Comparison
Armodafinil vs Melatonin
Side-by-side of Armodafinil and Melatonin. Every row below is pulled from the compound schema and will update as our data grows. For deeper reads, follow through to each compound page.
Armodafinil
Armodafinil is the R-enantiomer sold as Nuvigil. Half-life 10-15 h, 150 mg standard dose, narcolepsy and shift-work approvals, Schedule IV.
Melatonin
Melatonin as a sleep supplement: 0.3-1 mg matches physiological output, 3-10 mg is pharmacological. Shifts circadian phase, shortens sleep latency.
Effects at a glance
Armodafinil
- •FDA approved in 2007 for narcolepsy, shift-work sleep disorder, and OSA residual sleepiness
- •R-enantiomer of modafinil; 150 mg armodafinil is roughly equivalent to 200 mg modafinil
- •Schedule IV controlled in the US; prescription-only globally
- •Longer terminal half-life of about 15 hours produces extended late-day wakefulness coverage
- •Same CYP3A4 induction as modafinil; reduces hormonal contraceptive efficacy
- •Side-effect profile and dermatologic risk warnings mirror modafinil
Melatonin
- •Shortens sleep onset latency by ~7 to 12 minutes at physiological 0.3 to 1 mg doses
- •Advances circadian phase when taken 30 to 60 minutes before target bedtime, useful for jet lag and shift work
- •Does not meaningfully increase total sleep time in healthy adults without circadian misalignment
- •Endogenous nighttime production is not suppressed by short-term exogenous supplementation
- •Higher doses (3 to 10 mg) raise plasma levels above physiological range and often increase morning grogginess
- •Effective for delayed sleep-wake phase disorder and reducing jet-lag severity in eastward travel
Side-by-side
| Attribute | Armodafinil | Melatonin |
|---|---|---|
| Category | pharmaceutical | supplement |
| Also known as | Nuvigil, R-modafinil, (R)-(-)-modafinil | N-acetyl-5-methoxytryptamine |
| Half-life (hr) ↗ | 15 | 0.75 |
| Typical dose (mg) ↗ | 150 | 0.5 |
| Dosing frequency | daily, morning | daily, 30 to 60 minutes before target sleep time |
| Routes | oral | oral, sublingual |
| Onset (hr) | 1 | 0.5 |
| Peak (hr) | 3 | 1 |
| Molecular weight | 273.35 | 232.28 |
| Molecular formula | C15H15NO2S | C13H16N2O2 |
| Mechanism | Weak dopamine reuptake inhibition plus downstream activation of histaminergic, noradrenergic, and orexinergic wake systems; R-enantiomer of modafinil with longer half-life. | Agonist at MT1 and MT2 receptors in the suprachiasmatic nucleus, signaling biological night and promoting sleep-onset gating plus circadian phase shifts. |
| Legal status | Schedule IV (US); prescription-only globally; not a supplement | OTC in US; prescription in UK, EU, Japan |
| WADA status | banned | allowed |
| DEA / Rx | Schedule IV | OTC supplement in US; Rx in UK, EU, Japan, Australia |
| Pregnancy | Not recommended | Insufficient data; not routinely recommended |
| CAS | 112111-43-0 | 73-31-4 |
| PubChem CID | 9148206 | 896 |
| Wikidata | Q4791953 | Q179243 |
Safety profile
Armodafinil
Common side effects
- headache
- nausea
- dizziness
- anxiety
- insomnia (with later-day dosing)
- dry mouth
- mild blood pressure elevation
Contraindications
- recent myocardial infarction
- unstable angina
- left ventricular hypertrophy
- significant arrhythmia
- history of Stevens-Johnson syndrome
- psychotic disorders
- pregnancy
- concurrent MAOI use
Interactions
- hormonal contraceptives: CYP3A4 induction reduces contraceptive efficacy; use barrier method(major)
- cyclosporine: reduced cyclosporine levels via CYP3A4 induction(major)
- warfarin: CYP2C9 inhibition raises INR(moderate)
- phenytoin: CYP2C19 inhibition raises phenytoin levels(moderate)
- MAOIs: potential hypertensive reaction(major)
- classical stimulants: additive cardiovascular and sleep-disruption effects(moderate)
Melatonin
Common side effects
- vivid dreams
- morning grogginess (higher doses)
- headache
- dizziness
Contraindications
- autoimmune disease (theoretical)
- concurrent anticoagulant therapy without monitoring
Interactions
- fluvoxamine: CYP1A2 inhibition raises melatonin levels substantially(major)
- warfarin: possible increased bleeding risk(moderate)
- benzodiazepines and alcohol: additive sedation(moderate)
- antihypertensives: may alter blood pressure response(minor)
Which Should You Take?
Melatonin comes out ahead for most readers on the criteria we weight: 2 catalogued goals, OTC, oral dosing, with a Tier-A outcome catalogued. Armodafinil is the right call when one of the conditionals below applies.
- → If your priority is wakefulness, pick Armodafinil.
- → If your priority is focus or working memory, pick Armodafinil.
- → If your priority is sleep onset or sleep quality, pick Melatonin.
- → If your priority is circadian regulation, pick Melatonin.
Edge case: If you want to avoid controlled substance, Melatonin is the more accessible choice.
Default choice: Melatonin. Wider use case, a Tier-A evidence outcome catalogued, and broader goal coverage. Reach for Armodafinil only if your priority sits squarely in the goals it owns above.
This verdict is generated from each compound's schema (goals, legal status, evidence outcomes, dosing route). It updates automatically as our compound data evolves; the deeper read sits on each individual compound page.
Common questions
What is the difference between Armodafinil and Melatonin?
Armodafinil and Melatonin differ in category (pharmaceutical vs supplement), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, Armodafinil or Melatonin?
Armodafinil half-life is 15 hours; Melatonin half-life is 0.75 hours.
Can you stack Armodafinil with Melatonin?
Stack compatibility depends on mechanism overlap, legal status, and individual response. Check each compound page for specific interactions and contraindications before combining.
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