Life Extension Buffered Vitamin C Powder

Our assessment

Our assessment: Calcium is an essential mineral, but you need to be careful with supplementation. The data shows that while calcium supports bone health, high intakes from supplements may increase the risk of heart disease and prostate cancer [NIH ODS].

How it works

Think of calcium as a building block for your skeleton. It supports bone mineralization and density, and it also plays a role in nerve signaling and muscle relaxation [NIH ODS].

Safety profile

FDA received 592,059 total adverse event reports for this product category. Side effects from high calcium levels include constipation, nausea, weight loss, extreme tiredness, abnormal heart rhythms, and poor kidney function [FDA data] [NIH ODS]. Calcium can also reduce the absorption of medications such as bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS].

Our recommendation

Our recommendation: Get your calcium primarily from food. If you do supplement, keep your total intake from all sources within safe limits and talk to your doctor, especially if you take any of the medications listed above [NIH ODS].

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