NOW Calcium & Magnesium
Brand: NOW · Form: TABLET [E0155]
Our assessment
Our assessment: This supplement provides two essential minerals, but the evidence shows you need to be careful with dosing. Calcium supports bone health, but high intakes carry risks [NIH ODS]. For most adults, the data supports using this product only if you cannot meet your needs through diet alone.
How it works
Think of calcium as a structural builder for your bones and a signal conductor for your nerves. It supports bone density and mineral deposition, and it helps with muscle relaxation and nerve signaling [NIH ODS]. The magnesium in this product also plays a role in these processes, though specific data on its mechanism is not provided here.
Safety profile
Safety is a key concern here. Data not available on specific side effect counts for this product alone, but the FDA has received 592059 total adverse event reports across all supplements. High calcium levels can cause constipation, nausea, weight loss, extreme tiredness, frequent need to urinate, abnormal heart rhythms, and a high risk of death from heart disease [NIH ODS]. Some research suggests high intakes might increase the risk of heart disease and prostate cancer [NIH ODS]. Calcium can also reduce absorption of medications like bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS].
Our recommendation
Our recommendation: Only use this supplement if you have a confirmed calcium or magnesium deficiency. Start with the lowest effective dose and never exceed the RDA from all sources combined. Take it with food and separate from other medications by at least 2 hours [NIH ODS]. Consult your doctor before starting, especially if you have kidney issues or take prescription medications.
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