21st Century Calcium Citrate +D3 Maximum
Brand: 21st Century · Form: TABLET [E0155] On Market
Our assessment
The evidence shows that this combination of calcium and vitamin D is foundational for bone health. Our assessment: for most adults, this supplement can help you meet your daily calcium needs, but you must be careful with dosing. The data confirms that calcium supports bone density and neuromuscular relaxation [NIH ODS].
How it works
Think of calcium as the building block for your bones, working with vitamin D to ensure proper mineral deposition. The mechanism involves bone mineralization and supporting muscle relaxation and nerve signaling [NIH ODS].
Safety profile
FDA received 592059 total adverse event reports across all products. For calcium specifically, side effects can include constipation, nausea, weight loss, extreme tiredness, frequent need to urinate, and abnormal heart rhythms at high levels [FDA data] [NIH ODS]. High calcium intakes might also increase the risk of heart disease and prostate cancer [NIH ODS]. Calcium can reduce the absorption of several medications, including bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS].
Our recommendation
Start by checking your total daily intake from food and supplements. Do not exceed the tolerable upper intake level. Take this supplement with food, and separate it from thyroid medication or antibiotics by at least 2 hours [NIH ODS].
AI-assisted analysis. Data sourced from NIH DSLD.
Supplement Facts
| Brand | 21st Century |
|---|---|
| Serving Size | |
| Contents | 60.0 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