Melanotan 2 (MT2) · Research brief

Buy MT2 (Melanotan II) — Research Supplier Guide

Real Peptides Research TeamEditorial

Updated March 26, 20269 min read

48 WORDS

Short answer

Two vials of MT2 can carry identical labels, identical stated purity, and still contain measurably different amounts of peptide. Purity and net peptide content are different numbers measured in different ways, and only one of them tells a laboratory how much compound is actually sitting in the vial.

Key takeaways

MT2 (Melanotan II) is a cyclic lactam analog of alpha-MSH carrying CAS number 121062-08-6, molecular formula C50H69N15O9 and a molecular weight near 1024.2 g/mol.
The literature describes MT2 as a non-selective melanocortin receptor agonist active at MC1R, MC3R, MC4R and MC5R rather than a single receptor subtype.
HPLC purity and net peptide content are separate measurements, and labs that buy MT2 on purity alone can receive less peptide per vial than the label implies.
A usable certificate of analysis carries a lot number matching the vial, an analysis date, an HPLC chromatogram and a mass spectrum confirming the expected molecular ion.
Lyophilized MT2 is stored at minus 20 degrees Celsius or colder, desiccated and light-protected; reconstituted solution is refrigerated at 2 to 8 degrees Celsius.
Anyone deciding where to buy MT2 should weight published, batch-specific documentation above price per milligram, because Melanotan II is not approved for human or veterinary use and is supplied for laboratory research only.

Our team fields this constantly from researchers who buy MT2 for melanocortin receptor work. The sourcing decision isn't about who lists the lowest price per milligram. It's about whose documentation survives scrutiny.

Where can researchers buy MT2 (Melanotan II) for laboratory use?

Researchers buy MT2 from research-chemical suppliers that publish batch-specific certificates of analysis, confirm CAS number 121062-08-6, and verify a molecular weight near 1024.2 Da by mass spectrometry. Melanotan II is not approved for human or veterinary use in any jurisdiction and is supplied strictly as a research-use-only compound.

The oversimplification worth killing early: a high HPLC purity figure alone does not certify what is in the vial. Purity describes what fraction of the peptide material present is the target sequence. Net peptide content describes how much of the vial's total mass is peptide at all, once counterions and bound water are subtracted. This guide covers what MT2 does at the receptor level, the documentation to demand before you buy MT2, and the handling failures that ruin correctly manufactured material after delivery.

What MT2 actually is at the molecular level

MT2, or Melanotan II, is a synthetic cyclic lactam analog of alpha-melanocyte-stimulating hormone (alpha-MSH), the endogenous peptide that signals pigment-producing cells. It carries CAS number 121062-08-6, the molecular formula C50H69N15O9, and a molecular weight of roughly 1024.2 g/mol. Those three identifiers are the first thing to check when you buy MT2, because they're objective: a supplier either matches them on a mass spectrum or doesn't.

The compound came out of melanocortin peptide research at the University of Arizona, where the objective was a metabolically stable alpha-MSH analog. Cyclization through an Asp-Lys lactam bridge gives it far greater resistance to enzymatic degradation than the native hormone. Pharmacologically, the literature describes it as a non-selective melanocortin receptor agonist, engaging MC1R, MC3R, MC4R and MC5R rather than a single subtype.

MC1R sits on melanocytes, where receptor activation raises intracellular cAMP and drives the transcription factor MITF, which in turn upregulates tyrosinase and shifts melanin synthesis toward eumelanin. MC3R and MC4R are concentrated in the central nervous system, which is why published work on melanocortin agonists spans pigmentation, energy homeostasis and sexual behaviour. Bremelanotide (PT-141) belongs to the same chemical lineage. Researchers who buy MT2 are usually working somewhere across that receptor map, not on pigmentation alone.

The paperwork that separates a real supplier from a repackager

A certificate of analysis is only useful if it's batch-specific. Generic COAs with no lot number, no analysis date and no instrument trace are marketing documents, not analytical ones. Before you buy MT2, the minimum set is a lot number on the COA that matches the vial label, an HPLC chromatogram showing retention time and area percentage, and a mass spectrum confirming the expected molecular ion near 1024.2.

Here's the detail most buyers miss, and it's the single most common reason two honestly labelled vials price out so differently. Reverse-phase HPLC purification uses trifluoroacetic acid, and the finished lyophilized powder retains TFA counterions bound to basic residues, plus residual water. So purity and net peptide content answer different questions. A powder can be 98 percent pure by HPLC while peptide accounts for a meaningfully smaller fraction of the gross mass in the vial. Suppliers reporting only the purity figure aren't necessarily lying. They're answering the easier question.

Our team has reviewed third-party reports across this entire catalog, and the pattern holds: suppliers who volunteer net peptide content alongside purity are the same ones whose chromatograms look clean. Real Peptides synthesizes in small batches with exact amino-acid sequencing and publishes its analytical documentation openly, so the lot in hand can be matched to its report before anyone opens it. When labs buy MT2 without that trace, they're buying a label.

Handling MT2 after it arrives

Lyophilized peptide stays stable for extended periods under cold, dark, dry storage and degrades quickly outside it. Standard laboratory practice for lyophilized MT2 is storage at minus 20 degrees Celsius or colder, desiccated and protected from light. Once reconstituted in a sterile diluent, solution is held at 2 to 8 degrees Celsius and the usable window shortens sharply.

The sequence itself explains the light sensitivity. MT2 contains a tryptophan residue, and tryptophan is among the most photo-oxidation-prone amino acids, which is why amber vials and foil overwraps aren't cosmetic packaging choices. Repeated freeze-thaw cycling is the other avoidable failure. Each cycle concentrates solutes at the ice interface and promotes aggregation, so labs that buy MT2 in bulk typically aliquot on receipt rather than reopening one stock vial repeatedly.

Cold-chain integrity in transit matters as much as bench storage. Dry powder tolerates brief ambient excursions far better than solution does, but brief doesn't mean indefinite. Anyone planning to buy MT2 should confirm the packing method and transit time before ordering, not after a package turns up warm on a Friday afternoon.

The information here describes laboratory handling of a research-use-only compound. It isn't guidance for human or veterinary use, and study parameters should follow institutional protocols and applicable regulations.

Buy MT2: comparing three sourcing routes

Sourcing channels differ less in chemistry than in what they can prove about a specific lot. This table compares the routes laboratories typically use when they buy MT2, scored on traceability.

Sourcing route	Documentation typically available	Identity verification possible	Main practical risk	Bottom line
Dedicated research-peptide supplier with published COAs	Batch-specific COA, HPLC chromatogram, mass spectrometry report, lot number matched to the vial	Full: CAS number, molecular weight and purity can all be cross-checked against the report	Higher price per milligram than bulk channels	The only route where material in hand traces back to a named analytical run before the vial is opened. 5/5 for traceability.
Bulk overseas reseller or general marketplace listing	Often one generic COA reused across lots, sometimes with no instrument trace at all	Partial: label claims exist but cannot be tied to the shipped lot	Lot-to-lot variability and unverifiable net peptide content	Workable only if the seller produces a lot-matched report on request. Most won't. 2/5 for traceability.
Analytical reference standard from a catalogue chemical house	Full specification sheet and reference-standard documentation	Full, usually to a tighter specification than research-grade material	Sold in small analytical quantities at a steep price premium	Correct for assay calibration, impractical as a working research supply. 5/5 for traceability.
Forum or social-media reseller	Screenshots, or nothing	None that can be independently confirmed	Unknown provenance, repackaging, and no recourse	Not a legitimate research supply channel under any procurement standard. 1/5.

What If: MT2 sourcing and handling scenarios

What if the certificate of analysis has no lot number or date?

Treat it as unverified and request the batch-specific report before ordering. A COA without a lot number can't be matched to the vial in hand, which defeats the entire purpose of the document. Genuine analytical reports name the method, the run date and the specific batch tested. Suppliers running real third-party testing have these on file and send them without friction. Suppliers recycling a template from an older batch usually stall. Labs that buy MT2 regularly build this check into procurement rather than treating it as an optional extra.

What if the powder looks like a thin film instead of a fluffy cake?

Photograph it, don't discard it, and query the supplier before reconstituting. Lyophilization cake appearance varies with fill volume, peptide mass and the freeze-drying cycle, so a thin film or a small pellet at the base of the vial isn't automatically a defect. A 10mg fill in a standard vial simply produces less visible material than people expect. What does warrant a query is discoloration, visible moisture, or a cake collapsed into sticky residue, which points to moisture ingress during storage or shipping.

What if the vial arrives warm?

Record the receipt condition, then contact the supplier before putting it into an experiment. Lyophilized peptide is considerably more tolerant of ambient excursions than reconstituted solution, and brief warmth in transit is common and often inconsequential. Prolonged heat is a different problem, because thermal stress on dry peptide can drive aggregation and deamidation that no visual inspection will ever reveal. Suppliers with real quality systems replace material after a documented transit failure rather than arguing about it.

What if two suppliers quote the same purity at very different prices?

Compare net peptide content and the underlying documentation before comparing the price. Identical purity claims with a wide price gap usually reflect one of three things: different net peptide content per vial, different synthesis scale and quality-control burden, or a number that was never independently measured. Researchers who buy MT2 on price per milligram of gross powder aren't comparing equivalent quantities of peptide at all. Ask for both figures and the chromatogram, then compare.

What if the reconstituted solution is cloudy or has particulates?

Stop, document it, and keep that solution out of quantitative work. Cloudiness in a reconstituted peptide generally indicates aggregation, incomplete dissolution or microbial contamination, and each carries different implications for the experiment. Concentration, diluent choice and pH all influence solubility, so a solution that clouds on standing may be behaving predictably rather than being defective. Either way, data generated from a turbid solution is uninterpretable and the run is wasted.

The blunt truth about cheap MT2

Let's be direct about this: price per milligram is the worst single metric available for this decision. An unverified vial isn't cheaper material, it's unknown material, and an experiment run on unknown material produces unknown results. The gap between suppliers isn't the compound. The sequence is public and the synthesis is routine. The gap is whether anybody measured what came off the column and will hand over the trace without being asked twice. Labs that buy MT2 on price alone tend to make the purchase twice: once cheaply, once properly.

Real Peptides supplies Melanotan II (MT2) 10mg for laboratory research, with analytical documentation published in the certificate of analysis library and the wider research peptide catalog available to labs that buy MT2 alongside other compounds from a single verified source. Facility and shipping details sit on the company information page for researchers who need them for procurement records. Every compound listed is research use only.

Researchers who buy MT2 without reading the chromatogram are running an experiment with an undeclared variable already in it. The sequence is public, the synthesis is routine, and the molecular weight is a fixed number that either shows up on the mass spectrum or doesn't. What varies between suppliers isn't chemistry. It's whether anyone bothered to measure, and whether they'll produce the measurement on request without hesitating. That single behaviour predicts more about what's in the vial than any purity percentage printed on a label ever will.

References

Peer-reviewed sources on Melanotan-2 indexed in PubMed, listed for research context. Real Peptides supplies Melanotan-2 for laboratory research use only.

Melanotan II: a possible cause of renal infarction: review of the literature and case report. CEN case reports, 2020. PMID 31953620. doi:10.1007/s13730-020-00447-z
Topical MTII Therapy Suppresses Melanoma Through PTEN Upregulation and Cyclooxygenase II Inhibition. International journal of molecular sciences, 2020. PMID 31968661. doi:10.3390/ijms21020681
The effects of the melanocortin agonist (MT-II) on subcutaneous and visceral adipose tissue in rodents. The Journal of pharmacology and experimental therapeutics, 2007. PMID 17567964. doi:10.1124/jpet.107.123091
Assessment of the aversive consequences of acute and chronic administration of the melanocortin agonist, MTII. International journal of obesity and related metabolic disorders : journal of the International Association for the Study of Obesity, 2003. PMID 12704398. doi:10.1038/sj.ijo.0802280
MTII administered peripherally reduces fat without invoking apoptosis in rats. Physiology & behavior, 2003. PMID 12834806. doi:10.1016/s0031-9384(03)00118-5
Exploring the site of anorectic action of peripherally administered synthetic melanocortin peptide MT-II in rats. Brain research, 2003. PMID 12834882. doi:10.1016/s0006-8993(03)02683-0

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Questions

Research-use-only MT2 is supplied by peptide vendors that publish batch-specific certificates of analysis and can confirm CAS number 121062-08-6 against the shipped lot. The practical selection filter is documentation: an HPLC chromatogram, a mass spectrum near 1024.2 Da, and a lot number that matches the vial. Melanotan II is not approved for human or veterinary use in any jurisdiction and is sold strictly for laboratory research.

Check four elements: the lot number on the COA against the number printed on the vial, the date the analysis was performed, an HPLC chromatogram showing retention time and area percentage, and a mass spectrometry result confirming the expected molecular ion. A COA with no lot number or no instrument trace cannot be tied to the material you receive. If a supplier can only produce a generic document covering all batches, treat the identity as unconfirmed.

Net peptide content is the proportion of a vial's total mass that is actually peptide, as distinct from HPLC purity, which measures what fraction of the peptide material is the correct sequence. Reverse-phase purification with trifluoroacetic acid leaves TFA counterions bound to basic residues, and lyophilized powder also retains residual water. A vial can therefore be 98 percent pure by HPLC while containing noticeably less peptide by mass than the label weight suggests.

MT2 is offered as a research-use-only chemical to researchers, laboratories and institutions, not to consumers or patients. Legal status for possession, import and sale varies significantly between countries and regions, and regulators in several jurisdictions have issued public warnings about unregulated supply of Melanotan II. Buyers are responsible for confirming the rules that apply where they are located and for using the compound only in a laboratory research context.

No. Melanotan II is not approved as a drug for human or veterinary use in any major jurisdiction and is supplied only as a research compound. A structurally distinct alpha-MSH analog, afamelanotide, has received regulatory approval in some jurisdictions for a rare photosensitivity disorder, but that approval applies to a different molecule and a specific licensed product, not to MT2.

Both are melanocortin receptor agonists from the same chemical lineage, but they differ in structure and receptor engagement profile. MT2 is a cyclic lactam analog of alpha-MSH described in the literature as broadly non-selective across MC1R, MC3R, MC4R and MC5R, which is why melanogenesis features heavily in MT2 research. Bremelanotide lacks the same MC1R-driven pigmentation emphasis and appears in a different body of published work.

Standard practice for lyophilized peptides of this class is storage at minus 20 degrees Celsius or colder, desiccated and protected from light. Once reconstituted in a sterile diluent, the solution is held at 2 to 8 degrees Celsius with a much shorter usable window. Single-use aliquots are preferred over one repeatedly opened stock vial, because each freeze-thaw cycle concentrates solutes at the ice interface and promotes aggregation.

Three factors account for most of the spread: differences in net peptide content per vial, differences in synthesis scale and quality-control burden, and whether the stated purity was independently measured at all. A supplier running batch-level HPLC and mass spectrometry through a third-party lab carries costs that a repackager does not. Comparing price per milligram of gross powder without comparing documentation compares two different things.

Published work describes MT2 as a non-selective agonist at MC1R, MC3R, MC4R and MC5R. MC1R activation on melanocytes raises intracellular cAMP and drives MITF, which upregulates tyrosinase and shifts melanin synthesis toward eumelanin. MC3R and MC4R are concentrated centrally, which is why melanocortin agonist studies extend into energy homeostasis and behaviour. Non-selectivity matters for study design because effects at one subtype are difficult to isolate from the others.

Dermatology case reports have described changes in melanocytic nevi in the context of unregulated Melanotan II use, and the literature generally treats this as a reason for caution rather than a settled causal finding. These reports involve uncontrolled, non-laboratory use rather than supervised study conditions. Research-grade MT2 supplied for laboratory work is not intended for human administration under any circumstances.

RESEARCH USE ONLY · NOT EVALUATED BY THE FDA