Comparison
Melatonin vs Omega-3 (EPA/DHA)
Side-by-side of Melatonin and Omega-3 (EPA/DHA). 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.
Melatonin
Melatonin as a sleep supplement: 0.3-1 mg matches physiological output, 3-10 mg is pharmacological. Shifts circadian phase, shortens sleep latency.
Omega-3 (EPA/DHA)
Omega 3 fish oil profile: EPA/DHA marine fatty acids, 2-4 g/day cuts triglycerides 20-30%, REDUCE-IT showed 25% cardiovascular risk reduction on icosapent eth.
Effects at a glance
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
Omega-3 (EPA/DHA)
- •Reduces fasting triglycerides 20-50% at 2-4 g/day in hypertriglyceridemic patients
- •REDUCE-IT showed 25% relative risk reduction in major CV events at 4 g/day icosapent ethyl
- •Modest antidepressant effect (SMD ~0.40) for EPA-dominant formulations at 1-2 g/day
- •Atrial fibrillation incidence rises ~30-50% at 4 g/day; relevant for older patients with pre-existing CV disease
- •Tissue omega-3 index (RBC EPA + DHA) target ~8%; Western baseline typically 4-5%
- •Triglyceride and re-esterified triglyceride forms absorb ~70% better than ethyl esters in fasted state
Side-by-side
| Attribute | Melatonin | Omega-3 (EPA/DHA) |
|---|---|---|
| Category | supplement | supplement |
| Also known as | N-acetyl-5-methoxytryptamine | fish oil, EPA, DHA, marine omega-3 |
| Half-life (hr) ↗ | 0.75 | 48 |
| Typical dose (mg) ↗ | 0.5 | 2000 |
| Dosing frequency | daily, 30 to 60 minutes before target sleep time | 1 to 2 times daily with food |
| Routes | oral, sublingual | oral |
| Onset (hr) | 0.5 | 4 |
| Peak (hr) | 1 | 12 |
| Molecular weight | 232.28 | 302.45 |
| Molecular formula | C13H16N2O2 | C20H30O2 (EPA); C22H32O2 (DHA) |
| Mechanism | Agonist at MT1 and MT2 receptors in the suprachiasmatic nucleus, signaling biological night and promoting sleep-onset gating plus circadian phase shifts. | Substitutes arachidonic acid in membrane phospholipids, shifting eicosanoid production toward less-inflammatory 3-series prostaglandins and 5-series leukotrienes. Activates PPAR-alpha to lower hepatic VLDL/triglyceride synthesis. DHA modulates synaptic membrane fluidity and neuronal function. |
| Legal status | OTC in US; prescription in UK, EU, Japan | Dietary supplement; prescription forms (icosapent ethyl, omega-3 acid ethyl esters) for severe hypertriglyceridemia |
| WADA status | allowed | allowed |
| DEA / Rx | OTC supplement in US; Rx in UK, EU, Japan, Australia | Not scheduled |
| Pregnancy | Insufficient data; not routinely recommended | Recommended at 200 to 600 mg DHA/day for fetal development |
| CAS | 73-31-4 | 10417-94-4 |
| PubChem CID | 896 | 446284 |
| Wikidata | Q179243 | Q207688 |
Safety profile
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)
Omega-3 (EPA/DHA)
Common side effects
- fishy aftertaste
- eructation (fish burps)
- mild dyspepsia
- loose stools at high doses
Contraindications
- fish allergy (use algal omega-3 alternative)
- active bleeding disorders
- scheduled surgery (discontinue 5-7 days prior)
Interactions
- warfarin and DOACs: additive antiplatelet effect at 2+ g/day; meaningful bleeding risk(moderate)
- aspirin and antiplatelet agents: additive bleeding risk at high doses(moderate)
- statins: complementary cardiovascular effects; no pharmacokinetic interaction(minor)
- antiarrhythmics: high-dose omega-3 increases AF risk; relevant in pre-existing arrhythmia(moderate)
Which Should You Take?
Omega-3 (EPA/DHA) comes out ahead for most readers on the criteria we weight: 3 catalogued goals, OTC dietary supplement, oral dosing, with a Tier-A outcome catalogued. Melatonin is the right call when one of the conditionals below applies.
- → If your priority is sleep onset or sleep quality, pick Melatonin.
- → If your priority is circadian regulation, pick Melatonin.
- → If your priority is cardiovascular health, pick Omega-3 (EPA/DHA).
- → If your priority is healthspan extension, pick Omega-3 (EPA/DHA).
Edge case: Half-lives differ materially (Melatonin ~0.75 hr vs Omega-3 (EPA/DHA) ~48 hr). Omega-3 (EPA/DHA) reaches steady state faster; Melatonin is easier to dial in if tolerability is uncertain.
Default choice: Omega-3 (EPA/DHA). Lower friction to source, a Tier-A evidence outcome catalogued, and broader goal coverage. Reach for Melatonin 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 Melatonin and Omega-3 (EPA/DHA)?
Melatonin and Omega-3 (EPA/DHA) differ in category (supplement vs supplement), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, Melatonin or Omega-3 (EPA/DHA)?
Melatonin half-life is 0.75 hours; Omega-3 (EPA/DHA) half-life is 48 hours.
Can you stack Melatonin with Omega-3 (EPA/DHA)?
Stack compatibility depends on mechanism overlap, legal status, and individual response. Check each compound page for specific interactions and contraindications before combining.
Go deeper