NOW Magnesium Oxide Pure Powder
Brand: NOW · Form: POWDER [E0162]
Our assessment
The evidence shows that magnesium is a valuable mineral for overall health, but the specific form you are considering—Magnesium Oxide—has important limitations. Our assessment: Magnesium Oxide is one of the least absorbable forms of magnesium, meaning your body may not get the full benefit you are hoping for [NIH ODS].
How it works
Think of magnesium as a key player in hundreds of biochemical reactions. It supports bone mineralization, helps your muscles relax after contracting, and assists with nerve signaling. Magnesium oxide works by providing a concentrated source of elemental magnesium, but its absorption rate is significantly lower than other forms like citrate or glycinate [NIH ODS].
Safety profile
FDA received 592,059 total adverse event reports for all supplements, though specific data for magnesium oxide alone is not available in this data set. High levels of magnesium in the blood can cause poor muscle tone, low phosphate levels, constipation, nausea, weight loss, and abnormal heart rhythms [FDA data] [NIH ODS].
Our recommendation
For general magnesium supplementation, we recommend choosing a more absorbable form such as magnesium citrate or glycinate. If you choose to use magnesium oxide, start with a low dose and take it with food to minimize digestive upset. If you are taking any medications, check with your pharmacist about potential interactions [NIH ODS].
AI-assisted analysis. Data sourced from NIH DSLD.
Supplement Facts
| Brand | NOW |
|---|---|
| Serving Size | |
| Contents | 8.0 oz. 227.0 Gram(s) |
| Market Status | Off Market |
How to Read This Label
Supplement labels contain several key sections regulated by the FDA:
- Serving Size — The recommended amount per dose. Always check this — some products require multiple capsules per serving.
- Amount Per Serving — Shows the quantity of each nutrient in the product, typically in IU (International Units), mg (milligrams), or mcg (micrograms).
- % Daily Value (%DV) — Indicates how much a nutrient in a serving contributes to a daily diet. 5% DV or less is low; 20% DV or more is high.
- Other Ingredients — Lists inactive ingredients like fillers, binders, and capsule materials (e.g., gelatin, cellulose, magnesium stearate).
- Suggested Use — The manufacturer's recommended directions for taking the supplement, including timing and dosage.
Source: FDA Dietary Supplement Labeling Guide