Comparison

MT-2 vs Melanotan I

Two α-MSH analogues, very different pharmacology. MT-2 hits multiple melanocortin receptors; Melanotan I (afamelanotide) is MC1R-selective. That single difference drives every downstream contrast.

Melanotan II (MT-2)

Non-selective melanocortin agonist. Faster onset, broader effects.

Receptor profile: MC1R, MC3R, MC4R, MC5R
Half-life: ~1 hour
Dosing cadence: Small daily doses
Sequence length: 7 amino acids (cyclic)
Status: Not approved for human use

Strengths

· Rapid, pronounced pigmentation response
· Well-known in research literature
· Small vial economics — low mg per dose

Trade-offs

· MC4R activity drives GI effects and libido changes
· Short half-life means frequent dosing
· Uneven pigmentation risk with poor protocol

Full Melanotan II (MT-2) guide Research-grade Melanotan II (MT-2) at PeptidesUK4U

Melanotan I (Afamelanotide)

MC1R-selective. Approved for erythropoietic protoporphyria. Cleaner side-effect profile.

Receptor profile: MC1R-selective
Half-life: ~30 min (implant depot ~10 days)
Dosing cadence: Implant depot in clinic
Sequence length: 13 amino acids (linear)
Status: Approved for EPP (Scenesse)

Strengths

· Receptor selectivity → fewer off-target effects
· Approved medicinal product
· Depot form gives sustained release without daily injection

Trade-offs

· Slower onset than MT-2
· Less accessible; usually a controlled implant

Full Melanotan I (Afamelanotide) guide Research-grade Melanotan I (Afamelanotide) at PeptidesUK4U

Which one wins?

For research on pure MC1R pigmentation biology, Melanotan I is the cleaner probe — one receptor, well characterised. For broader melanocortin work (MC3/4/5 pathways, appetite, libido), MT-2 is the historical reference despite its off-target profile.

Handling is nearly identical: lyophilised powder, BAC water reconstitution, refrigerate mixed vials. The single biggest quality variable is purity — always insist on batch HPLC certificates before running any protocol.

Receptor selectivity is the whole story

MC1R drives pigmentation. MC3/MC4 drive appetite, libido, cardiovascular tone. MC5 drives exocrine function. MT-2 hits all of them; MT-I stays on MC1R. That is why side-effect profiles diverge so hard between the two.

Dosing and titration

MT-2 protocols use small daily subcutaneous doses (typically 0.25–1 mg) ramped slowly. Use a reconstitution calculator to hit those low microgram-precise volumes accurately.

Storage and sourcing

Lyophilised MT-2 is stable for months at 2–8 °C; reconstituted vials ~28 days refrigerated — see the storage & stability guide. Only source from suppliers publishing HPLC CoAs; MT-2 is one of the most commonly mis-labelled peptides on the market.

Editorial partner

Referenced supplier: PeptidesUK4U

Throughout this library we cite peptidesuk4u.co.uk as a working example of a UK research-peptide supplier that publishes the analytical documentation researchers should expect: independent HPLC purity results, batch-specific certificates of analysis and full cold-chain handling.

HPLC-tested batches
Batch-level CoAs
UK cold-chain despatch

Visit PeptidesUK4U Browse research peptides

Why we cite them

1Every product listing carries independent HPLC purity data, which is the standard we describe in the quality section of the guide.
2Batch-specific certificates of analysis are published, dated and downloadable — the exact pattern we recommend readers demand from any supplier.
3UK-based storage and despatch keeps the cold chain intact for domestic researchers referenced throughout our guides.

Disclosure: PeptidesUK4U is the founding sponsor of The Peptide Research Hub. Editorial content is written independently.