NOW Double Strength L-Arginine Amino Acid 1000 mg
Brand: NOW · Form: TABLET [E0155]
Our assessment
The evidence shows that this product contains 1000 mg of L-Arginine per serving, but the available data does not include specific safety or efficacy information for L-Arginine itself. Data not available for this specific ingredient. For context, we have data on a different ingredient, Calcium, which is a mineral involved in bone mineralization and neuromuscular relaxation [NIH ODS].
How it works
Think of Calcium as a structural and signaling mineral — it supports bone density and mineral deposition, and it helps your muscles relax and nerves signal properly [NIH ODS].
Safety profile
FDA received 592,059 total adverse event reports across all supplements, but specific report counts for this product are not available. Data not available for L-Arginine side effects. Regarding Calcium, high levels 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 bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS].
Our recommendation
Data not available to make a specific recommendation for this L-Arginine product. You should consult your healthcare provider before starting any new supplement, especially given potential interactions and side effects seen with other ingredients like Calcium [NIH ODS].
AI-assisted analysis. Data sourced from NIH DSLD.
Supplement Facts
| Brand | NOW |
|---|---|
| Serving Size | |
| Contents | 120.0 Tablet(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