Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.
| GHK-Cu | IGF-1 LR3 | |
|---|---|---|
| Category | Growth Factors | Growth Factors |
| Standard Dose | Research indicates 1-2 mg daily via subcutaneous injection, or topical application at 1-3% concentration in cream/serum. | Research indicates 20-50 mcg daily via subcutaneous or intramuscular injection. |
| Timing | Evening administration preferred for skin rejuvenation (aligns with nocturnal repair cycles). Topical can be applied morning and evening. | Post-workout administration for muscle growth. Can be injected locally (intramuscularly) into target muscle groups. Morning dosing on rest days. |
| Cycle Duration | 8-12 weeks for injectable cycles. Topical use can be ongoing. | 4-6 week cycles maximum. Longer cycles risk significant side effects and receptor desensitization. |
| Evidence Level | moderate_human | moderate_human |
GHK-Cu is a naturally occurring copper-binding tripeptide (glycyl-L-histidyl-L-lysine) that modulates gene expression affecting 31.2% of human genes. It activates Wnt/beta-catenin signaling for hair follicle growth, stimulates TGF-beta pathway for tissue remodeling, and promotes collagen and glycosaminoglycan synthesis while modulating metalloproteinase activity. The copper ion serves as a cofactor for enzymes essential to wound healing including superoxide dismutase and lysyl oxidase.
Research indicates 1-2 mg daily via subcutaneous injection, or topical application at 1-3% concentration in cream/serum.
Evening administration preferred for skin rejuvenation (aligns with nocturnal repair cycles). Topical can be applied morning and evening.
8-12 weeks for injectable cycles. Topical use can be ongoing.
IGF-1 LR3 (Long Arginine 3-IGF-1) is an 83-amino acid synthetic analog of IGF-1 with an arginine substitution at position 3 and 13 additional N-terminal amino acids. These modifications eliminate binding to IGF-binding proteins, making it approximately 3x more potent than native IGF-1 with a half-life of 20-30 hours (vs 12-15 minutes for native IGF-1). It activates the IGF-1R tyrosine kinase receptor, triggering IRS-1/PI3K/Akt/mTOR and PI3K/Akt/GSK3-beta pathways to drive protein synthesis, muscle hypertrophy, and hyperplasia (new muscle cell formation).
Research indicates 20-50 mcg daily via subcutaneous or intramuscular injection.
Post-workout administration for muscle growth. Can be injected locally (intramuscularly) into target muscle groups. Morning dosing on rest days.
4-6 week cycles maximum. Longer cycles risk significant side effects and receptor desensitization.
Fast buy links (we may earn a small commission at no extra cost).
Take our free assessment to get personalized recommendations based on your health goals, current stack, and biomarkers.
Get Your Free Protocol →or take the assessment →