Strontium

otherstrontium atom

What is it

Strontium is a trace alkaline earth metal chemically similar to calcium. It is not classified as essential for humans but accumulates in bone, where it can substitute for calcium in hydroxyapatite. Strontium ranelate, a prescription drug, has been used to treat osteoporosis in some countries.

How it works

Strontium is absorbed in the small intestine alongside calcium, sharing similar transport mechanisms. Because of its chemical similarity, about 99% of body strontium is stored in bone, where it can replace a small fraction of calcium in the bone matrix. Strontium ranelate (the prescription form) is thought to both stimulate osteoblast (bone-forming) activity and reduce osteoclast (bone-resorbing) activity, producing a dual effect on bone metabolism. Over-the-counter strontium citrate is structurally different, has not been studied in large clinical trials, and is not approved as a medication. Effects observed with prescription strontium ranelate cannot be assumed to apply to OTC strontium citrate. Strontium also displaces calcium in bone scans, producing falsely elevated bone density readings on DEXA that overstate true bone mineral changes.

Evidence for 3 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Osteoporosis (with prescription strontium ranelate)

Grade B

Good evidence

Strontium ranelate at 2 g/day reduced vertebral and non-vertebral fractures in postmenopausal osteoporosis in the SOTI and TROPOS trials. However, the drug was withdrawn or restricted in many countries due to cardiovascular and skin reaction risks. OTC strontium citrate has not been demonstrated to provide equivalent benefits.

Tooth sensitivity (topical)

Grade B

Good evidence

Strontium-containing toothpastes have been used for tooth sensitivity for decades, with moderate evidence of efficacy in reducing pain from dentin hypersensitivity.

Osteoporosis (with OTC strontium citrate)

Grade D

Mixed evidence

Despite marketing, OTC strontium citrate has not been studied in large fracture-prevention trials. Apparent bone density improvements on DEXA scans largely reflect strontium displacing calcium in the measurement, not true bone strength gains.

3 commercial forms

Strontium citrate (OTC)

The form sold as a supplement; not formally studied in large trials.

Marketed for bone health. Lacks fracture-prevention evidence and may distort DEXA readings.

Strontium ranelate (prescription, restricted)

The form with positive RCT evidence, but withdrawn or restricted in many countries due to safety concerns.

Used historically for osteoporosis. Cardiovascular and skin reaction risks led to widespread market withdrawal.

Strontium chloride (topical in toothpaste)

Acts locally on dentin, not systemically absorbed in meaningful amounts.

Used in sensitive teeth toothpaste formulations for decades.

Dosage

There is no RDA or AI for strontium. Typical dietary intake is 1-3 mg/day. OTC strontium supplements (usually strontium citrate) typically provide 340-680 mg of elemental strontium per day. Prescription strontium ranelate was dosed at 2 g/day, providing about 680 mg of elemental strontium. No formal UL is established. Avoid taking with calcium since they compete for absorption.

When and how to take it

Strontium should be taken on an empty stomach, separated from calcium, dairy, and calcium-fortified foods by at least 2 hours. Evening dosing 2 hours after dinner is common. Maintain consistent daily timing if used. Stop at least 5 days before any DEXA bone density scan to minimize artifact.

Food sources

Food	Amount	%DV
Brazil nuts (1 oz)	Trace amounts (notable for nuts)	—
Seafood (3 oz)	Trace amounts	—
Whole grains	Trace amounts	—
Leafy greens	Trace amounts	—
Drinking water (varies)	Trace amounts	—

Safety

Prescription strontium ranelate was associated with increased risk of venous thromboembolism, myocardial infarction, and severe skin reactions (DRESS syndrome), leading to its withdrawal from many markets. OTC strontium citrate has not been studied at large scale, so its safety profile at the doses sometimes used is uncertain. Strontium also distorts DEXA bone scans, making density readings unreliable. Best avoided in people with clotting risk, cardiovascular disease, or pregnancy.

Who should be cautious

Avoid in pregnancy and lactation. Contraindicated in personal history of venous thromboembolism, cardiovascular disease, uncontrolled hypertension, or active malignancy in the case of prescription strontium ranelate. People undergoing DEXA scans should know that strontium distorts results. Generally not recommended without clinician oversight.

Interactions

Strontium competes with calcium for intestinal absorption and should be taken at least 2 hours apart from calcium-containing foods or supplements. Quinolone and tetracycline antibiotics bind strontium, reducing absorption of both. Antacids and certain medications may affect uptake. Caution with anticoagulants, hormone replacement therapy, and any condition that increases thrombosis risk.

Frequently asked questions

Will strontium really build my bones?⌄

Prescription strontium ranelate reduces fractures in osteoporosis but has serious cardiovascular and skin risks. OTC strontium citrate has not been studied at scale and apparent DEXA improvements often reflect measurement artifact rather than real bone strengthening.

Is OTC strontium safe?⌄

Long-term safety is not well-established at supplement doses. People with clotting risk, cardiovascular disease, or pregnancy should avoid it. Use only with clinician input.

Does strontium affect my DEXA scan?⌄

Yes. Strontium has a higher atomic number than calcium and exaggerates apparent bone density on DEXA scans by 5-10% or more. Tell your doctor if you are using strontium before any bone density test.

Should I take strontium with calcium?⌄

No. They compete for absorption. Separate them by at least 2 hours.

Is strontium a better alternative to bisphosphonates?⌄

Bisphosphonates have decades of strong evidence and a well-characterized safety profile. OTC strontium does not match this evidence base. Prescription strontium ranelate, where it remains available, is generally reserved for cases where bisphosphonates can't be used.

References

EMA review of strontium ranelate — European Medicines Agency link
Strontium - Wikidata — Wikidata link

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Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you're pregnant, breastfeeding, on medications, or managing a chronic condition.