Strontium

Supplements · Minerals · Supplement, Typed Supps

A mineral chemically similar to calcium that gets built into bone — proven to reduce fractures as a now largely discontinued prescription drug, but not proven in the over-the-counter form most people actually buy.

Stage by stage

Intake (Capsule (strontium citrate)): Best taken away from calcium-rich food or supplements.
Intestine (Absorbed): Competes with calcium for absorption.
Bloodstream (Circulates): Distributes systemically to bone tissue.
Bone (Incorporated): Incorporated into the bone mineral matrix, substituting for some calcium.

What the evidence supports

Reducing vertebral fracture risk and increasing bone mineral density, as the prescription drug strontium ranelate — strong evidence. Strontium ranelate at 2 g/day showed genuine anti-fracture efficacy in large postmenopausal osteoporosis trials — but this refers specifically to the prescription ranelate salt, not the strontium citrate sold over the counter.
Improving bone density or reducing fracture risk from over-the-counter strontium citrate supplements — insufficient evidence. There are no well-designed fracture-outcome trials for the citrate form sold as a supplement. Bone density (DEXA) improvements reported anecdotally are also confounded, since strontium’s higher atomic weight than calcium inflates DEXA readings.
Evidence on Increased risk of blood clots (venous thromboembolism) and heart attack with strontium ranelate — strong evidence. This safety signal was significant enough that European regulators restricted strontium ranelate’s use and it was withdrawn from most markets by 2017. It’s the reason the prescription drug is essentially unavailable today despite working.

Typical dose

OTC strontium citrate products commonly provide around 680 mg/day

Upper limit: No established UL for supplemental strontium citrate

Timing

Take away from calcium sources, commonly at bedtime on an empty stomach.

Time to effect

Unclear: The OTC citrate form has no dedicated fracture-outcome trial timeline; DEXA-measured density changes are also confounded by strontium’s atomic weight.

Common myth

“Strontium supplements are proven to reduce fracture risk just like the prescription drug was.” In reality: That fracture-risk reduction was shown for strontium ranelate specifically, a prescription salt now withdrawn from most markets over cardiovascular risk — the over-the-counter strontium citrate sold today hasn’t been through equivalent trials.