ConsumerLab.com recently purchased popular zinc supplements, testing their contents and reviewing their dosage against products shown to work in clinical studies.
Zinc lozenges have been shown to reduce the duration and symptoms of a cold if taken properly. However, among four marketed zinc lozenges, only one provided the proven dosage.
A specific formula of zinc with antioxidants is known to reduce the progression of advanced macular degeneration, as demonstrated in the large Age-Related Eye Disease Study (AREDS). ConsumerLab.com found that two of the purchased products met this specification. Although nearly identical, one product cost 30% less than the other.
Zinc supplementation may be useful in treating other conditions including acne, depression and anorexia nervosa, as well as to prevent and correct zinc deficiency. ConsumerLab.com found that most general-use zinc supplements met quality standards. Although lead contamination can occur in zinc supplements, none of those tested were contaminated. However, a large variation in price was found, with the cost to obtain 50 mg of zinc ranging from as little as 3 cents to as much as 18 cents, or even more for products with additional ingredients.
“Our report on zinc supplements can help guide consumers to products that are properly made and deliver the correct dosage for specific uses,” said Dr. Cooperman. He cautioned that people should avoid taking too much zinc over long periods of time, as it can have adverse effects, including reduced copper absorption and immune suppression.