21st Century Calcium Citrate +D3 Maximum
Brand: 21st Century · Form: SUPPLEMENT FORM, OTHER [E0172]
Our assessment
The evidence shows that 21st Century Calcium Citrate +D3 Maximum provides a well-absorbed form of calcium with added vitamin D. For most adults, calcium is essential for bone health, but this product’s dosage and your individual needs require careful evaluation. Data not available for the specific vitamin D content in this product.
How it works
Think of calcium as the building block for your bones and teeth. It supports bone mineralization and density, and it also helps your muscles relax and your nerves signal properly [NIH ODS]. The citrate form in this product is often better absorbed than calcium carbonate, especially if you take it on an empty stomach or have low stomach acid.
Safety profile
FDA received 592,059 total adverse event reports, though this number covers all supplements, not just this product. High calcium intakes can increase the risk of heart disease and prostate cancer [NIH ODS]. Side effects from excessive calcium include constipation, nausea, weight loss, extreme tiredness, frequent urination, abnormal heart rhythms, and a high risk of death from heart disease [NIH ODS]. High levels of calcium in the blood and urine can also cause poor muscle tone, poor kidney function, and low phosphate levels [NIH ODS].
Our recommendation
Start by checking your total daily calcium intake from food and other supplements. Do not exceed 2,000 mg of calcium per day from all sources. Take this supplement with a meal to improve absorption. Because calcium can reduce absorption of several medications, separate this supplement from bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin by at least 2 hours [NIH ODS]. Consult your healthcare provider before starting, especially if you have kidney disease or a history of heart problems.
AI-assisted analysis. Data sourced from NIH DSLD.
Supplement Facts
| Brand | 21st Century |
|---|---|
| Serving Size | |
| Contents | 240.0 Caplet(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