Methylliberine

Methylliberine is an isolate of coffee beans, tea, cola nuts, guarana, cocoa, and yerba mate. It is structurally related to Liberine.

Pharmacodynamics
Based on its structural similarity to caffeine and theacrine methylliberine is widely believed to be an adenosine receptor antagonist, although as of 2023 no scientific studies have been done to confirm this action. There is no evidence that methylliberine augments dopamine receptors in a way that is distinct from caffeine, contrary to claims made by manufacturer.

Pharmacokinetics
Methylliberine has a short half-life of only 1.5 hours compared to the 5-7 hour half life of caffeine. An interaction study showed concomitant administration of both caffeine and methylliberine increases the half-life of caffeine by about 2 fold. This is likely due to inhibition of the CYP1A2 enzyme. Safety studies of methyliberine have been conducted in rats and it is approved for use as a dietary supplement in the US.