Theacrine is a purine alkaloid that is structurally similar to caffeine and uric acid. This alkaloid is usually isolated from Cupuaçu (Theobroma grandiflorum) and Camellia kucha (Camellia assamica variant kucha). It is sometimes regarded as an alternative to caffeine although small doses of theacrine appear to have sedative effects. At least in kucha leaves, theacrine is synthesized from caffeine .
Can Theacrine Replace Caffeine?
A recent pilot study partly funded by Compound Solutions, Inc.  reported that 200 mg dose of theacrine (as TeaCrine™) caused significant improvements in energy and reductions in fatigue with a trend towards improved concentration. Rats injected with 24 or 48 mg/kg theacrine exhibited a dose-dependent increase in activity levels, where higher dose significantly increased locomotor activity compared to control while lower dose tended to do so . This significantly enhanced activity levels were shown to be mediated by both the adenosinergic and dopaminergic systems ; the same signalling is reported for caffeine . At low oral doses (10 mg/kg) it appears to have potent sedative and hypnotic properties .
Unlike caffeine , chronic theacrine exposure did not cause any locomotor sensitization or tolerance in mice;  the reason for this difference between theacrine and caffeine is currently not known.
For now, there is lack of evidence to support the claim that theacrine might be a replacement for caffeine. However, it seems that effects of theacrine are similar to that of caffeine but without tolerance build up. There are also no toxicological studies in humans.
Benefits for Exercise
Recently, theacrine has been tested on muscular strength and muscular endurance. While caffeine has been reported to improve exercise performance and strength , 200 mg of theacrine failed to provide effective acute aide for improving either muscular strength or muscular endurance . However, as apparent adenosine receptor antagonist, it provided positive effects on mood, energy, motivation, and focus.
Stress-related Liver Damage
Theacrine might also be helpful in the prevention of stress-related diseases and is potential therapeutic candidate for hepatic diseases. In mice subjected to restraint stress, theacrine was found to attenuate markedly elevated levels of ALT and AST, two markers of liver damage, as well as the decreased inflammatory cell infiltration and focal necrosis in the liver .
Experimental animal studies also report antidepressant effect of theacrine probably due to its influence on monoamine neurotransmitter . In mice, theacrine also exhibited anti-inflammatory and exerted dose dependent analgesic properties (reduced pain) .
Safety and Side Effects
No adverse effects were reported so far. At high doses side effects would probably be same as with caffeine. Theacrine appears to be well tolerated at small doses and doses typically found in tea. In mice, acute oral LD50 is around 810 mg/kg .
(Other common names: 1,3,7,9-tetramethyluric acid, TeaCrine)
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