21st Century Calcium Plus
Brand: 21st Century · Form: SUPPLEMENT FORM, OTHER [E0172] On Market
Our assessment
The evidence shows that calcium is a critical mineral for bone health, but you need to be very careful with dosing. Our assessment is that while calcium supports bone density and nerve signaling, the data reveals significant safety concerns at high intakes that you must take seriously [NIH ODS].
How it works
Think of calcium as a structural builder for your skeleton. It supports bone mineralization and density, and it also helps your muscles relax and your nerves send signals properly [NIH ODS].
Safety profile
FDA received 592,059 total adverse event reports for this product category. For calcium specifically, high intakes may increase the risk of heart disease and prostate cancer. Side effects from high blood or urine calcium levels include constipation, nausea, weight loss, extreme tiredness, frequent urination, abnormal heart rhythms, and a high risk of death from heart disease [FDA data] [NIH ODS]. Calcium can also reduce the absorption of medications like bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS].
Our recommendation
Start with a low dose and get your calcium levels checked by your doctor. Be aware that high intakes carry real risks, and you must separate calcium supplements from your thyroid or antibiotic medications by at least 4 hours. Data not available on a specific recommended daily dose from this product label [NIH ODS].
AI-assisted analysis. Data sourced from NIH DSLD.
Supplement Facts
| Brand | 21st Century |
|---|---|
| Serving Size | |
| Contents | 120.0 Caplet(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