Home / Supplements /
Caffeine supplementation
This page is a reference summary of published evidence and regulatory documents. It is not a substitute for individual medical advice, and it is not a recommendation to take or avoid any medicine.
Medically reviewed by Dr. Sofia Lindqvist, · Last reviewed 5 March 2026
Caffeine sold as a supplement — usually as 100mg or 200mg anhydrous tablets — delivers a fixed, known dose in a way that beverages do not. The pharmacology is the same molecule as dietary caffeine; what differs is dose accuracy, absorption speed, and the risk profile of the most concentrated forms.
On this page
Dose accuracy vs beverages
A cup of brewed coffee can contain anywhere from roughly 70mg to over 150mg of caffeine depending on bean, roast, and brew method, making beverage dosing inherently variable. A 100mg or 200mg anhydrous tablet delivers a fixed, labelled amount, which is why tablets are often used in research settings and by people who want to titrate a specific, repeatable dose.
Absorption differences
Anhydrous caffeine in tablet form is absorbed slightly faster than caffeine consumed in a beverage, because there is no accompanying fluid volume, sugar, or fat to slow gastric emptying. Peak plasma concentration after a tablet is typically reached within 30 to 60 minutes, compared with a somewhat more gradual rise from a hot beverage consumed over several minutes.
The risk profile of pure powder
High-risk product
The specific neural site or circuit responsible for modafinil’s wake-promoting effect has not been definitively localised. DAT binding is established as necessary, but necessary is not the same as sufficient, and how DAT blockade translates into the specific pattern of cortical and subcortical arousal seen with modafinil — as opposed to other DAT-active compounds — is not fully resolved in the published literature.
EFSA limits
| Measure | EFSA guidance |
|---|---|
| Single dose | Up to 200mg unlikely to raise safety concerns in healthy adults |
| Total daily intake | Up to 400mg/day unlikely to raise safety concerns in healthy, non-pregnant adults |
| Pregnancy | Up to 200mg/day total from all sources |
| Rapid consumption (e.g. before exercise) | Doses at or above 3mg/kg body weight taken shortly before exercise flagged as a specific area of concern |
How much caffeine is in a typical tablet?
Most over-the-counter caffeine tablets contain 100mg or 200mg of anhydrous caffeine per tablet, a fixed, labelled amount.
Is tablet caffeine absorbed differently from coffee?
Anhydrous caffeine in a tablet is absorbed slightly faster than caffeine in beverages because there is no accompanying fluid volume or food matrix to slow gastric emptying.
Why is pure caffeine powder considered dangerous?
A teaspoon of pure powder can contain roughly the same caffeine as 25 cups of coffee, and the FDA has linked bulk powder products to fatal overdoses from dosing error.
What is the EFSA guidance on caffeine intake?
EFSA considers single doses up to 200mg and total daily intake up to 400mg unlikely to raise safety concerns for most healthy adults.