Magnesium vs Melatonin
Magnesium and Melatonin compared on absorption, gut tolerance, and real cost per dose — the cheapest of each pulled live from the Amazon US catalog.
Updated October 2026
Side by side
| Attribute | Magnesium | Melatonin |
|---|---|---|
| Type | Mineral | Hormone |
| Main effect on sleep | Relaxation, quality (modest) | Shifts sleep timing |
| Evidence for sleep | Limited and mixed | Good for jet lag and delayed sleep |
| Typical dose | 200–350 mg elemental | 0.5–3 mg |
| Active deals tracked | 180 | 68 |
| Cheapest cost per dose | $0.03 (per 400 mg) | $0.02 (per 3 mg) |
Melatonin is absorbed quickly and acts within about an hour on your circadian clock. How well magnesium is absorbed depends on the form — glycinate and citrate well, oxide poorly — and any effect on sleep builds over weeks.
Which to avoid / caveats
- Compare cost per elemental / active content, not the compound milligrams printed on the label — a bigger number on the front can hide less of what you actually absorb.
- The cheapest sticker price isn’t always the best value: our “cheapest per dose” figures normalise price across bottle sizes, so a larger count only wins if it truly costs less per serving.
Melatonin
Best for: Jet lag and a delayed sleep schedule, short-term.
Best Melatonin by cost per doseCheapest Magnesium
NEW
🌙 Magnesium
Magnesium Oxide 400mg, 500 Capsules | Elemental Form for Max…
Cost per serving
$0.03
Cheap·−91%500 servings · ~500-day supply
Low absorption
$15.19Price from Amazon.com
Micro Ingredients · Amazon.com 0
See the offer Cheapest Melatonin
NEW
😴 Melatonin
Piping Rock Melatonin 3mg | 250 Tablets | Adult Support…
Cost per serving
$0.02
Cheap·−92%250 servings · ~250-day supply
$5.49Price from Amazon.com
Piping Rock · Amazon.com 0
See the offer Frequently asked
Is magnesium or melatonin better for sleep?+
Melatonin, if the problem is timing — jet lag or falling asleep late. Magnesium has weaker evidence and helps mostly people who are low in it, but it is not a hormone and suits nightly use. Not medical advice.
Can you take magnesium and melatonin together?+
Yes; they work differently, there is no known interaction between them, and some products combine them. Keep supplemental magnesium at or under 350 mg a day and melatonin low-dose. Not medical advice.
Is Magnesium or Melatonin cheaper per dose?+
The cheapest Magnesium we track is $0.03 per serving; the cheapest Melatonin is $0.02 per serving — so Melatonin costs less per dose right now (October 2026).
How much Magnesium do you need per day?+
RDAs depend on age and sex. Adult men need 400-420 mg; adult women need 310-320 mg. Pregnancy is 350-400 mg and lactation 310-360 mg. Children range from 80 mg (1-3 years) to 240 mg (9-13 years); infants have AIs of 30-75 mg. — per the NIH Office of Dietary Supplements; general information, not medical advice.
Can you take too much Magnesium?+
Yes. The Tolerable Upper Intake Level for supplemental magnesium is 350 mg for adults. High supplement or medication doses can cause diarrhea, nausea, and abdominal cramping. Very high doses cause toxicity: hypotension, vomiting, difficulty breathing, irregular heartbeat, and cardiac arrest; fatal hypermagnesemia has occurred. — per the NIH Office of Dietary Supplements; general information, not medical advice.
Dosage & safety answers sourced from the NIH Office of Dietary Supplements. General information, not medical advice.
What the research says
Too much magnesium from food does not pose a health risk in healthy individuals because the kidneys eliminate excess amounts, but high doses from dietary supplements or medications often cause diarrhea, nausea, and abdominal cramping. The Tolerable Upper Intake Level (UL) for supplemental magnesium is 350 mg/day for adults — per the NIH Office of Dietary Supplements.
Groups more likely to be at risk of magnesium inadequacy include people with gastrointestinal diseases (such as Crohn's disease and celiac disease), people with type 2 diabetes, people with alcohol dependence, and older adults. Early signs and symptoms of deficiency include loss of appetite, nausea, vomiting, fatigue, and weakness; as it worsens, numbness, tingling, muscle contractions and cramps, seizures, personality changes, abnormal heart rhythms, and coronary spasms can occur, and severe deficiency can cause hypocalcemia or hypokalemia — per the NIH Office of Dietary Supplements.
Related
Best Magnesium by cost per doseBest Melatonin by cost per doseMagnesium dosage & factsMelatonin dosage & factsSupplement price-spread study
People also compare
References & sources
- Health Professional fact sheet — NIH Office of Dietary Supplements
- USP Verified product participants — U.S. Pharmacopeia
- NSF certified products — NSF
We link primary sources and paraphrase their findings — never copy their text, tables, or images. Cost-per-dose figures are our own first-party catalog data.