Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Head-to-head comparison of GHRP-2 and IGF-1 LR3 — mechanism, side effects, legal status, and pricing.
GHRP-2 (pralmorelin) is a synthetic hexapeptide ghrelin receptor agonist that stimulates pituitary growth hormone release. It is approved in Japan (Kaken Pharmaceutical, 2004) as a single-dose diagnostic agent for GH deficiency, but is NOT FDA-approved in the US and is research-only. Unlike ipamorelin, GHRP-2 is non-selective and modestly raises ACTH, cortisol, and prolactin.
IGF-1 LR3 is an 83-amino-acid modified IGF-1 analog with a 13-residue N-terminal extension (MFPAMPLSSLFVN) and an Arg-3 substitution. These modifications reduce binding to IGF binding proteins (IGFBPs), extending effective half-life and increasing tissue bioavailability relative to native IGF-1. It is a research/cell-culture reagent and is NOT FDA-approved for any human use. Do not confuse with mecasermin (Increlex), which is recombinant human IGF-1 and IS FDA-approved for severe primary IGF-1 deficiency.
GHRP-2
IGF-1 LR3
Category
Legal Status
Mechanism
Half-life
Side Effects
COA-verified vendors · trust score ≥70 required · single-vial price — bulk/bundle deals may be lower
GHRP-2
IGF-1 LR3
COA corpus from Disclosed Labs — independently tested batches only.
GHRP-2
13
COAs
99.3%
Avg purity
6
Labs
IGF-1 LR3
42
COAs
98.7%
Avg purity
9
Labs
GHRP-2 is among peptides under FDA review for the Category 1 (503A) list; if added, it would require a prescription to be compounded by registered 503A/503B pharmacies — not yet authorized. IGF-1 LR3 remains research-only. In April 2026 the FDA removed 12 peptides from Category 2, which does not place them on the Category 1 list or authorize compounding. The FDA's Pharmacy Compounding Advisory Committee is advisory and meets July 23–24, 2026 to review nominations and make recommendations to the FDA.
GHRP-2 is approved in Japan (Kaken Pharmaceutical, 2004) as pralmorelin for single-dose diagnostic GH-stimulation testing; Chihara et al. (2007, PMID 17609397) validated a 100 mcg IV dose with a peak-GH <15 mcg/L cut-off against the insulin tolerance test. Arvat et al. (1997, PMID 9285939) showed GHRP-2 raises GH, prolactin, ACTH, and cortisol in healthy men, with hormonal effects similar to hexarelin. Laferrère et al. (2005, PMID 15699539) demonstrated that IV GHRP-2 significantly increases food intake in healthy men, consistent with its ghrelin-like activity. Pralmorelin review: Drugs R D 2004 (PMID 15230633). GHRP-2 is more potent than ipamorelin for raw GH output but is non-selective; grey-market anti-aging, muscle-gain, and performance use is not clinically validated in the US.
Key references
Francis et al. (J Mol Endocrinol 1992; PMID 1378742) characterized LR3-IGF-1 as a fusion analog whose enhanced biological potency derives from reduced IGFBP binding; in IGFBP-free cell systems LR3 was actually LESS potent than native IGF-1, underscoring that the 'potency' is really reduced sequestration rather than intrinsically stronger receptor activation. Tomas (Growth Horm IGF Res 2001; PMID 11472075) infused LR(3)IGF-I into food-restricted rats and found it preserved body weight and nitrogen retention but did NOT conserve skeletal muscle protein — which contradicts the common 'potent muscle builder' framing from preclinical literature alone. There are no controlled human trials supporting bodybuilding use. Epidemiologic and mechanistic work reviewed by Grimberg (Cancer Biol Ther 2003; PMID 14688466) links elevated IGF-1 axis activity to breast, prostate, and colorectal cancer risk, so chronic systemic LR3 exposure carries a concrete — not merely theoretical — tumorigenesis concern. IGF-1 and its analogs are banned at all times under the WADA Code.
GHRP-2 and IGF-1 LR3 are both in the Performance category and may have overlapping mechanisms. Researchers should review both profiles carefully, understand the mechanisms of action, and monitor the relevant biomarkers when combining compounds in the same class. As always, consult a licensed healthcare provider before making any decisions about combining research compounds.
This platform provides informational tools only, not medical advice. This comparison is for educational purposes only. Consult a licensed provider.
Contraindications
Lab Testing
Key references
Disclosed Labs