Source comparison
9. MT-II vs PT-141 — the same scaffold, different selectivity
MT-II and PT-141 (bremelanotide) share the cyclic heptapeptide backbone but differ in receptor selectivity owing to a single structural change. C-terminus Amide (-NH₂) Free carboxyl (-OH) MC1R activity High (Ki ~0.25 nM) Reduced (Ki ~2.8 nM) MC4R activity High
This comparison does not assign a generated winner or score.
- MT-II and PT-141 (bremelanotide) share the cyclic heptapeptide backbone but differ in receptor selectivity owing to a single structural change.
- C-terminus
- Amide (-NH₂)
- Free carboxyl (-OH)
- MC1R activity
- High (Ki ~0.25 nM)
- Reduced (Ki ~2.8 nM)
- MC4R activity
- High (Ki ~1.5 nM)
- High (Ki ~0.6 nM)
- Tanning effect
- Pronounced
- Minimal (focal only)
- Regulatory approval
- None
- FDA Vyleesi 2019 (HSDD)
- Half-life
- ~33 min
- ~2.7 h
- Primary research use
- MC1R / pigmentation
- MC4R / sexual function
- For UK research protocol design, choose MT-II for MC1R-focused pigmentation biology; choose PT-141 for MC4R-focused sexual function, neurobiology, or obesity research.