Comparison
Melatonin vs Semaglutide
Side-by-side of Melatonin and Semaglutide. 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.
Semaglutide
Semaglutide for weight loss: GLP-1 agonist (Ozempic, Wegovy) drives 15-17% mean loss at 2.4 mg/week in STEP trials. Watch lean-mass loss.
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
Semaglutide
- •Long-acting GLP-1 receptor agonist with a ~7-day half-life that supports once-weekly subcutaneous dosing
- •STEP trials reported ~15 to 17% mean body-weight loss at 2.4 mg/week over 68 weeks in adults with obesity
- •Lowers HbA1c by ~1.0 to 1.8 percentage points in type 2 diabetes versus placebo
- •SELECT trial showed reduced major cardiovascular events in adults with prior CVD and overweight or obesity
- •Up to 25 to 40% of weight lost can be lean mass; pairing with resistance training and protein intake mitigates this
- •GI effects (nausea, vomiting, constipation) drive most discontinuations and ease with slow titration
Side-by-side
| Attribute | Melatonin | Semaglutide |
|---|---|---|
| Category | supplement | pharmaceutical |
| Also known as | N-acetyl-5-methoxytryptamine | Ozempic, Wegovy, Rybelsus |
| Half-life (hr) ↗ | 0.75 | 168 |
| Typical dose (mg) ↗ | 0.5 | 2.4 |
| Dosing frequency | daily, 30 to 60 minutes before target sleep time | weekly (SC); daily (oral Rybelsus) |
| Routes | oral, sublingual | subcutaneous, oral |
| Onset (hr) | 0.5 | 24 |
| Peak (hr) | 1 | 72 |
| Molecular weight | 232.28 | 4113.58 |
| Molecular formula | C13H16N2O2 | - |
| Mechanism | Agonist at MT1 and MT2 receptors in the suprachiasmatic nucleus, signaling biological night and promoting sleep-onset gating plus circadian phase shifts. | Long-acting GLP-1 receptor agonist; potentiates glucose-dependent insulin secretion, suppresses glucagon, slows gastric emptying, and acts on hypothalamic satiety centers. |
| Legal status | OTC in US; prescription in UK, EU, Japan | Prescription only (FDA-approved, EMA-approved) |
| WADA status | allowed | allowed |
| DEA / Rx | OTC supplement in US; Rx in UK, EU, Japan, Australia | Rx only (not a controlled substance); FDA-approved for type 2 diabetes (2017) and chronic weight management (2021) |
| Pregnancy | Insufficient data; not routinely recommended | Not recommended; discontinue 2 months before planned pregnancy |
| CAS | 73-31-4 | 910463-68-2 |
| PubChem CID | 896 | 56843331 |
| Wikidata | Q179243 | Q27089394 |
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)
Semaglutide
Common side effects
- nausea
- vomiting
- diarrhea
- constipation
- decreased appetite
- injection-site reactions
- fatigue
Contraindications
- personal or family history of medullary thyroid carcinoma
- multiple endocrine neoplasia type 2
- pregnancy
- history of pancreatitis (use caution)
Interactions
- insulin: additive hypoglycemia risk; insulin dose typically reduced(major)
- sulfonylureas (glipizide, glyburide): hypoglycemia risk, sulfonylurea dose often reduced(major)
- oral medications (general): delayed gastric emptying can alter absorption kinetics(moderate)
- warfarin: monitor INR due to altered absorption(moderate)
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. Semaglutide 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 metabolic health and glucose control, pick Semaglutide.
- → If your priority is fat loss, pick Semaglutide.
Edge case: If you want to avoid prescription-only, Melatonin is the more accessible choice.
Default choice: Melatonin. Wider use case, a Tier-A evidence outcome catalogued, and broader goal coverage. Reach for Semaglutide 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 Semaglutide?
Melatonin and Semaglutide differ in category (supplement vs pharmaceutical), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, Melatonin or Semaglutide?
Melatonin half-life is 0.75 hours; Semaglutide half-life is 168 hours.
Can you stack Melatonin with Semaglutide?
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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