Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.
| Adrafinil | Modafinil | |
|---|---|---|
| Category | Nootropics | Nootropics |
| Standard Dose | 300-600 mg once daily (for educational context — unregulated prodrug of a prescription medication) | 100-200 mg once daily (for educational context only — prescription medication in most jurisdictions) |
| Timing | Early morning on an empty stomach for faster hepatic conversion. Onset delayed 60-90 minutes. Avoid afternoon/evening dosing due to long effective duration. | Early morning to avoid insomnia; 1 hour before desired peak alertness. With or without food (food slows absorption by ~1 hour but does not reduce bioavailability). Half-life is approximately 12-15 hours. |
| Cycle Duration | Short-term or intermittent use strongly preferred. Avoid continuous daily use exceeding 3 months without liver function monitoring. | Not typically cycled in clinical use. Some off-label users cycle to maintain sensitivity (5 days on, 2 off; or as-needed use). |
| Evidence Level | moderate_human | strong_human |
Inactive prodrug that is hepatically metabolized to modafinil (via hepatic amidase enzymes) and its inactive acid metabolite modafinilic acid. The active metabolite modafinil then exerts its effects as a DAT inhibitor with downstream orexinergic, histaminergic, and noradrenergic activation. Conversion is incomplete — approximately 33-50% of adrafinil is converted to modafinil, with the remainder forming inactive metabolites. The hepatic first-pass metabolism means onset is delayed (60-90 minutes vs. 30-60 minutes for modafinil).
300-600 mg once daily (for educational context — unregulated prodrug of a prescription medication)
Early morning on an empty stomach for faster hepatic conversion. Onset delayed 60-90 minutes. Avoid afternoon/evening dosing due to long effective duration.
Short-term or intermittent use strongly preferred. Avoid continuous daily use exceeding 3 months without liver function monitoring.
Atypical eugeroic (wakefulness-promoting agent) that primarily inhibits the dopamine transporter (DAT), increasing extracellular dopamine in the prefrontal cortex and nucleus accumbens. This primary action cascades through multiple systems: indirect activation of orexinergic neurons in the lateral hypothalamus via potentiation of glutamatergic transmission; downstream stimulation of histaminergic neurons in the tuberomammillary nucleus (via orexin-mediated disinhibition of GABAergic inputs); and enhancement of norepinephrine release in the locus coeruleus. The net effect is broad-spectrum arousal without the peripheral sympathomimetic effects of classical stimulants.
100-200 mg once daily (for educational context only — prescription medication in most jurisdictions)
Early morning to avoid insomnia; 1 hour before desired peak alertness. With or without food (food slows absorption by ~1 hour but does not reduce bioavailability). Half-life is approximately 12-15 hours.
Not typically cycled in clinical use. Some off-label users cycle to maintain sensitivity (5 days on, 2 off; or as-needed use).
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