NOW Bone Calcium

Our assessment

Our assessment is that NOW Bone Calcium is a straightforward calcium supplement designed to support your bone health. The evidence shows that calcium is essential for bone mineralization and neuromuscular function [NIH ODS]. However, you need to be aware that the data on high calcium intake includes some important safety considerations, and you should always check with your healthcare provider before starting any new supplement.

How it works

Think of calcium as a building block for your skeleton. It supports bone density and mineral deposition, which helps keep your bones strong [NIH ODS]. It also plays a key role in neuromuscular relaxation, supporting proper muscle relaxation and nerve signaling [NIH ODS]. If you are taking this for bone health, you should know that calcium works best when paired with vitamin D and magnesium, though those are not included in this specific product.

Safety profile

FDA has received 592,059 total adverse event reports for all dietary supplements, but specific report counts for this product are not available. The data shows that high calcium intakes might increase the risk of heart disease and prostate cancer [NIH ODS]. 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]. Calcium can also reduce the absorption of several medications, including bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS].

Our recommendation

Our recommendation is to first check your total calcium intake from all sources (diet plus supplements) to ensure you do not exceed the tolerable upper intake level. Separate calcium doses from medications like thyroid hormone or antibiotics by at least two hours [NIH ODS]. Because of the potential risks associated with high intakes, do not take more than the label directs without your doctor’s approval. Data not available on the exact calcium dose per serving from the product 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