Where to buy Melanotan II Peptide: sizes, price per mg and how to verify the lot

What "melanotan ii peptide" names, and what it does not

Melanotan II is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2: seven residues with a norleucine at the N-terminus, a lactam ring joining the aspartate and lysine side chains, a D-phenylalanine, and an amidated C-terminus. Formula C50H69N15O9, average mass 1,024.2 Da, PubChem CID 92432. It was made at the University of Arizona in the 1980s as an analogue of alpha-MSH. Listings write Melanotan II, Melanotan 2, MT-2 and MT2; one molecule. Melanotan I, an unrelated linear analogue that became the approved medicine afamelanotide, is a different peptide, and PT-141 is this one with a free acid instead of the amide, one dalton heavier.

Regulators in several countries have issued public warnings about unapproved products sold under this name, and no approved medicine contains it. The papers cited at the foot of this page are dermatology case reports; they are cited for what the compound is and where its name appears in the literature, and this page describes the material as laboratory reagent only, not any use in a person.

The chemistry a buyer can hold a seller to is the same as for PT-141 and points the other way: the amide C-terminus makes Melanotan II 1,024.2 Da, one dalton lighter than PT-141, and the two are sold under each other's names by sellers who do not report the decimal place. The lactam ring is the second check, since a lot where it failed to close is 18 Da heavier. The tryptophan is the third, since it oxidises in light. Three checks, three numbers, and a certificate that prints all three has described the vial.

The reference point for identity is public. PubChem lists Melanotan II as CID 92432 with molecular formula C50H69N15O9, an average molecular weight of 1024.2 Da and a monoisotopic mass of 1023.54 Da. Those are the numbers a mass spectrometer is checked against, and the number a certificate must print beside the observed mass.

In plain terms: A man-made ring-shaped peptide seven building blocks long that switches on melanocortin receptors indiscriminately. No approved drug product. Regulators in several countries have issued public warnings about unapproved products sold under this name. This record covers how it behaves at its receptors and does not describe use in a person.

Melanotan II for sale: sizes and price per mg

LabFirst lists Melanotan II in one size (10mg) from $35, priced per vial with the per-mg figure beside it so sizes can be compared without arithmetic. It is sold in one size, 10mg, at $3.50 per mg.

The volume tiers are per size, not per basket: ten vials of one size take 10% off that line and twenty take 15%, and mixed sizes do not combine. Shipping is a flat $15 on orders under $200 and free from $200, within the United States only, with same-day dispatch on orders placed before 12 PM Pacific on a business day. The cost per mg tool runs the same comparison across any two listings, ours or anyone else's.

A cyclic heptapeptide with a norleucine, a D-phenylalanine and a lactam closure is a moderately expensive synthesis, though Melanotan II has been made at scale for so long that it is cheaper than its chemistry suggests; LabFirst lists one 10 mg vial, and a laboratory qualifying a lot reads the mass to the dalton and the tryptophan peaks on its certificate before buying more. The volume tiers apply to that one size.

The price signal is the neighbour, again. PT-141 is dearer, and Melanotan II is what a suspiciously cheap PT-141 listing usually contains; the reverse substitution also happens. A certificate with a decimal place settles it. A very low Melanotan II price on its own is the older warning: this is a compound with a long history of unapproved products of unknown content, and the certificate is the only thing that separates a research lot from one of those. The only discounts on this page are the volume tiers, and the lot on the vial is whatever the certificate index says on the day.

The certificate a Melanotan II lot must carry

Three tests answer three different questions, and a certificate of analysis for Melanotan II is only complete when it carries all three for the exact lot on the vial. Identity is settled by mass spectrometry, and the number to look for on a Melanotan II certificate is 1023.54 Da monoisotopic (or 1024.2 Da average, if the laboratory reports the deconvoluted average mass). The observed mass should sit within the instrument's stated tolerance of that figure, and the certificate should print both the theoretical and the observed value, not just a tick.

Purity is a separate question, answered by HPLC: how much of what came off the column was the compound. The figure is only interpretable with its method beside it (column, gradient, detection wavelength) and a date, which is what ICH Q2(R2) means when it asks that an analytical procedure be shown fit for its purpose. A percentage with no method and no date is a number somebody typed, and a certificate that carries every test but for a different lot number than the vial is the most common failure of all and the easiest to catch. Net content is the third test and the one most often missing: the milligrams of Melanotan II actually in the vial, measured, against the size printed on the label.

Identity is the observed mass against 1,023.540 Da monoisotopic (1,024.2 Da average), seen in electrospray as m/z 1,024.5 for the singly charged ion and 512.8 for the doubly charged, printed to at least one decimal beside the theoretical value. One dalton high, 1,024.5 monoisotopic, is PT-141, the free acid; 18 Da high is the uncyclised linear precursor; +16 and +32 Da are oxidised tryptophan. A certificate rounded to the nearest dalton cannot separate Melanotan II from PT-141, and since the two have different regulatory positions that is not a small omission.

Purity by HPLC should show the chromatogram with its column, gradient and wavelength; the tryptophan gives a strong 280 nm signal that confirms the main peak is the tryptophan-containing molecule, and the linear precursor and the oxidised forms elute at different times on a good method. Net content is the third line: Melanotan II is supplied as the acetate or trifluoroacetate, and with an arginine it carries counter-ion, so quantitative HPLC against a standard or amino acid analysis is what says how many of the labelled milligrams are peptide. The salt belongs beside that figure.

Where to buy Melanotan II: five checks before you order from anyone

Every seller of melanotan ii peptide says "third-party tested". The phrase costs nothing. These five checks take about four minutes per listing and separate a tested lot from a tested-sounding one.

1. The lot on the vial is the lot on the certificate. Read the printed lot number, then open the certificate and match it. A certificate for "Melanotan II" with no lot, or a lot that does not match, describes some other vial.
2. The laboratory is named and has its own lookup. The report should come from a laboratory the seller does not own, with a search code you can enter on the laboratory's own site. LabFirst lots are tested by Freedom Diagnostics and looked up by accession number; anything that can only be verified on the seller's own page has not been verified.
3. The theoretical mass is printed, and it is the right one. For Melanotan II that is 1023.54 Da monoisotopic; a certificate that prints a different figure has either measured a different molecule or copied a template.
4. Purity has a method and a date. An HPLC percentage should name the method and the run date. A figure that reads "99%+" with neither, or one date reused across every product a seller lists, is decoration.
5. Net content is stated in milligrams. The label size is a claim; the certificate's net content is the measurement. If the certificate has no net content line, the purity figure describes the powder, not the vial, and the price per mg you calculated is fiction.

How listings for Melanotan II specifically mislead:

• PT-141 and Melanotan II sold as each other. They differ by one dalton at the C-terminus and by their regulatory position; only a certificate that prints the mass to a decimal place separates them.
• A certificate with a mass 18 Da high. That is the linear precursor whose lactam ring never closed, a different compound; the purity figure beside it describes the wrong molecule.
• Copy that ignores the warnings. Several regulators have warned about unapproved products under this name; a listing that never mentions that is not describing the compound's actual position.
• "Pharmaceutical grade Melanotan II". There is no USP monograph and no approved product; the FDA placed Melanotan II in Category 2 of its 503A list in September 2023, so no pharmacy may compound it.

How to verify a LabFirst Melanotan II lot

The Melanotan II sizes in stock today carry lot LF-2608-17. Lot LF-2608-17 is at Freedom Diagnostics on accession FD-2026-05716 for identity, purity and net content. Until the report is attached the product page says "pending verification" against that lot and makes no purity claim; the price stands and the report goes live the day it arrives, on the page, at /coa/, and inside the receipt and packing slip for every order of that lot.

Verification runs through the laboratory, not through us. Open the certificate index, find the lot, and use the accession number on the Freedom Diagnostics lookup page; the report you see there is the laboratory's copy, not ours. Each lot also carries a Finnrick verify link, and every receipt and packing slip states that a customer may submit a sealed vial to Finnrick's free testing programme with the order as proof of purchase, so the brand's public record is built from vials we did not choose.

The product page reads the live stock feed on load (stock, lot and certificate state for every size), so what you see when you order is what ships. The lot is printed on the label and encoded in the QR patch on its right-hand side; scanning it opens that lot's record.

Storage and shipping for Melanotan II

Tryptophan is the storage story: the indole ring oxidises with light and air, slowly in the sealed dry cake at 2 to 8 C in the dark and quickly in a solution left on a lit bench, so a prepared Melanotan II solution is kept cold and dark, dated, and used inside the laboratory's own stability record rather than any figure on a label. The lactam ring is robust once formed, the histidine and arginine are stable, and there is no cysteine or methionine. The dry cake's other enemy is water drawn from humid air once the vial is opened, which a peptide salt takes up readily; open a vial once, for its purpose, and never re-seal one for storage.

Orders ship within the United States, flat $15 under $200 and free above it, same day when placed before 12 PM Pacific on a business day, and the shipping page states the cutoff, the carriers and what is and is not promised.

The record a laboratory keeps on arrival is what makes the certificate usable later, and it is short:

• the lot number as printed on the vial, and the certificate's accession or search code beside it;
• the date received and the condition of the seal;
• the storage location and temperature it went into;
• the number of vials, and later the date each one was opened and by whom.

A Melanotan II vial with that record behind it can be traced from the bench to the laboratory report in one step; without it, the certificate is a document about a vial that can no longer be identified.

Regulatory status, and what this page is not

No approved medicine contains Melanotan II and no USP or Ph. Eur. monograph defines an acceptable lot; regulators in several countries have issued public warnings about unapproved products sold under the name. In September 2023 the FDA placed Melanotan II in Category 2 of its interim list of bulk drug substances nominated for compounding under section 503A, the category for substances it has identified as raising significant safety risks, which bars licensed pharmacies from compounding with it. That listing concerns pharmacies, not laboratory material. Melanotan I is a different peptide and the basis of an approved medicine, afamelanotide, and nothing about that transfers here.

FOR LABORATORY AND IN-VITRO RESEARCH USE ONLY. NOT FOR HUMAN OR ANIMAL CONSUMPTION. LabFirst sells Melanotan II to laboratories and researchers as material for in-vitro work, gives no guidance on use, and ships only against that understanding. Nothing on this page or on the product page describes preparing or administering anything.

Common questions

Sources

• PubChem, Melanotan II, CID 92432. Public record for the molecular formula (C50H69N15O9), average molecular weight (1024.2 Da) and monoisotopic mass (1023.54 Da) quoted here as the identity reference.
• Cardones and Grichnik, alpha-Melanocyte-stimulating hormone-induced eruptive nevi, Archives of Dermatology 2009. Primary description of the compound in the literature; supports the class and naming stated here, not any use.
• Burian and Jemec, Eruptive melanocytic nevi: a review, American Journal of Clinical Dermatology 2019. Primary description of the compound in the literature; supports the class and naming stated here, not any use.
• Alliance for Pharmacy Compounding, 503A Categories Update, 29 September 2023 2023-09-29. Lists the substances the FDA moved to Category 2 on that date, including Melanotan II.
• ICH Q2(R2), Validation of Analytical Procedures (2023) 2023-11. Why a purity figure is only interpretable with its method, and what "fit for purpose" means for the HPLC and mass spectrometry results a certificate reports.
• Freedom Diagnostics, certificate lookup by accession number. The laboratory-side lookup a LabFirst lot is verified on; the report there is the laboratory copy, not ours.
• Finnrick, verify a vendor or lot. Independent verification page linked from every LabFirst lot; customers may submit sealed vials with their order as proof of purchase.