The Misunderstood Mineral: How Strontium Safely Builds Bones (and Makes Them Stronger)
There may be no other substance shrouded in as much confusion as strontium. That goes for both patient and practitioner!
So this page will help clear the confusion and even serve as a springboard to effective new bone health protocols for your own patients and clients.
- The history of strontium
- 3 strontium myths that could hurt patient outcomes
- Optimal dosage and directions for effective strontium citrate use
- Studies demonstrating strontium’s efficacy in patients with bone loss
- Contraindications of strontium citrate use
You already know strontium is a trace mineral naturally found in soil. Strontium is element 38 in the periodic table, right below calcium and magnesium. Approximately 99% of the body’s strontium is found in the bones.
In fact, research on strontium and bone health goes back well over 100 years. So let’s begin there.
Strontium Has 100-Year History of Efficacy and Safety
Here’s a brief look on the discovery and resulting research on strontium:
Strontium’s potential for bone health was recognized as early as 1910. A study of strontium treatments reports that:
“In 1910, the first elaborate investigation of the effects of stable strontium on bone suggested that it greatly stimulates the formation of osteoid tissues and tends to repress the resorptive process in bones.”
So early in the twentieth century, feelings about strontium were overwhelmingly positive. In fact, strontium was used medicinally for over a hundred years till this point.
Medicinal use of strontium salts was first described in Squire’s Companion to the British Pharmacopeia in 1916. This work was written by Sir Peter Wyatt Squire, a pharmaceutical chemist and druggist for the royal family, and provided an overview of accepted medicinal treatments at the time.
Strontium was also listed in the Dispensatory of the United States until 1955.
Researchers at the Mayo Clinic conducted one of the first human studies investigating strontium’s effects on bone. They administered 1.7 grams of natural strontium daily (in the form of strontium lactate) to 32 patients with osteoporosis. The patients took strontium for anywhere from three months to three years.
Of course, limitations included small sample size and length of treatment variability. There was also no control group. However, since some patients saw improvements for a full three years, it showed promise.
Notably, no adverse side effects were reported — even when strontium was taken for years and at much greater levels than a typical diet. All patients experienced relief of bone pain, with 16% reporting moderate improvement and 84% reporting significant improvement. And 78% showed an increase in bone mass.
Now, X-rays in the 1950s weren’t as sophisticated as modern DEXA scans. So it’s difficult to say precisely how much improvement was seen.
Regardless, the results of this study were positive and should’ve propelled strontium into the limelight — both for its potential therapeutic use in the treatment of osteoporosis and its remarkable safety profile.
Unfortunately, events on the world stage interfered.
To understand how strontium fell out of favor, we need to back up a bit. During World War II, the United States launched the Manhattan Project with support from the United Kingdom and Canada. The Manhattan Project was the codename for the research and development effort to create nuclear weapons.
In 1945, the first atomic bomb was detonated. But nuclear testing didn’t end there. It went on for years into the 50s and 60s. And amongst other issues, fallout from this nuclear testing produced a dangerous, radioactive form of strontium called strontium-90.
Of course, the media ran many stories about radioactive strontium poisoning the American people. So in the public mind, strontium became known as a poison.
In all likelihood, this is why the early studies showing the benefits of natural strontium in the treatment of osteoporosis were disregarded until nearly 30 years later…
In 1985, Dr. Stanley C. Skoryna of McGill University, picked the research thread back up again. Dr. Skoryna was intrigued by strontium’s potential — especially after seeing success in a study he conducted in 1981 on the effect of strontium gluconate on patients with metastatic bone cancer.
So, he conducted a small-scale human study that once again showed the potential benefits of strontium treatment for humans.
Skoryna administered strontium carbonate to three women and three men with osteoporosis. The women were given 700 mg a day, while the men received 600 mg a day for a period of six months. A bone biopsy was taken before and after the six month period.
The results from these biopsies showed a 172% increase in the rate of bone formation, but no change in bone resorption. In addition, the patients noted reduced bone pain and improved mobility. And again, no adverse effects were reported.
Of course, this sample is extremely small. But it’s worth mentioning because it marked the beginning of a renewed interest in strontium.
And ultimately, this interest would lead to the development of an entirely new form of strontium, the man-made strontium ranelate.
Strontium ranelate is a prescription drug sold under a brand name.
When researchers started to revisit strontium as a potential bone health treatment in the late 20th century, a pharmaceutical company developed and patented a drug version of strontium called strontium ranelate.
Remember, strontium can’t exist on its own. So, strontium ranelate is strontium bound with ranelic acid. And ranelic acid is a synthetic compound that’s potentially toxic. In light of this information, the long list of side effects associated with strontium ranelate starts to make sense.
In 2014, the European Medicines Agency’s Pharmacovigilance Risk Assessment Committee (PRAC) recommended that strontium ranelate no longer be used as an approach for severe bone loss.
This assessment was reviewed by the European Medicines Agency’s Committee for Medicinal Products for Human Use (CHMP). In the end, the committee recommended that strontium ranelate be further restricted. Basically, patients can only be treated with strontium ranelate if they can’t take any other approved medicines.
For these reasons, strontium ranelate has never been approved by the Food and Drug Administration (FDA). That means strontium ranelate isn’t available in Canada or the United States.
Strontium ranelate is becoming more and more restricted in Europe as safety concerns grow. Natural strontium citrate, on the other hand, is widely available around the world.
The problem remains that people (and practitioners!) often confuse the natural forms of strontium with the unnatural strontium ranelate form.
3 Strontium Myths That Could Hurt Patient Outcomes
- Strontium Increases Fracture Risk. Some critics conclude that strontium causes cortical bone to become thicker, reducing tensile strength and increasing the risk of fractures.
- Strontium Supplements Have Side Effects. Strontium has been painted a villain due to undesirable and serious side effects of one form: strontium ranelate.
- Strontium Skews DEXA Results Too Much To Be Reliable. Since strontium is denser than calcium, it affects bone improvement readings on a DEXA scan. Therefore, some question whether strontium is really increasing bone density or if improvements are just a false positive.
Let’s take an empirical look at each of them.
Myth #1: Strontium Increases Fracture Risk
Some strontium critics claim that strontium causes cortical bone to become thicker, and may increase risk of fractures. But as you’ll see, there’s no scientific basis for that claim. First, the miniscule amount of strontium ions that deposit in our bones prefer to do so in trabecular, not cortical bone.
Second, as you’re about to see, strontium can actually help reduce fracture risk by strengthening bone.
Strontium critics base their claims on these 2 studies:
- Boivin, Deloffre, Perrat, et al.. Strontium distribution and interactions with bone mineral in monkey iliac bone after strontium salt (S 12911) administration. J Bone Miner Res. 1996 Sep;11(9):1302-11.
- Blake and GM, Fogelman I. (2006 JBMR 21(9) 1417-24 Strontium ranelate: a novel treatment for postmenopausal osteoporosis: a review of safety and efficacy. Clin Interv Aging. 2006;1(4):367-75.
In both cases, the authors drew POSITIVE conclusions about strontium’s bone supporting role!
In the first:
“In conclusion, taken up by bone, Strontium … induced no major modifications of the bone mineral at the crystal level. As a result, a treatment with Strontium should not induce any alteration of bone mineral.”
Nowhere is it proposed that strontium is weakening bone.
The second study drew this conclusion:
“Strontium … is the only treatment proven to be effective at preventing both vertebral and hip fractures in women aged 80 and over.”
Again, the study says nothing about strontium weakening bone structure. And neither study shows strontium depositing primarily into cortical bone.
The trabecular bone is far more metabolically active and incorporates more strontium ions than the cortical bone. Cortical bone also accumulates far more slowly. In both bone types, strontium substitutes for less than 1 calcium ion in 10, inside apatite crystals.
The research shows that strontium, in addition to its beneficial effects that boost osteoblast and slow osteoclast activity, also indirectly modulates resorption of the calcified bone matrix by stabilizing hydroxyapatite crystals.
What’s more, strontium is the only trace mineral in human bone whose level in bone correlates with bone compressive strength, i.e., resistance to fracture.
The bottom line is: Strontium (in its natural citrate form) improves healthy bone mineralization and resistance to fracture.
Myth #2: Strontium Supplements Have Side Effects
The drug, strontium ranelate, has a long list of side effects. And since the drug has much more media exposure than the nutritional supplement strontium citrate, the two are often confused.
Most blogs, websites, and even practitioners do not know that strontium citrate is a completely different molecule from strontium ranelate. Equating them is like suggesting sodium chloride and sodium bicarbonate are the same. They both contain sodium, but the other molecule they’re attached to changes their behavior wildly!
Another issue is that some strontium ranelate drugs contain aspartame – an ingredient known for causing reactions on its own.
But natural strontium citrate has an excellent safety record. The one caveat to this is a Turkish paper that found high dietary levels of strontium in soil were associated with rickets in young children. It should be noted that their calcium intake was also inadequate.
Myth #3: Strontium Skews DEXA Results Too Much To Be Reliable
The belief is strontium supplementation results in larger concentrations of strontium in the bones, which will overstate bone mineral density (BMD) on DEXA scans.
True, strontium’s atomic weight is more than double calcium’s, so it can overstate BMD. But the actual effect is minor at worst.
Strontium ions replace less than one calcium ion out of 10, so the overestimation is not great enough to discount DEXA results showing improvements in BMD.
The latest science shows results may be overstated by 8.5% – 11.2%. But don’t throw the baby out with the bath water. Even after adjusting a patient’s score down by about 10%, an increase in bone density is still an increase!
For example, a patient who gained a modest 1% on DEXA after taking strontium citrate would still have realized approximately 0.9% BMD increase. That’s a big win when the norm is to simply lose more and more bone with time!
Don’t be fooled by the strontium critics. The increased density in the strontium studies (including the AlgaeCal studies) are still outright increases in bone density in older adults who should be losing bone. And increased bone density is closely correlated with lowered risk of fracture.
Besides, strontium has been shown to reduce fracture risk independent of bone density.
It should be noted that strontium and calcium share a common carrier system in the intestinal wall, which will always choose to carry calcium rather than strontium from our digestive tract into our bloodstream. Strontium competes with calcium for absorption – and calcium wins every time. Also, strontium is eliminated more readily than calcium from kidneys.
To understand strontium’s method of action in bone tissue, review this abstract on strontium’s bone-building effects on both osteoblasts and osteoclasts.
Studies on Strontium Citrate
Study #1 Changes in Total Body Bone Mineral Density Following a Common Bone Health Plan With Two Versions of a Unique Bone Health Supplement: A Comparative Effectiveness Study
Study link: https://www.ncbi.nlm.nih.gov/pubmed/21492428
Type of study: Clinical Trial (Nutrition Journal)
Summary: The aim of this study was to evaluate the effectiveness and safety of two slightly different bone health supplements (AlgaeCal formulations) in combination with strontium citrate (Strontium Boost). Note that though the AlgaeCal formulation varied between the two groups, the amount of strontium citrate administered remained the same.
Results: Both groups significantly increased their BMD compared to expectation. Specifically, the first group increased their BMD by an average of 0.48% compared to the expected change over this timeframe, and the second group by 2.18%!
Notably, no clinically significant changes were found in a 43-chemistry blood test panel, and there were no changes in self-reported quality of life in either group.
Of course, strontium citrate was administered alongside a bone health supplement, so the bone density increases seen can’t be attributed to strontium alone.
Study #2 Combination of Micronutrients for Bone (COMB) Study: Bone Density After Micronutrient Intervention
Type of study: Retrospective Cohort Study
Summary: The goal of this study was to investigate the effects of supplemental micronutrient therapy on bone mineral density. The micronutrient therapy included a combination of vitamin D3, vitamin K2, strontium citrate, magnesium, and docosahexaenoic acid (DHA).
Researchers identified a sample of 77 patients who followed the micronutrient intervention plan for one year.
The patients included in the study were predominantly postmenopausal women (81%). Of these patients, many had declined standard treatment, or had tried other treatments without success.
At the end of one year, the researchers found “significant improvement in bone density” as measured by DEXA scan.
In fact, patients increased on average: 4% for the femoral neck, 3% for the total hip, and 6% for the total spine. The researchers reported the majority of patients increased their BMD by more than 3% within the first year of micronutrient therapy alone.
None of the participants experienced a fracture or reported adverse side effects. So these results further support the safety of taking 680 mg of strontium citrate a day, but for a full year this time.
Note that AlgaeCal didn’t fund this study and wasn’t involved in any way.
Study #3 7-Year Longitudinal Trial of the Safety and Efficacy of a Vitamin/Mineral Enhanced Plant-Sourced Calcium Supplement
Study link: https://www.ncbi.nlm.nih.gov/pubmed/26885697
Type of study: Pragmatic Clinical Trial (Journal of the American College of Nutrition)
Summary: The objective of this study was to determine the long-term safety and efficacy of a bone health plan that included an AlgaeCal formulation and strontium citrate (Strontium Boost). The participants were recruited from AlgaeCal customers who had taken this supplement regimen for one to seven years.
Results: The results showed a significant, linear increase in BMD of over 1% a year for the group who took AlgaeCal and strontium citrate. That means, over the seven-year study period, women taking the AlgaeCal, strontium citrate duo saw an average increase of over 7%!
The safety of this bone-building regimen was established through a 45-measurement blood chemistry panel. No adverse effects or safety concerns were found. Notably, no adverse changes were found in any of the lipid measurements from the seven-year study period.
For a comprehensive view of each study, please see our Research page.
How Much Supplemental Strontium Do You Need for Healthy Bones?
Patients with low bone density will receive the most benefit from a 680 mg daily dose of strontium citrate.
This is the dose that has been used in nearly all clinical research conducted on stable strontium salts. (It’s also the same dose of strontium citrate provided by 2 capsules of AlgaeCal’s Strontium Boost.)
If a patient’s bones are currently healthy, they may still wish to consider supplementing with a 340 mg daily dose. This will help protect and maintain a healthy bone mineral density.
To maintain proper balance between calcium and strontium, more calcium than strontium must be consumed, preferably twice as much calcium.
Contraindications for Strontium Citrate Supplementation
> Individuals with chronic kidney disease
Since strontium is eliminated through the kidneys, it may accumulate in patients with chronic kidney disease.
In patients with chronic renal failure, blood levels of strontium are increased four-fold when creatinine clearance is less than 50 mL/minute. Supplemental strontium should be avoided in individuals with a creatinine clearance less than 50 mL/minute or who are on dialysis. A creatinine clearance rate of 90 or greater indicates normal healthy kidney function. A creatinine clearance rate of 60-89 indicates the initial stage of kidney disease.
Bone levels of strontium are often high in chronic kidney disease patients on dialysis.
Dialysis fluid can contain high concentrations of strontium, so not surprisingly, some dialysis patients are known to have elevated bone strontium concentrations and a high strontium/calcium ratio in bone. As a result, about 5% of dialysis patients develop osteomalacia.
Natural strontium citrate is both safe and beneficial for bone health. Anyone who questions its safety is confusing it with the two other kinds: Strontium ranelate and radioactive strontium.
Natural forms of strontium have been safely used in medicine for over 100 years. Indeed, studies demonstrated strontium’s bone health benefits as early as 1910. Unfortunately, due to a case of “mistaken identity” after World War II, strontium fell out of favor.
Again in the 21st century, natural strontium became confused with strontium ranelate — a synthetic version with many potential adverse effects.
Thankfully, there’s a growing pool of clinical evidence to support the safety and efficacy of natural strontium citrate. Four human clinical studies from the last decade have demonstrated that strontium citrate helps increase bone density, without causing any adverse side effects, even when taken for a prolonged period of time.
For the practitioner who wants to help patients’ bone health outcomes, consider strontium citrate as a welcome solution in your natural formulary.
To discuss strontium in more depth, or to discover how to improve patients’ bone health outcomes in your practice, schedule a free consult.