Tests Supplements Containing Calcium, Vitamin D, or Vitmain K

A report by on supplements relating to bone health showed five products to provide only 52.5% to 89% of the listed amounts of calcium or vitamin K. also noted wide variation in the suggested daily dosage across products, including a 50-fold variation in the dose of vitamin D (from 100 IU to 5,000 IU).

Calcium supplements have been popular for bone health for many years. Vitamin D, which is critical for calcium uptake into bone, has become a popular supplement due to growing evidence that it may also reduce the risk of diseases including multiple sclerosis, depression, obesity, arthritis, cardiovascular disease, and upper respiratory infection. In fact, a recent survey by showed that more than one-third of supplement users now take a vitamin D supplement and more than one-half use a calcium supplement. Interest in vitamin K has also increased due to studies published over the past few years suggesting that higher intakes may increase bone mineral density and reduce the risk of hip fracture.

“The new test reports help consumers understand which supplements are accurately labeled and which are not, as well as whether or not a supplement may help them and at what dosage,” said Tod Cooperman, MD, President of The reports also discuss key differences among the many chemical forms of the supplements now marketed, such as vitamins D2 and D3, vitamin K1 and K2 (including menaquinone-4 and -7) and the many forms of calcium including calcium carbonate and calcium citrate.’s results appear in three separate Product Review reports: Calcium Supplements, Vitamin D Supplements, and Vitamin K Supplements. The reports cover single-ingredient and combination products for adults as well as children including tablets, chewables, capsules, softgels, liquids, wafers, and powders. Results are provided for thirty-four products, of which selected twenty-two. Twelve were tested at the request of their manufacturers/distributors through CL's Voluntary Certification Program and are included for having passed testing. Also described are five products similar to ones that passed testing but are sold under different brand names.

Brands included in the reports are Adora, Allergy Research Group, Caltrate, Carlson, Citracal, DaVinci Laboratories of Vermont, Floradix, Garden of Life, GNC, Isotonix (Market America), Julian Whitaker MD, Kirkland (Costco), Lifetime, Li’l Critters, Nature’s Bounty, Nature Made, Nature’s Plus, Nature’s Life, Nutrition Now, OSCal, Puritan’s Pride, Physiologics, Pure Encapsulations, Quest, Rite Aid, Standard Process, Sundown, Trader Darwin’s (Trader Joe’s), Twinlab, Vitamin Shoppe, and Vitamin World.

Reviews of other popular types of supplements are also available at New reviews to be released in coming months cover multivitamins, glucosamine, chondroitin, MSM and many other popular supplements. is a leading provider of consumer information and independent evaluations of products that affect health and nutrition. The company is privately held and based in Westchester, New York. It has no ownership from, or interest in, companies that manufacture, distribute, or sell consumer products. is affiliated with, which helps consumers evaluate online pharmacies and drug prices, and, which reviews and rates Medicare Part D plans. Subscription to is available online.

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