Ipamorelin vs Tesamorelin: GHRP vs GHRH analogue — two different receptor mechanisms for GH axis stimulation. Ipamorelin amplifies GH pulses via ghrelin receptors; Tesamorelin stimulates GH synthesis via GHRH receptors.
Mechanism Comparison
Ipamorelin: binds GHS-R1a (ghrelin receptor) to amplify GH pulse amplitude. Tesamorelin: binds GHRH receptor to stimulate GH synthesis and secretion. Different receptors — combining them produces synergistic GH release.
Clinical Evidence
Tesamorelin: FDA-approved for HIV-associated lipodystrophy, multiple Phase 3 trials, validated IGF-1 elevation. Ipamorelin: extensive research use but no FDA approval; clinical data is less formal than tesamorelin.
Combination Protocol
Ipamorelin + Tesamorelin combination: Ipamorelin 200–300 mcg + Tesamorelin 1–2 mg, administered simultaneously once daily before sleep. The GHRP + GHRH combination produces synergistic GH release greater than either compound alone.