Reference

Last reviewed: 29 Apr 2026
Sources cited: 8

Compound class1,024.18 Da

Synthetic cyclic heptapeptide α-MSH analogue — non-selective melanocortin (MC1R/MC3R/MC4R/MC5R) agonist

7-residue cyclic peptide structurally similar to PT-141 (same core ring; differs in C-terminal modification). Contains non-natural Nle, D-Phe, N-acetylation, C-amidation, and Asp-Lys side-chain cyclisation. The standard 3-letter sequence parser handles linear natural-amino-acid peptides only, hence the fallback.

Melanotan II

Last verified: 2026-04-29

At a glance


Also known as	MT-II, MT2, Melanotan-2
Class	Synthetic cyclic heptapeptide α-MSH analogue; non-selective melanocortin receptor agonist (MC1R, MC3R, MC4R, MC5R)
Typical route	Subcutaneous injection, daily during loading phase, then 2–3× weekly for maintenance
Half-life	~33 minutes (terminal); functional effect window ~6–8 hours per dose
Molecular weight	1,024.18 Da
Sequence	Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂ (7 residues, cyclised between Asp and Lys side chains; N-acetylated and C-amidated — closely related to PT-141 but with a free amide rather than free acid C-terminal)
UK status	Not approved. MHRA explicitly warns against use; sale for human consumption is unlawful. Sold as a research chemical.
US status	Not FDA-approved for any indication. Not DEA-controlled but explicitly flagged by FDA as illegal to sell for human use. Sold as a research chemical labelled “not for human consumption.”8
Australia status	TGA has issued explicit consumer warnings against use.

What it is

Melanotan II is a synthetic cyclic heptapeptide derived from α-MSH (alpha-melanocyte stimulating hormone), originally developed at the University of Arizona in the 1990s as a potential photoprotective tanning agent. It was envisaged as a way to induce melanin production without UV exposure, theoretically reducing skin cancer risk. Clinical development was discontinued; the related compound afamelanotide (Melanotan I) was developed instead and now has limited regulatory approval for specific photosensitivity disorders, but Melanotan II itself never received approval anywhere.

The compound is structurally close to PT-141 (covered separately in this encyclopedia) — both are cyclic α-MSH analogues with the same core ring structure, differing only in the C-terminal modification (Melanotan II has an amide, PT-141 has a free acid). PT-141 was the daughter compound, developed deliberately to shift selectivity towards MC4R and away from MC1R to give the sexual effect without the pigmentation effect. Melanotan II retains broad melanocortin agonism — MC1R driving pigmentation, MC4R driving sexual response and appetite suppression, MC3R and MC5R contributing additional effects.

The biohacker / research-chem community uses Melanotan II primarily for tanning — the UV-independent darkening effect. The sexual response (spontaneous erections in men, libido enhancement in some women) is a feature for some users and an unwanted side effect for others. The appetite suppression is variable. The compound is genuinely effective at producing pigmentation in users with sufficient melanocyte capacity (responds poorly in users with skin types 1–2, who are the population most interested in tanning).

The safety picture is the central editorial weight on this profile. Melanotan II has accumulated a documented case-report literature of eruptive atypical melanocytic naevi, dysplastic mole changes, and at least four published reports of melanomas emerging during or shortly after use. The FDA, MHRA, TGA, and Health Canada all explicitly warn against it. This isn’t a compound where the regulatory caution is generic — there’s a specific mechanistic concern (MC1R activation in melanocytes) and a specific case-report pattern.

Mechanism

Melanotan II is a non-selective agonist at all four melanocortin receptors (MC1R, MC3R, MC4R, MC5R), with effects mediated through each receptor:

MC1R (skin / melanocytes): activates tyrosinase, drives melanin synthesis (preferentially eumelanin — the darker, more photoprotective pigment). This is the tanning effect.
MC4R (hypothalamus): the same target as PT-141. Drives sexual desire and arousal (the “spontaneous erection” effect documented in men) and appetite suppression.
MC3R (hypothalamus): contributes to appetite regulation and energy balance.
MC5R (peripheral tissues): modulates exocrine secretions including sebaceous glands; contributes to the complaints about increased oiliness and acne some users report.

The compound’s design predates the era of receptor-selective melanocortin agonists. PT-141 was developed specifically to give the MC4R effect without the MC1R effect; Melanotan II is the original less-selective parent. The breadth of effects is both why it produces pigmentation effectively and why its side-effect profile is broad.

The half-life is short (~33 minutes), but the downstream pigmentation effect persists for weeks to months because melanocyte stimulation produces melanin that’s deposited in skin and gradually cycles out as skin turns over. This is why “loading then maintenance” dosing exists — you load to build pigmentation, then maintain at much lower frequency because the pigment itself persists.

Routes of administration

Subcutaneous injection (the standard route)


Bioavailability	Sufficient for the documented melanocortin effects
Onset	Pigmentation darkening becomes visible after 5–10 days of loading dosing; sexual effects within 1–2 hours per dose
Duration	Pigmentation persists weeks-to-months after a complete loading-and-maintenance cycle
Typical dose (loading phase)	250 mcg subQ daily for 1–2 weeks; some protocols start at 100 mcg first dose
Typical dose (extended loading)	500 mcg subQ daily for 2–3 additional weeks
Typical dose (maintenance)	500–1000 mcg subQ 2× weekly to maintain pigmentation
Equipment	Insulin syringe (29G–31G, U-100), bacteriostatic water, alcohol wipes
When this route makes sense	Default. Almost all community use is subQ.

Intranasal (rare)

Some research-chem vendors sell intranasal Melanotan II spray. Bioavailability is much lower than subQ and the dose-response is unpredictable. Not standard practice; the subQ route is what the dose protocols are designed around.

Oral, sublingual, intramuscular

Not viable. Melanotan II is GI-degraded; sublingual absorption is unreliable; IM offers no advantage over subQ.

Cross-route comparison

SubQ is the only meaningful route. All dose protocols, all community use, and all documented safety signals are from subQ administration.

What the evidence says

Honest summary: Melanotan II reliably produces UV-independent pigmentation through MC1R activation. The mechanism is well-characterised and the effect is real. The safety picture is dominated by documented case reports of dysplastic naevi, atypical mole changes, and at least four reports of melanomas emerging during or shortly after use. There is no FDA-approved or MHRA-approved formulation; the compound was developed in the 1990s, never brought to registrational trials, and is currently flagged by major regulators as unsafe for human use.

What’s mechanistically supported

Melanin synthesis via MC1R activation — well-established preclinical and clinical pharmacology
Sexual effects via MC4R activation — same mechanism as PT-141, documented in early development
Appetite suppression — MC3R/MC4R-mediated, dose-dependent

What’s documented in case-report literature

Eruptive atypical melanocytic naevi — multiple case reports describing new moles appearing or existing moles changing morphology during or shortly after Melanotan II use5 7
Dysplastic naevus changes — darkening, irregular borders, irregular pigmentation patterns in pre-existing moles
Melanoma — at least four published case reports describe melanomas emerging from existing moles during or shortly after Melanotan II use. The case-report literature does not establish causality — these are individual cases, not controlled comparisons — but the temporal pattern is consistent and mechanistically plausible enough that major regulators cite it
Systemic toxicity (rhabdomyolysis) — at least one reported case of severe systemic toxicity after a 6 mg single dose (six times the loading dose), highlighting the dose-response edge

What’s documented in larger consumer warning evidence

MHRA, FDA, TGA, Health Canada — all four regulators have issued explicit consumer warnings about Melanotan II
Hospital admissions — Australia in particular has reported hospital admissions for Melanotan II side effects, including the systemic toxicity case above

What the evidence does NOT show

No registrational trials — the compound was never developed beyond early-phase work
No long-term safety characterisation in any controlled population
No characterisation of melanoma risk attribution — the case reports don’t establish whether Melanotan II causes melanoma, accelerates pre-existing precursors, or co-occurs with other skin cancer risk factors. The mechanistic concern is real; the epidemiological case is unsettled
No comparison with afamelanotide (Melanotan I) — the related compound that did receive limited regulatory approval for specific medical indications

The evidence for the tanning effect is reasonable. The evidence for the safety claim is the inverse — there isn’t a body of safety data, there’s a body of case reports flagging concerns and a regulatory consensus against use.

Typical use patterns

Loading-then-maintenance (the dominant community pattern)

The standard protocol takes advantage of the pharmacology — load to build pigmentation, then maintain at lower frequency:

Loading phase (2–4 weeks):

Days 1–3: 100–250 mcg subQ daily (sensitive start to assess nausea tolerance)
Days 4–14: 250 mcg subQ daily
Days 15–28: 500 mcg subQ daily (if continuing to push pigmentation)

Maintenance phase:

500–1000 mcg subQ 2–3× weekly to maintain pigmentation
Most users settle at 500 mcg 2× weekly indefinitely if continuing
Some users complete a single loading cycle (4–6 weeks total) and stop, accepting that pigmentation will fade over months

Pre-UV-exposure dosing

A common pattern: load over 2–4 weeks to build pigmentation, then add modest UV exposure (sun or tanning bed) to deepen and stabilise the colour. The UV exposure produces less burn risk in already-pigmented skin, which is part of the (theoretical) photoprotective use case. The MHRA and dermatology societies do not endorse this approach — the melanoma-precursor concerns make any UV exposure under Melanotan II potentially additive risk.

Bedtime dosing for nausea management

Nausea affects 80–90% of users during loading, peaks 2–4 hours post-injection, and lasts 4–6 hours. Bedtime dosing (with empty stomach) is the dominant convention because it places the worst of the nausea during sleep. Some users also pre-dose with ondansetron 30–60 minutes before injection to mitigate.

Why a user might choose Melanotan II

Tanning without UV for users with type 3–6 skin who want darker pigmentation
Tanning preparation for users who burn easily and want some baseline pigmentation before sun exposure
Combined effect — tanning plus sexual response plus appetite suppression in users who want all three

Why a user should be cautious

Type 1–2 skin — limited tanning response, full side-effect exposure (the compound works less well in the population most interested in tanning)
Pre-existing moles, especially dysplastic naevi or family history of melanoma — relative contraindication
Users uncomfortable with the sexual side effects (spontaneous erections, libido changes) — these are not optional features
Users with cardiovascular concerns — blood pressure increases are documented

Stacking

PT-141 — redundant; same receptor system. Stacking accelerates pigmentation accumulation and produces additive cardiovascular effects.
Other melanocortin agonists — same redundancy concern
GLP-1 agonists — both compounds suppress appetite; the combined effect can be excessive in some users
No documented direct interactions with peptides outside the melanocortin family

For sensitive systems

Melanotan II’s profile in sensitive-systems users is distinct from the rest of the encyclopedia because the receptor system it acts on (melanocortin) is implicated in autonomic regulation, immune signalling, and food intake beyond its peripheral pigmentation effects. Sensitive-systems users are the population most likely to react to the compound’s broader effects.

Start dose for sensitive users. 100 mcg subQ at bedtime, empty stomach, with ondansetron pre-dose. Hold for 3–5 days. The first-dose nausea risk is dose-related; starting at one-third the standard loading dose dramatically reduces the introduction-period burden.

Ramp. If 100 mcg is tolerated, 200–250 mcg for the next phase; many sensitive users find sub-loading-dose protocols sufficient (low-dose cycles producing modest pigmentation rather than aggressive loading).

Expected adjustment profile:

Nausea — affects 80–90% of users, especially during loading. Peaks 2–4 hours post-dose. The dominant first-week effect. Often improves with subsequent doses.
Facial flushing and warmth — common, melanocortin-mediated.
Yawning and stretching — common, especially within 1–2 hours of dosing.
Spontaneous erections in men — typical with MC4R activation. Not optional.
Libido changes — variable in both directions.
Appetite suppression — modest in most users but can be more pronounced in some.
Increased skin oiliness, acne, sebaceous gland changes — MC5R-mediated.
Blood pressure increase — modest but documented; consider monitoring.
Pigmentation in unexpected locations — face, lips, gums, areolae, scars, freckles. Pigmentation is not uniformly distributed across the body.
New mole formation or existing mole darkening — documented; stop and consult dermatology if this occurs.

What’s not normal and warrants stopping: severe nausea unrelieved by antiemetics, persistent blood-pressure elevation, atypical chest sensations, syncope, severe muscle pain (the rhabdomyolysis case report involved 6× normal dose), any change in existing moles (size, shape, colour, asymmetry), new pigmented lesions with concerning features.

For MCAS / histamine-sensitive users. No specific histamine activity documented but the flushing and broader autonomic effects can mimic mast-cell reactions. Tolerance varies widely in this population; sensitive-start dosing is essential.

For POTS users. Worth specific caution. The blood-pressure changes plus the broader autonomic effects of melanocortin agonism produce more variable responses than for non-POTS users. Some POTS users tolerate Melanotan II with cautious dosing; others find the cardiovascular effects unmanageable. Monitor HR/BP for several hours post-dose.

For users with cardiovascular risk factors. Relative contraindication. Hypertension, prior MI, family history of premature CHD, diabetes — the cumulative cardiovascular exposure plus the case-report data on cardiac events make Melanotan II a poor choice in this population.

For users with melanoma risk factors. Strong relative contraindication. Personal or family history of melanoma, dysplastic naevus syndrome, large numbers of pre-existing moles, fair skin with lots of sun damage — these are exactly the populations the case-report melanoma signals come from. The mechanistic concern (MC1R activation in melanocytes) is most directly relevant here. Choose a different approach.

For users on photosensitising medications. Tetracyclines, certain SSRIs, isotretinoin, others — the combination with Melanotan II’s UV-modulating effects has not been characterised; pragmatic caution is warranted.

For pregnancy and breastfeeding. Contraindicated; no safety data and broad melanocortin effects on fetal development are not characterised.

Interactions worth considering:

PT-141 — redundant; same system.
Antihypertensives — monitor BP.
GLP-1 agonists — combined appetite suppression can be excessive.
Photosensitising medications — combined effects uncharacterised.

Reasonable expectations

Onset. Pigmentation darkening typically becomes visible after 5–10 days of loading dosing, deepens over 2–4 weeks, and peaks 1–2 weeks after the loading phase ends. Sexual and appetite effects per-dose appear within 1–2 hours.

Response rate. Melanin response is highly skin-type-dependent. Users with type 3–4 skin (already tan or olive) respond well — modest doses produce noticeable darkening. Users with type 5–6 (already dark) get less differential effect. Users with type 1–2 (very fair, burns easily) often respond poorly — the melanocyte capacity isn’t there to drive substantial pigmentation, and they get the side-effect profile without the pigmentation benefit. The skin type that benefits least is the skin type most interested in the compound — this is the central practical paradox.

What the evidence actually supports.

UV-independent pigmentation increase in users with sufficient melanocyte capacity
MC4R-mediated sexual response — spontaneous erections in men are pharmacologically reliable
Appetite suppression — modest, dose-dependent

What the evidence does not support.

Photoprotection from melanin alone — increased pigmentation does provide some natural sun protection but is not equivalent to sunscreen and does not offset the melanoma signals
Safety claims of any kind — the case-report literature consistently flags concerns; no controlled safety data exists
“Bronzed glow” predictability — pigmentation is patchy and unpredictable in distribution, especially in mole-rich skin

What not to expect.

Even, predictable tanning. Pigmentation darkens existing pigmented sites disproportionately — moles, freckles, scars, areolae, gums all darken first.
Effect in fair skin types. Type 1–2 skin responds poorly.
Permanent pigmentation. Without maintenance dosing, pigmentation fades over weeks to months as skin turns over.
Safe with concurrent UV exposure. UV plus Melanotan II is potentially additive risk for the documented case-report concerns.

Cost

Melanotan II is not available through any licensed pharmacy in the UK, US, EU, or Australia.

Research-chemical UK market:

10 mg vials: ~£20–50
Combined Melanotan II vials are dominant; some vendors sell 5 mg as well

Monthly cost during loading at 250–500 mcg/day: approximately £15–35/month Monthly cost during maintenance at 500 mcg 2×/week: approximately £8–20/month

The compound is among the cheapest peptides in the research-chem market, which reflects how widely it’s manufactured rather than its quality consistency.

Sensitive-start economics. A user starting at 100 mcg/day uses ~40% of the standard loading dose. A 10 mg vial covers ~100 sensitive-start doses, well over the 30-day reconstituted shelf life — most of the vial will be discarded. Smaller vials help if available.

Reconstitution

What’s in the box

Research-chemical Melanotan II ships as lyophilised white powder in a glass vial, typically 10 mg per vial. 5 mg vials exist but are less common; 10 mg is the dominant size.

You’ll also need:

Bacteriostatic water (BAC water) — sterile water with 0.9% benzyl alcohol.
Insulin syringe (U-100) — 1 mL with 29G–31G needle.
A larger syringe (3 mL or 5 mL) for transferring BAC water into the vial.
Alcohol wipes, a clean working surface.

The math

10 mg vial, 2 mL BAC water (the standard)

Concentration: 5 mg/mL (5,000 mcg/mL)
100 mcg sensitive-start = 0.02 mL = 2 units (below the readability floor; consider 5 mL BAC for sensitive-start protocols)
250 mcg = 0.05 mL = 5 units (right at the readability floor)
500 mcg = 0.1 mL = 10 units
1000 mcg (1 mg) = 0.2 mL = 20 units

10 mg vial, 5 mL BAC water (for sensitive-start protocols)

Concentration: 2 mg/mL (2,000 mcg/mL)
100 mcg = 0.05 mL = 5 units
250 mcg = 0.125 mL = 12–13 units
500 mcg = 0.25 mL = 25 units

The Peptrax Vial Plan calculator handles the same math interactively.

Reconstitution procedure

Same procedure as the rest of the encyclopedia: alcohol-wipe stoppers, slow water injection down the vial side, no shaking, label vial, refrigerate.

Storage and stability

Melanotan II reconstituted with BAC water is stable for ~30 days refrigerated — at the longer end of the research-chem peptide range, similar to PT-141 and the GLP-1s.

Conservative: 21–28 days
Middle: 30 days
Optimistic: 30+ days

Store at the back of the refrigerator. Do not freeze.

If you reconstitute with plain sterile water, the vial is single-use — discard within 24 hours.

For a 10 mg vial during loading at 250–500 mcg/day: roughly 20–40 doses, comfortably within stability. Maintenance dosing at 2×/week extends the vial duration past stability and most users discard product.

What gets miscalculated

mcg vs mg confusion. Melanotan II is dosed in mcg (100–1000 mcg). 1000 mcg = 1 mg.
Reading “units” as mg.
Skipping nausea management. First-dose nausea is the rule; ondansetron pre-dose mitigates.
Loading without monitoring moles. Photograph existing moles before starting. This is the only way to identify changes that warrant stopping. Many users skip this and lose the baseline comparison.
Stacking with PT-141 or other melanocortin agonists. Redundant and accumulative for both pigmentation and CV exposure.

Areas of concern ⚠

Melanoma and atypical naevus risk

Multiple published case reports describe a recurring pattern:

Eruptive atypical melanocytic naevi (new moles appearing during use)
Dysplastic mole changes (existing moles darkening, becoming irregular)
At least four published reports of melanomas emerging during or shortly after Melanotan II use

The case-report literature does not establish causality — these are individual cases, not controlled trials. But the mechanism (MC1R activation in melanocytes drives both pigmentation and proliferation) is plausible enough that all major regulators cite the concern explicitly.

For users with personal or family history of melanoma, dysplastic naevus syndrome, or significant existing mole burden: treat Melanotan II as a strong relative contraindication. The risk-benefit calculation is unfavourable.

For all users: photograph existing moles before starting. Monitor for ABCDE changes (Asymmetry, Border irregularity, Colour variation, Diameter >6mm, Evolution). Any change in an existing mole is a stop-and-see-dermatology signal, not wait-and-see.

Cardiovascular effects

Documented blood-pressure increases (modest in most users; case reports of more pronounced effects in others), nausea-related vomiting and electrolyte effects, and the systemic toxicity case report at supratherapeutic dosing. Users with cardiovascular risk factors should treat Melanotan II as a relative contraindication.

Priapism

Melanotan II is a documented cause of priapism (sustained painful erection >4 hours) in men. Priapism is a urological emergency. Users who experience erection lasting >2 hours that won’t resolve should seek immediate care. The mechanism is the same MC4R agonism that produces the desired sexual response; the line between “spontaneous erection” and “priapism” is dose-related and individually variable.

Long-term safety entirely uncharacterised

There are no controlled long-term safety studies. The compound was never developed past early-phase work. Multi-year effects in healthy users are unknown. Mechanistic concerns:

Cumulative MC1R activation and melanocyte proliferation
Cumulative cardiovascular exposure even from transient per-dose effects
Unknown effects of chronic broad melanocortin activation on appetite regulation, immune function, and other physiological systems

Quality and sourcing

Standard research-chem caveats apply, with the additional concern that Melanotan II is one of the older and most widely manufactured peptides — quality variance is genuinely large. Lab-tested vendors with mass-spec or HPLC certificates are the meaningful quality marker. Some research-chem Melanotan II has been found to contain PT-141 instead (or vice versa) — the molecules are similar enough to look the same on a label but produce different effect profiles.

Populations where Melanotan II is contraindicated or high-risk

Personal or family history of melanoma — strong relative contraindication
Dysplastic naevus syndrome or significant existing mole burden — strong relative contraindication
Skin types 1–2 (very fair, burns easily) — poor pigmentation response with full side-effect exposure; risk-benefit unfavourable
Active or significant cardiovascular disease — relative contraindication
Hypertension, especially uncontrolled — caution
Pregnancy and breastfeeding — contraindicated
Under 18 — not studied; no use case justifies the safety profile in this population
Severe renal or hepatic impairment — caution; limited data
Photosensitising medication users — uncharacterised combined effects

Measurement and dosing pitfalls

mcg vs mg confusion — doses are in mcg.
Skipping the photographic baseline — without before-photos of moles, you can’t identify ABCDE changes.
Self-treating mole changes — any mole change warrants dermatology, not protocol adjustment.
Stacking with PT-141 — redundant; accelerates accumulation.
Ignoring nausea management — first-dose tolerance can be much better with ondansetron pre-dose.

What the community gets wrong

“Safer than tanning beds because no UV.” The melanoma signals from case reports complicate this comparison materially. Tanning beds carry well-quantified UV-mediated melanoma risk; Melanotan II carries less-quantified but mechanistically plausible melanocortin-mediated risk. Neither is a “safe” tanning option.
“Just for tanning, no other effects.” The compound activates four receptors and produces substantial off-target effects — sexual response, appetite changes, autonomic effects. These are not optional.
“Approved in some countries.” Melanotan I (afamelanotide) has limited approval for specific photosensitivity indications in some jurisdictions. Melanotan II has no approval anywhere. The two are different compounds and the approval status does not transfer.
“Lasts forever.” Pigmentation fades over weeks to months without maintenance dosing. The melanin itself is gradually shed with skin turnover.

FDA / regulatory status

Jurisdiction	Status	Last verified
US (FDA)	Not approved. FDA has explicitly flagged Melanotan II as illegal to sell for human use; the compound is sold as a research chemical labelled “not for human consumption.”8	2026-04-29
UK (MHRA)	Not approved. MHRA has issued explicit consumer warnings. Sale for human consumption is unlawful. Sold as a research chemical.	2026-04-29
EU (EMA)	Not approved. Multiple EU regulators have issued warnings.	2026-04-29
Australia (TGA)	Explicit consumer warning. The TGA has urged consumers to avoid Melanotan II. Hospital admissions for adverse effects have been documented.	2026-04-29
Canada (Health Canada)	Not approved. Consumer warnings issued.	2026-04-29
WADA (sport)	Not specifically prohibited, but compound use may trigger concerns under broader anti-doping rules; consult specific sport governing bodies.	2026-04-29

Narrative. Melanotan II is the compound in this encyclopedia with the broadest negative regulatory consensus. Every major Western regulator has issued explicit warnings; none has approved it. The case-report safety literature is the basis for this consensus. For all readers — UK, US, EU, Australia — there is no licensed pathway and the regulatory position is “do not use.” Research-chemical purchase is the only access route, and the legal grey-area is wider than for compounds with neutral regulatory positions.

What to track in Peptrax

A baseline photographic mole map is non-negotiable before the first dose of Melanotan II. Without before-photos, the ABCDE changes the case-report literature flags can’t be identified — the user has no comparison anchor. High-resolution photos of every existing pigmented lesion, taken in consistent lighting against a neutral background, are the foundation that everything else in the tracking protocol rests on.

For most users, the highest-signal log is per-dose nausea, BP changes, and any pigmentation observations (where it’s appearing, which sites are darkening unevenly, whether existing moles are changing). The pigmentation distribution is unpredictable, and tracking which sites darken first gives the user a sense of how their melanocortin response is patterning. Cumulative loading-phase dose count matters because the side-effect profile worsens with cumulative exposure within a loading phase.

For sensitive-systems users, the priority log is the first 1–2 weeks of loading: nausea severity, BP response, autonomic symptoms, and any orthostatic or mast-cell-pattern changes. A written stop criterion before starting matters here more than for most compounds, given the broader autonomic effects.

Across all users, monthly mole self-examination logs are the single most important Peptrax tracking pattern for this compound. Photograph the same sites every month during use and for 6 months after stopping. Any ABCDE change is a stop-and-see-dermatology signal. The app cannot substitute for clinical dermatology, but it can hold the timeline that makes the conversation with a dermatologist precise: “I started Melanotan II on date X, this mole looked like Y on date X+30, like Z on date X+60.”

For personal tracking and informational purposes only — not medical advice.