Nature's Plus Ultra Source of Life

Our assessment

The evidence shows that calcium is a critical mineral for your health, specifically for maintaining strong bones and supporting nerve function. However, this supplement's value depends entirely on your existing diet and health status. For most adults, getting calcium from food is preferred, and supplementing requires careful consideration of total intake, as high levels carry real risks [NIH ODS].

How it works

Think of calcium as the structural building block for your skeleton. It works through a process called bone mineralization, helping your body deposit minerals into bone tissue to keep your skeleton dense and strong. At the same time, calcium acts as a messenger for your nervous system, supporting muscle relaxation and nerve signaling so your muscles can contract and relax properly [NIH ODS].

Safety profile

Safety data is critical here. The FDA has received a total of 592,059 adverse event reports for this product category. For calcium specifically, the risks are notable: high intakes might increase the risk of heart disease and prostate cancer. Very high levels in your blood and urine can lead to poor muscle tone, poor kidney function, low phosphate levels, constipation, nausea, weight loss, extreme tiredness, frequent urination, abnormal heart rhythms, and a high risk of death from heart disease [FDA data] [NIH ODS].

Our recommendation

We recommend you first calculate your total daily calcium intake from food. If you are not meeting the RDA through diet alone, consider a low-dose supplement, but do not exceed 500 mg of supplemental calcium at one time. Be aware that calcium can reduce the absorption of several medications, including bisphosphonates, tetracycline and fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS]. Data on the specific dosage in this product is not available, so consult your pharmacist or doctor before starting to ensure it is safe for you.

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