Hexarelin vs IGF-1 LR3

Hexarelin

Synthetic hexapeptide ghrelin receptor (GHS-R1a) agonist and one of the most potent GH secretagogues studied in humans, with additional cardiac data. Its defining practical problem is tachyphylaxis: repeated dosing blunts the GH response over roughly two to four weeks, which is why it is cycled short rather than run continuously. It also lacks the selectivity of ipamorelin, so prolactin and cortisol elevation are expected at higher doses.

IGF-1 LR3

A modified insulin-like growth factor 1: an arginine substitution at position 3 plus a 13-residue N-terminal extension sharply reduce binding to the IGF binding proteins, so more of the peptide stays free and active than native IGF-1 would. It is a growth factor that acts directly on the IGF-1 receptor, NOT a growth hormone secretagogue — it does not ask the pituitary for anything, it bypasses that axis entirely. That distinction is why it sits under "other" rather than with ipamorelin or GHRP-2, and it is also why the risk profile is different: secretagogues are self-limited by pituitary feedback, this is not. Its legitimate life is as a cell-culture supplement and a research reagent; recombinant IGF-1 itself (mecasermin) is an approved medicine for severe primary IGF-1 deficiency, but the LR3 analogue is not approved for anything in humans and has no controlled human dosing trials behind it. Everything below is bodybuilding practice, not clinical evidence, and no reliable human pharmacokinetics exist for this analogue, which is why no half-life is listed. Dosing is genuinely in the tens of micrograms — roughly 20-100 mcg per day, not milligrams — which is why vials are sold at 1 mg rather than the 10 mg typical elsewhere on this site: a single 1 mg vial is many weeks of use. Reconstitute and measure carefully, because a decimal error here is an insulin-shock-scale mistake rather than a wasted dose.