This page shows what was measured, who it was measured in, and what that does not settle.
What Melanotan II does in the body
Unapproved tanning injections.
Sunlight damages DNA in skin cells; the cells respond by releasing a hormone that tells the pigment cells to make more melanin. Melanotan II is a laboratory-built copy of that hormone, redesigned as a ring so that enzymes cannot chew it up. Injected, it produces the tanning signal without the sun. The problem is that the body has five receptors in this family and this molecule hits four of them. The one in the skin makes pigment. The ones in the brain control appetite, blood pressure and sexual arousal, and they are switched on at the same time. Almost every reported side effect is one of those other receptors doing its job.
What happened in people
It darkens skin, but no study has shown how much sun protection that provides.
✓ Reviewed first-read answer
Where this came from
A person wrote this and a reviewer approved it against this exact record. It carries no effect size.
A reviewer approved this against this record. The reviewed-claim record carrying the exact population and effect size does not exist yet.
No source is stored against this line.
The limit that matters most
Users often also use sunbeds, making reported skin-cancer cases difficult to interpret.
Where it acts
Melanocortin receptors on epidermal melanocytes, and MC3R and MC4R in the hypothalamus
Kind of result
The kind of result is not recorded
Supervision
RNAWiki has not recorded a supervision or regulatory status for this substance.
What the registries record it as
The substance registry classes this as chemical.
FDA substance registry · UPF5CJ93X7 · read 2026-08-29
Its recorded molecular formula is C50H69N15O9, weighing 1024.2.
PubChem record · 92432 · read 2026-08-29
Where each sentence above came from
No recorded sentence describes the change this makes in a way that stands on its own. The page opens with what it is taken for instead, and the recorded explanation follows below.
Shown as the opening line on this page.
The limit a reviewer approved as the one that matters most here.
The four opening statements run to 131 words.
Words this page uses
Four words worth knowing first
Chosen from what this page shows, with each one explained before the word it depends on.
Biomarker
A biomarker is a number from a test that stands in for something about health.
A picture of it, and where the picture fails
A biomarker is like a fuel gauge.
Where that stops being true. A gauge is wired to the tank. Many biomarkers are only loosely tied to health.
What people get wrong. A better number is read as a better life. Several medicines improved a number and helped nobody.
A measurable indicator used as a substitute for a clinical outcome of interest.
Placebo
A placebo is a dummy treatment given so the real one can be compared with it.
A picture of it, and where the picture fails
A placebo is like a blank control in an experiment.
Where that stops being true. A blank does nothing. People given a placebo often do get better.
What people get wrong. A placebo effect is read as imaginary. The improvement is measured and real.
An inactive intervention matched in appearance to the test intervention, used to control for non-specific effects.
Comparator
A comparator is whatever the treatment was measured against.
A picture of it, and where the picture fails
It is like the other runner in a race.
Where that stops being true. A race has one winner. A study can show both arms improved.
What people get wrong. Results are read without asking what the other group got. Beating nothing is not beating a treatment.
The control condition against which the experimental intervention is assessed.
What happened in people◇Read from sources, not yet reviewed
What happened in people
Each card is one study: the exact question it asked, who was in it, and whether it showed what it set out to show.
No registered phase 3 trial, no approved label and no established dose exist for this molecule in any jurisdiction
✗ The study did not show it
Who was studied
No completed clinical development programme exists for melanotan II
How many people
0
Study design
None completed
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Not applicable
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. No limitation is recorded for this study.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Subcutaneous injection of reconstituted lyophilised peptide; also sold as a nasal spray
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Adverse events temporally associated with melanotan II use: melanoma, atypical naevi, rhabdomyolysis, renal infarction, priapism, PRES, oral mucosal change
✓ The study showed what it set out to show
Who was studied
Published case reports, 2012 to 2026
How many people
0
Study design
Case reports and case series
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Descriptive. Case reports establish that events occur and give no denominator, so no rate can be calculated
Repeated elsewhere
Partially Replicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. Product content is unverified in every published case, so attribution is to "a product sold as melanotan II" rather than to a measured quantity of the peptide.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Subcutaneous injection of reconstituted lyophilised peptide; also sold as a nasal spray
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
RNAWiki holds 2 written-up human studies for this substance, each with the question it asked.
How we know it
Each card names the study, the number of people and what the study set out to measure.
What this does not prove
These summaries were written by a person and have not been signed off as reviewed claims.
Why it matters
A study that failed is as informative as one that worked, and both are here.
What we still do not know
No reviewed claim exists, so no exact population, effect size or interval is published yet.
What happened in people◇Read from sources, not yet reviewed
How close this is to real life
The top step is something a person would feel or care about. The bottom is a guess from software. Filled steps are where evidence exists for this substance.
□Living longer, or avoiding a major eventNo evidence recorded. Death, a heart attack, a stroke, a hospital stay.No registered study measures this.
□What a body can do day to dayNo evidence recorded. Walking, dressing, breathing, recovering.No registered study measures this.
□Measured performanceNo evidence recorded. How much was lifted, how far was run, how fast.No registered study measures this.
□Symptoms and quality of lifeNo evidence recorded. Pain, tiredness, mood, sleep, as the person rated it.No registered study measures this.
□A number that stands in for healthNo evidence recorded. Cholesterol, blood sugar, bone density. A stand-in, not the thing itself.No registered study measures this.
■A step measured inside a personEvidence recorded. Something measured in human tissue or human cells.A human record sits on the stored organism ladder.
□AnimalsNo evidence recorded. Mice, rats, dogs. Useful for ideas, not proof about people.No animal record is stored.
□Cells in a dishNo evidence recorded. Cells or chemistry on a bench, far from a whole body.No cell or bench record is stored.
□A guess from softwareNo evidence recorded. Nobody measured it. RNAWiki never publishes one as a finding.RNAWiki stores no prediction for this record. Software can suggest a link. RNAWiki does not publish one as a finding.
Higher on these steps means closer to something a person would feel. It does not mean better done.
What it changes in the body◇Read from sources, not yet reviewed
The path through the body
From what a person takes to what changes. A solid line is a step measured in people. A dashed line is a step nobody has measured that way.
Start
Melanotan II
What a person takes: Subcutaneous injection of reconstituted lyophilised peptide; also sold as a nasal spray.
The measurement behind this step
Supplied as a freeze-dried powder in an unmarked vial, reconstituted by the user with water and injected subcutaneously. The labelled milligram figure on such vials refers to gross fill weight rather than peptide content, which is typically lower once counterions and residual water are accounted for, so nobody using it knows their dose even approximately. Nasal spray preparations have their own case literature including a report on oral mucosal melanoma.
Getting in
Injected subcutaneously after reconstitution
It comes as a freeze-dried powder that the user mixes with water and injects under the skin. It is also sold as a nasal spray.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Lyophilised peptide reconstituted with bacteriostatic or sterile water and injected subcutaneously. The cyclic lactam confers resistance to proteases, giving a longer duration than native alpha-MSH. Nasal administration is increasingly reported and has its own case literature.
Reaches melanocortin receptors on skin and in the brain
It travels in the blood to the pigment cells in the skin and also reaches receptors in the brain that control appetite, arousal and blood pressure.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Distributes to epidermal melanocytes expressing MC1R and to hypothalamic neurons expressing MC3R and MC4R. It also engages MC5R in exocrine tissue. The only melanocortin receptor it does not meaningfully engage is MC2R, the adrenal ACTH receptor.
It is not selective. One receptor gives the tan; the others give nausea, appetite loss, erections and blood pressure changes.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Potent agonism at MC1R, MC3R, MC4R and MC5R, all Gs-coupled, raising intracellular cyclic AMP. MC1R activation on melanocytes is the intended effect. MC4R activation in the hypothalamus produces the appetite suppression and the erectile response, the latter being the effect bremelanotide was licensed for.
Cyclic AMP rises inside the pigment cell, tyrosinase is switched on, and the cell starts making the dark form of melanin.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
MC1R-driven cyclic AMP raises MITF expression and tyrosinase activity, shifting melanogenesis from pheomelanin towards eumelanin and increasing melanosome transfer to keratinocytes. Existing naevi darken along with the surrounding skin, and new melanocytic lesions have been reported to erupt.
The skin darkens as intended. The published harms are melanoma, new atypical moles, muscle breakdown, kidney infarction, prolonged erection and a blood-pressure-related brain syndrome.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Pigmentation is the reliable, intended outcome. The reported adverse events map onto the non-MC1R receptors and onto the pigment change itself: melanoma and atypical naevi from melanocyte stimulation, priapism from MC4R, rhabdomyolysis and renal infarction from mechanisms the nephrology literature describes as thrombotic or directly toxic, and PRES from blood pressure lability.
No suggested links are held for this record, so nothing is hidden from this path.
What we know
The record describes 5 steps from taking it to an effect in a person.
How we know it
Each step names the study behind it in the technical detail beside it.
What this does not prove
A change inside the body is a reason to look. It is not a result in a person.
Why it matters
A reader can see exactly where the chain stops being measured in people.
What we still do not know
No reviewed claim binds any of these steps to a named population.
What is missing or unclear◇Read from sources, not yet reviewed
Were people like you studied?
RNAWiki cannot tell whether a study fits you. It can show who was in it, and where the result stops carrying.
Who was studied
People similar to this profile were included.
People wanting a tan, particularly younger people attending gyms, and men using it for its erectile effect. It is sold as a lyophilised powder for reconstitution and injection, and increasingly as a nasal spray.
Who is missing from the studies
Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
Where the result stopped carrying
No development programme was ever completed; there is no registered phase 3, no label and no established dose anywhere in the world
Product content is unverified in every published case, so even the exposure in the case literature is nominal rather than measured
This is a scope explorer, not a diagnosis engine.
It shows who was studied so you can see whether people similar to you were included.
RNAWiki cannot tell whether a study fits you. It can show who was in it.
What it would be like to take◇Read from sources, not yet reviewed
Why it might seem to do nothing
A real effect and a noticed effect are different things. These are the recorded reasons the two come apart.
It was studied in different people
The people in the studies were not much like the reader.
On this record: Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
The evidence may simply be wrong
Small early studies often do not hold up.
On this record: RNAWiki has not yet published a reviewed conclusion for this use.
Other reasons RNAWiki checked and found nothing for (11)
It was studied for a different goal
The studies measured something else entirely. Nothing in this record points to this reason.
A different form was studied
The studied form is not the form on the shelf. Nothing in this record points to this reason.
There was nothing to correct
Where a level is already normal, topping it up may change nothing. Nothing in this record points to this reason.
Something else had to happen too
In the studies it was paired with training, a diet or another treatment. Nothing in this record points to this reason.
The change is too small to feel
A real change can still sit below what a person notices. Nothing in this record points to this reason.
Day-to-day swing hides it
Sleep, food, stress and time of day move most numbers more than this would. Nothing in this record points to this reason.
Not enough time yet
The studies ran longer than the person has waited. Nothing in this record points to this reason.
It was not taken as studied
Missed days change the result, and studies count them. Nothing in this record points to this reason.
Something else changed at the same time
Two changes at once cannot be told apart afterwards. Nothing in this record points to this reason.
The product may not be what it says
Contents of a sold product are not always what the label states. Nothing in this record points to this reason.
No recorded reason
RNAWiki has nothing stored that would explain it. Nothing in this record points to this reason.
None of these is a reason to take more. Taking more is not a step this page ever suggests.
What it would be like to take◇Read from sources, not yet reviewed
What taking it involves
The recorded facts about getting hold of it and using it. Nothing here is a suggestion about what you should do.
How it is supplied
Not available
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Read from the recorded approval status.
No source is stored against this line.
Form and route
Subcutaneous injection of reconstituted lyophilised peptide; also sold as a nasal spray
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form and route recorded on this substance.
No source is stored against this line.
Who oversees it
RNAWiki has not recorded a supervision or regulatory status for this substance.
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
No register row and no identity class settled the question.
No source is stored against this line.
What is in the pack
Supplied as a freeze-dried powder in an unmarked vial, reconstituted by the user with water and injected subcutaneously.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on how this is sold. The rest of the recorded wording: The labelled milligram figure on such vials refers to gross fill weight rather than peptide content, which is typically lower once counterions and residual water are accounted for, so nobody using it knows their dose even approximately. Nasal spray preparations have their own case literature including a report on oral mucosal melanoma.
No source is stored against this line.
Where it is registered
Regulatory records are listed in the technical disclosure at the foot of this page.
# Counted from records
Where this came from
A count of rows RNAWiki holds. It describes our records, not your body.
Register entries are stored per jurisdiction and shown with their dates.
No source is stored against this line.
Why people stop
Not recorded.
∅ Nothing recorded
Where this came from
RNAWiki holds nothing here and says so rather than guessing.
No record of why people stopped taking it is stored for this substance.
No source is stored against this line.
What it would be like to take◇Read from sources, not yet reviewed
What can go wrong
Sorted by where each line came from. A regulator's label and a report somebody sent in are not the same kind of fact.
·Worth asking a clinician aboutWritten into the record from the studies named on this page
No safety database exists because no development programme was completed. The published harms are melanoma and eruptive atypical naevi, rhabdomyolysis, renal infarction, priapism, posterior reversible encephalopathy syndrome, oral mucosal pigment change and depigmented patches. Nausea, flushing and appetite suppression follow from MC4R agonism and are near-universal in reports; the same effects appear as the commonest adverse events in the phase 3 trials of the approved analogue bremelanotide, where nausea, flushing and headache each occurred in 10% or more of treated participants.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
Over a long time. No completed tested study window is recorded, so long-term effects are not established by the registry record.
Groups the studies covered thinly. Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What is missing or unclear◇Read from sources, not yet reviewed
Does the exact form matter?
Evidence belongs to the exact thing that was tested. A different salt, a different mixture or a different preparation is a different question.
The form that was studied
Subcutaneous injection of reconstituted lyophilised peptide; also sold as a nasal spray
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form used in the studies cited on this page.
No source is stored against this line.
What is sold
A recorded note compares this form with the others that are sold. It is kept below, word for word.
§ A fixed RNAWiki sentence
Where this came from
Wording RNAWiki always uses, not a finding about this substance.
The recorded note, unchanged: The labelled milligram figure on such vials refers to gross fill weight rather than peptide content, which is typically lower once counterions and residual water are accounted for, so nobody using it knows their dose even approximately. Nasal spray preparations have their own case literature including a report on oral mucosal melanoma.
No source is stored against this line.
What is recorded as being sold
5 products list this as an active ingredient in the United States drug directory. 5 of them contain it and nothing else.
FDA National Drug Code directory · 73212-031 · read 2026-08-29
They are sold as powder.
FDA National Drug Code directory · 73212-031 · read 2026-08-29
788 marketed supplement labels list this ingredient, classed as amino acid/protein, botanical, non-nutrient/non-botanical and other combinations.
Those labels carry all other, nutrient and structure/function claims. A claim of that kind is written by the manufacturer and is not assessed by any regulator, so its presence says nothing about whether it is true.
Evidence carries across two names for one substance. It does not carry across a salt, a mirror form or a mixture.
What it would be like to take◇Read from sources, not yet reviewed
What you could measure
This one is decided with a clinician, so this section holds questions to ask rather than a plan to run.
RNAWiki could not confidently classify this substance, so no self-experiment plan is offered.
Questions worth asking
Which of the trials of Melanotan II studied people like me?
What was measured, and for how long?
Was the result a laboratory value or a health outcome?
What would we watch for, and when would we stop?
Tracking can show whether something changed for you. It cannot show what caused it.
RNAWiki records evidence. It does not say whether this substance is right for you.
What is missing or unclear◇Read from sources, not yet reviewed
Claims that go past the evidence
Things said about this substance that sound reasonable, and the exact step that is missing between the evidence and the claim.
✗Goes past the evidence
That induced pigmentation is photoprotective — never measured in humans, and the documented pattern is concurrent sunbed use rather than substitution
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That the case reports establish a rate of harm; they establish occurrence with no denominator, and this page gives no rate
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That approval of bremelanotide implies anything about melanotan II beyond shared core pharmacology
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
What is missing or unclear◇Read from sources, not yet reviewed
What nobody knows yet
Open questions, each with why it is open and what would close it.
How much did people take in the studies?
The sources RNAWiki checked hold nothing for this field.
Why it matters. A result belongs to an amount. Without the amount the result floats free.
What would answer it
A stored source that records it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
How fast does the body clear it?
The sources RNAWiki checked hold nothing for this field.
Why it matters. Without this, nothing on this page can say how long anything lasts.
What would answer it
A stored source that records it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing populations
Which groups were under-represented in the studies has not been recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing long-term data
No completed tested study window is recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
No reviewed conclusion
RNAWiki has not yet published a reviewed conclusion for this use.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing interaction studies
No interaction was found in the registers checked. Not finding one is not the same as showing there is none.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Formulation uncertainty
Several salts, forms or products of Melanotan II are recorded. Results from one form may not transfer to another.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Mechanism not reviewed
No reviewed mechanism story exists for this substance.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
What happened in people◇Read from sources, not yet reviewed
Check any of this yourself
Every line above traced back to the study it came from. This is the technical layer, and the vocabulary changes here.
Every line above can be traced to the study named beside it. Follow the link and read it.
Melanoma reported three months after a four-week course
In plain words
A 20-year-old woman with pale skin was found to have a melanoma on her buttock three months after a three-to-four-week course of self-injected melanotan II alongside sunbed use.
What was measured
Histologically confirmed melanoma following documented melanotan II exposure
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Hjuler and Lorentzen reported a 20-year-old woman with Fitzpatrick skin type II referred with a suspicious black melanocytic lesion in the left gluteal region and universally intensely pigmented skin. Histology confirmed melanoma. Three months before excision she had completed a three- to four-week course of MT-II self-injections intended to augment sunbed tanning. The authors are careful about what this shows: melanocyte stimulation by MT-II combined with sunbed use coincided with melanoma, in a single patient. They state that because the drug is unlicensed and incompletely tested, the extent and types of adverse effect are unknown. A 2026 case report describes five primary melanomas in situ in a patient with recent tanning bed use, melanotan exposure and anabolic hormone use, and a 2025 report raises melanotan II nasal spray as a possible risk factor for oral mucosal melanoma.
Written into the record, not signed off as a reviewed claim
Systemic toxicity with rhabdomyolysis after injection
In plain words
A 2012 report in Clinical Toxicology described systemic toxicity including muscle breakdown after melanotan II injection, and it generated correspondence in the journal.
What was measured
Creatine kinase and renal function following melanotan II injection
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
A case published in Clinical Toxicology in 2012 described melanotan II injection resulting in systemic toxicity and rhabdomyolysis, and drew a letter to the editor with a published response the following year — the exchange itself is a useful record of how contested attribution is for an unlicensed injectable of unknown content. Rhabdomyolysis with melanotan II is subsequently cited in the nephrology literature as an established association, alongside a reported case of renal infarction in which the authors consider both a thrombotic pharmacological influence and a possible direct toxic effect on renal parenchyma.
Written into the record, not signed off as a reviewed claim
Priapism, renal infarction and posterior reversible encephalopathy syndrome
In plain words
Published cases include prolonged painful erection requiring treatment, a kidney infarction, and a brain syndrome associated with sudden blood pressure changes.
What was measured
Documented cases of priapism, renal infarction and PRES following melanotan use
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Priapism after melanotan is documented in at least two independent case reports, in BMJ Case Reports and in Sexual Medicine. Renal infarction attributed to melanotan II is reported with a literature review in CEN Case Reports. Posterior reversible encephalopathy syndrome associated with melanotan was reported in Annals of Internal Medicine in 2013. These are mechanistically coherent rather than random: MC4R agonism in the hypothalamus drives erectile response — which is precisely the effect that bremelanotide was approved to produce — and melanocortin agonism has documented cardiovascular effects on blood pressure and sympathetic outflow. The side effects are the drug working, on the receptors nobody was aiming at.
Written into the record, not signed off as a reviewed claim
Eruptive atypical naevi and pigment changes
In plain words
Injecting melanotan can make existing moles darker and new atypical moles appear, which is a problem in itself: it makes skin cancer harder to spot.
What was measured
Appearance of new atypical naevi and darkening of existing naevi after exposure
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Atypical melanocytic naevi following melanotan injection were reported in the Irish Medical Journal in 2013, and melanotan appears in reviews of eruptive melanocytic naevi as a recognised trigger. Reports also describe depigmented facial and neck patches following melanotan use, and changes in oral mucosa associated with melanotan II injections. The clinical consequence is second-order and easy to miss: a drug that darkens existing naevi and produces new ones degrades the visual criteria dermatologists use to identify melanoma early, in exactly the population most likely to be using sunbeds at the same time.
Written into the record, not signed off as a reviewed claim
A tan from melanotan is not sun protection
In plain words
The pigment produced is real, but nobody has measured how much ultraviolet protection it gives, and the people using it are typically using sunbeds at the same time.
What was measured
That melanotan-induced pigmentation is photoprotective, a claim never measured in humans and undercut by the concurrent sunbed use described in the case series
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The implied argument for melanotan II is that induced pigmentation substitutes for sun exposure and therefore reduces ultraviolet damage. No study has measured the sun protection factor conferred by melanotan-induced pigmentation in humans, and the case reports describe concurrent sunbed use rather than substitution — the 20-year-old with melanoma was using MT-II specifically to augment sunbed tanning. A related compound, afamelanotide, is licensed for erythropoietic protoporphyria, but its evidence base and its indication are its own and do not transfer. This page records the absence of any measured photoprotection rather than assuming a direction.
Written into the record, not signed off as a reviewed claim
The molecule next to it got approved; this one did not
In plain words
Bremelanotide differs from melanotan II by a single chemical group at one end, and it is an FDA-approved drug. Melanotan II was never developed, and the difference is instructive.
What was measured
That the two peptides can be treated as interchangeable because they differ by one terminal group, when one has a completed phase 3 programme and a label and the other has neither
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Bremelanotide is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH; melanotan II is the same peptide with a C-terminal amide instead of the free acid. Bremelanotide completed two identical phase 3 trials in 1,267 women, was approved by the FDA in 2019 as Vyleesi under NDA 210557, and carries a label describing its dose, its contraindications and its adverse effects. Melanotan II has no completed programme, no registered phase 3, no label and no dose. The same core pharmacology therefore exists in two forms, one of which a reader can look up in a prescribing information document and one of which is a powder in an unmarked vial. The relevant lesson is not that melanotan II must be dangerous because it was not developed, but that everything a label would tell you about it is simply absent.
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Written for a clinical reader, and about the medicine as a whole rather than about one indication, population and set of trials. RNAWiki does not treat it as a programme conclusion and no reviewer has signed it off in that form. It is here word for word because it is what the record holds.
A non-selective melanocortin agonist that darkens skin exactly as advertised, is unlicensed in every country, and appears in published case reports of melanoma, eruptive atypical naevi, rhabdomyolysis, renal infarction, priapism and posterior reversible encephalopathy syndrome.
Recorded evidence blocks (4)
Q1
What did Melanotan II's largest trial (60 people) and its longest (2 years) measure?
60 people in Melanotan II's largest registered study, 2 years in its longest registered window, measuring Change from baseline in Vitiligo Area Scoring Index (VASI) total score. ClinicalTrials.gov · 2026-09-01
1 phase2; NCT07437560; 2028-02-17; no ageing endpoint recorded
Interpretation These counts include studies where Melanotan II was a comparison treatment, a background treatment or an exposure in an observational study, and the longest window may be a planned end date. Trial roles have not yet been classified for this record.
Show the evidence
phase2
1
recorded 2026-09-01 · last checked 2026-09-04
Q2
Melanotan II was tested only in human — what did it show?
Interpretation Change from baseline in Vitiligo Area Scoring Index (VASI) total score
Show the evidence
TrialNCT07437560
"Melanotan II (MT-II) as an Adjunct to NB-UVB Phototherapy for Repigmentation in Stable Nonsegmental Vitiligo"; n 60; "Change from baseline in Vitiligo Area Scoring Index (VASI) total score"; 2028-02-17
recorded 2026-09-01 · last checked 2026-09-04
Q4
At the median, Melanotan II's trials enrolled 60 people — anything larger?
Median enrolment
60
Largest enrolment
60
Registered trials counted
1
Where it is registeredIdentifiers, relations and other names
ClinicalTrials.gov — US Government work · Europe PMC — metadata only, under the recorded legal gate · derived from this page's own recorded fields; no external licence
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