Melanotan II is a synthetic cyclic analog of alpha-melanocyte-stimulating hormone (alpha-MSH) that non-selectively agonizes melanocortin receptors MC1, MC3, MC4, and MC5. MC1R activation stimulates eumelanin synthesis through tyrosinase upregulation, producing tanning. MC3R activation in the CNS increases libido and produces erectile responses. MC4R activation suppresses appetite. The cyclic structure provides enhanced in vivo stability (half-life 1-2 hours) and increased blood-brain barrier permeability compared to linear alpha-MSH.
Research indicates 250-500 mcg daily via subcutaneous injection during loading, reducing to 250 mcg 2-3 times weekly for maintenance.
Administer 4-6 hours before UV exposure for optimal tanning synergy. Can be taken at any time of day.
Loading phase 1-2 weeks, then maintenance as long as desired. Pigmentation fades gradually upon discontinuation.
TB-500 is a synthetic fragment of Thymosin Beta-4, a 43-amino acid protein that sequesters G-actin monomers, preventing premature polymerization and facilitating cellular migration and morphological changes essential for wound healing. It upregulates actin to promote cell migration, proliferation, and differentiation of stem/progenitor cells at injury sites. TB-500 also enhances angiogenesis, reduces inflammation, and promotes tissue remodeling through increased re-epithelialization and vascular density.
Research indicates 2-2.5 mg administered twice weekly via subcutaneous injection.
No strict timing requirements. Can be administered at any time of day. Systemic action means injection location is not critical.
Loading phase: 4-6 weeks. Total cycle: 8-16 weeks.
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