Home Ingredients Strontium (Citrate / Ranelate)
Bone Health

Strontium (Citrate / Ranelate)

Evidence Level
Limited
2 Clinical Trials
4 Documented Benefits
2/5 Evidence Score

Strontium is a mineral chemically similar to calcium that incorporates into bone matrix. Strontium ranelate was approved as a prescription osteoporosis drug in some European countries (Protelos®/Protaxos®), but it was restricted in 2014 over cardiovascular and severe skin-reaction concerns and the product was subsequently discontinued and withdrawn from the market, so it is no longer marketed as a medicine. Strontium citrate (the supplement form) is widely sold for bone health, but it has no published human fracture or bone-density outcome trials of its own; the fracture data belong to the prescription drug and cannot be assumed to transfer to the citrate salt. Critical: distinct from radioactive strontium-90; supplemental strontium is non-radioactive natural strontium.

Studied Dose Strontium ranelate (prescription): 2 g/day; strontium citrate (supplement): 680 mg elemental strontium is the typical label dose, but this figure is simply back-calculated to match the elemental strontium in the 2 g/day prescription ranelate dose — it has not itself been evaluated in any human trial of the citrate form
Active Compound Strontium (atomic number 38)

Benefits

Fracture Data Belong to the Prescription Drug Strontium Ranelate — Not the Supplement

These are results for the prescription medicine strontium ranelate at 2 g/day (Protelos/Protaxos), not for the strontium citrate sold as a dietary supplement. In the SOTI trial, ranelate 2 g/day reduced vertebral fractures by about 41% vs placebo over 3 years in postmenopausal osteoporosis, and the companion TROPOS trial reported fewer non-vertebral fractures. That evidence supported European prescription approval until safety concerns (myocardial infarction, venous thromboembolism, severe skin reactions) led to EMA restriction in 2014, after which the product was discontinued and withdrawn from the market. No comparable fracture trial has ever been run on strontium citrate.

Supported by Trial 1, Trial 2

Dual Action — Bone Formation and Resorption Inhibition

This is a mechanistic description drawn largely from laboratory and animal work and from studies of the ranelate drug, not a demonstrated clinical effect of supplemental strontium citrate. In those models strontium increases osteoblast (bone-forming) activity while decreasing osteoclast (bone-resorbing) activity, whereas bisphosphonates mainly inhibit resorption. Whether supplemental strontium citrate reproduces this dual action in humans has not been tested.

Supported by Trial 1, Trial 2

Strontium Citrate (Supplement) Theoretical Effects

Strontium citrate is the typical supplemental form — provides similar elemental strontium to ranelate but not same drug. Any bone-supportive effect is theoretical and extrapolated entirely from drug data. Critical: there are no published human fracture or bone-density outcome trials of strontium citrate — the citrate form has not been tested for bone outcomes in people at all, at any size or quality. The only cited head-to-head comparison of the salts (Tomczyk-Warunek 2024) is an ovariectomized mouse study, and in it strontium citrate produced the weakest effect of the three forms tested, with ranelate and chloride performing better. Evidence generated with a prescription drug should not be read as evidence for the citrate supplement.

Supported by Trial 1, Trial 2

DEXA Scan Artifact (False BMD Increase)

Critical consideration: strontium has higher atomic weight than calcium; even modest strontium incorporation into bone creates ARTIFACTUAL increase in DEXA bone density readings (~10% per 1% strontium content). This OVERESTIMATES true bone density gains with strontium. Real bone strength gains are smaller than DEXA suggests.

Supported by Trial 1

Mechanism of action

1

Bone Matrix Incorporation

Strontium substitutes for calcium in bone hydroxyapatite — creating strontium-containing bone matrix. Mechanism similar to calcium incorporation but with different physical properties.

2

Calcium-Sensing Receptor Modulation

Strontium activates calcium-sensing receptor (CaSR) on osteoblasts and osteoclasts — basis for dual action on bone formation and resorption.

3

Osteoblast Stimulation

Increases osteoblast number, activity, and bone formation markers. Distinct from bisphosphonates which only inhibit resorption.

4

Osteoclast Inhibition

Reduces osteoclast differentiation and activity — decreasing bone resorption.

Clinical trials

1
SOTI Trial — Prescription Strontium Ranelate (Drug Evidence, Not the Supplement)

Phase 3 registration trial of the prescription medicine strontium ranelate (Protelos/Protaxos) at 2 g/day vs placebo in 1,649 postmenopausal women with osteoporosis over 3 years. The agent tested was the drug, not the strontium citrate sold as a supplement.

1,649 postmenopausal osteoporosis patients.

About a 41% reduction in vertebral fracture risk vs placebo, which supported European prescription approval of strontium ranelate as an osteoporosis medicine. Important context: this drug was later restricted by the EMA in 2014 and then withdrawn from the market, and no trial of this kind has been conducted with strontium citrate supplements.

2
Strontium Ranelate Cardiovascular Safety Concerns

Pooled analyses of strontium ranelate trials examining cardiovascular events.

Pooled trial populations.

Increased risk of myocardial infarction, venous thromboembolism. Combined with severe skin reactions (DRESS syndrome cases) led to EMA restriction in 2014 — limited to severe osteoporosis where alternatives unavailable. The product was subsequently discontinued and withdrawn from the market, and is no longer sold as a medicine. Whether the same cardiovascular signal applies to supplemental strontium citrate has never been studied.

Side effects and drug interactions

Common Potential side effects

Strontium ranelate (prescription) — increased cardiovascular events (MI, VTE), severe skin reactions (DRESS syndrome, Stevens-Johnson), restricted use in EU 2014.
Strontium citrate (supplement) — no dedicated cardiovascular or long-term safety trials have been published. Apparent good tolerability reflects the absence of studies rather than demonstrated safety, and the myocardial-infarction and clotting signal seen with the ranelate drug has not been ruled out for the citrate form at supplemental doses.
Nausea, diarrhea (initial).
Headache.
Dermatitis.
Memory disturbance rare.
DEXA artifact creating false-high BMD readings (consideration for monitoring).

Important Drug interactions

Calcium supplements — strontium and calcium compete for absorption; separate BY 2-3 hours minimum.
Tetracyclines, fluoroquinolones — strontium reduces absorption similarly to calcium; separate.
Levothyroxine — strontium reduces absorption; separate by 4 hours.
Iron, zinc, magnesium supplements — competition for absorption; separate.
Bisphosphonates (alendronate, etc.) — strontium may interfere; separate by hours.
Anticoagulants — no specific interaction is documented, but note the prescription ranelate form carried an increased risk of venous thromboembolism and myocardial infarction; discuss any strontium use with a clinician if you have cardiovascular disease or take anticoagulants.
Antibiotics that chelate divalent cations — separate.

Featured in these supplement guides

Bone Density→

More Bone Health Ingredients

Bone Health
Calcium
Calcium is the most abundant mineral in the body — about 99% stored in bones and teeth, wi…
Bone Health
Vitamin D
Vitamin D is a fat-soluble vitamin and steroid hormone precursor essential for calcium abs…
Bone Health
Copper
Copper is an essential trace mineral and cofactor for over 30 enzymatic reactions, includi…
Bone Health
Ferrous Sulfate
Ferrous sulfate is the most common, cheapest, and longest-established oral iron form — rec…

Explore Other Ingredients

Immune Support
Vitamin C
Vitamin C (L-ascorbic acid) is a water-soluble essential nutrient that humans cannot synth…
Antioxidant
Setria® Glutathione
Setria® is Kyowa Hakko's patented reduced L-glutathione (GSH) produced via fermentation —…
Hair, Skin & Nails
Hyaluronic Acid
Hyaluronic acid is a naturally occurring substance in the body, primarily found in connect…

Frequently asked questions about Strontium (Citrate / Ranelate)

What is strontium used for?

Strontium (as strontium citrate in supplements) is taken for bone support, since it is chemically similar to calcium and is incorporated into bone. It is worth knowing that the human fracture and bone-density research was done with a prescription drug, strontium ranelate, and not with the citrate form sold as a supplement. It is distinct from radioactive strontium; supplemental strontium is the stable, non-radioactive mineral.

Does strontium help with bone density?

A prescription form, strontium ranelate, had bone-density and fracture research behind it, but it was restricted in 2014 over cardiovascular and skin-reaction risks and has since been withdrawn from the market. Supplemental strontium citrate is sold on the strength of that drug research, yet it has no published human fracture or bone-density outcome trials of its own; the one published comparison of the salts was done in mice, and citrate performed worst of the three tested. Note that strontium can inflate bone-density scan readings because it is denser than calcium.

How much strontium should I take?

Supplemental strontium citrate is commonly sold at around 680 mg of elemental strontium per day, a figure chosen to match the elemental strontium in the 2 g/day prescription ranelate dose rather than one established in any trial of the citrate form. No dose of strontium citrate has been validated in human bone outcome research. Take it separately from calcium (by at least 2 hours), since they compete for absorption.

Is strontium safe?

Supplemental strontium citrate has not been studied for long-term safety, so little can be said either way. The prescription ranelate form was linked to heart attacks, clotting events, and severe skin reactions, which led to EMA restriction in 2014 and then withdrawal of the product from the market; whether those risks extend to the citrate supplement is unknown rather than excluded. Given these concerns, use strontium cautiously and discuss it with your doctor, especially with cardiovascular risk factors.

What is Strontium?

Strontium is a mineral chemically similar to calcium that incorporates into bone matrix. Strontium ranelate was approved as a prescription osteoporosis drug in some European countries (Protelos®/Protaxos®), but it was restricted in 2014 over cardiovascular and severe skin-reaction concerns and the product was subsequen…

What is the recommended dosage of Strontium?

The clinically studied dose is Strontium ranelate (prescription): 2 g/day; strontium citrate (supplement): 680 mg elemental strontium is the typical label dose, but this figure is simply back-calculated to match the elemental strontium in the 2 g/day prescription ranelate dose — it has not… Always follow the product label and check with a healthcare provider for personal advice.

Is Strontium safe, and does it have side effects?

For most healthy adults, Strontium is well tolerated at studied doses. Reported effects can include: Strontium ranelate (prescription) — increased cardiovascular events (MI, VTE), severe skin reactions (DRESS syndrome, Stevens-Johnson), restricted use in EU 2014. Strontium citrate (supplement) — no dedicated cardiovascular or long-term safety trials have been published. It may also interact with some medications. Strontium is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does Strontium interact with any medications?

Possible interactions include: Calcium supplements — strontium and calcium compete for absorption; separate BY 2-3 hours minimum. Tetracyclines, fluoroquinolones — strontium reduces absorption similarly to calcium; separate. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Strontium?

NutraSmarts rates the evidence for Strontium as Limited (2 out of 5). It is backed by 2 clinical trials and 6 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(6 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Kanis JA, Johansson H, Oden A, McCloskey EV. A meta-analysis of the effect of strontium ranelate on the risk of vertebral and non-vertebral fracture in postmenopausal osteoporosis and the interaction with FRAX(®). Osteoporos Int. 2011;22(8):2347-55. doi: 10.1007/s00198-010-1474-0.PubMedUsed to support: Meta-analysis showing strontium ranelate reduced vertebral and non-vertebral fracture risk in osteoporosis. Note: this strong evidence is for the prescription drug strontium ranelate, not the strontium citrate sold as a supplement.
  2. Malaise O, Bruyere O, Reginster JY. Strontium ranelate normalizes bone mineral density in osteopenic patients. Aging Clin Exp Res. 2007;19(4):330-3. doi: 10.1007/BF03324710.PubMedUsed to support: Randomized trial in which strontium ranelate increased bone mineral density in osteopenic patients. Supports strontium's effect on bone density, again with the prescription ranelate form.
  3. Barrionuevo P, Kapoor E, Asi N, Alahdab F, Mohammed K, Benkhadra K, Almasri J, Farah W, Sarigianni M, Muthusamy K, Al Nofal A, Haydour Q, Wang Z, Murad MH. Efficacy of Pharmacological Therapies for the Prevention of Fractures in Postmenopausal Women: A Network Meta-Analysis. J Clin Endocrinol Metab. 2019;104(5):1623-1630. doi: 10.1210/jc.2019-00192.PubMedUsed to support: Network meta-analysis of prescription pharmacological therapies for fracture prevention in postmenopausal women, which included the drug strontium ranelate among the agents compared. It evaluates medicines only and contains no data on strontium citrate supplements.
  4. Tomczyk-Warunek A, Turżańska K, Posturzyńska A, Kowal F, Blicharski T, Pano IT, Winiarska-Mieczan A, Nikodem A, Dresler S, Sowa I, Wójciak M, Dobrowolski P. Influence of Various Strontium Formulations (Ranelate, Citrate, and Chloride) on Bone Mineral Density, Morphology, and Microarchitecture: A Comparative Study in an Ovariectomized Female Mouse Model of Osteoporosis. Int J Mol Sci. 2024;25(7):. doi: 10.3390/ijms25074075.PubMedUsed to support: Animal study in ovariectomized mice comparing three strontium salts (ranelate, citrate, and chloride) on bone mineral density, morphology, and microarchitecture. This is the only cited reference that includes the citrate form used in supplements, and in it citrate produced the weakest effect of the three salts, with ranelate and chloride performing better. It is a mouse study, not a human outcome trial.
  5. Reginster JY. Strontium ranelate in osteoporosis. Curr Pharm Des. 2002;8(21):1907-16. doi: 10.2174/1381612023393639.PubMedUsed to support: Review of strontium ranelate in osteoporosis, summarizing its dual action on bone formation and resorption. Background for the bone mechanism.
  6. Collette J, Bruyère O, Kaufman JM, Lorenc R, Felsenberg D, Spector TD, Diaz-Curiel M, Boonen S, Reginster JY. Vertebral anti-fracture efficacy of strontium ranelate according to pre-treatment bone turnover. Osteoporos Int. 2010;21(2):233-41. doi: 10.1007/s00198-009-0940-z.PubMedUsed to support: Meta-analysis of strontium ranelate's vertebral anti-fracture efficacy across baseline bone-turnover levels. Reinforces the bone evidence for the ranelate form. (Strontium ranelate was later restricted over cardiovascular safety, so supplemental strontium should be used cautiously.)