During a recent analysis of potassium supplements sold in the U.S. and Canada, ConsumerLab.com, White Plains, NY, discovered significant contamination with the toxic heavy metal arsenic in pills from one brand. Although the FDA has not established a limit for arsenic contamination in supplements, the amount found exceeds California’s limit for reproductive health—above which a warning label is required, and is just below that state’s threshold for a cancer warning. A daily serving contained more arsenic than the U.S. EPA permits in a full liter of drinking water. None of the other products were found to be contaminated with arsenic, lead or cadmium.

Among the products that passed contamination testing and contained the listed amounts of potassium, ConsumerLab.com identified several as its Top Picks, some of which sell for as little as little as 2 cents for a 99 mg dose of potassium. Ironically, the contaminated supplement was the most expensive product, underscoring the fact that higher price does not assure supplement quality—as demonstrated in other reviews by ConsumerLab.com.

Potassium is essential for functioning of the nervous, skeletal, and cardiovascular systems. It can be easily obtained through the diet, although it was recently reported that average intake by Americans may not be adequate. Certain drugs, such as diuretics, or conditions affecting the kidneys or gut may cause potassium deficiencies which require supplementation. Magnesium supplementation may also be helpful when correcting potassium deficiency. In people who consume too much sodium, potassium may help reduce hypertension.

Potassium supplement quality ratings and ingredient comparisons are now available in ConsumerLab.com’s Potassium Supplements Review (https://www.consumerlab.com/reviews/Potassium_Supplements_Review/Potassium/ ). The review includes clinical information regarding the use of potassium such as dosage, drug interactions, and side effects. It also provides information about food sources of potassium. It explains how to avoid being misled by supplement names and labels and differences among forms of potassium (e.g., potassium chloride, potassium gluconate, and potassium citrate).