Melanotan II — Apex Research Reference

01 / IDENTITY

Compound Profile

7

AMINO ACIDS

~1.02

kDa MW

SC

ROUTE

1–2h

HALF-LIFE

CLASSIFICATION

Cyclic heptapeptide; synthetic analog of α-MSH (alpha-melanocyte stimulating hormone)

RECEPTORS

MC1R — melanocytes → skin pigmentation (tanning)
MC3R — hypothalamus → appetite suppression, energy balance
MC4R — brain/spinal cord → sexual arousal, erectile function (libido)

SEQUENCE

Ac-Nle-c[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂

DEVELOPED BY

University of Arizona — Dr. Mac Hadley & Dr. Victor Hruby, 1980s–1990s. Originally designed as a sunless tanning agent and skin cancer prevention tool.

DISTINCTION FROM MT-1

Melanotan I (afamelanotide) = MC1R selective only (tanning, no libido). Melanotan II = non-selective MC1R + MC3R + MC4R (tanning + appetite + sexual effects).

02 / RESEARCH HISTORY

Development Timeline

1980s

Hruby & Hadley at University of Arizona synthesize early MSH analogs while researching sunless tanning. The goal: create a compound that stimulates melanin production without UV exposure to reduce skin cancer risk.

1991

Melanotan II synthesized — the cyclic, more potent and metabolically stable analog of α-MSH. Self-experimentation by researchers (most famously, Norman Walker's documented self-injection) demonstrates profound tanning effect and unexpectedly strong erection as side effect.

1996–2000

University of Arizona Phase I/II trials establish MT-II's efficacy for erectile dysfunction (MEDLINE: Wessells et al., 1998, Journal of Urology). MT-II triggers erection via central CNS mechanism (MC4R in the paraventricular nucleus) independent of testosterone or NO/PDE5 pathway — works where Viagra fails in some cases.

2000–2005

Palatin Technologies develops bremelanotide (PT-141) — a stabilized MT-II derivative — for female sexual dysfunction. MT-II research splits: PT-141 → pharmaceutical development track; MT-II → tanning/grey market. Palatin drops MT-II due to BP side effect profile; pursues PT-141 intranasal formulation.

2010–present

MT-II remains one of the most widely researched peptides in the bodybuilding/aesthetics community globally. Extensive anecdotal database accumulated on tanning protocols, libido effects, appetite suppression, and side effect management. Continued use in research settings for melanocortin system studies.

03 / BENEFITS

Primary Effects

01

Accelerated Skin Tanning (MC1R)

MT-II stimulates melanocyte production of eumelanin (brown/black pigment) via MC1R activation. Requires UV exposure to "set" the tan — MT-II primes melanocytes; UV light triggers melanin transfer. Users typically achieve a 2–4 week tan in 5–10 sessions vs. months without. Tan persists 4–8 weeks post-cycle.

02

Sexual Function & Libido (MC4R)

MC4R activation in the paraventricular nucleus of the hypothalamus generates spontaneous erections in males and increased genital arousal in females. Clinical trials documented 80%+ response rate for erectile function independent of PDE5 inhibitors. Works in patients unresponsive to Viagra/Cialis by targeting a completely different mechanism (central vs. vascular).

03

Appetite Suppression (MC3R/MC4R)

Hypothalamic melanocortin system is a primary regulator of energy homeostasis. MT-II MC3R/MC4R activation reliably reduces hunger. Many users report 20–40% reduction in caloric intake during tanning cycles without intentional calorie restriction. Useful as an adjunct in fat loss protocols.

04

Photoprotection

Increased melanin production provides measurable UV protection. Dense melanin pigmentation (Fitzpatrick type IV–VI equivalent) reduces UV damage, DNA strand breaks, and sunburn. Not a replacement for sunscreen, but a functional benefit alongside cosmetic tanning.

04 / RECONSTITUTION

Preparation Protocol

// 10MG VIAL — STANDARD RECONSTITUTION

10,000 mcg ÷ 300 units BAC water = 33.3 mcg per unit

Add 3.0 mL (300 units) bacteriostatic water to 10mg lyophilized vial.

TARGET DOSE	UNITS TO DRAW	VOLUME	NOTE
INTRO250 mcg0.25 mg	7.5 units	0.075 mL	First use — assess nausea/side effects
LOW500 mcg0.5 mg	15 units	0.15 mL	Minimal side effects; moderate tanning
STANDARD1 mg1,000 mcg	30 units	0.30 mL	Standard tanning protocol
HIGH1.5 mg1,500 mcg	45 units	0.45 mL	Rapid loading; higher nausea risk

Storage: Lyophilized — refrigerate or room temp (light-protected). Reconstituted: refrigerate (2–8°C), 30-day stability. Do not freeze reconstituted peptide.

05 / DOSING PROTOCOL

Dual Protocol — Tanning vs. On-Demand

// TANNING PROTOCOL

LOADING PHASE

0.5–1.0 mg SC daily × 5–10 days (until desired base tan achieved). Pair each injection with 10–20 min UV exposure within 4 hours.

MAINTENANCE

0.5–1.0 mg SC 1–2×/week with brief UV exposure to maintain tan color.

TIMING

Inject 30–90 min before UV exposure. Side effects (nausea, flushing) peak at 30–60 min — plan accordingly.

// ON-DEMAND (LIBIDO/ED)

DOSE

0.5–1.0 mg SC approximately 90–120 minutes before desired activity.

FREQUENCY

As needed — not daily. Tolerance to sexual effects develops with frequent use. Use max 2–3× per week.

NOTE

Spontaneous erections may occur within 1–2 hours of injection. Normal physiological response. Reduces with lower doses.

Side Effects: Nausea (most common, 30–60 min post-injection), facial flushing, yawning, spontaneous erections. Nausea typically resolves by weeks 2–3 of use. Nausea management: inject in the evening before sleep; use 250–500 mcg starting doses; stay hydrated.

Mole/Nevus Monitoring: MC1R activation accelerates pigmentation of existing moles and nevi. Users must monitor existing moles for changes in size, shape, or color. Consult dermatologist if new moles develop or existing moles change during use. Do not use if personal/family history of melanoma.

06 / TIMING

Administration Timing

TANNING WINDOW

Inject 30–90 minutes before UV exposure. Plasma peak at 30–60 min. Melanocyte priming occurs over hours — UV exposure within 4 hours of injection is ideal.

EVENING DOSING

Preferred for side effect minimization. Sleep through the nausea and flushing window. Wake with effects resolved. More sustainable for loading protocols.

FOOD STATE

Empty stomach increases nausea risk. Light meal 1 hour before injection reduces GI side effects without blunting peptide absorption.

HALF-LIFE NOTE

MT-II has short plasma half-life (~1–2h) but biological effects persist much longer due to receptor internalization and downstream pigmentation processes (days to weeks).

FREQUENCY

Loading: daily × 5–10 days. Maintenance: 1–2×/week. On-demand: as needed, max 3×/week. Tolerance to tanning effects develops slowly — cycling is recommended.

UV PAIRING

10–20 min natural sunlight or tanning bed within 4 hours of injection dramatically amplifies melanin production. MT-II alone without UV produces minimal tanning.

07 / BIOMARKERS

Monitoring Panel

// SKIN SAFETY

MARKER	METHOD	CLINICAL RANGE	MONITOR FOR
Nevus/Mole MappingDermatoscopy	Dermatologist exam	CLINABCDE criteria (Asymmetry, Border, Color, Diameter, Evolution)	FLAGAny change in existing nevi — stop use, consult derm
Total Body Mole CountBaseline + Follow-up	Dermatologist mapping	CLINBaseline established before first use	FLAGNew moles during use — evaluate immediately

// CARDIOVASCULAR

MARKER	TEST	CLINICAL RANGE	EXPECTED
Blood PressureSystolic/Diastolic	Home BP monitor	CLIN<120/80 mmHg	NOTETransient rise (5–10 mmHg) for 1–2h post-injection is normal; monitor baseline
Heart RateResting HR	Wearable / pulse ox	CLIN60–100 bpm	NOTEMild tachycardia (flushing response) 30–90 min post-injection

// HORMONAL (LIBIDO PROTOCOL)

MARKER	TEST	CLINICAL RANGE	OPTIMAL
Total TestosteroneTotal T	Serum (AM, fasted)	CLIN300–1000 ng/dL	OPT600–900 ng/dL
SHBGSex Hormone Binding Globulin	Serum	CLIN10–57 nmol/L	OPT20–35 nmol/L
ProlactinSerum Prolactin	Serum	CLIN2–18 ng/mL (M)	OPT<10 ng/mL (elevated prolactin can blunt MT-II libido response)

08 / CYCLE PROTOCOL

Recommended Cycle

4–8

WEEKS LOADING

1–2×

MAINTENANCE/WK

8–12

WEEKS OFF

4–8wks

TAN LASTS

Loading (Weeks 1–2): Begin at 250 mcg to assess tolerance. Progress to 500 mcg after 3–5 doses if tolerated. Dose nightly. Combine each injection day with 10–20 min UV. Significant tan typically visible by days 7–14.

Loading (Weeks 3–4+): Advance to 1.0 mg if desired darkness not achieved. Most users reach target tan within 2–4 weeks. Loading phase can extend to 6–8 weeks for very fair skin (Fitzpatrick I–II).

Maintenance: 0.5–1.0 mg once or twice weekly with brief UV exposure maintains achieved tan indefinitely. Many users maintain a tan year-round on this protocol.

Off Cycle: Take 8–12 weeks off annually. Tan fades over 4–8 weeks without maintenance dosing. Recommended to see dermatologist for mole mapping annually, preferably during off-cycle.

Research Compound Notice: Melanotan II is not FDA-approved. Human clinical trials (University of Arizona) demonstrated efficacy for erectile dysfunction and demonstrated safety in controlled settings. Long-term use safety profile, particularly regarding nevus development, is not established in large-scale studies. Mandatory mole monitoring before, during, and after use. Not for use in individuals with personal or family history of melanoma or dysplastic nevus syndrome.