A prescription wakefulness drug that reliably fights sleepiness and preserves mental sharpness when sleep is short. In rested people, thinking gains are real but small. Benefits for everyday fatigue are mixed, with no proven longevity effect. Best treated as an occasional tool for demanding days, not a daily longevity intervention. (Full Review)

Protocol

Dose

100–200 mg

200 mg is the typical effective dose; off-label optimizers often use 50–100 mg to limit side effects

Timing

Early morning

Taken on waking; the long half-life means later dosing predictably harms night sleep

Dosing pattern

Single morning dose

Split or late dosing is avoided, as a second dose extends drug presence into the evening

Time to effect

Onset

30–60 min

Effects felt from the first dose; no build-up needed

Peak

2–4 hours

Peak plasma level and effect

Duration

Much of the day

A single morning dose covers a full workday

Benefits

High: Sustained wakefulness and reduced excessive sleepiness; preserved cognitive performance during sleep deprivation

Medium: Modest enhancement of executive function and attention on complex tasks; reduction of pathological fatigue

Low: Improved mood, motivation, and task engagement; mild appetite suppression and short-term weight reduction

Speculative: Anti-inflammatory and neuroprotective effects; direct longevity or lifespan extension

Contraindications

Hypersensitivity or prior serious rash to modafinil/armodafinil

Clinically significant arrhythmia

Recent myocardial infarction (<90 days)

Unstable angina

Left ventricular hypertrophy or mitral valve prolapse with prior stimulant-associated changes

Pregnancy and breastfeeding

History of psychosis or mania

Key Interactions

CYP2C19 substrates (phenytoin, diazepam, propranolol, tricyclic antidepressants, omeprazole)

Warfarin

Caffeine and other OTC stimulants

Stimulant/nootropic supplements (L-tyrosine, yohimbine, synephrine)

MAOIs (phenelzine, tranylcypromine)

Hormonal contraceptives

Risk & Side Effects

High: Insomnia and sleep disruption; headache; anxiety, nervousness, and irritability

Medium: Cardiovascular stimulation; reduced hormonal contraceptive efficacy; dependence and misuse potential

Low: Serious skin reactions; psychiatric effects: psychosis and mania

Speculative: Unknown long-term effects of chronic off-label use

Monitoring

Marker	Target	Why
Blood pressure	<120/80 mmHg	Detects modafinil-related cardiovascular stimulation
Resting heart rate	50–70 bpm	Flags stimulant-driven fast heart rate and palpitations
Electrocardiogram (ECG)	Normal sinus rhythm	Screens for arrhythmia risk before stimulant exposure
Liver enzymes (ALT, AST)	ALT/AST <25 U/L	Modafinil is liver-metabolized; screens for impairment affecting clearance
Fasting glucose	70–90 mg/dL	Establishes metabolic baseline given appetite and energy effects

Cadence: Baseline before starting, 2–4 weeks after starting or dose changes, then every 6–12 months with continued intermittent use

Qualitative Assessment

Sustained daytime alertness without needing escalating doses
Sharper sustained focus on demanding tasks, judged against baseline output
Preserved night-time sleep quality on and after dosing days
Stable mood and low anxiety rather than a wired, irritable state
No rebound fatigue dependence, meaning off-days remain functional without the drug

Modafinil for Health & Longevity

Protocol

Benefits

Risk & Side Effects

Monitoring

Qualitative Assessment