Caffeine
A natural stimulant found in coffee, tea, and other plants, also taken as a standalone supplement for alertness and exercise performance.
What it is
Caffeine is a bitter substance that occurs naturally in more than 60 plants, including coffee beans, tea leaves, kola nuts, and cacao pods. Synthetic caffeine is also added to some medicines, foods, and drinks. It stimulates the central nervous system, acts as a diuretic, and increases stomach acid release. As a standalone supplement, it's commonly used for alertness and as an ergogenic aid before exercise.
Known interaction categories
- Monitor
- Insufficient evidence
- Informational
- Use caution
Published interaction pages on this site
- Caffeine and CalciumMonitor
- Caffeine and IronInsufficient evidence
- Caffeine and OmeprazoleInsufficient evidence
- Caffeine and SpironolactoneInsufficient evidence
- Caffeine and CreatineInformational
- Caffeine and MagnesiumInsufficient evidence
- Caffeine and CiprofloxacinMonitor
- Caffeine and Vitamin KInsufficient evidence
- Caffeine and LevothyroxineInsufficient evidence
- Caffeine and Vitamin B12Insufficient evidence
- Caffeine and CoQ10 (Coenzyme Q10)Insufficient evidence
- Caffeine and TurmericInsufficient evidence
- Caffeine and PotassiumInsufficient evidence
- Caffeine and St. John's WortInsufficient evidence
- Caffeine and CopperInsufficient evidence
- Caffeine and ZincInsufficient evidence
- Caffeine and LisinoprilInsufficient evidence
- Caffeine and WarfarinUse caution
- Caffeine and MetforminInsufficient evidence
- Caffeine and MelatoninInsufficient evidence
- Caffeine and DoxycyclineInsufficient evidence
- Caffeine and ProbioticsInsufficient evidence
- Caffeine and SertralineInsufficient evidence
- Caffeine and AtorvastatinInsufficient evidence
- Caffeine and Vitamin DInsufficient evidence
Sources
Last reviewed 2026-08-23
Medical information disclaimer: this information is general and educational. It does not diagnose conditions, prescribe treatment, or determine whether a combination is safe for you personally. Follow your prescription label and ask a pharmacist or clinician before starting, stopping, or combining products. Full disclaimer.