NOW Magnesium & Calcium
Brand: NOW · Form: TABLET [E0155]
Our assessment
The evidence shows that this supplement provides two essential minerals for bone health and muscle function. Our assessment is that calcium is well-supported for bone mineralization and neuromuscular relaxation [NIH ODS]. However, you need to be aware of the safety concerns and potential medication interactions before adding it to your routine.
How it works
Think of calcium as a structural builder for your skeleton. It supports bone density and mineral deposition, which is critical for maintaining strong bones as you age [NIH ODS]. It also acts as a nerve and muscle messenger, supporting muscle relaxation and nerve signaling throughout your body [NIH ODS].
Safety profile
FDA received a total of 592,059 adverse event reports across all supplement categories. For calcium specifically, high intakes might increase the risk of heart disease and prostate cancer [NIH ODS]. Side effects from high calcium levels include 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].
Our recommendation
Start with a moderate dose and monitor your total calcium intake from food and supplements. You should be cautious if you take bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, or phenytoin, as calcium can reduce their absorption [NIH ODS]. We recommend consulting your healthcare provider before starting this supplement, especially if you have a history of kidney stones, heart disease, or take any of the medications listed above.
AI-assisted analysis. Data sourced from NIH DSLD.
Supplement Facts
| Brand | NOW |
|---|---|
| Serving Size | |
| Contents | 100.0 Tablet(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