NOW Magnesium & Potassium Aspartate
Brand: NOW · Form: CAPSULE [E0159]
Our assessment
The evidence shows that the combination of magnesium and potassium in this supplement can support muscle function and electrolyte balance. However, the calcium content in the formulation requires careful consideration due to established risks at high intakes [NIH ODS]. For you, the key is understanding how these minerals work together and whether this specific product fits your health needs.
How it works
Think of magnesium and potassium as essential partners for your muscles and nerves. Magnesium supports neuromuscular relaxation and nerve signaling, while potassium helps maintain proper cellular fluid balance [NIH ODS]. The calcium in this product plays a role in bone mineralization, but you should be aware that high calcium intakes might increase the risk of heart disease and prostate cancer according to some research [NIH ODS].
Safety profile
FDA received a total of 592,059 adverse event reports across all supplements, though specific numbers for this product are not available. For calcium specifically, 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 several medications, including bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS].
Our recommendation
Start by checking your current dietary intake of calcium, magnesium, and potassium before adding this supplement. If you take any medications listed in the interactions section, separate them by at least two hours from this supplement [NIH ODS]. For most adults, food sources are preferable to high-dose supplements. Consider choosing a magnesium- and potassium-only product if you do not need additional calcium, as the risks from high calcium intake are significant [NIH ODS].
AI-assisted analysis. Data sourced from NIH DSLD.
Supplement Facts
| Brand | NOW |
|---|---|
| Serving Size | |
| Contents | 120.0 Veg 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