Is Strontium Safe and Effective for Bone Health?

Many people question the safety of strontium. You may have concerns about this yourself. After all, there’s a lot of conflicting information out there, and it’s not always easy to tell fact from fiction…

So in this article, we’re going to clear up the safety concerns about strontium supplementation once and for all. You’ll discover:

    • How strontium has been safely used for over a hundred years to support bone health, and how it can help you increase your bone density too
    • The different forms of strontium, including which ones are safe to take
    • The clinical evidence and research on strontium’s safety and efficacy
    • And everything else you need to know about strontium to make an informed decision for your health!

What is Strontium?

Strontium is a natural trace mineral. It’s a member of group two of the periodic table of elements — right below calcium and magnesium!  

Strontium can be found in soil, water, and everyday foods like grains, beans, spinach, lettuce, and celery.

It’s also naturally present in your body. Like calcium, 99% of the strontium in your body is in your bones. In fact, these two minerals are closely related. They’re both absorbed in your gut, incorporated into bone the same way, and eliminated from your body through your kidneys.

Strontium takes after its relative calcium when it comes to bone health benefits too. Years of research show this mineral has incredible bone-strengthening properties. In fact, research on strontium and bone health showed promise as early as 1910!

So let’s have a closer look at the research in question…

History of Strontium Supplements

Click on the dates below for additional details on that period!


Strontium gets its name from the Scottish village, Strontian, where it was first discovered in a supply of ore in 1787.


The strontium element was first isolated by Sir Humphrey Davy in 1808.


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… before the events that would cause it to fall out of favor. (More on this in just a moment.)


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.

The Dispensatory of the United States is used to this day and provides a comprehensive review of medical treatments recognized by the United States Pharmacopeia, the British Pharmacopeia, and the National Formulary. It’s a kind of “encyclopedia” of known treatments, tests, processes, and dosages used in medicine.


In 1959, 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.

Right off the bat, you can see there were some limitations to this study. The sample was small and the length of treatment varied greatly. There was also no control group (a group of participants that don’t take the treatment), which is preferred in clinical studies to rule out the possibility of a placebo effect. That said, since some patients saw improvements for a full three years, it’s more likely their improvements were real, and not psychological.

Despite these limitations, the results of the study showed great promise. Notably, no side effects were reported — even when strontium was taken for years and at much greater levels than you’d get from 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, and whether improvements also would’ve been seen in the other 22% given a more accurate scan.

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, there were no two ways about it — 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…

In his study, natural strontium, in the form of strontium carbonate, was administered 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, which is a test that takes a sample of tissue from your bone, 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 side effects were reported.

Now, there were a grand total of six participants in Dr. Skoryna’s study. Of course, this sample is extremely small, so we can’t generalize any of the findings from this study. 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 called strontium ranelate.

Now, we’ll get into the details on strontium ranelate in a moment. But note that much of the modern research on strontium and bone density has been on the man-made ranelate form. And much of the modern bad reputation of strontium comes from this form too.

Thankfully, there have also been several human studies using natural strontium citrate with extremely positive results. You may have noticed them on the visual timeline above. Not to worry, we’ll go over these in detail in the section after next…  

But first, it’s important to distinguish between the three different types of strontium we’ve introduced briefly so far: Natural strontium, strontium ranelate, and radioactive strontium.

Strontium Forms, Compared

There are several forms of strontium, and not all of them are equally beneficial.

The reason there are different forms of strontium, is that like calcium and magnesium, this mineral can’t exist by itself. It has to bond with other materials to form a stable salt. (A stable salt is a compound that has an equal number of positively charged and negatively charged ions.)

These salts can be formed with natural materials like strontium lactate, strontium carbonate, and strontium citrate.

Or strontium salts can be made in a laboratory with synthetic materials. The most common example of this is the prescription drug strontium ranelate, which is made with ranelic acid. And of course, there’s also radioactive strontium, which is an unstable form of the mineral.

The key point to understand here is that taken at the right dosage and with the right complementary nutrients, natural strontium salts are safe and extremely beneficial for your bones. (We’ll go over how to get the most out of your strontium supplement a little later on!)

On the other hand, strontium ranelate and radioactive strontium come with safety concerns and can cause adverse side effects.

Let’s take a closer look at each of the different forms of strontium:

Natural Strontium Salts (Strontium Citrate)

Like we saw in the early research on strontium, there are several natural forms of this mineral. In fact, studies on strontium carbonate, strontium lactate, and strontium gluconate all showed promise for bone health back in the 20th century.

Another common form of natural strontium is strontium citrate. Strontium citrate is just naturally occurring strontium (the kind you’ll find in soil, everyday foods, and your bones) bound with citric acid. Now, citric acid is natural too, and as you may have guessed from its the name, comes from citrus fruits like lemons and oranges.

And strontium citrate is the form of strontium commonly used in supplements. Because it’s made with a natural binder, strontium citrate doesn’t cause any of the nasty side effects you may have read about online. (These side effects are related to strontium ranelate, which we’ll cover next.)

In fact, in recent years, several human clinical studies have been conducted using strontium citrate and no adverse side effects were reported in any of them! (For more details on these studies, click here to skip to the next section on strontium’s safety.)

This safety profile is the reason why strontium citrate is the form of the mineral used in Strontium Boost.

Strontium Ranelate (Drug)

Strontium ranelate is a prescription drug sold under a brand name. Now, natural strontium salts can’t be patented. So the only reason strontium ranelate can be sold under a brand name is because it’s a laboratory-made, synthetic form of strontium.

But how did strontium ranelate come to be?

Well, 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.

But strontium ranelate is the form of strontium you may have read worrying information about!

Remember, strontium can’t exist on it’s 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 of the 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.

And as we covered earlier, 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 is that people often confuse the natural forms of strontium with the unnatural strontium ranelate form. You may even have been advised to steer clear of strontium by your doctor. Unfortunately, this may be a case of mistaken identity. A doctor that advises against using strontium is usually mistaking natural strontium salts for strontium ranelate and erring on the side of caution.

If your doctor has advised you against taking a strontium supplement, we have a handy, printable information sheet you can show them. Our sheet explains the safety and efficacy of the strontium citrate used in Strontium Boost, and how it’s different from the drug version of strontium. Click here to see this “Take it to Your Doctor” information sheet.

Radioactive Strontium

There are two forms of radioactive strontium: Strontium-89 and strontium-90.

Strontium-89 and -90 are the result of nuclear fallout and are considered unstable, but strontium-90 is particularly dangerous.

Strontium-90 is found in soil, although generally in small quantities. The big concern from the 1950s and 60s was that strontium-90 found its way into the food supply and ingesting it could lead to increased risk of certain cancers. Thankfully, levels of strontium-90 today are very low.

Strontium-89 has been used therapeutically to treat metastatic cancer. But the concern with this use of radioactive strontium is that it can damage bone marrow and act as a potential carcinogen (a substance that can cause cancer) itself at high doses.

There are also two isotopes of radioactive strontium (an isotope is a variant of an element that has a different number of neutrons): 85Sr and 89Sr. These isotopes are used to deliver chemotherapy drugs, and in kinetic studies. (Kinetics is the study of the rate at which chemical processes occur.)

But as you can see, radioactive strontium is not used in strontium supplements, or any kind of osteoporosis treatment.

The bottom line is, there’s a lot of confusion between these three types of strontium. So even though natural strontium has been used therapeutically for hundreds of years — and all the evidence points to its safety and efficacy — people often dismiss it due to preconceived notions.

But the tide is turning… and thanks to several modern studies, we now have clinical evidence that natural strontium citrate is a safe and effective approach for increasing bone density. So let’s dig into said research!

Strontium Safety and Efficacy

As noted in the history section, the vast majority of research on strontium from the past decade was conducted using strontium ranelate.

And yes, these studies show that strontium ranelate can benefit bone health. In fact, two large randomized controlled trials (RCTs) on strontium ranelate [1, 2] showed that it significantly reduced fracture risk and increased BMD.

Another study analyzed data from these two RCTs and determined that strontium ranelate reduced vertebral fracture risk by 40% after three years. Notably, this effect was independent of individual risk factors for osteoporotic fractures like baseline BMD, family history, and baseline body mass index. In other words, strontium was able to reduce fracture risk even without taking into account bone density. A pretty amazing feat!  

So these studies suggest that strontium is effective at strengthening bone over long periods of time. And even though these studies were on strontium ranelate, the positive effects can be attributed to the strontium portion of the drug, and not the ranelic acid.

Indeed, experts report that, “It appears to be the strontium portion of the molecules which exerts most or all of the positive effect on bone.”

The problem is the side effects that come with strontium ranelate. The ranelic acid in strontium ranelate detracts from strontium’s good work, and quite frankly, the risk associated with this treatment is not worth the potential gain.

But what if you replace ranelic acid with a natural binder like citric acid? Well, in theory, you’d be left with all the incredible bone health benefits of strontium, and none of the adverse side effects of its drug form. That’s exactly what modern research on natural strontium citrate supplementation shows.

To date, there are four human clinical studies that demonstrate strontium citrate’s safety and efficacy. Now, please note that though strontium citrate has a remarkable safety profile, there’s one contraindication, which we’ll go over a little further down the page.

But first, here’s a summary of the modern 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 1

Study link:

Type of study: Clinical Trial — A human study where participants are assigned to one or more interventions to evaluate health outcomes.

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.

The first group of participants included 125 adults. Participants took a DEXA scan to determine their baseline bone density, a 43-chemistry blood test panel, and a quality of life inventory at the start of the study. Then, they followed a bone health plan for six months.

The plan included:

  • An AlgaeCal formulation that delivered calcium, magnesium, vitamin D3, vitamin K2, and traces of boron, copper, manganese, silicon, nickel, selenium, strontium, phosphorus, potassium, vanadium, and zinc
  • Strontium citrate at a dose of 680 mg a day
  • A pedometer-based activity program
  • Health literacy information

The second group of participants included 51 adults, and they followed the exact same protocol as the first group. The only difference between the two groups (notwithstanding sample size), was the AlgaeCal formulation provided. The second formulation contained additional magnesium and boron, added vitamin C, and vitamin K7 instead of vitamin K2. But in terms of the participants, there were no significant differences in variables like baseline bone mineral density (BMD), age, sex, and weight.

At the end of six months, participants took another DEXA scan to determine BMD changes from their baseline measurement. 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% compared to the expected change over this timeframe!  

What’s more, safety was assessed through daily tracking self-reports, and another 43-chemistry blood test panel and quality of life inventory taken at the end of the study. Notably, no clinically significant changes were found in the blood test panel, and there were no changes in self-reported quality of life in either group. Simply put, no adverse side effects were reported.

Results: The results of this study were noteworthy, as after age 40, humans normally lose around 1% bone density a year. So to not only stem that loss, but significantly increase bone density was a landmark result.

Of course, strontium citrate was administered alongside a bone health supplement, so the bone density increases seen can’t be attributed to strontium alone.

But the fact that strontium was evaluated in combination with calcium and other nutrients is actually a positive, as this is a more realistic, balanced approach to bone health. In other words, strontium shouldn’t be considered a replacement for calcium, but rather a complementary nutrient capable of supporting bone density gains.

Finally, no participant in this study reported any adverse side effects, and no negative changes in blood chemistry were found. So this study demonstrated the safety of taking 680 mg of strontium citrate a day for a duration of six months.

Note that this study was funded by AlgaeCal, the maker of the bone health supplement regimen tested. AlgaeCal funded this study because, quite simply, the research wouldn’t have happened otherwise. And we believed that our product had the ability to increase bone density and change lives, so it was crucial to fund a study to support (or disprove) our belief.

But this in no way detracts from the results of the study. There was no conflict of interest as the study was independently conducted by a third party research organization and published in the Nutrition Journal, a prestigious peer-reviewed publication.  

Study 2: Combination of Micronutrients for Bone (COMB) Study: Bone Density After Micronutrient Intervention

study 2

Study link:

Type of study: Retrospective Cohort Study — “Retrospective” refers to the fact that this study wasn’t preplanned, but researchers looked back on existing data. “Cohort” refers to the participants being chosen from a specific group (in this case, an environmental health clinic).

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) which is a type of omega 3 fatty acid.

Starting in 2006, patients with low bone density who attended an environmental health clinic in Canada, were provided with different options for treatment — one being micronutrient therapy. These patients were given medical literature on the efficacy of micronutrient interventions, as well as information on traditional treatments.

Many patients were interested in micronutrient therapy. Often, they’d already tried traditional treatments without success. In the end, researchers identified a sample of 77 patients who followed the micronutrient intervention plan for one year.

The plan included:

  • DHA (from purified fish oil): 250 mg a day
  • Vitamin D3: 1000 IU a day
  • Vitamin K2: 100 ug a day
  • Strontium citrate: 680 mg a day
  • Elemental magnesium: 25 mg a day

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 a 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.

What’s more, none of the participants experienced a fracture while following this bone health plan, nor were any adverse side effects reported. Note that the dose of strontium citrate administered in this study was the same as the previous clinical trial: 680 mg. But in this study, patients safely took a daily dose of strontium citrate for a full year.

Results: The results from this study were impressive. The fact that all participants significantly increased their bone density in one year supports the use of this kind of “multi-nutrient” approach — similar to the plan from the previous AlgaeCal study.  

Again, strontium citrate can’t take credit for all the bone density gains seen in this study.

Nonetheless, the results of this study were especially promising because not one of the participants experienced a fracture. And of course, fracture prevention is a key measure of success when it comes to osteoporosis treatments.

Once again, none of the participants reported adverse side effects. So these results further support the safety of taking 680 mg of strontium citrate a day, but for the duration of a full year this time.

Note that AlgaeCal didn’t fund this study and wasn’t involved in any other way.

Study 3: A 7-Year Longitudinal Trial of the Safety and Efficacy of a Vitamin/Mineral Enhanced Plant-Sourced Calcium Supplement

Study 3

Study link:

Type of study: Pragmatic Clinical Trial (PCT) — A pragmatic clinical trial, also called a practical clinical trial, is a human intervention study that strives to examine the safety and efficacy of treatments under real-world conditions.

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.

To qualify, participants had to have had at least one previous DEXA scan to establish a baseline, and they couldn’t be taking any other bone medications. Participants took a new DEXA scan to measure bone density changes as well as a 45-measurement blood chemistry panel to establish the safety of the treatment.

Blood chemistry panel

In the end, data was acquired for a total of 172 participants. Bone density changes were calculated for this group and compared to expected or normal changes in BMD. The stats for the “normal changes” comparison group were obtained from three databases; the Centers for Disease Control, GE Lunar Norms, and the IHTI Longitudinal Database of Medical Biomarkers.

The comparison group was carefully chosen to create a similar control group. Data was only included for women who had completed multiple DEXA scans, and who consumed a variety of dietary supplements (other than AlgaeCal) over the same seven-year period.

In addition, to reproduce age-matching, the percentage of subjects of each age was calculated for the AlgaeCal group. Then, this same percentage was selected from the database. (For example, if 5% of the participants in the AlgaeCal group were 58, then the same percentage of 58-year-olds were randomly selected from the database.)

Using these methods, a total of 2,540 women were included in the control group. The size of this group established a strong basis for comparison. And even though the control group was much larger than the AlgaeCal group, the percentage of women in each age group was the same.

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 duo saw an average increase of over 7%!

Notably, no adverse changes were found in any of the lipid measurements from the seven-year study period. Lipid measurements, taken as part of the blood chemistry panel, refer to the concentration of cholesterol and triglycerides in the blood.

This is a key finding to report, since in the past, researchers have raised concerns about calcium supplements increasing the risk of cardiovascular disease. But in this study, lipid levels weren’t affected, even with prolonged calcium supplementation. In fact, no adverse effects or safety concerns were reported whatsoever.

Results: The findings from this study were very exciting. They showed that not only is AlgaeCal and strontium citrate effective in the short-term, but this regimen can continue to increase bone density year after year, for seven years! This is quite the contrast to participants in the control group, who lost on average -0.4% bone density a year.

What’s more, the safety of this bone-building regimen was established through a 45-measurement blood chemistry panel. And again, no adverse effects or safety concerns were found. Note that the blood chemistry panels of participants in the AlgaeCal group were also compared to the control group, and there were no significant differences.

So once more, a daily dose of 680 mg of strontium citrate, taken alongside a multi-nutrient calcium supplement, was found to be a safe and effective treatment for bone loss. But this time, it’s safety was established for a full seven-year period!

JACN Ragus SealThe level of evidence from this study was considered so strong that it won the Ragus Award for Best Original Research Paper of 2016 from the Journal of the American College of Nutrition.

Note that this study was funded by AlgaeCal, the maker of the bone health supplement regimen tested. We wanted to examine the safety and efficacy of AlgaeCal and Strontium Boost (strontium citrate) over long periods of time. And again, without funding a study, the research wouldn’t have happened.

But as with the previous study, the research was independently conducted by a third party research organization and went through a rigorous peer-reviewing process prior to publication.

Study 4: Melatonin-Micronutrients Osteopenia Treatment Study (MOTS): A Translational Study Assessing Melatonin, Strontium (Citrate), Vitamin D3 and Vitamin K2 (MK7) on Bone Density, Bone Marker Turnover and Health Related Quality of Life in Postmenopausal Osteopenic Women Following a One-Year Double-Blind RCT and on Osteoblast-Osteoclast Co-Cultures

MOTS study results

Study link:

Type of study: Double-blind Randomized Controlled Trial (RCT) — A double-blind trial is a human study where neither the researchers nor the patients know who’s in the placebo control group versus in the treatment group.

Summary: This intriguing one-year RCT looked into the effects of a bone health regimen that included; melatonin, strontium citrate, vitamin D3, and vitamin K2. The researchers dubbed this treatment “MSDK”. Their goal was to assess BMD and quality of life in postmenopausal osteopenic women who received MSDK treatment.

Although 184 women applied to participate, many did not meet the study criteria. For example, some had normal bone density scores, some were on conflicting medications, and some had other conditions like ulcerative colitis and rheumatoid arthritis.

So, of these applicants, 79 were invited to join the study. Unfortunately, 50 individuals chose not to participate for personal reasons like fear of being in the placebo group. In the end, data was collected for 22 osteopenic, postmenopausal women, between the ages of 49 and 79.

These women were placed in either the placebo control or MSDK treatment group. The control group took two placebo capsules a day that contained plant fiber. The MSDK group took two capsules a day that contained:

  • Melatonin: 5 mg
  • Strontium citrate: 450 mg
  • Vitamin D3: 2000 IU
  • Vitamin K2: 60 mcg

A DEXA scan was taken at the beginning and end of the one-year study period to measure changes in BMD. Fracture risk was also assessed at the beginning and end of the study using the Fracture Risk Assessment Tool (FRAX). Participants kept track of their daily pill intake, sleep duration, physical activity, and any other information about their well-being in a journal.

At the end of the one year study period, the women in the MSDK group showed significant bone density improvements compared to the women in the placebo group. They increased their lumbar spine BMD by 4.3% and left femoral neck BMD by 2.2%.

What’s more, the MSDK group decreased their risk of major osteoporotic fracture by 6.48% based on FRAX data. This is in stark contrast to the placebo group whose risk of fracture increased by 10.8%. Finally, participants in both groups reported no adverse effects through their daily logs or during their bi-monthly check-ups.

Results: Although the number of participants in this study was limited, the strength of the study design lends weight to its findings. This was the first, modern double-blind randomized controlled trial to investigate the effects of strontium citrate, in combination with other nutrients, on bone health.

The fact that the MSDK regimen not only increased bone density, but significantly reduced fracture risk compared to the placebo group is extremely promising. Note that this finding comes from FRAX data, which is an assessment tool that predicts the risk of fracture based on clinical risk factors.  

Of course, strontium citrate was taken in combination with melatonin, vitamin D3, and vitamin K2. So the improvements can’t be attributed to strontium alone. But again, this supports the use of strontium citrate as an integral part of a multi-nutrient approach to bone health.

The dose of strontium citrate was a little lower in this study: 450 mg. Nonetheless, participants reported no adverse side effects over the course of a full year. So now, we’ve seen four human clinical studies where strontium citrate was taken, with no side effects for periods ranging from six months to seven years!

It’s also worth noting the researchers monitored serum (blood) bone formation markers in this study. And they found that MSDK treatment decreased the ratio of bone resorption to bone formation! This lines up with what we know about strontium’s dual-effect on bone. Namely, that strontium stimulates bone-building and slows bone resorption. For more information on strontium’s specific bone health benefits, visit our “Strontium Benefits” page.

Again, note that AlgaeCal didn’t fund this study and wasn’t involved in any other way.

Strontium Myths

Now, you’ve seen an abundance of research that shows natural strontium citrate is a safe and effective way to increase bone density.

You’ve also discovered the vast difference between natural strontium citrate and synthetic strontium ranelate, which comes with a long list of side effects.

But you may still be wondering whether other claims you’ve heard about strontium are true. For example, there’s a common misconception that strontium skews DEXA results. But the truth is, the amount that strontium impacts DEXA results is insignificant.

Another common misconception is that strontium can actually cause bones to become more fragile and prone to fracture. But this is based merely on speculation and not any kind of scientific evidence.

On the contrary, strontium has been shown to reduce fracture risk independent of bone density! So regardless of any increases in bone density you may see, strontium can help you avoid a fracture… which is the ultimate goal of any regimen for improving bone health.

For a more detailed explanation of these misconceptions, check out our article, “Strontium Side Effects Are Overblown: Get the Facts” written by our Resident Bone Health Expert, Lara Pizzorno.

Strontium Bone Health Benefits

Strontium is truly an exceptional mineral for bone health. In fact, it can do something no other mineral in the world can…

As we touched on earlier, strontium both stimulates the rate of new bone building, and slows the rate of bone break down. This powerful dual-effect is no doubt a big contributor to the bone density increases seen in clinical studies using strontium citrate.

Plus, strontium has four other important benefits for bone health too. To read more about all of the science-backed benefits of strontium, visit our “Strontium Benefits” page.

Strontium Rich-Foods

As mentioned at the beginning of this article, strontium is atrace mineral! So traces of strontium can be found in food, but it’s not overly abundant. That said, some foods are richer sources of strontium than others.

To find out how to incorporate strontium into your diet effectively, visit our “Strontium-Rich Foods” page.

Strontium Contraindications

As we’ve seen, strontium citrate is safe and adverse side effect-free for the majority of people. But there’s one exception to the rule!

If you have chronic kidney disease, you may want to moderate or refrain from strontium supplementation depending on the severity of the condition. This is because strontium is eliminated by the kidneys. And of course, people with this condition can’t remove waste as well through their kidneys, so an excess of strontium can accumulate in the body.

What’s more, if you’re on dialysis for kidney disease, dialysis fluid can contain high concentrations of strontium. So not surprisingly, some dialysis patients have elevated bone strontium concentrations and a higher strontium to calcium ratio in their bones. This can contribute to osteomalacia — a condition where the bones become soft.

Note that osteomalacia is frequently seen in individuals with kidney disease who aren’t on dialysis and have normal bone strontium levels. This is because failing kidneys lose their ability to activate vitamin D, which is key for calcium absorption. In addition, they’re less able to reabsorb calcium that’s passing through the kidneys. So calcium is doubly hard to come by! All this to say, more often than not, strontium has nothing to do with osteomalacia seen in chronic kidney disease.

The best test to measure kidney function is called estimated glomerular filtration rate (eGFR). It can help determine what stage of kidney disease you’re at. Simply put, the lower your eGFR, the more impaired your kidney function.

For context, here’s a table from the National Kidney Foundation that shows what a normal eGFR number is based on age:

Age Average estimated eGFR













The National Kidney Foundation also reports that an eGFR below 60 for three or more months indicates chronic kidney disease.

So if your eGFR is 60 or lower, our Resident Bone Health Expert, Lara Pizzorno, recommends you cut your dose of Strontium Boost in half — take one capsule rather than two capsules daily. This is to “lighten the load” on your kidneys.

But please note, it’s always best to check with your medical professional as recommendations may vary on a case by case basis.

As a general rule, however, you may want to moderate or forgo strontium supplementation if:

    • Your eGFR is 60 or lower
    • You’re on dialysis for chronic kidney disease

It’s worth noting that strontium is also not advised for children. It may alter the architecture of rapidly growing bones, and no studies have been done using high doses of strontium on children.

How to Get the Most Out of Your Strontium Supplement

Take 680 mg of strontium citrate a day

If you have low bone density, you’ll get the most benefit from a dose of 680 mg of strontium citrate a day. Why 680 mg? If you recall, the majority of human clinical studies on strontium citrate were conducted using this dose. These studies showed that 680 mg of strontium citrate a day was both safe and effective at increasing bone density. Note: That’s why this is the daily dose provided in two capsules of Strontium Boost.

Separate calcium and strontium intake by at least two hours

Calcium and strontium are chemically similar minerals, and they use the same absorption pathway. So if you take your calcium and strontium at the same time, they would compete for absorption — a competition that calcium always wins. That means, you wouldn’t end up benefiting from your strontium supplement at all! This issue is easily avoided by taking your calcium and strontium supplements at least two hours apart. For example, we recommend taking two capsules of AlgaeCal Plus at breakfast and two capsules at lunch. Then, two capsules of Strontium Boost before bed. To make this easier to remember, here’s a printable PDF with instructions on “How to Take AlgaeCal Products”.

Limit processed food consumption

Phosphate (a chemical compound that contains phosphorus, often a salt) significantly lowers strontium absorption. Phosphates are used as preservatives in most processed foods, so make sure you read nutrition labels closely. Most often, phosphates are found in foods like sodas, sweet bakery products, cereals, crackers, pizza, cured meats, poultry, processed vegetables, egg products, candy, and chocolate.

Include all essential bone-building nutrients

Although strontium offers remarkable bone-supporting benefits, it’s by no means a “magic bullet”. And as you can see from the research on strontium citrate, it’s best to use it in combination with other nutrients! That’s because bone-building is a team effort. Your bones require 13 essential minerals (one of which is strontium) and 3 vitamins. These include calcium, magnesium, boron, and vitamins D3, K2, and C — to name just a few! AlgaeCal’s Bone Builder Pack (AlgaeCal Plus and Strontium Boost) provides all of these nutrients in the perfect proportions to support strong, healthy bones.

Safely and Naturally Reclaim Your Bone Density with Strontium

Strontium’s bone health benefits have never been in question. Its safety, on the other hand, has…

But the key takeaway here is that natural strontium citrate is both safe and extremely beneficial for your bones. And that anyone who questions the safety of natural strontium 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” strontium fell out of favor in the 1950s.

And again, in the 21st century, natural strontium became confused with strontium ranelate — a synthetic version with many potential adverse side 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.

The bottom line? Strontium citrate (Strontium Boost) is a natural, safe, and scientifically validated way to support your bone health. In fact, it’s guaranteed to increase your bone density in as little as six months when taken with AlgaeCal Plus.



Which AlgaeCal is Right For You?

Early-Stage Support
A Bottle of AlgaeCal
Stop Bone Loss
Those looking to prevent bone loss and maintain healthy bones every single day As far as prevention goes it’s never too early to start!
Shop Now
Mid-Stage Support
A Bottle of AlgaeCal Plus
AlgaeCal Plus
Increase Bone Density
Those who haven’t had a DEXA scan yet but bone loss is on their radar due to family history or age. They want to strengthen their bones.
Shop Now
Late-Stage Support
A Bone Builder Pack
Bone Builder Pack
Stronger Bones For Life
Those who have been diagnosed with low bone density or suffered a fracture. They are actively looking to increase bone density.
Shop Now