Caffeine, also known as liquid crack, is a stimulatory anti-sleep compound extracted from coffee beans. L-Theanine is one of the main active ingredients found in green tea which helps promote relaxation without drowsiness, making it synergistic with caffeine. Together, Caffeine and L-Theanine make for one of the most popular and effective and preworkout stimulant stacks.

  • Caffeine works as a stimulant by blocking different adenosine receptors in the brain due to its similar chemical structure to adenosine. By blocking the A1 receptor, Caffeine staves off sleepiness and drowsiness, thereby increasing endurance. By blocking the A2A receptor, Caffeine can raise the levels of dopamine and epinephrine (adrenaline) in the brain, thereby increasing focus and power output.
  • While these acute effects of Caffeine are beneficial and sought after, your receptors eventually get desensitized from caffeine overstimulation, meaning production of dopamine and epinephrine neurotransmitters gets downregulated to the point where you need Caffeine just to achieve normal levels. This is the phenomenon we think of when we talk about caffeine dependence and high tolerance. It is important to carefully regulate Caffeine intake in order to avoid unpleasant mental and physical crashes as well as unwanted withdrawal symptoms.
    • Figure 1 – Caffeine’s Effect on Adenosine Receptors (Figure adapted from Ferré. J Neurochem. 2008 [7])
  • L-Theanine comes into play here because it can tame the overexcitability and unpleasant jitters and anxiety associated with Caffeine without actually reducing Caffeine’s stimulatory effect [1, 2 3]! Theanine on its own has otherwise minimal effects on exercise performance, but it really shines when combines with Caffeine. Combination of Caffeine with Theanine improve concentration, focus, and attention span in a synergistic manner [4, 5, 6].
  • The research available suggests taking 100-200 mg of Caffeine (up to 400 mg/day) with an equal dose of Theanine 30 minutes before aerobic exercise for a boost in performance intensity and focus.
  • For especially strenuous anaerobic performance, 400+ mg of Caffeine may be taken with 300mg of L-Theanine an hour before working out; however, such high doses should not be taken more than twice a week!
    • Figure 2 – Caffeine Content (Figure adapted from [8, 9, 10, 11, 12, 13])
PRIME(X) contains 150 mg of Caffeine Anhydrous and 150 mg of L-Theanine per serving for enhanced clean energy and focus without the crash! We like to keep our caffeine doses moderate (about the same as a Monster energy drink) so we can get after it on the daily and still have our morning coffee, but feel free to add a little extra on those HEAVY days!







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    2. Lekh Raj Juneja, Djong-Chi Chu, Tsutomu Okubo, Yukiko Nagato, Hidehiko Yokogoshi. L-theanine—a unique amino acid of green tea and its relaxation effect in humans, Trends in Food Science & Technology. 1999 (10) 199-204. org/10.1016/S0924-2244(99)00044-8.
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    10. Ludwig IA, Mena P, Calani L, Cid C, Del Rio D, Lean ME, Crozier A. Variations in caffeine and chlorogenic acid contents of coffees: what are we drinking? Food Funct. 2014 Aug;5(8):1718-26. doi: 10.1039/c4fo00290c. PMID: 25014672.
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