Side-by-side · Research reference

Melanotan-IIvsTB-500

Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.

APhase 1Reviewed9/43 cited

BPhase 2Reviewed8/46 cited

Melanotan-II

MC1R + MC4R agonist · Tanning + sexual response

0.25–1.0 mgPer doseDorr 1996

Phase 1Evidence levelDorr 1996

~1 hrHalf-life

SQ · Abdomen · Loading 5–7 days, then maintenance

TB-500

Thymosin β4 fragment · Healing

2 mgPer doseGoldstein 2012

Phase 2Evidence levelGoldstein 2012

~2 hrHalf-life

SQ or IM · Multiple sites · 2–3×/week

01Mechanism of Action

Parameter

Melanotan-II

TB-500

Primary target

MC1R (skin) + MC3R + MC4R (CNS sexual / appetite)Dorr 1996

G-actin (sequestering) + cell-surface integrinsGoldstein 2012

Pathway

MC1R agonism → melanocyte tyrosinase → eumelanin synthesis. MC4R → autonomic sexual arousal centresDorr 1996 Simerly 2023

Actin remodelling → cell migration; integrin-linked signaling → angiogenesis; anti-inflammatory cytokine modulationGoldstein 2012 Malinda 1999

Downstream effect

Skin darkening, photo-protection, increased sexual desire / spontaneous erectionDorr 1996

Accelerated wound healing, endothelial migration, hair follicle regeneration, cardiac repair (preclinical)Goldstein 2012

Feedback intact?

—

Endogenous protein at baseline; supplementation amplifies

Origin

Cyclic 7-AA modified α-MSH analog; designed at University of ArizonaDorr 1996

17-AA active fragment of endogenous 43-AA thymosin β4 (TMSB4X gene)Goldstein 2012

Antibody development

—

02Dosage Protocols

Parameter

Melanotan-II

TB-500

Loading phase

0.25–0.5 mg/day SQ × 5–7 daysDorr 1996

Builds up to visible tan.

—

Maintenance

0.5–1.0 mg 1–2×/week

After visible tan develops; supports with UV exposure.

—

Frequency

Daily during loading; 1–2× per week maintenance

2× per week (loading); then 1× per week (maintenance)

Lower / starter dose

0.1 mg / day

Conservative starter — assess tolerability for nausea.

1 mg per injection

Evidence basis

Phase 1 + anecdotalDorr 1996

Animal-strong + Phase 2 dermal/ocular trialsGoldstein 2012

Duration

8–12 weeks per cycle

4–8 weeks loading; longer maintenance for chronic injury

Reconstitution

Bacteriostatic water; protect from light

Bacteriostatic water, 1–2 mL per 5 mg vial

Timing

Evening preferred (24h tan-development cycle)

Evening or pre-rest preferred (anecdotal)

Half-life

~1 hour plasma; effects on melanocytes persist days

~2 hours (estimated; tissue uptake longer)

Standard dose

—

2 mg per injectionGoldstein 2012

Anecdotal community range; clinical Phase 2 trials used 70–840 mcg/kg IV.

04Side Effects & Safety

Parameter

Melanotan-II

TB-500

Nausea

Common, especially loading phase

—

Flushing

Common transient

—

Spontaneous erection

Common in men — MC4R cross-effectDorr 1996

—

Increased mole / freckle pigmentation

Existing moles darken; new lesions possible

—

Melanoma risk

Theoretical concern — increased melanocyte activity; CAUTION in melanoma history

—

Appetite suppression

MC4R-mediated; mild

—

Pregnancy / OB

Contraindicated

Avoid

Injection site reaction

—

Mild erythema, transient pain

GI symptoms

—

Rare nausea (anecdotal)

Cancer risk

—

Theoretical via angiogenesis pathway

Lethargy / fatigue

—

Reported anecdotally during loading phase

Antibody formation

—

No data (no long-term human trials)

Long-term safety

—

Unknown beyond Phase 2

Absolute Contraindications

Melanotan-II

·History of melanoma or atypical mole syndrome
·Pregnancy / breastfeeding
·Active uncontrolled hypertension

TB-500

·Active malignancy (theoretical angiogenesis concern)
·Pregnancy / breastfeeding

Relative Contraindications

Melanotan-II

·Significant freckling / dysplastic nevus
·Personal or family melanoma history

TB-500

·Cancer history
·Concurrent VEGF inhibitor therapy

05Administration Protocol

Parameter

Melanotan-II

TB-500

1. Reconstitution

Add 2 mL bacteriostatic water to 10 mg vial → 5 mg/mL = 500 mcg per 0.1 mL. Light-protected.

Add 1–2 mL bacteriostatic water to 5 mg vial → 2.5–5 mg/mL. Roll gently.

2. Injection site

SQ — abdomen. Rotate sites.

SQ near injury site (preferred), or systemic SQ (abdomen). Rotate sites.

3. Timing

Evening preferred. UV exposure (sunlight or tanning bed) helps develop tan.

Evening or pre-sleep is most common anecdotal timing.

4. Storage

Lyophilised: refrigerate, light-protected. Reconstituted: refrigerate ≤30 days.

Lyophilised: room temp, light-protected. Reconstituted: refrigerate, ≤30 days.

5. Needle

29–31G insulin syringe.

27–31G, 4–8 mm insulin syringe.

06Stack Synergy

Melanotan-II

— no documented stacks

TB-500

+ BPC-157

Strong

View BPC-157 →

TB-500 and BPC-157 cover complementary halves of tissue repair: BPC-157 upregulates VEGFR2-driven angiogenesis and fibroblast outgrowth; TB-500 sequesters G-actin to enable endothelial / epithelial migration. The anecdotal canonical "healing stack" — pairs especially well for tendon and ligament injuries.

TB-500: 2 mg SQ · 2× per week
BPC-157: 250–500 mcg SQ · daily
Primary benefit: Combined angiogenesis + cell migration for tendon/ligament/muscle repair