Side-by-side · Research reference

IGF-1 LR3vsMelanotan-II

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

AAnimal-StrongHUMAN-REVIEWED10/58 cited

BPhase 1HUMAN-REVIEWED9/43 cited

IGF-1 LR3

IGF-1 Analogue · Research

3–10×Potency vs IGF-I

Low IGFBPBinding affinity

ResearchStatus

Research only · SQ typical in animal models

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

01Mechanism of Action

Parameter

IGF-1 LR3

Melanotan-II

Primary target

IGF-1 receptor (IGF-1R)McTavish 2009

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

Pathway

IGF-1R → IRS-1 → PI3K/Akt → Cell proliferation, protein synthesis, anti-apoptosisMuhlbradt 2009

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

Downstream effect

Enhanced cell proliferation, muscle anabolism, inhibition of apoptosis, increased telomerase activity

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

Feedback intact?

No — exogenous IGF analogue bypasses GH-mediated regulation

—

Origin

Synthetic 83-AA analogue: 13-AA N-terminal extension + Arg substitution at position 3

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

Antibody development

—

02Dosage Protocols

Parameter

IGF-1 LR3

Melanotan-II

Research dose (animal models)

Variable by protocol and species

In vivo murine atherosclerosis studies used sustained delivery.

—

In vitro typical concentration

10–1000 ng/mLThomas 2007

Dose-dependent effects on follicle growth and estradiol production.

—

Half-maximal stimulation

0.6 nM LR3 vs 1.5 nM native IGF-1Price 2004

2.5-fold greater potency in lung fibroblast proliferation.

—

Evidence basis

Animal / in vitro only

Phase 1 + anecdotalDorr 1996

Human use

Not FDA-approved; no published human trials

—

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

Lower / starter dose

—

0.1 mg / day

Conservative starter — assess tolerability for nausea.

Duration

—

8–12 weeks per cycle

Reconstitution

—

Bacteriostatic water; protect from light

Timing

—

Evening preferred (24h tan-development cycle)

Half-life

—

~1 hour plasma; effects on melanocytes persist days

03Metabolic / Fat Loss Evidence

Parameter

IGF-1 LR3

Melanotan-II

Mechanism

IGF-1R activation → lipolytic signaling; secondary to anabolic effects

—

Direct lipolytic evidence

Minimal — primarily anabolic/anti-apoptotic in literature

—

Atherosclerotic plaque effects

Reduced stenosis and core size in ApoE-KO micevon 2011

Plaque stabilization via vSMC phenotype modulation, not direct fat loss.

—

Human data

None published

—

04Side Effects & Safety

Parameter

IGF-1 LR3

Melanotan-II

Hypoglycemia risk

Theoretical — IGF-1 analogues can lower blood glucose

—

Excessive cell proliferation

Mitogenic signaling; theoretical tumor promotion risk

—

Telomerase activation

2–10-fold increase in prostate cancer cells (PC-3, DU-145, LAPC-4)Wetterau 2003

Critically involved in cancer cell immortalization.

—

Oocyte degeneration

Increased oocyte degeneration at high doses (≥1000 ng/mL) in bovine folliclesThomas 2007

—

Unregulated anabolism

Bypasses physiological GH/IGF-1 feedback; no pulsatility control

—

Unknown human safety profile

No published human trials; safety data absent

—

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

Absolute Contraindications

IGF-1 LR3

·Active malignancy or history of cancer
·Not approved for human use

Melanotan-II

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

Relative Contraindications

IGF-1 LR3

·Diabetes or glucose intolerance
·Family history of cancer

Melanotan-II

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

05Administration Protocol

Parameter

IGF-1 LR3

Melanotan-II

1. Research use only

IGF-1 LR3 is not FDA-approved for human use. All administration data derives from animal or in vitro studies.

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

2. Typical research route

Subcutaneous or intraperitoneal injection in animal models. In vitro: added directly to culture medium at concentrations of 10–1000 ng/mL.Thomas 2007

SQ — abdomen. Rotate sites.

3. Reconstitution (research)

Lyophilised powder reconstituted in sterile water or buffered saline per manufacturer protocol. Store at 2–8 °C after reconstitution.

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

4. Stability

Enhanced stability vs native IGF-1 due to reduced IGFBP binding; exact half-life in vivo not fully characterized in humans.

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

5. Needle

—

29–31G insulin syringe.

06Stack Synergy

IGF-1 LR3

+ GHRP-6

Multi-pathway

View GHRP-6 →

GHRP-6 stimulates endogenous GH release, which drives hepatic IGF-1 synthesis. IGF-1 LR3 provides exogenous, IGFBP-resistant IGF signaling. Combining upstream GH stimulation with downstream IGF receptor activation creates a dual-pathway anabolic effect. However, this bypasses natural feedback and carries compounded mitogenic risk.

GHRP-6: 100–200 mcg SQ · 2–3× daily
IGF-1 LR3: Research doses variable · post-workout typical in animal models
Note: Research context only — no human protocols exist
Primary benefit: Theoretical maximal anabolic signaling (GH + IGF axes)

+ Ipamorelin

Multi-pathway

View Ipamorelin →

Ipamorelin (selective GHRP) stimulates pulsatile GH release without cortisol/prolactin elevation. IGF-1 LR3 directly activates IGF-1R independent of GH. This stack targets both upstream (GH secretion) and downstream (IGF receptor) nodes but eliminates physiological feedback, raising safety concerns around unchecked proliferation.

Ipamorelin: 200–300 mcg SQ · evening
IGF-1 LR3: Research doses only · timing variable
Caution: No human data; animal/in vitro only
Primary benefit: Dual-axis anabolic signaling (theoretical)

Melanotan-II

— no documented stacks