NOW Magnesium Bisglycinate Powder
Brand: NOW · Form: POWDER [E0162]
Our assessment
The evidence shows that calcium is a critical mineral for bone health, but the data also highlights important safety considerations. For a general audience seeking to support bone density and nerve function, calcium supplementation can be effective, but you must be mindful of dosage and potential interactions with medications [NIH ODS].
How it works
Think of calcium as a structural builder and signal messenger. It supports bone mineralization and density, and it plays a key role in neuromuscular relaxation and nerve signaling. This means it helps your muscles relax after contracting and supports the transmission of signals through your nervous system [NIH ODS].
Safety profile
The FDA received a total of 592,059 adverse event reports across all supplements, though specific counts for calcium alone are not isolated in this data. The NIH ODS data reports that high calcium intakes might increase the risk of heart disease and prostate cancer. High levels of calcium in the blood and urine can cause poor muscle tone, poor kidney function, low phosphate levels, constipation, nausea, weight loss, extreme tiredness, frequent need to urinate, abnormal heart rhythms, and a high risk of death from heart disease [NIH ODS] [FDA data].
Our recommendation
Start by assessing your dietary calcium intake before adding a supplement. Be aware that calcium can reduce the absorption of several medications, including bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS]. If you take any of these medications, separate your calcium dose by at least two hours. Data not available for specific dosing guidance for this product from the provided information.
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