**Magnesium** at 250mg per tablet lands within the clinical supplemental range of 100–400mg — but the form is magnesium oxide, which has roughly 4% absorption. That means your body is likely taking in only about 10mg of usable magnesium from each serving, well below what you'd need for meaningful support with sleep, stress, or muscle recovery.
The tablet also includes 65mg of **Calcium** as calcium carbonate, but that's a fraction of the 200–600mg supplemental range and won't move the needle for bone support. There are no complementary nutrients like vitamin D or K2 to enhance absorption of either mineral.
If you're supplementing magnesium for a specific health goal, the oxide form is the biggest limitation here. You'd absorb substantially more from a glycinate, citrate, or threonate form at the same dose — and those forms are also gentler on the stomach.
BioStacks
Best for
Ingredients (2)
Magnesium
100%Dose
250 mg
Target
100–400 mg
Form
Budget
Calcium
65 mgTrace amount — not scored
Other Ingredients (4)
KelpFood
Dried brown seaweed used as a whole-food source of iodine and trace minerals.
Microcrystalline CelluloseBinder
Plant-derived cellulose used as a binder and filler in supplements
Croscarmellose SodiumDisintegrant
Cross-linked cellulose derivative used as a superdisintegrant
Stearic AcidLubricant
Saturated fatty acid used as tablet lubricant
How to Take It
Best taken in the evening
Magnesium oxide is poorly absorbed (~4%) and the most laxative form. Most of a dose stays in the gut, which is why it's mainly used for constipation — a poor pick if you're supplementing for magnesium itself.
With or without food
Space it a couple of hours from Iron and Calcium
On the label
Directions: As a mineral supplement, adults take one (1) tablet daily with any meal or as directed by a healthcare provider.
General guidance based on the ingredients, not a substitute for the label or your doctor.
Price Check
$4.99
Cheaper than 99% of 579 magnesium supplements
Track this supplement in your stack
Get personalized insights, interactions, and coverage recommendations.
Get Started FreeSimilar Supplements
Sources & Scoring
Nutrient data (RDA, UL, and safety thresholds) sourced from the NIH Office of Dietary Supplements and the National Academies Dietary Reference Intakes (DRI).
This is not medical advice. Consult a healthcare provider before making changes to your supplement routine.
The score analyzes what's on the label: ingredient doses vs. studied ranges, chemical forms, evidence levels, and known interactions. It does not verify label accuracy or test for contaminants — for that, look for third-party certifications like USP or NSF.