A reference work, not a recommendation to use: this profile describes mechanism and evidence and does not replace medical advice. The claims come from marketing and forums and are tested here, not endorsed.

Mechanism of action

Evidence map: Modafinil

Each line stands for a published finding; line style and color show where it comes from. The filter hides weaker evidence levels. Sources: see references.

For a long time, modafinil was regarded as a wake-promoting drug with an unknown mechanism. In cells expressing human transporters, it inhibits the reuptake of dopamine (IC50 6.4 µM) much more strongly than that of noradrenaline (IC50 35.6 µM) and practically not that of serotonin (IC50 > 500 µM); in rhesus monkeys, PET showed occupancy of dopamine transporters in the striatum and of noradrenaline transporters in the thalamus [1]. In a screen of various receptors and transporters, modafinil showed measurable activity only at the dopamine transporter (IC50 4.0 µM in rat synaptosomes) and raised dopamine in the nucleus accumbens of rats without changing serotonin [2].

In humans, a placebo-controlled PET study in 10 healthy men confirmed this mechanism: modafinil occupied about 54% of dopamine transporters in the caudate nucleus and increased extracellular dopamine, including in the nucleus accumbens [3]. Mice lacking the dopamine transporter suggest that this protein is required for the wake-promoting effect: they no longer responded to modafinil with longer wakefulness [4]. Both enantiomers inhibit the transporter more weakly than cocaine; R-modafinil (armodafinil) binds about three times more strongly than S-modafinil and differs from cocaine in the way it binds [5].

Modafinil also activates wakefulness centers in the hypothalamus of rats: the activity marker Fos increased in histaminergic neurons of the tuberomammillary nucleus and in orexin neurons [6]. Whether this activation is a cause or a consequence of the dopamine effect has not been resolved. Modafinil is broken down mainly in the liver by amide hydrolysis, and its half-life is about 12 to 15 hours; in laboratory experiments, it induces the enzymes CYP3A4, CYP1A2 and CYP2B6 and inhibits CYP2C19 [7]. In humans, CYP3A4 induction mainly lowered the levels of triazolam and, to a lesser extent, those of ethinyl estradiol [8].

Synaptik serves solely to explain biochemistry and pharmacology and is not medical advice or a recommendation to take anything.

Mechanism of action only. Schematic cross-section of a striatal dopaminergic synapse with a neighbouring noradrenergic terminal, plus an inset with a serotonergic terminal on the left; not to scale. Particle numbers, speeds and the bars of the live readout come from an illustrative model, not from measurements. Only for methylphenidate and modafinil does the share of blocked dopamine transporters (6 and 5 of 10) match a rounded PET occupancy, from two different studies; all other shares are illustrative.

DAT: 5 of 10 blocked by modafinil · NET weaker · dopamine lingers

DAT
inhibitedIC50 6.4 µM; PET ≈ 54% (n = 10)
NET
more weakly inhibitedIC50 35.6 µM
SERT
hardlyIC50 above 500 µM
synthesis (TH, AADC)
unchanged
dopamine in the cleft (model)
moredirection from PET study
Drug
View

dopamine  noradrenaline  serotonin  cAMP  drug  cross = transporter blocked

In cells expressing human transporters, modafinil inhibits DAT (IC50 6.4 µM) much more strongly than NET (IC50 35.6 µM) and SERT hardly at all (IC50 above 500 µM) [17]. In a placebo-controlled PET study of 10 healthy men it occupied about 54% of dopamine transporters in the caudate and raised extracellular dopamine [18]. Mice lacking DAT no longer stayed awake longer on modafinil [19]. In rats, pretreatment with modafinil reduced methamphetamine-induced dopamine release [20]. The blocked NET (1 of 4) is illustrative.

Tap or focus a labelled part for a short explanation.

Also acting here, not drawn

  • Flmodafinil: DAT inhibition only from unpublished commissioned data (evidence level 0)
  • Saffron: at SERT only a computer simulation (docking), no measured binding or inhibition

What the figure shows, and how sure we are

Mechanism-of-action explainer only. Not medical advice, and no statement about benefit, risk, amount or use; each profile gives the legal status.

What was simplified. One terminal and one cleft stand for a striatal dopamine synapse; sizes, cleft width, numbers of vesicles, transporters and receptors, and all speeds are illustrative. Drugs are drawn on the outside of the transporter, not at their binding sites. The positions of TH, AADC and COMT are schematic. The occupancy values for methylphenidate and modafinil come from two studies with different amounts, brain regions and participants and are not directly comparable; the values for the other drugs come from cells, synaptosomes or animal studies. The numbers in [14] to [28] are in the Synaptik profiles of the drugs, where they were checked against the abstracts; [1] to [13] and [29] were checked on PubMed for this figure (26 Oct 2026), [2] bibliographically only.

If medicines or other substances are causing problems, a GP or a local addiction counselling service can help.

Targets

TargetTypeActionKey dataEvidence
Dopamine transporter (DAT)TransporterInhibitorIC50 6.4 µM (human DAT, cell culture); IC50 4.0 µM (rat synaptosomes); about 54% occupancy in the caudate nucleus (human, PET) Human, randomised[1][2][3]
Noradrenaline transporter (NET)TransporterInhibitorIC50 35.6 µM (human NET, cell culture); occupancy in the thalamus (rhesus monkey, PET) Animal study[1]
CYP3A4/5EnzymeExpression ↑Induction; triazolam levels markedly lowered in humans Human, randomised[7][8]
CYP2C19EnzymeInhibitorreversible inhibition (human liver microsomes) Laboratory[7]

Effect profile

Which signaling systems the compound affects according to current data. ↑ enhanced, ↓ dampened, ≈ modulated, ○ no effect; dots = evidence level.

  • Dopamine↑ · Inhibits the dopamine transporter and increases extracellular dopamine, including in the nucleus accumbens (human, PET)[1][2][3][4]
  • Noradrenalinemodulated · Occupies noradrenaline transporters in the thalamus (rhesus monkey); noradrenaline itself not measured[1]
  • Serotoninno effect · Hardly any inhibition of the serotonin transporter; serotonin in the nucleus accumbens unchanged (rat)[1][2]
  • Acetylcholineno data
  • Glutamate · AMPAno data
  • Glutamate · NMDAno data
  • GABAno data
  • Histamine↑ · Histaminergic neurons in the tuberomammillary nucleus activated (Fos, rat)[6]
  • Orexin↑ · Orexin neurons in the hypothalamus activated (Fos, rat); whether this mediates wakefulness is unresolved[6]
  • Adenosineno data
  • Opioidsno data
  • Melatoninno data
  • Neurotrophinsno data
  • Blood flowno data
  • Nitric oxideno data
  • Energy metabolismno data
  • Insulin · glucoseno data
  • Inflammation · oxidativeno data
  • Stress axisno data
  • Testosterone axisno data
  • Endocannabinoidsno data
  • Autophagy · senescenceno data
  • Immune systemno data
  • Lipid metabolismno data
  • Coagulation · fibrinolysisno data
  • Methylationno data

Human studies

  • PET of dopamine and the dopamine transporter

    placebo-controlled, PET · healthy (men) · n = 10 · single doses

    Measured: Dopamine transporter occupancy, extracellular dopamine

    Result: About 54% transporter occupancy in the caudate nucleus; dopamine increased in the striatum and nucleus accumbens.[3]

    Human, randomised

  • Neuropsychological test battery

    RCT, double-blind, parallel groups · healthy (young men) · n = 60 · single dose

    Measured: Memory, attention, planning, inhibitory control

    Result: Better performance in digit span, visual recognition, spatial planning and the stop-signal task; no effect on spatial working memory, sustained attention or attentional set-shifting.[13]

    Human, randomised

  • Systematic review in well-rested healthy people

    systematic review (studies 1990–2014) · healthy, not sleep-deprived · mostly single doses

    Measured: Cognition

    Result: Executive functions improved in most simple tests, attention and memory in only about half; more consistent improvements in more complex tasks.[10]

    Human, randomised

  • Meta-analysis of 19 studies

    meta-analysis of placebo-controlled studies · healthy people and patients with mental disorders, not sleep-deprived · single dose

    Measured: Attention, executive functions, memory, processing speed

    Result: Small overall effect (g = 0.10; 95% CI 0.05–0.15), with no difference between domains.[11]

    Human, randomised

  • Meta-analysis of 14 studies

    meta-analysis of placebo-controlled studies · healthy, not sleep-deprived · single dose

    Measured: Cognitive subdomains

    Result: Small overall effect (SMD 0.12), most pronounced for updating of working memory (SMD 0.28).[12]

    Human, randomised

  • Interaction with the contraceptive pill and triazolam

    placebo-controlled, single-blind · healthy (women using oral contraceptives) · n = 41 · 4 weeks

    Measured: Pharmacokinetics of ethinyl estradiol and triazolam

    Result: Triazolam levels markedly lowered, ethinyl estradiol levels less so; CYP3A4/5 induction mainly in the gut.[8]

    Human, randomised

Risks and warnings

  • Abuse potential

    Raises dopamine in the nucleus accumbens, which is considered an indication of abuse potential [3]. According to a review, abuse and dependence are rarely reported [14]; the US classification in Schedule IV was controversial [9].

    Human, non-randomised

  • Common side effects

    Most frequently reported: headache, insomnia, anxiety, diarrhea, dry mouth, and increases in blood pressure and heart rate [14].

    Human, non-randomised

  • Serious skin reactions

    Rare serious skin reactions up to Stevens-Johnson syndrome, reported mainly in children [14].

    Human, non-randomised

  • Pregnancy

    After a 2019 regulatory warning about malformations, registry studies reached conflicting results [15]. In the largest French cohort to date, the risk was not significantly increased compared with untreated women (aRR 1.23; 95% CI 0.76–1.99), but it was compared with methylphenidate (aRR 1.77; 1.01–3.07); a moderately increased risk cannot be ruled out [16].

    Human, non-randomised

  • Interactions via CYP enzymes

    Induces CYP3A4/5 and thereby lowers the levels of some drugs; inhibits CYP2C19 in the laboratory [7][8].

    Human, randomised

Interactions

  • Hormonal contraception (ethinyl estradiol): Ethinyl estradiol levels slightly lowered [8]; whether contraceptive reliability decreases was not studied.
  • Triazolam and other CYP3A4 substrates with a high first-pass effect: Levels and half-life of triazolam markedly reduced [8].
  • Methamphetamine: Pretreatment with modafinil reduced methamphetamine-induced dopamine release and locomotor activity in rats [2].

Fact check: common claims

  • partly supported

    “Modafinil markedly boosts the mental performance of healthy people”

    Placebo-controlled studies show effects, but meta-analyses find only small ones (g = 0.10; SMD 0.12) [11][12]; the effects were more consistent in complex tasks [10].

  • refuted

    “Modafinil works differently from stimulants and not via dopamine”

    Modafinil inhibits the dopamine transporter and raises dopamine in the human brain [3]; without the dopamine transporter, it loses its wake-promoting effect in mice [4].

  • refuted

    “Modafinil has no side effects”

    Headache, insomnia and anxiety are common; serious skin reactions occur rarely [14].

  • partly supported

    “Modafinil is not addictive”

    Dependence is rarely reported [14], but the rise in dopamine in the nucleus accumbens points to abuse potential in susceptible people [3].

Pharmacokinetics

Absorption
Well absorbed, peak plasma levels after 2–4 hours [7].
Half-life
About 12–15 hours, determined mainly by the longer-lived R-enantiomer [7].
Metabolism
Mainly in the liver, chiefly by amide hydrolysis, in addition by CYP-mediated oxidation; less than 10% excreted unchanged in the urine; the main metabolites modafinil acid and modafinil sulfone are inactive [7][14].
Entry into the brain
Occupies dopamine transporters in the human striatum (PET) [3].

Legal status

Germany
Prescription-only, but not covered by the German Narcotics Act (BtMG) [17]; the EU-wide restriction to narcolepsy applies [9]. Primary sources: entry “Modafinil” in Annex 1 of the German Ordinance on Prescription-Only Medicines (AMVV) [18]; not listed in Annexes I–III of the Narcotics Act [19]. According to the EMA, modafinil was on the market in Germany, among other countries, in 2010 [20]; national marketing authorizations not checked against AMIce/PharmNet.
EU
Following an EU risk assessment procedure (CHMP recommendation 2010, Commission decision January 27, 2011), approved only for the treatment of sleepiness in narcolepsy, no longer for sleep apnea or shift work [9][20]. The basis is the risk assessment procedure under Article 31 of Directive 2001/83/EC (EMEA/H/A-31/1186): the CHMP confirmed its recommendation after re-examination on November 18, 2010, and the European Commission issued its decision on January 27, 2011; obstructive sleep apnea, shift work sleep disorder and idiopathic hypersomnia were removed, and use in children is advised against because of serious skin reactions [20]. No centrally authorized product in the EMA data export (as of October 24, 2026).
USA
Approved by the FDA; classified as a Schedule IV substance (low abuse potential) [9].
Other countries
Sport: listed by name on the WADA 2026 Prohibited List in section S6.A (“Non-specified stimulants”); S6 applies in competition only [21]. The German publication of the list in the Federal Law Gazette (BGBl.) Part II was not checked.

Related compounds

ArmodafinilR-enantiomerAdrafinilprodrug (German only)Flmodafinilanalog (German only)Hydrafinilanalog (German only)

Open questions

  • What share of the effect is due to noradrenaline, orexin and histamine, independently of the dopamine transporter?
  • Does repeated use over weeks and months help or harm well-rested healthy people?
  • Does modafinil in early pregnancy increase the risk of malformations?

References

  1. Madras BK, Xie Z, Lin Z, Jassen A, Panas H, Lynch L, et al. Modafinil occupies dopamine and norepinephrine transporters in vivo and modulates the transporters and trace amine activity in vitro. J Pharmacol Exp Ther. 2006;319(2):561–9. doi:10.1124/jpet.106.106583 · PubMed
  2. Zolkowska D, Jain R, Rothman RB, Partilla JS, Roth BL, Setola V, et al. Evidence for the involvement of dopamine transporters in behavioral stimulant effects of modafinil. J Pharmacol Exp Ther. 2009;329(2):738–46. doi:10.1124/jpet.108.146142 · PubMed
  3. Volkow ND, Fowler JS, Logan J, Alexoff D, Zhu W, Telang F, et al. Effects of modafinil on dopamine and dopamine transporters in the male human brain: clinical implications. JAMA. 2009;301(11):1148–54. doi:10.1001/jama.2009.351 · PubMed
  4. Wisor JP, Nishino S, Sora I, Uhl GH, Mignot E, Edgar DM. Dopaminergic role in stimulant-induced wakefulness. J Neurosci. 2001;21(5):1787–94. doi:10.1523/JNEUROSCI.21-05-01787.2001 · PubMed
  5. Loland CJ, Mereu M, Okunola OM, Cao J, Prisinzano TE, Mazier S, et al. R-modafinil (armodafinil): a unique dopamine uptake inhibitor and potential medication for psychostimulant abuse. Biol Psychiatry. 2012;72(5):405–13. doi:10.1016/j.biopsych.2012.03.022 · PubMed
  6. Scammell TE, Estabrooke IV, McCarthy MT, Chemelli RM, Yanagisawa M, Miller MS, et al. Hypothalamic arousal regions are activated during modafinil-induced wakefulness. J Neurosci. 2000;20(22):8620–8. doi:10.1523/JNEUROSCI.20-22-08620.2000 · PubMed
  7. Robertson P Jr, Hellriegel ET. Clinical pharmacokinetic profile of modafinil. Clin Pharmacokinet. 2003;42(2):123–37. doi:10.2165/00003088-200342020-00002 · PubMed
  8. Robertson P Jr, Hellriegel ET, Arora S, Nelson M. Effect of modafinil on the pharmacokinetics of ethinyl estradiol and triazolam in healthy volunteers. Clin Pharmacol Ther. 2002;71(1):46–56. doi:10.1067/mcp.2002.121217 · PubMed
  9. Scholte SJ, Yaqub O. Making modafinil: classification and serendipity in drug development. Soc Stud Sci. 2025;55(6):842–61. doi:10.1177/03063127251322113 · PubMed
  10. Battleday RM, Brem AK. Modafinil for cognitive neuroenhancement in healthy non-sleep-deprived subjects: a systematic review. Eur Neuropsychopharmacol. 2015;25(11):1865–81. doi:10.1016/j.euroneuro.2015.07.028 · PubMed
  11. Kredlow MA, Keshishian A, Oppenheimer S, Otto MW. The efficacy of modafinil as a cognitive enhancer: a systematic review and meta-analysis. J Clin Psychopharmacol. 2019;39(5):455–61. doi:10.1097/JCP.0000000000001085 · PubMed
  12. Roberts CA, Jones A, Sumnall H, Gage SH, Montgomery C. How effective are pharmaceuticals for cognitive enhancement in healthy adults? A series of meta-analyses of cognitive performance during acute administration of modafinil, methylphenidate and D-amphetamine. Eur Neuropsychopharmacol. 2020;38:40–62. doi:10.1016/j.euroneuro.2020.07.002 · PubMed
  13. Turner DC, Robbins TW, Clark L, Aron AR, Dowson J, Sahakian BJ. Cognitive enhancing effects of modafinil in healthy volunteers. Psychopharmacology (Berl). 2003;165(3):260–9. doi:10.1007/s00213-002-1250-8 · PubMed
  14. Sousa A, Dinis-Oliveira RJ. Pharmacokinetic and pharmacodynamic of the cognitive enhancer modafinil: relevant clinical and forensic aspects. Subst Abus. 2020;41(2):155–73. doi:10.1080/08897077.2019.1700584 · PubMed
  15. Marin B, Arnulf I, Latour M, Vauzelle C, Coulm B, Beghin D, et al. [Potential teratogenicity of modafinil – conflicting evidence, need for research]. Gynecol Obstet Fertil Senol. 2023;51(3):186–9. doi:10.1016/j.gofs.2023.01.003 · PubMed
  16. Kanoun M, Bouazza N, Treluyer JM, Collier M. Prenatal exposure to modafinil and the risk of major congenital anomalies and other adverse neonatal and pediatric outcomes. Pharmacoepidemiol Drug Saf. 2026;35(8):e70448. doi:10.1002/pds.70448 · PubMed
  17. Dominik P, Waßmer MP, Soyka M, Franke AG. Stimulant abuse as a coping strategy – forensic and criminal consequences of stimulant abuse for neuroenhancement. Front Public Health. 2022;10:1028654. doi:10.3389/fpubh.2022.1028654 · PubMed
  18. Verordnung über die Verschreibungspflicht von Arzneimitteln (Arzneimittelverschreibungsverordnung – AMVV), Anlage 1 (zu § 1 Nr. 1 und § 5). Bundesministerium der Justiz [Internet]. Abgerufen am 24.10.2026. Verfügbar unter: https://www.gesetze-im-internet.de/amvv/anlage_1.html
  19. Gesetz über den Verkehr mit Betäubungsmitteln (Betäubungsmittelgesetz – BtMG), Anlagen I bis III (zu § 1 Abs. 1). Bundesministerium der Justiz [Internet]. Abgerufen am 24.10.2026. Verfügbar unter: https://www.gesetze-im-internet.de/btmg_1981/anlage_i.html (Anlage II und III unter anlage_ii.html bzw. anlage_iii.html)
  20. European Medicines Agency. Modafinil – referral (Article 31), EMEA/H/A-31/1186: Einschränkung der Anwendungsgebiete auf Narkolepsie. CHMP-Gutachten nach erneuter Prüfung 18.11.2010, Kommissionsbeschluss 27.01.2011 [Internet]. London: EMA [abgerufen 24.10.2026]. Verfügbar unter: https://www.ema.europa.eu/en/medicines/human/referrals/modafinil
  21. World Anti-Doping Agency. The 2026 Prohibited List (International Standard), Abschnitt S6 „Stimulants“, S6.A „Non-specified stimulants“ [Internet]. Montreal: WADA; 2025. Abgerufen am 24.10.2026. Verfügbar unter: https://www.wada-ama.org/en/prohibited-list
How this profile was checked

Last reviewed: 2026-10-25. All sources with a DOI or PMID were resolved automatically via Crossref or doi.org and PubMed.

Translated from the German profile (version of 2026-10-25); translation checked on 2026-10-26.

Checked

  • October 25, 2026 (decision q117): legal status cross-checked against primary sources; no findings, no changes. EMA referral page and referral data export EMEA/H/A-31/1186: CHMP opinion after re-examination November 18, 2010, Commission decision January 27, 2011, restriction to narcolepsy, advice against use in children, Germany in the list of countries [20]; openFDA (Drugs@FDA): Provigil NDA 020717, ORIG approved on December 24, 1998, “Prescription”, US prescribing information “Schedule IV controlled substance” (supports status.usa, where [9] remains the citation); AMVV Annex 1 with the entry “Modafinil” [18] and BtMG Annexes I–III without an entry [19] retrieved again. `rx_referenz` set (decision q040; prescription requirement in status.deutschland with AMVV source).
  • October 25, 2026 (q012): the ratings in `versprechen` and `behauptungen` are based on the abstracts (abstract only checked); full texts only for [9] and [17].
  • All 17 DOIs resolved via Crossref and all PMIDs via PubMed with tools/pruefe_profile.py.
  • Key figures checked against the abstracts: IC50 DAT 6.4 µM, NET 35.6 µM, SERT > 500 µM [1]; IC50 4.0 µM, serotonin unchanged [2]; n = 10, DAT occupancy in the caudate 53.8% [3]; DAT knockout without wake-promoting effect [4]; R ≈ 3-fold higher affinity [5]; Fos in the TMN and orexin neurons [6]; Tmax 2–4 h, t½ 12–15 h (abstract: “l-enantiomer” = R-(−)-modafinil), < 10% unchanged, CYP profile [7]; n = 41, CYP3A4/5 induction mainly in the gut [8]; g = 0.10 (19 studies) [11]; SMD 0.12 and 0.28 (14 studies) [12]; n = 60 and test results [13]; side effects and Stevens-Johnson syndrome [14]; aRR 1.23 and 1.77 [16].
  • In the full text [17]: modafinil described as a prescription-only non-stimulant that is not covered by the German Narcotics Act.
  • In the full text (Europe PMC): Schedule IV classification by the FDA in 1998 and EMA/MHRA restriction to narcolepsy in 2010 [9].
  • ClinicalTrials.gov: 227 entries for modafinil (October 23, 2026).
  • Legal status checked against primary sources on October 24, 2026: AMVV Annex 1, entry “Modafinil” [18]; BtMG Annexes I–III without an entry [19]; EMA referral page and referral data export for EMEA/H/A-31/1186 (CHMP opinion after re-examination November 18, 2010, Commission decision January 27, 2011, list of countries including Germany, removal of sleep apnea, shift work sleep disorder and idiopathic hypersomnia, advice against use in children) [20]; EMA medicines export without a centrally authorized product; WADA Prohibited List 2026 (HTML, cross-checked with the PDF), S6.A “Modafinil” [21].
  • October 25, 2026, trade names harmonized (q018; guideline section “Handelsnamen”, decision of October 25, 2026: the Article 57 database counts as a source on a par with the EPAR, the summary of product characteristics and Drugs@FDA; US names only where there are no DE/EU names; no combination products): “Vigil” added to synonyme, “Provigil” and “Modiodal” were already listed. Source: EMA database under Article 57 (Article 57 product data, EMA/518502/2018 Rev. 90, data as of October 9, 2026, retrieved on October 25, 2026): “Vigil” (oral, modafinil) in Germany and Czechia, “Modiodal” in six countries (including Denmark, the Netherlands and Spain), “Provigil” in four (Belgium, Ireland, Italy, Luxembourg); Provigil is therefore also an EU name (in addition, Drugs@FDA NDA 020717, see above). Products whose name combines the active substance and the company name were not included.

Not verified

  • National marketing authorizations in Germany not checked against AMIce/PharmNet (prescription requirement and BtMG status now documented from the legal text [18][19]).
  • The list of side effects comes from a narrative review [14]; the underlying studies were not checked individually (hence evidence level 3).
  • The Danish, Swedish-Norwegian and US registry studies on pregnancy (JAMA 2020, JAMA Intern Med 2021) have no abstract with figures; their results are classified only via the review [15].
  • Studies under sleep deprivation (e.g., comparison with caffeine) deliberately not included in order to stay at 16 references.

No dosages, no sources of supply. This information does not replace medical advice.

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