Source comparison
Pharmacokinetic Comparison
The pharmacokinetic profiles diverge as sharply as the structures. Tmax ~36 h ~1-2 h Intrinsic t1/2 ~30 min Apparent t1/2 ~15 h (implant-driven) Cmax 3.7 ng/mL Not well characterised BBB penetration Minimal Yes SC bioavailability 100% (implant formulation) Ass
This comparison does not assign a generated winner or score.
- The pharmacokinetic profiles diverge as sharply as the structures.
- Tmax
- ~36 h
- ~1-2 h
- Intrinsic t1/2
- ~30 min
- Apparent t1/2
- ~15 h (implant-driven)
- Cmax
- 3.7 ng/mL
- Not well characterised
- BBB penetration
- Minimal
- Yes
- SC bioavailability
- 100% (implant formulation)
- Assumed high
- Oral bioavailability
- 0%
- Negligible
- Nasal bioavailability
- Not applicable
- Low, variable, unquantified
- Duration of effect
- Weeks post-depletion
- Hours
- Afamelanotide is administered as a 16 mg bioresorbable subcutaneous (under-the-skin) implant every 60 days. The implant provides controlled release: median Tmax at approximately 36 hours, with over 90% of drug liberated by day 5 and plasma levels undetectable by day 10.⁹¹¹ The intrinsic elimination half-life of the free peptide is approximately 30 minutes, but the slow-release formulation yields an apparent half-life of roughly 15 hours through flip-flop kinetics.⁹
- MT-II, by contrast, is rapidly absorbed after subcutaneous injection (absorption half-life 0.07-0.79 hours) with elimination half-life of 0.8-1.7 hours.¹⁰ Nasal spray administration — the route popularised on social media — has substantially lower and more variable bioavailability than subcutaneous injection. No published clinical trial has used the intranasal route, and no quantitative pharmacokinetic comparison between nasal and subcutaneous delivery exists in the literature.
- Despite its short pharmacokinetic presence, afamelanotide’s melanogenic effects persist for weeks beyond the period of detectable drug levels, reflecting the time required for melanin turnover in the epidermis. No late effects have been reported in volunteers followed for 25 years after first exposure.⁴⁹