21st Century Calcium Citrate +D3 Maximum
Brand: 21st Century · Form: TABLET [E0155]
Our assessment
The evidence shows that this product provides calcium, a mineral essential for bone health. The data confirms that calcium supports bone mineralization and neuromuscular relaxation [NIH ODS]. However, you should be aware of the safety considerations and potential interactions before taking this supplement.
How it works
Think of calcium as a building block — your body uses it to deposit minerals into bone tissue, maintaining bone density and strength. It also helps your muscles relax and your nerves signal properly [NIH ODS].
Safety profile
FDA received a total of 592,059 adverse event reports across all products. For calcium specifically, high intakes might increase the risk of heart disease and prostate cancer. High levels of calcium in the blood and urine can cause poor muscle tone, poor kidney function, low phosphate levels, constipation, nausea, weight loss, extreme tiredness, frequent need to urinate, abnormal heart rhythms, and a high risk of death from heart disease [NIH ODS] [FDA data]. Calcium can also reduce the absorption of several medications, including bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS].
Our recommendation
For most adults, the goal is to meet your daily calcium needs through food first, then supplement if needed. Be cautious with high doses. Separate calcium supplements from medications like thyroid hormone and antibiotics by at least 2 hours [NIH ODS]. Consult your doctor before starting this product, especially if you have kidney concerns or take prescription medications.
AI-assisted analysis. Data sourced from NIH DSLD.
Supplement Facts
| Brand | 21st Century |
|---|---|
| Serving Size | |
| Contents | 240.0 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