Comparison
Caffeine vs Adrafinil
Caffeine
The most widely consumed psychoactive substance in human history — roughly 80% of the global population uses it daily, mostly via coffee and tea. A competitive adenosine receptor antagonist that lifts the brake on dopamine and norepinephrine signalling. The canonical pairing is 100 mg caffeine + 200 mg L-theanine for clean focus without the jitter.
Adrafinil
Prodrug of modafinil. Converted in the liver. Used historically before modafinil was widely available.
| Field | Caffeine | Adrafinil |
|---|---|---|
| Category | stimulant | stimulant |
| Dose range | 50–400mg | 300–1200mg |
| Half-life | 5h | 1h |
| Onset | 30min | 60min |
| Evidence | EVIDENCEA | EVIDENCEB |
| Safety | ●●●●○ | ●●●○○ |
| Legal (US) | USOTC | USUnscheduled |
| PubMed refs | 25000 | 60 |
The comparison in plain English
Auto-generated from dataCaffeine and Adrafinil are both in the stimulant category respectively. Caffeine The most widely consumed psychoactive substance in human history — roughly 80% of the global population uses it daily, mostly via coffee and tea. Adrafinil Prodrug of modafinil.
Bottom line
Caffeine (evidence A, safety 4/5) has a weaker evidence base than Adrafinil (evidence B, safety 3/5). Caffeine has the slightly cleaner safety profile. For users new to either, the higher-evidence option is the safer first try.
Choose Caffeine if
Caffeine is the better fit when your goal aligns with its mechanism (Competitively blocks adenosine A1 and A2A receptors) and the dose range (50–400mg) suits your protocol. Half-life is 5h.
Choose Adrafinil if
Adrafinil is the better fit when your goal aligns with its mechanism (Hepatic conversion to modafinil via cytochrome P450 metabolism) and the dose range (300–1200mg) suits your protocol. Half-life is 1h.