The application of 1,3,7,8-Tetramethylxanthine

Caffeine is a central nervous system (CNS) stimulant of the methylxanthine class and it is the world's most widely consumed psychoactive drug.  The most prominent work mechanism of caffeine is that it reversibly blocks the action of adenosine on its receptor and consequently prevents the onset of drowsiness induced by adenosine. Caffeine also stimulates certain portions of the autonomic nervous system [1]. Compared with caffeine, methylcaffeine contains more one methyl and it is a xanthine that can be extracted from the green coffee bean, and it seems to have a very strong adenosine response and bronchodilatory response. Actually, methylcaffeine is something other than caffeine, and it is a metabolite of caffeine that relaxes smooth muscles and increases breathing [2]. 

As we all know, caffeine is 1,3,7 N-methyl caffeine, and the important thing to note here is that N-methylation (as with all normal xanthines) and methylation of a double bond (8-methylcaffeine) are two totally different things. The liver can remove the methyl part from N quite easily. However, the methylation of the double bond prevents the main metabolic path of xanthines (8-oxidation by the enzyme xanthine oxidase making it much more water soluble so that it will be excreted by the urine). This ends up making 8-methylcaffeine harder to the liver than normal caffeine gives it a longer half-life. 

Slim FX is the athletic product, and relative information was shown in graph 1.

Graph 1 Information of Slim FX

Know from the recipe of Silm FX, 1,3,7,8-tetramethylxanthine is one of the components. The product claims it is useful for men and women who are striving to lose weight, but frequently fall short due to tiredness and unhealthy snack cravings throughout the day. The central to successful weight loss plan is the ability to suppress your appetite, especially cravings for unhealthy carbs like sugar. Slim FX works by curbing, not eliminating appetite, so people can remain healthy by eating a small balanced diet and controlling intra-meal cravings. Take Slim FX and eat three sensible meals a day and curb the cravings for unhealthy snack foods between meals. But some data from the US Army Aberdeen Proving Grounds, the action of STIM X as well as Venom stem from an 8-substituted methylxanthine. People have mentioned the habitual use of both will really dry you out and make you cramp. Also, a rapid water loss could be mistaken for fat loss by many people. So some people think caffeine and paraxanthine are actually better fat loss agents than the 8-subbed versions.

Reference

[1] https://en.wikipedia.org/wiki/Caffeine
[2] https://forum.bodybuilding.com/showthread.php?t=883110&page=