NOW Magnesium & Potassium Aspartate

Our assessment

The evidence shows that NOW Magnesium & Potassium Aspartate is a supplement providing two essential minerals. However, the data available specifically for this product is limited. The formula is designed to support electrolyte balance and nerve function, but you should understand the specific roles and risks of its ingredients based on available research [NIH ODS].

How it works

Think of the ingredients in this supplement as key regulators for your body's basic functions. The calcium component supports bone mineralization and neuromuscular relaxation, which helps your muscles and nerves signal properly [NIH ODS]. The potassium and magnesium work together to maintain healthy fluid balance and support normal heart rhythm, though specific data on the aspartate form is not available in the provided information.

Safety profile

Data not available for this specific product from the FDA adverse event reports. The total number of adverse event reports across all supplements is 592,059 [FDA data]. For the calcium component, high intakes may increase the risk of heart disease and prostate cancer. High levels in blood and urine can cause poor muscle tone, poor kidney function, constipation, nausea, weight loss, extreme tiredness, and abnormal heart rhythms [NIH ODS]. Calcium can also reduce the absorption of medications such as bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS].

Our recommendation

Start by consulting your healthcare provider before taking this supplement, especially if you take any prescription medications. Do not exceed the dosage on the label. If you experience nausea, constipation, or changes in heart rhythm, stop use and contact your doctor. For most adults, getting these minerals from food sources is often sufficient, but a supplement can be helpful if you have a confirmed deficiency [NIH ODS].

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