One stretches out like a line. The other folds into a ring—and that shape changes the entire research story.
That is the memorable difference in Melanotan 1 vs 2, two peptides often grouped together under the consumer search term “tanning peptides.”
Melanotan 1 is the longer linear analog; melanotan 2 is the shorter cyclic analog with broader melanocortin-receptor activity.
Both come from alpha-melanocyte-stimulating hormone research. They are not the same molecule.
Melanotan 1 vs 2 at a glance
| Question | Melanotan 1 | Melanotan 2 |
|---|---|---|
| Other name | MT-1, Melanotan I | MT-2, Melanotan II |
| Shape | Linear peptide | Cyclic peptide |
| Length | 13 amino acids | 7 amino acids |
| Main research focus | MC1R and pigmentation | Broader melanocortin-receptor activity |
| Certiva vial size | 10 mg | 10 mg |
The two best memory words are linear and cyclic.
Melanotan 1 keeps a longer alpha-MSH-like chain. Melanotan 2 uses a shorter ring that gives it a compact, stable shape and wider receptor activity.
What is Melanotan 1?
Melanotan 1 is a synthetic linear analog of alpha-melanocyte-stimulating hormone, or alpha-MSH. It is also known as [Nle4-D-Phe7]-alpha-MSH and is closely associated with the name afamelanotide in clinical literature.
Alpha-MSH connects with melanocortin receptors. At the MC1 receptor on melanocytes, this signaling is tied to the production of melanin, the pigment that gives skin and hair color.
Human research reported that Melanotan 1 increased eumelanin content and visible pigmentation at several measured skin sites. Read the Melanotan 1 eumelanin study on PubMed.
That research history makes MT-1 the more direct, pigmentation-first reference in this comparison.
What is Melanotan 2?
Melanotan 2 is a shorter cyclic heptapeptide. Heptapeptide means seven amino acids. Cyclic means part of the chain is joined into a ring.
That ring is not decoration. Cyclization changes the peptide’s shape, stability, and receptor behavior.
Research describes Melanotan 2 as a potent, nonselective melanocortin-receptor agonist. It interacts beyond MC1R, including receptor systems used in appetite, behavioral, and neuroendocrine models.
A modern human-receptor study called MT-2 a potent and unselective agonist across melanocortin receptors. Read the Melanotan 2 receptor paper on PubMed.
An early pilot study also documented pigmentation activity in three male volunteers. See the Melanotan 2 pilot study on PubMed.
The broader receptor reach is the biggest reason MT-2 should not be treated as a shorter copy of MT-1.
Are Melanotan 1 and 2 both tanning peptides?
That is the popular search phrase, and both peptides do appear in pigmentation research.
But “tanning peptide” hides the most useful scientific difference:
- Melanotan 1 is longer, linear, and more centered on the MC1R pigmentation pathway.
- Melanotan 2 is shorter, cyclic, and active across a broader range of melanocortin receptors.
For a buyer, the exact Roman numeral matters. “Melanotan” alone is an incomplete product name.
Which is better: Melanotan 1 or 2?
The better reference depends on the receptor question.
- Choose Melanotan I for linear alpha-MSH analog, MC1R, eumelanin, and pigmentation-pathway research.
- Choose Melanotan II for cyclic-peptide research and broader melanocortin-receptor comparisons.
- Choose separate vials of both when the study compares how linear and cyclic design changes receptor activity.
If the experiment needs a narrow pigmentation-first story, MT-1 is easier to position. If it needs broader receptor pharmacology, MT-2 is the clearer match.
What formats can I order?
Certiva supplies:
- Melanotan I: 10 mg per vial;
- Melanotan II: 10 mg per vial; and
- standard packaging: 10 vials per box.
Bulk quantities and custom requests are available by inquiry.
What should I check before buying?
Closely related names make batch identity especially important.
Check:
- whether the product is Melanotan I or Melanotan II;
- whether the description says linear or cyclic;
- the vial amount and box quantity;
- the matching lot number;
- HPLC purity and identity testing; and
- storage, shipping, and lead time.
Use our guide on how to choose a peptide supplier to compare documentation instead of relying on a product nickname.
Why the structural difference matters
Melanotan 1 is the linear, pigmentation-first reference. Melanotan 2 is the cyclic, broader-receptor reference.
Choose by structure and receptor scope, then confirm the Roman numeral on every inquiry, vial, and batch document.
Certiva supplies both products strictly for laboratory research use only, not for human consumption.
Compare Melanotan 1 and 2 COAs
Tell us which peptide, quantity, destination country, and documentation your project requires. We will reply with availability, applicable batch information, lead time, and a quote.
Compare Melanotan I and II COAs →
Sources and further reading
- PubMed: Melanotan 1 and eumelanin research
- PubMed: Melanotan 2 as a broad melanocortin-receptor agonist
- PubMed: pilot Melanotan 2 pigmentation study
Frequently asked questions
What is the main difference between Melanotan 1 and Melanotan 2?
Melanotan 1 is the longer linear analog; melanotan 2 is the shorter cyclic analog with broader melanocortin-receptor activity.
Is Melanotan 1 the same as Melanotan 2?
No. Melanotan 1 is a linear 13-amino-acid analog of alpha-MSH, while Melanotan 2 is a cyclic seven-amino-acid analog with broader melanocortin-receptor activity.
Which is more MC1R-focused, Melanotan 1 or Melanotan 2?
Melanotan 1 is the more MC1R- and pigmentation-focused research reference. Melanotan 2 is a potent, nonselective agonist used across broader melanocortin-receptor research.
Are Melanotan 1 and Melanotan 2 tanning peptides?
Both are widely called tanning peptides because melanocortin and MC1R signaling are connected to melanin production and pigmentation research.
What vial sizes does Certiva supply?
Certiva supplies Melanotan I and Melanotan II in 10 mg vials, with 10 vials per standard box. Bulk quantities are available by inquiry.
For research use only. Not for human consumption. This article is educational and makes no medical, therapeutic, or dosing claims.
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