Strontium is a trace element widely found in nature. It became famous in the 1960s when a radioactive form of strontium produced by atomic bomb testing, strontium-90, became prevalent in the environment. Nonradioactive strontium has recently undergone study as a treatment for osteoporosis, with some promising results.

Requirements/Sources

There is no known daily requirement for strontium.

Therapeutic Uses

Strontium has fundamental chemical similarities to calcium. When dietary intake of strontium is raised, strontium begins to take the place of calcium in developing bone. This replacement appears to be beneficial (at least with low doses of strontium—see Safety Issues), leading to an increase in bone formation, a decrease in bone breakdown, and an overall rise in bone density.1-5

The net result is a reduced incidence of fractures due to osteoporosis, according to two very large studies.1,6

In addition, highly preliminary evidence hints that strontium might also help prevent cavities by strengthening dental enamel.7

What is the Scientific Evidence for Strontium?

The major human studies of strontium for osteoporosis involved a special form of the mineral called strontium ranelate.

In a 3-year, double-blind, placebo-controlled study of 5,091 women with osteoporosis, use of strontium at a dose of 2 grams daily significantly improved bone density and reduced incidence of all fractures as compared to placebo.1 Additionally, in a 3-year, double-blind, placebo-controlled study of 1,649 postmenopausal women with osteoporosis and a history of at least one vertebral fracture, use of strontium ranelate at a dose of 2 grams daily reduced the incidence of new vertebral fractures by 49% in the first year and 41% in the full 3-year period (as compared to placebo).6 Use of strontium also significantly increased measured bone density. No significant side effects were seen.

Benefits were also seen in an earlier, smaller study.5

A fourth study tested strontium ranelate for preventing osteoporosis in postmenopausal who have not yet developed it.4 In this 2-year, double-blind, placebo-controlled study, 160 women received either placebo or strontium ranelate at a dose of 125 mg, 500 mg, or 1 gram daily. The results showed greater gains in bone density the more strontium taken.

While some treatments for osteoporosis act to increase bone formation, and other decrease bone breakdown, some evidence suggests that strontium ranelate has a dual effect, providing both these benefits at once.14

Other forms of strontium besides strontium ranelate, such as strontium chloride, have shown potential benefits in animal studies, but have not undergone significant testing in people.3,8-13

Therapeutic Dosages

Based on current evidence strontium ranelate can be taken at a dose of 500 mg to 1 gram daily to prevent osteoporosis and at a higher dose of 2 grams daily to treat existing osteoporosis.

Note: It is not yet clear whether combining strontium with standard treatments for osteoporosis will enhance or diminish the ultimate benefits.

Safety Issues

When taken in recommended doses, strontium supplements appear to be safe and usually free of side effects other than occasional mild gastrointestinal upset, including diarrhea. There is some weak evidence that long term use of strontium ranelate could, rarely, cause memory loss or seizures.15 Similarly weak evidence hints that strontium could raise risk of blood clots;15 however, one small study was somewhat reassuring on this score.16

Excessive intake of strontium can actually weaken bone by replacing too much of the bone’s calcium with strontium.11

Maximum safe doses of strontium in young children, pregnant or nursing women, or people with severe liver or kidney disease have not been established.

Interactions You Should Know About

If you are taking standard treatment for osteoporosis, it is not clear whether the addition of strontium will enhance or diminish the benefits.