Modafinil is a prescription medicine for narcoleptics that increases alertness and prevents sleep. It just so happens to also increase cognition and memory, and is a potent and highly regarded supplement in the category of nootropics.

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All Essential Benefits/Effects/Facts & Information

Modafinil is an a wakefulness enhancing drug that was created for treatment of daytime sleep related disorders such as Narcolepsy. It seems to have benefits for cognition via increasing levels of stimulatory neurotransmitters in the brain, and is used recreationally as a smart-drug.

Things to know

Also Known As

2-(Diphenylmethyl) sulfinylacetamide, Provigil, Modalert, Modapro, Alertex

Do Not Confuse With


Things to Note

  • At least in the US and Canada, Modafinil is labeled a prescription drug and may not be easily acquirable. It is a Schedule IV controlled substance in the US.


How to Take

Recommended dosage, active amounts, other details

Standard dosages are 100-200mg, or perhaps 4mg/kg bodyweight, either taken in a sleep deprived state (if the user desires to not fall asleep) or taken first thing in the morning if the user does not wish to impair sleep.


Structure and Properties

1.1. Origin

Modafinil is a pharmaceutical designed for usage in sleep-related disorders, and is related to improved mental function in a sleep deprived state.

1.2. Forms of Modafinil

The term ‘modafinil’ refers to a racemic mixture of two isomers, R-modafinil and S-modafinil. The R-isomer by itself is referred to as armodafinil.

Modafinil is a racemic mixture of S-modafinil and R-modafinil, whereas Armodafinil is just the R-modafinil by itself



2.1. Serum

The half-life of modafinil appears to be 13-15 hours, and steady state concentrations in serum are reached 2 days following supplementation.[3] Although the S-isomer by itself seems to have a short elimination half-life (4-5 hours) whereas the R-isomer is more prolonged (15 hours)[4][5] ingesting armodafinil does not appear to significantly differ from modafinil.[3][6][7]

An analysis of studies has noted, however, that armodafinil has an 18% higher Cmax value (5.44+/-1.64µg/mL relative to 4.61+/-0.73µg/mL) with a more rapid Tmax (1.8 hours relative to 2.5)[3]and that the overall AUC of armodafinil appears to be 32-40% greater than modafinil.[3]

Although the two variants of modafinil (modafinil and armodafinil) appear to have similar half-lives, armodafinil has a higher overall exposure to the body (assessed by AUC) as well as a higher and more rapid peak in the blood

2.2. Localization

According to c-Fos immunocytochemistry (c-Fos being a gene that rapidly activates in response to stimuli[8][9] and can be detected following neuronal stimulation[10][11] or sleep deprivation[12]), modafinil administration to cats is associated with strong c-Fos activation in the anterior hypothalamic nucleus and surrounding areas with weaker activation in the dorsal portion of the suprachiasmatic nuclei (SCN) with minimal activation in other brain regions such as the cortex or striatum.[13] This selective activation of the hypothalamus has been noted elsewhere, and the amygdala also implicated.[14][15] Modafinil has been confirmed in humans to have a different profile than does amphetamine.[16]

In contrast to amphetamine or methylphenidate induced wakefulness (characterized by widespread neuronal activation), modafinil appears to be somewhat selective for the hypothalamus and amygdala with some influence on the SCN



3.1. Dopaminergic interactions

Modafinil seems to be able to increase extracellular levels of dopamine in the rat nucelar accumbens[17] and prefrontal cortex[18] and the dog caudate nucleus.[19] It has been shown to occupy both the dopamine and noradrenaline receptors (in the striatum)[20] and prevention of dopamine receptor occupancy abolishes the sleep-promoting effects in mice[21], suggesting this mechanism of action is crucial to the sleep-promoting effects.[22]

Past studies have noted a lack of potency of modafinil on dopaminergic systems[23][24][25] which may be due to the lower dosages they used in those studies relative to more recent ones.

3.2. Adrenergic interactions

The wakefulness effects of modafinil are significantly attenuated by antagonists of adrenergic receptors (both alpha and beta subunits)[26] although inhibiting catecholamine synthesis via α-methylparatyrosine does not appear to impair these effects.[26][27][28]

3.3. Serotonergic interactions

3.4. Orexinergic interactions

In those with faulty orexin levels (narcoleptics)[29], modafinil shows benefit possibly by acting on orexic neurons directly.[30][31] This effect is more potent in orexin-knockout mice than in normal mice[32], and the effects of modafinil on the orexin system of healthy persons is unknown.[2]

3.5. Sedation and Alertness

Some studies assess the effects of modafinil on intentional sleep deprivation, and modafinil (300mg) appears to be effective in reducing the disturbed mood and cognition seen during sleep deprivation with a potency comparable to 20mg D-amphetamine.[33][1] Elsewhere, it has been noted that the impairment of self-monitoring (ability to accurately assess oneself and their environment) is effectively reversed to a degree where an overconfidence effect (higher percieved assessment of skills relative to actual skills) is seen.[34]

These studies have extended up to 64 hours (two nights sleep deprivation) with a single dose of modafinil every 15 hours.[33][1]

Modafinil intervention prior to sleep can highly disrupt the sleep cycle and accompanying sedation, and usage of modafinil in this manner can attenuate the side-effects of sleep deprivation (cognitive and mood impairment)

Rebound hypersomnia is the phenomena where an anti-sleep agent is successful in reducing sleep, but after the effects of the drug wear off the user is significantly sleepier than before. Unlike amphetamine based drugs, modafinil does not appear to be associated with rebound hypersomnia in the cat[26][35] nor rats[36][37][38] or mice.[39] In humans who miss two nights sleep due to modafinil intervention (64 continuous hours awake), there does not appear to be any rebound hypersomnia like is seen with D-amphetamine.[1]

Modafinil does not appear to be associated with rebound hypersomnia

The increase in alertness during sleep deprivation seen with 300mg modafinil appears to be comparable to 20mg D-amphetamine over the course of 10-12 hours following one-time administration.[33][16][1][34]

The anti-sleep efficacy of modafinil (300mg) appears to be comparable to 20mg D-amphetamine

The sleep wake cycle of the brain is a balance of the ‘ascending arousal system’ consisting of arousing neurotransmitters (catecholamines, acetylcholine, orexin, etc.) and the neurotransmitters (GABA, Galanin) which act to suppress stimulation and promote sleep.[40][41] Varying levels of arousing and depressing neurotransmitters form an ‘on-off’ switch for arousal and sleep.[2]

Overall regulation of the wakefulness and rest cycle seems to be in part due to the circadian rhythm, mediated by the Suprachiasmatic Nuclei (SCN), and in part due to homeostatic needs for sleep that are gained during wakefulness.[40][41]

Modafinil seems to be able to interact with a multitude of stimulatory systems including serotonergic, noradrenergic, dopaminergic, glutaminergic, histaminergic, and orexinergic pathways; and also influences GABAergic pathways.[42]

Some studies that use modafinil for the treatment of some other states note that the side-effect of insomnia persists more than placebo[43] and modafinil is able to prevent participants from voluntarily falling asleep when taken prior to sleep.[44]

Supplementation of modafinil is able to preserve cognition in fatiged states.[44]


3.6. Memory and Cognition

In otherwise healthy persons, 100mg or 200mg of modafinil taken two hours prior to cognitive testing is able to improve working memory (digit span tests), visuospatial planning, and reaction time[45] whereas elsewhere it was found to improve cognition (task enjoyment, planning, and working memory) in completely normal and non-sleep deprived persons at 200mg.[46] Working memory and processing accuracy have been found to be improved with 200mg elsewhere.[47]

Alongside the improvements in working memory are improvements in the actual performance of the task, most notably an increase in motivation and enjoyment for undergoing the task.[46]

There is some cognitive enhancing properties of modafinil acute usage in otherwise healthy persons, and may increase motivation and enjoyment from doing a cognitive task

In methamphtamine dependent persons (known to have a degree of cognitive impairment[48][49]), modafinil at 400mg for three days is able to improve working memory and trended to improve fatigue in those with worse baseline scores yet was unable to improve performance in those with higher baseline scores[50] and 200mg for a single dose does not appear to be cognitive enhancing in this same population.[51]

In persons with possible cognitive decline associated with methamphetamine usage, modafinil has the potential to improve cognition although acute usage doesn’t appear to be effective and the overall cognitive enhancement is relatively minor

3.7. Appetite

Studies that assess the effects of modafinil sometimes report a reduction in appetite as a side-effect, measured at 16% (164 persons[43])

Studies that note reductions in appetite sometimes note trends towards weight loss over a period of weeks, but usually do not reach statistical significance.[43]

3.8. Attention

Supplementation of modafinil in the range of 170–425mg for six weeks (dose titrated up from 170mg to 425mg unless tolerance was compromised) was able to reduce symptoms of ADHD as assessed by both CGI-I and ADHD-RS-IV in youth.[43]

3.9. Addiction

Due to the inability for modafinil to activate neuronal pathways involved in addiction, it is thought to have a low abuse potential relative to other drugs.[52][53]

It is thought that modafinil has a low potential for wide-spread drug abuse

Response inhibition (the ability to inhibit a prepotent response,[54] and thought to be indicative of impulsivity in persons undergoing drug abuse[55]) is improved in rats[56] and humans (alcohol dependence,[57] methamphetamine dependence,[51] and gambling[58]) with modafinil, but only in those with worse baseline scores rather than the whole group.

It is possible for modafinil to reduce impulsivity in persons addicted to drugs or some addictive behaviours, although this only appears to be significantly effective for persons with worse impuslivity prior to testing


Interaction with Medical Conditions

4.1. Multiple Sclerosis

Acute supplementation of armodafinil (250mg) in persons with multiple sclerosis has noted improvements in memory recall relative to placebo, although other measured parameters (fatigue, executive function, processing speed) were unaffected by supplementation.[59] This inefficacy on fatigue and arousal has not been noted elsewhere, where modafinil is attributed to possessing an antifatigue effect in MS.[60]



Safety and Toxicology

5.1. General

Adverse effects usually reported in trials are predominantly headache, dizziness, increased diuresis, palpitations and tachycardia, restlessness, nervousness, gastrointestinal complains such as nausea, dry mouth and abdominal pain. Despite these isolated adverse events, they usually do not differ significantly from placebo and thus modafinil is seen as well tolerated.

Reported side-effects that sometimes occur significantly more than placebo include insomnia and sleeplessness as well as appetite reduction.[43]

General side-effects of modafinil include insomnia and/or sleeplessness as well as a reduction in appetite


Scientific Support & Reference Citations


  1. Buguet A, et al. Modafinil, d-amphetamine and placebo during 64 hours of sustained mental work. II. Effects on two nights of recovery sleepJ Sleep Res. (1995)
  2. Approved and Investigational Uses of Modafinil: An Evidence-Based Review.
  3. Darwish M, et al. Armodafinil and modafinil have substantially different pharmacokinetic profiles despite having the same terminal half-lives: analysis of data from three randomized, single-dose, pharmacokinetic studiesClin Drug Investig. (2009)
  4. Wong YN, et al. A double-blind, placebo-controlled, ascending-dose evaluation of the pharmacokinetics and tolerability of modafinil tablets in healthy male volunteersJ Clin Pharmacol. (1999)
  5. Wong YN, et al. Open-label, single-dose pharmacokinetic study of modafinil tablets: influence of age and gender in normal subjectsJ Clin Pharmacol. (1999)
  6. Robertson P Jr, Hellriegel ET. Clinical pharmacokinetic profile of modafinilClin Pharmacokinet. (2003)
  7. Darwish M, et al. Pharmacokinetic profile of armodafinil in healthy subjects: pooled analysis of data from three randomized studiesClin Drug Investig. (2009)
  8. Sheng M, Greenberg ME. The regulation and function of c-fos and other immediate early genes in the nervous systemNeuron. (1990)
  9. Morgan JI, Curran T. Stimulus-transcription coupling in neurons: role of cellular immediate-early genesTrends Neurosci. (1989)
  10. Shiromani PJ, et al. Cholinergically induced REM sleep triggers Fos-like immunoreactivity in dorsolateral pontine regions associated with REM sleepBrain Res. (1992)
  11. Fritschy JM, Frondoza CG, Grzanna R. Differential effects of reserpine on brainstem catecholaminergic neurons revealed by Fos protein immunohistochemistry.Brain Res. (1991)
  12. Pompeiano M, Cirelli C, Tononi G. Effects of sleep deprivation on fos-like immunoreactivity in the rat brainArch Ital Biol. (1992)
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  14. Engber TM, et al. Differential patterns of regional c-Fos induction in the rat brain by amphetamine and the novel wakefulness-promoting agent modafinilNeurosci Lett. (1998)
  15. Scammell TE, et al. Hypothalamic arousal regions are activated during modafinil-induced wakefulnessJ Neurosci. (2000)
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  17. Modafinil enhances extracellular levels of dopamine in the nucleus accumbens and increases wakefulness in rats.
  18. de Saint Hilaire Z, et al. Variations in extracellular monoamines in the prefrontal cortex and medial hypothalamus after modafinil administration: a microdialysis study in ratsNeuroreport. (2001)
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  20. Madras BK, et al. Modafinil occupies dopamine and norepinephrine transporters in vivo and modulates the transporters and trace amine activity in vitroJ Pharmacol Exp Ther. (2006)
  21. Modafinil inhibits rat midbrain dopaminergic neurons through D2-like receptors.
  22. Dopheide MM, et al. Modafinil evokes striatal {(3)H}dopamine release and alters the subjective properties of stimulantsEur J Pharmacol. (2007)
  23. Lack of pre-synaptic dopaminergic involvement in modafinil activity in anaesthetized mice: In vivo voltammetry studies.
  24. Mignot E, et al. Modafinil binds to the dopamine uptake carrier site with low affinitySleep. (1994)
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  27. Simon P, et al. Non-amphetaminic mechanism of stimulant locomotor effect of modafinil in miceEur Neuropsychopharmacol. (1995)
  28. Duteil J, et al. Central alpha 1-adrenergic stimulation in relation to the behaviour stimulating effect of modafinil; studies with experimental animalsEur J Pharmacol. (1990)
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  32. Modafinil more effectively induces wakefulness in orexin-null mice than in wild-type littermates.
  33. Pigeau R, et al. Modafinil, d-amphetamine and placebo during 64 hours of sustained mental work. I. Effects on mood, fatigue, cognitive performance and body temperatureJ Sleep Res. (1995)
  34. Baranski JV, Pigeau RA. Self-monitoring cognitive performance during sleep deprivation: effects of modafinil, d-amphetamine and placeboJ Sleep Res. (1997)
  35. Lin JS, et al. Effects of amphetamine and modafinil on the sleep/wake cycle during experimental hypersomnia induced by sleep deprivation in the catJ Sleep Res. (2000)
  36. Wisor JP, et al. Armodafinil, the R-enantiomer of modafinil: wake-promoting effects and pharmacokinetic profile in the ratPharmacol Biochem Behav. (2006)
  37. Touret M, Sallanon-Moulin M, Jouvet M. Awakening properties of modafinil without paradoxical sleep rebound: comparative study with amphetamine in the rat.Neurosci Lett. (1995)
  38. Edgar DM, Seidel WF. Modafinil induces wakefulness without intensifying motor activity or subsequent rebound hypersomnolence in the ratJ Pharmacol Exp Ther. (1997)
  39. Willie JT, et al. Modafinil more effectively induces wakefulness in orexin-null mice than in wild-type littermatesNeuroscience. (2005)
  40. Hypothalamic regulation of sleep and circadian rhythms.
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  44. Gill M, et al. Cognitive performance following modafinil versus placebo in sleep-deprived emergency physicians: a double-blind randomized crossover study.Acad Emerg Med. (2006)
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  51. Dean AC, et al. Acute modafinil effects on attention and inhibitory control in methamphetamine-dependent humansJ Stud Alcohol Drugs. (2011)
  52. Myrick H, et al. Modafinil: preclinical, clinical, and post-marketing surveillance–a review of abuse liability issuesAnn Clin Psychiatry. (2004)
  53. Jasinski DR, Kovacević-Ristanović R. Evaluation of the abuse liability of modafinil and other drugs for excessive daytime sleepiness associated with narcolepsy.Clin Neuropharmacol. (2000)
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  59. Bruce J, et al. Impact of armodafinil on cognition in multiple sclerosis: a randomized, double-blind crossover pilot studyCogn Behav Neurol. (2012)
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