NOW Iron Complex

Our assessment

The evidence shows that calcium is a critical mineral for your health, but it requires careful attention to dosage and timing. For a general audience, the data underscores that calcium supports bone density and nerve function, but high intakes carry real risks [NIH ODS].

How it works

Think of calcium as a foundation builder for your skeleton and a signal regulator for your nerves. It supports bone mineralization and helps your muscles relax after contracting [NIH ODS].

Safety profile

FDA received 592,059 total adverse event reports for this product category. Specific risks from high calcium intake include constipation, nausea, weight loss, extreme tiredness, frequent urination, abnormal heart rhythms, and a high risk of death from heart disease. Some research also suggests high intakes might increase the risk of heart disease and prostate cancer [FDA data] [NIH ODS].

Our recommendation

Start by getting your calcium from food first. If you use a supplement, take it with meals and separate it from medications like thyroid hormone or antibiotics by at least two hours, as calcium can reduce their absorption [NIH ODS]. Monitor your total daily intake to avoid exceeding safe levels.

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