I didn’t know either until I read about it from guys taking mk677.
Huperzine A is a natural plant compound used for memory like ginkgo biloba but research shows it’s a pretty strong somatostatin inhibitor so in theory It will keep Somatostatin from inhibiting your pituitary released GH. By using Huperzine A to inhibit the Somatostatin release, your body will have more active/usable HGH.
Seems very interesting , I order some and will post up results