Independent reference & toolkit 100 compounds graded · Last reviewed June 2026

Compare · GH secretagogue

Hexarelin vs MK-677

Both are gh secretagogue compounds. Here's how they line up on the evidence — graded the same way.

HexarelinMK-677
Evidence 6/10 7/10
ClassGH secretagogueGH secretagogue
SummaryA synthetic ghrelin-mimicking peptide that reliably spikes growth hormone in small studies, but was never approved and is banned in sport.MK-677 reliably raises growth hormone and IGF-1, but disease trials failed and one was stopped for a heart-failure signal. Investigational, never approved.
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Hexarelin

Hexarelin is a lab-made peptide (a short chain of amino acids) that copies what the hunger hormone ghrelin does: it tells the body to release a quick, short burst of growth hormone (GH). Small human studies in the 1990s showed it does this dependably. But every one of those trials was tiny, brief,…

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MK-677

MK-677, also called ibutamoren, is one of the odder entries you'll find in any peptide reference — because it isn't actually a peptide. It's a man-made molecule that tricks the body into releasing more of its own growth hormone. And unlike most of the products sold to the fitness and "anti-aging"…

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