Melanotan 2 and PT-141: What Sets the Two Apart

Quick answer: PT-141 and Melanotan 2 are two closely related synthetic peptides built on the same small ring of amino acids. They differ mainly at one chemical end of the molecule, and published research has examined them in overlapping but not identical areas. Because the two are so alike, checking identity on the Certificate of Analysis matters more than usual.

Are PT-141 and Melanotan 2 the same peptide?

No. They are close analogs, meaning two molecules with almost the same structure. PT-141 is also written as Bremelanotide. Melanotan 2 is often shortened to MT2 or Melanotan II.

Both are cyclic peptides of seven amino acid residues. Both carry an acetyl cap at one end. The difference is at the other end. Melanotan 2 finishes with an amide group. PT-141 finishes with a free acid group. That small change gives each a slightly different mass and slightly different behavior in testing.

How do they compare side by side?

Which receptors does each one target?

Melanocortin receptors are a family of cell-surface proteins. Researchers number them MC1R through MC5R. They take part in pigment signaling, hormone regulation and signaling in the brain.

Published laboratory work describes Melanotan 2 as a broad agonist, meaning it switches on several of these receptors. PT-141 is also described as acting on more than one melanocortin receptor. Discussion of it centers on receptors in the central nervous system, especially MC4R. Our product page describes PT-141 as studied for a neural signaling mechanism rather than a direct effect on blood vessels.

What has research examined for each?

For PT-141, early-2000s laboratory studies in rodents examined sexual behavior and motivation-related signaling. Later work looked at how melanocortin activation in the brain connects to neuroendocrine pathways. Most of this is preclinical, and we do not draw conclusions from it for any real-world use.

For Melanotan 2, published research has looked at pigmentation signaling through MC1R as well as the wider melanocortin system. The evidence for both compounds is early and uneven. We also do not compare half-life here, because published figures come from different study types and we cannot confirm them for these vials.

If you want a different reproductive-signaling peptide for contrast, see our overview of Kisspeptin-10. It works through a separate receptor system.

What is in the PT-141 vial?

Our PT-141 | 10mg ships as a lyophilized (freeze-dried) powder, and the product page marks it as needing reconstitution before laboratory work. The page does not list a CAS number or formula, so we do not quote them here. Our Melanotan 2 (MT2) | 10mg is a separate catalog item.

How do you tell them apart on a COA?

A Certificate of Analysis should show identity by mass, purity by HPLC and content per vial. For general background, see our line-by-line COA guide. For these two compounds, check the following:

• Compound name. The sample name and lot should match the product you ordered.
• Observed mass. The two masses sit only about one mass unit apart. A low-resolution result could blur them, so compare the reported mass with the expected value for the named compound.
• HPLC peak. Look for one dominant peak. A small neighboring peak can be a related impurity with a nearly identical mass.
• Content. Purity and content per vial are different numbers. Our article on why mass matters more than purity explains why.

The PT-141 COA above is the one to read alongside these points.

Frequently asked questions

Is Bremelanotide the same as PT-141?

Yes. Bremelanotide is the generic chemical name and PT-141 is the shorter research name. Both refer to the same peptide.

Is PT-141 a form of Melanotan 2?

It is a close analog, not the same molecule. The two differ at the chemical end of the ring peptide.

Why do PT-141 and Melanotan 2 have almost the same molecular weight?

They share the same seven-residue ring and acetyl cap. Only the end group differs, which changes the mass by about one unit.

Does PT-141 act on blood vessels or the brain?

Our product page describes it as studied for a central nervous system mechanism, acting through neural signaling. That description comes from the research framing, not from a claim about any outcome.

Is there strong evidence behind PT-141 research?

The research we describe is preclinical and still early. Treat it as a record of what was examined, not as settled conclusions.

All products sold by BioPure Peptides are intended strictly for in-vitro laboratory and research use only. They are not for human or animal consumption. These statements have not been evaluated by the U.S. Food and Drug Administration, and these products are not intended to diagnose, treat, cure, or prevent any disease.