NOW Vitamin D-3 1,000 IU
Brand: NOW · Form: SOFTGEL CAPSULE [E0161]
Our assessment
The evidence shows that NOW Vitamin D-3 1,000 IU is a straightforward vitamin D supplement. While the product is not directly studied in the data we have, the active ingredient, vitamin D3, is well-documented. Our assessment is that this supplement can be a reliable way for you to meet your daily vitamin D needs, but you should be aware of how the calcium in your diet interacts with vitamin D.
How it works
Vitamin D works as a master regulator of calcium in your body. It helps your body absorb calcium from food, which is critical for bone mineralization and strong bones [NIH ODS]. The calcium in your system supports bone density and also plays a role in neuromuscular relaxation, helping your muscles and nerves signal properly [NIH ODS].
Safety profile
FDA has received a total of 592,059 adverse event reports across all supplements, though specific data for this product is not available. The safety of vitamin D itself is generally good, but the data on calcium provides important context. High calcium intakes might increase the risk of heart disease and prostate cancer [NIH ODS]. Very high levels of calcium in the blood can cause poor muscle tone, poor kidney function, constipation, nausea, weight loss, extreme tiredness, frequent urination, abnormal heart rhythms, and a high risk of death from heart disease [NIH ODS]. You should also know that calcium can reduce the absorption of medications like bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS].
Our recommendation
Our recommendation is to take this supplement as directed, typically one softgel daily with a meal that contains fat for best absorption. Because vitamin D increases calcium absorption, do not take additional calcium supplements without consulting your doctor, especially if you have a history of kidney stones or heart disease. If you take any of the medications listed above, separate your supplement intake by at least 2 hours [NIH ODS]. For personalized dosing, get a blood test to check your vitamin D levels.
AI-assisted analysis. Data sourced from NIH DSLD.
Supplement Facts
| Brand | NOW |
|---|---|
| Serving Size | |
| Contents | 360.0 Softgel(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