NOW L-Arginine Amino Acid 500 mg
Brand: NOW · Form: CAPSULE [E0159]
Our assessment
The evidence shows that this product contains L-Arginine, but the data provided does not include specific studies or health claims for L-Arginine itself. Instead, the available data covers calcium. For calcium, our assessment is that it is a well-established mineral for bone health, but you must be cautious with dosing to avoid serious side effects [NIH ODS].
How it works
Think of calcium as a structural builder for your bones and a signal regulator for your nerves. It supports bone density through mineralization and helps your muscles relax and your nerves send signals properly [NIH ODS].
Safety profile
FDA received a total of 592,059 adverse event reports across all supplements. For calcium specifically, high intakes might increase the risk of heart disease and prostate cancer. 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] [FDA data].
Our recommendation
Data not available for L-Arginine-specific dosing. For calcium, do not exceed the tolerable upper intake level without medical supervision. Be aware that calcium can reduce the absorption of medications like bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS].
AI-assisted analysis. Data sourced from NIH DSLD.
Supplement Facts
| Brand | NOW |
|---|---|
| Serving Size | |
| Contents | 100.0 Capsule(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