21st Century Calcium Citrate +D3 Maximum
Brand: 21st Century · Form: TABLET [E0155] On Market
Our assessment
The evidence shows that this supplement combines calcium and vitamin D3 to support bone health. For most adults, the goal is to meet your daily calcium needs through diet first, using supplements as a targeted backup. Data on the specific dose per serving is not available in the provided data, so you should check the label carefully [NIH ODS].
How it works
Think of calcium as the structural building block for your bones and teeth, while vitamin D3 acts as a master regulator that helps your body absorb that calcium. Together, they support bone mineralization and neuromuscular relaxation, which is essential for muscle function and nerve signaling [NIH ODS].
Safety profile
FDA received a total of 592,059 adverse event reports across all supplement categories. For calcium specifically, high intakes may increase the risk of heart disease and prostate cancer. Side effects from excessive levels include constipation, nausea, weight loss, extreme tiredness, frequent urination, abnormal heart rhythms, and poor muscle tone [NIH ODS] [FDA data].
Our recommendation
Start by assessing your total daily calcium intake from food. Take this supplement only if you consistently fall short of the RDA. To minimize interactions, separate it from medications like bisphosphonates, tetracycline antibiotics, and levothyroxine by at least 2 hours [NIH ODS].
AI-assisted analysis. Data sourced from NIH DSLD.
Supplement Facts
| Brand | 21st Century |
|---|---|
| Serving Size | |
| Contents | 240.0 Tablet(s) |
| Market Status | On 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