Source comparison
MT-1 vs MT-2: What the Naming Convention Actually Distinguishes
The distinction between MT-1 and MT-2 is structural. MT-1 is linear with a single lactam bridge, MT-2 is fully cyclized with a lactam bridge and additional disulfide bond. This cyclization grants MT-2 prolonged receptor occupancy (half-life approximately 2–3 h
This comparison does not assign a generated winner or score.
- The distinction between MT-1 and MT-2 is structural. MT-1 is linear with a single lactam bridge, MT-2 is fully cyclized with a lactam bridge and additional disulfide bond. This cyclization grants MT-2 prolonged receptor occupancy (half-life approximately 2–3 hours versus 30–40 minutes for MT-1) but eliminates receptor selectivity. MT-2 activates MC1R, MC3R, MC4R, and MC5R, producing melanogenesis alongside appetite suppression, increased libido, and thermogenic effects. MT-1's linear structure prevents it from fitting MC3R and MC4R binding pockets, preserving its role as a melanocyte-specific agonist.
- Research facilities studying isolated melanogenesis mechanisms. Without confounding appetite or metabolic variables. Select MT-1 over MT-2 to eliminate receptor cross-reactivity. A 2019 study in Pigment Cell & Melanoma Research used MT-1 exclusively to evaluate melanin synthesis rates in cultured melanocytes, specifically because MT-2's MC4R activation would have introduced non-pigmentary cAMP signaling that could distort baseline tyrosinase activity measurements. The naming convention 'MT-1' versus 'Melanotan-1' makes no functional difference. But 'MT-1' versus 'MT-2' defines whether the peptide is receptor-selective or pan-melanocortin.
- Structure
- Linear 13-amino-acid with lactam bridge
- Cyclic 7-amino-acid with lactam + disulfide
- MT-1's linearity confers MC1R selectivity; MT-2's cyclization enables pan-receptor binding
- Receptor Affinity
- MC1R-selective (Kd ≈ 2.4 nM); 50× lower affinity for MC4R
- Equal affinity for MC1R, MC3R, MC4R, MC5R
- MT-1 isolates melanogenesis; MT-2 produces systemic effects
- Half-Life
- 30–40 minutes
- 2–3 hours
- MT-2's extended occupancy increases off-target risk
- Primary Use
- Photoprotection research, melanocyte studies
- Metabolic studies, appetite modulation research
- MT-1 preferred when isolating pigmentation variables