In a large review of supplements related to bone health, ConsumerLab.com tests showed wide variation in suggested dosage across products, including a 50-fold variation in the dose of vitamin D (from 100 to 5000 IU).

Tests also showed five products provided only 52.5% to 89% of the listed amounts of calcium or vitamin K. 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 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 with several 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 ConsumerLab.com, White Plains, NY. 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.

Results appear in three separate Product Review reports, which cover single-ingredient and combination products for adults as well as children, including tablets, chewables, capsules, softgels, liquids, wafers and powders.