← All supplements

Caffeine

Supplement stimulant energyfitness
Aka: caffeine anhydrous, 1,3,7-trimethylxanthine
Brands seen in Singapore: California Gold Nutrition, ALLMAX, JNX Sports, Nutricost, EVLution Nutrition
Not medical advice. Check with your doctor or pharmacist before you start, stop or change the timing of anything you take.
How to use
What it’s for
Endurance, team-sport work and alertness
When to take
Trials most often dose it 60 min before exercise
Take with
Water · tea and coffee add to the SAMe daily total
Pros & cons
Pros
  • 3–6 mg/kg improved performance across many trials
  • Helps attention and vigilance in most people
  • Works in trained and untrained alike
Cons
  • 9 mg/kg brings side-effects, no extra benefit
  • Sleep, jitters and raised blood pressure reported
  • Response varies by genetics and habitual intake
Sources
  1. NIH ODS — Dietary Supplements for Exercise and Athletic Performance (Health Professional) · read 2026-08-27
    what it says
    “Blocks activity of the neuromodulator adenosine; reduces perceived pain and exertion … Might enhance performance in endurance-type activities … risk of death with acute oral dose of approximately 10–14 g pure caffeine”
  2. ISSN position stand: caffeine and exercise performance (Guest et al., JISSN 2021) · read 2026-08-27
    what it says
    “Caffeine has consistently been shown to improve exercise performance when consumed in doses of 3–6 mg/kg body mass … Very high doses of caffeine (e.g. 9 mg/kg) are associated with a high incidence of side-effects”
  3. HSA — Guidelines on prohibited and restricted ingredients in health supplements and traditional medicines (Oct 2025, Annex A/B) · read 2026-08-27
    what it says
    “Excessive use may cause nervousness, irritability, sleep disturbances, diuresis, increased blood pressure, heart rate and gastrointestinal disturbances … Indicate the amount of caffeine in your product”
  4. Caffeine and taurine: systematic review and network meta-analysis (Deng et al., JISSN 2025) · read 2026-08-27
    what it says
    “the commonly available CAF and TAU doses in energy drinks, such as Red Bull® (CAF: 80 mg, TAU: 1 g), are ineffective in enhancing motor or cognitive performance”
  5. HSA — Guidelines on health supplements (Tables 4–5, maximum daily dose limits) · read 2026-08-27
    what it says
    “Table 4: Vitamins Limits … Table 5: Minerals Limits”
  6. iHerb Singapore — Caffeine category (default order) · read 2026-08-27
    what it says
    “California Gold Nutrition … ALLMAX … JNX Sports … Nutricost … EVLution Nutrition”
Report a correction View as JSON

Updated 2026-08-29. Every line above traces to a numbered source. Kozen-X is not a medical device and does not give medical advice. It lists what published sources have written down — nothing more. A pair not listed is unrecorded, not cleared. Before you start, stop or re-time anything, talk to your doctor or pharmacist.