Mean Substitution Rate of Strontium for Calcium in Newly Formed Bone Is 4.5 Percent

Human clinical trials have documented individual bone sites reaching a substitution rate of 4.5% (and slightly higher) of strontium for calcium, though it is not a whole-skeleton average.

In clinical trials for the osteoporosis drug strontium ranelate, paired bone biopsies of postmenopausal women treated for 36 months showed that strontium was exclusively incorporated into newly formed bone. In these specific, newly mineralized bone packets, the mean substitution rate of calcium by strontium ions was 4.5%, with some individual tissue samples revealing that up to 10% of calcium atoms (1 out of every 10) were replaced by strontium in the apatite crystal lattice. 

However, across the entire skeleton, the average retention is much lower—typically plateauing at around 1.5% to 2.0% of total bone tissue weight after 3 years of therapeutic dosing.

The DEXA Scan "Illusion": Strontium has a much higher atomic weight than calcium (87.6 vs. 40.1). Because it blocks X-rays far more effectively, every 1% of strontium substituted into the bone crystal causes a DEXA scan to overestimate bone mineral density (BMD) by roughly 10%. A person with a 5% substitution at a specific hip or spine site would see an artificially inflated BMD reading of up to 50%. Servier, the original manufacturer of strontium ranelate, stated that, after three years on strontium ranelate, BMD measured by DEXA scan could be inflated by 50%. 

https://pubmed.ncbi.nlm.nih.gov/19874195/

      https://pmc.ncbi.nlm.nih.gov/articles/PMC4708970/

My BMD Results from 2007 to 2024

2007 (my first DXA scan; osteoporosis diagnosis)

My T-score at the lumbar spine was -3.0 (-2.0 at L1, -2.7 at L2, -3.4 at L3 and -3.8 at L4).

My T-score at the left hip was -2.2 (-2.8 at neck, -2.0 at troch, -1.9 at inter).

My BMD results in g/cm2 were 0.712 at the spine (L1-L4), 0.53 at the left hip (neck), and 0.670 at the left hip (total).

2009 My second scan was done 07/06/09 after the following treatment: Fosamax 70 mg weekly from 06/18/07 to 12/24/07, two capsules Doctor's Best Strontium Bone Maker daily from 01/21/08 to 07/06/09.

Spine (L1-L4): BMD 0.749, T-Score -2.7

Lt. Hip (neck): BMD 0.563, T-Score -2.6

Lt. Hip (total): BMD 0.739, T-Score -1.7

2013 (4 years from previous scan; scores in osteopenia range)

0.871 g/cm2 at the spine from L1- L4 (T-score -1.6)

0.692 g/cm2 at the left femoral neck (-1.4 T-score),

0.775 g/cm2 at the left total hip (-1.4 T-score).

2016 (BMD scores improved but still in osteopenia range)

Spine: Total BMD of the spine (L1-4) is 0.897 g/cm2, with a T-score of -1.4.

Left Femoral Neck: BMD is 0.729 g/cm2, with a T-score of -1.1.

Left Total Hip: BMD is 0.812 g/cm2, with a T-score of -1.1.

Compared to the prior study (August 21, 2013), there was a 3% increase in BMD of the lumbar spine and a 5% increase in BMD of the left total hip.

January 2019 (Spine, left total hip, right total hip, right femoral neck show normal BMD; left femoral neck in osteopenia range)

Compared to the prior study, there has been 9% increase in spine density, 6% increase in left total hip density, but no change in left femoral neck density.

August 2022 (showed normal BMD at all sites)

November 2024. The 2024 scan included a TBS, which found normal bone microarchitecture! The only value that was slightly worse than my previous scan of 18 August 2022, was my left femoral neck BMD of 0.728 g/cm2 and a T-score of -1.1 (osteopenia) in 2024, compared to left femoral neck BMD of 0.741 g/cm2 and a T-score of -1.0 (normal density) in 2022.

For almost a year and a half (3/5/2023 through 8/17/2024), I reduced my daily dosage of strontium citrate from 682 mg of strontium per day to 341 mg 4X per week and 682 mg 3X per week. I resumed the full dosage on 8/18/2024.

Originally (2007), my worst BMD scores were for my spine. My most recalcitrant area now is my left femoral neck.

Slowing Biological Aging

Several studies have shown that it is possible to slow biological aging by taking certain supplements. Strength-training exercises may also help. 

One study gave participants 2000 IU/day of vitamin D and 1 g per day of omega-3s (330 mg EPA plus 660 mg DHA from marine algae) and asked them to follow an at-home, strength-training exercise program for 30 minutes 3X/week. To calculate biological ages, the team analysed five epigenetic ‘clocks’ in the blood samples. These clocks are biomarkers that measure DNA methylation — patterns of molecular tags on DNA — at specific sites in the genome. Methylation levels increase or decrease at particular sites in a relatively predictable manner with age. 

Omega-3 alone slowed the DNAm clocks, PhenoAge, GrimAge2 and DunedinPACE, and all three treatments had additive benefits on PhenoAge. 

https://www.nature.com/articles/s43587-024-00793-y

Another study showed that taking a daily multivitamin can slow signs of biological aging. Centrum Silver was used in the study. The supplement's anti-aging effect was greater in people who were already biologically older than their years.

https://www.nature.com/articles/s41591-026-04239-3 (original article)

https://www.nature.com/articles/d41586-026-00741-3 (summary article about the study)

Balance, Core, and Grip Strength Exercises and Sit-to-Stand (STS) Test

Based on fitness guidelines and studies, here are the recommended durations and benchmarks for balance, core, and grip strength exercises. Also included is the sit-to-stand (STS) test for measuring lower body strength, balance, and fall risk. 

1. Balancing on One Foot (Single-Leg Stand)

• Target Time: Aim for 30–60 seconds per leg.
• Benchmarks by Age (Goal):
  • Under 40: ~45 seconds.
  • 40–49: ~40 seconds.
  • 50–59: ~37 seconds.
  • 60–69: ~30 seconds.
  • 70–79: ~14–20 seconds.
  • 80+: ~6–10 seconds.
• Tip: If you cannot hold for at least 10 seconds, it may indicate a higher risk for fall-related injury. 

2. Holding a Plank (Core Strength)

• Target Time: 30 to 60 seconds is a solid, effective goal for most people.
• Advanced Goal: 2 minutes (considered a benchmark for excellent core stability).
• Benchmarks by Age:
  • 20s-30s: 1–2 minutes.
  • 40s: 1 minute or more.
  • 50s: 30–60 seconds.
  • 60+: 20–30 seconds.
• Note: If your form fails (back sags) before 30 seconds, hold for shorter intervals (e.g., 10-20 seconds) in multiple sets. 

3. Wall Sit (Lower Body/Quad Endurance)

• Target Time: Aim for 30–60 seconds, repeated 2-3 times.
• Advanced Goal: 90–120 seconds.
• Health Goal: A common protocol to lower blood pressure is 4 sets of 2-minute holds.
• Tips: Keep knees at 90 degrees and back flat against the wall. 

4. Grip Strength (Each Hand) 

• Measurement: Usually tested with a handheld dynamometer in kilograms (kg) or pounds (lbs). (You can buy dynamometers from Amazon for as low as $25.99.) 
• Average Standards (Adults):
  • Men: 40–50 kg (88–110 lbs).
  • Women: 24–32 kg (53–70 lbs).
• Age Factor: Grip strength peaks between ages 25-39 and gradually declines.
• Significance: Low grip strength is a key indicator of overall health and mortality risk in older adults. 

The sit-to-stand test (STS) measures lower body strength, balance, and fall risk by counting how many times a person can stand up from a chair and sit back down in a set time (often 30 seconds), or by timing how long it takes to do 5 repetitions, using an armless chair with feet flat and arms crossed over the chest to isolate leg muscles. A lower number of repetitions or longer time indicates poorer fitness, higher fall risk, and potential links to poorer health outcomes, making it a valuable tool for assessing functional fitness, especially in older adults or those with neurological conditions. 

How to Perform the 30-Second Sit-to-Stand Test (CDC Version)

Equipment: Use a standard armless chair with a straight back (about 17 inches high).
Position: Sit in the middle of the chair, feet flat and shoulder-width apart, arms crossed over your chest with hands on opposite shoulders.
Action: On "Go," stand up fully, then sit back down, repeating for 30 seconds.
Count: Count the total number of full stands in 30 seconds. 
Important: If you use your arms for support, stop the test and score 0.

DXA vs. REMS Scans

A 75-year-old lady who had been taking strontium citrate (680 mg strontium) for three years, had both a DXA scan and a REMS Echolight scan of her bones. When strontium is incorporated into bone, DXA scan BMD results are falsely elevated because strontium has a higher atomic number than calcium and therefore greater X-ray attenuation. The degree to which the BMD results are falsely elevated depends on the dosage of strontium, the number of years taken, how well the strontium is absorbed and incorporated into bone, the individual bones scanned, and the model of DXA scanner used. REMS is unaffected by strontium in bone. These are her results. You can see that the bone strontium effect varies for each bone scanned. The higher numbers are the DXA scan BMD numbers in g/cm2 and the lower numbers are the REMS scan numbers in g/cm2. The percentages are the difference between DXA numbers and the REMS numbers.

L1-L4   0.775, 0.673, 13.16%

L1   0.698, 0.525, 24.79%

L2   0.763, 0.636, 16.64%

L3  0.805, 0.720, 10.56%

L4. 0.815, 0.773, 5.15% (minimum difference)

Femoral Neck Left  0.772, 0.462, 40.16% (greatest difference)

Hip Total Left  0.750, 0.611, 18.53%

Femoral Neck Right  0.736, 0.467, 36.55%

Hip Total Right. 0.828, 0.617, 25.48%

So, the differences between her DXA and REMS scans varied from a low of 5.15% for L4 to a high of 40.16% for the left femoral neck. 

REMS Scans and Strontium

REMS, which is unaffected by strontium, will show increases in BMD for someone on strontium, but the increases will be real, and, therefore, more modest. I just read a post by a British woman who has been taking strontium citrate (not strontium ranelate, although available in the UK). She has been taking a half dose (340 mg strontium). She just had her third REMS scan, and her spine bone density and fragility scores both improved significantly. Her hip scores stayed the same as those from two years earlier but the hip fragility score was slightly worse. Had she been on the full dose of strontium, her hip scores would most likely have been better. She is a patient of Dr. Nick Birch, the founder of Osteoscan UK, He uses the Echolight REMS system to offer bone health assessments. 

https://healthunlocked.com/bonehealth/posts/149823299/rems-scan-and-strontium-citrate

REMS Reports from BoneForte and Dr. Andy Bush

BoneForte was founded in 2022 by Dr. Andy Bush, who partnered with Dr. Susan Jones and others.

Dr. Bush is a Board-Certified Orthopedic Surgeon, practicing for almost 30 years. He trained at the University of Medicine and Dentistry - NJMS, University Hospital in Newark, NJ.  He has been providing orthopedic surgery care in Sanford, North Carolina for the past 17 years as an independent private practitioner. Recently, he shifted the scope of his orthopedic practice from fracture fixation to fracture prevention. He is a member of the International Society of Clinical Densitometry and he has trained to be proficient in DXA interpretation; however, what sets his Bone Health practice apart from other practices is his embracing of REMS (Radiofrequency Echographic Multi Spectrometry) technology for densitometry and fracture risk determination. Currently, his practice is the largest clinical REMS practice in North America.

Boneforte's website includes six sample REMS reports from actual patients. 

https://www.boneforte.com/for-providers

Update on Strontium, Osteoarthritis, and Reduced Dose of Strontium Citrate

For almost a year and a half (3/5/2023 through 8/17/2024), I reduced my daily dosage of strontium citrate from 682 mg of strontium per day to 341 mg (half dose) 4X per week and 682 mg (full dose) 3X per week. That averages out to 487 mg/day, which is 37 mg more than the MOTS study dosage of 450 mg for osteopenia. 

Reducing my dosage was an experiment. I was not having any adverse events. On 8/18/2024, I resumed the full dose of strontium. During the year and a half at a reduced dose, I developed a myxoid cyst (digital mucous cyst) on my left thumb. Mucous cysts are frequently observed in individuals with osteoarthritis, especially in the distal interphalangeal (DIP) joint, which is the joint at the tip of the finger. Later, I developed a bump on the finger next to that thumb. It is likely a Bouchard's node. Bouchard's nodes are bony enlargements that develop on the middle joints (proximal interphalangeal joints) of the fingers. They are a common sign of osteoarthritis. 

So, my main reason for resuming my full dose was worsening osteoarthritis. I had never had bumps on my fingers before, and any other osteoarthritic signs, such as stiffness or joint pain, had always been, and still are, minimal. I want to keep it that way. 

I had a DXA scan with TBS on November 18, 2024. My left femoral neck BMD was slightly worse than my previous scan of 18 August 2022. It was 0.728 g/cm2 with T-score of -1.1 (osteopenia) in 2024, compared to 0.741 g/cm2 with T-score of -1.0 (normal density) in 2022. I had resumed my full dosage of strontium three months prior to the 2024 scan. My TBS showed normal bone microarchitecture! If I had not already resumed my full strontium dose, I probably would have done so after this scan due to the femoral neck results.

I caused my temporomendibular joint disorder (TMD) by clenching my jaws at night. I was unaware of doing that except that I would wake up with pain in my right jaw and right ear. Now, I wear Plackers Grind No More dental guards at night. They worked like a charm, and I have no more pain. Apparently, my TMD was not caused by osteoarthritis, which can affect the temporomendibular joint (TMJ), leading to TMJ disorder, also known as TMD. I had dental X-rays in January 2025, and my jaws and teeth looked fine. 

Juggling Medications and Supplements

It is a juggling act with medications and supplements.

I take my levothyroxine in the early morning hours (usually 1-3 a.m.) when I wake up to use the bathroom. This hormone stopped my hair from falling out! 

I take my first dose of CBD and a probiotic with breakfast. 

I take most of my vitamins and minerals and my second dose of CBD with supper, my largest meal. These include my calcium/magnesium/vitamin D3 supplement, multivitamin, zinc, selenium, citrus bioflavonoids, vitamin C, vitamin D3, natural vitamin E, lutein with zeaxanthin and others. 

I take my SrC and simvastatin a couple of hours before bedtime and about 30 minutes apart. 

I get magnesium in my Ca/Mg/D supplement. I had been taking a magnesium glycinate capsule at lunch time for a while, but I stopped taking it due to multiple bowel movements. I still give it to my husband. It is best to take magnesium at bedtime, but lunch seems to fit in better for us.

I take sublingual methylcobalamin (Vitamin B12), 5000 mcg, one tablet per week. My husband takes this high dose every day around 3:00 p.m. to keep his canker sores from returning.  

Credentials of Technologists Performing REMS Echolight Scans

You should always ask about the education and training of the technician performing your REMS Echolight scan. I recently had an online chat with a bot at Precision Bone Imaging, which performs scans at OsteoStrong facilities and other locations in Arizona, California, and Colorado.

I asked: 

What are the credentials of techs performing REMS scans?

The bot answered: 

Our technicians who administer REMS scans at our locations are trained ultrasound technicians. They not only have a background in ultrasound technology but also receive specialized training specific to REMS scanning. This additional training ensures they can perform accurate scans and guide patients smoothly through the process. 

Precision Bone Imaging, 3301 E Indian School Rd, Suite 101, Phoenix, AZ 85018, 

phone (888) 415-7377

https://www.precisionboneimaging.com/

https://app.acuityscheduling.com/schedule.php?owner=32710610

To become an ultrasound technician, you'll need to:

Complete high school

• You'll need a high school diploma or GED to enroll in a college or university program. 

  
  

  Earn an associate's or bachelor's degree
• You can earn an associate's degree in Diagnostic Medical Sonography from an accredited college or university. You can also earn a bachelor's degree in sonography. 

  
  

  Complete a certificate program
• You can complete a one-year certificate program in sonography at a college or hospital. 

  
  

  Complete clinical education
• You'll need to complete clinical education, where you'll apply your formal education in a hands-on setting. 

  
  

  Pass licensing exams
• You'll need to pass the proper licensing exams to become a licensed ultrasound technician.

  
  

  Become certified
• You can become certified through the American Registry for Diagnostic Medical Sonographers (ARDMS) or the American Registry of Radiologic Technologists (ARRT).

  
  

  Some courses you might take in an ultrasound technician program include:

Anatomy and physiology, Medical terminology, Applied sciences, General physics, Pharmacology, and Echocardiography pathology.

Many employers also require candidates to complete basic life support training. 

Echolight & NASA

 News release from Echolight Medical:

NASA NOW EQUIPPED WITH ECHOLIGHT DEVICES FOR BONE HEALTH MONITORING IN SPACEFLIGHT SIMULATIONS

 

HOUSTON, Oct. 21, 2024 /PRNewswire/ — Echolight, a global innovator in bone densitometry, announced that NASA is using its proprietary REMS (Radiofrequency Echographic Multi Spectrometry) technology to monitor bone changes in a human bedrest study and to assess the effects of unloading on bone mass given the paramount importance of Bone Health in space too.

Through a simple ultrasound scan of axial anatomical sites such as the spine and femur, the REMS innovative technology measures bone density and microarchitecture without using the radiation of traditional x-ray scans. This radiation-free technology allows scientists to perform repeated scans for monitoring bone health over time. In addition, the ability to automatically exclude artifacts commonly present with other densitometry procedures yields a highly reliable diagnostic assessment.

“Echolight is pleased with this additional milestone in the US adoption of REMS devices, where the diagnostic system for the unique, personalized and patient-centered assessment of bone health has registered a very high interest among the US medical community sharing the intent to reduce fragility fractures,” explained Sergio Casciaro, Echolight S.p.A. CEO and founder.

Prof. Aenor Sawyer, director of UCSF Skeletal Health Service and of UC Space Health, reported “Echolight technology provides a number of potential benefits for possible use during spaceflight missions including its portability (the unit is the size of a small suitcase), fast scan time of under 10 minutes, edge analytics, and the ability to scan frequently with no harmful radiation effects. NASA is currently unable to assess the bone loss of each astronaut occurring in spaceflight and make real-intime adjustments to their countermeasures. This will be increasingly important on longer missions such as those to the Moon and Mars, and REMS could potentially provide this critical in-mission information.”

Echolight was established in Italy with head office in Lecce, and in 2020 opened its offices in the United States. Since then, its sales network has grown to more than 40 distributors and several hundreds of satisfied customers across the world who have adopted the innovative R.E.M.S. technology for assessing the bone condition of their patients.

Created as a spin-off of the Italian National Research Council, Echolight is at the forefront of medical innovation, introducing new cutting-edge solutions to contribute to human wellbeing. It has been awarded all the standard certificates: UNI CEI EN ISO 13485: 2016, Quality Management System UNI EN ISO 9001: 2015, CE mark, FDA clearance, and other major certificates worldwide for innovative solutions considered as the best practice in bone health for personalized medicine.

Dexa Bone Density Axial Skeleton with TBS on 18 November 2024

Below are the results of my latest DXA scan and my first TBS. I am so excited about my TBS showing normal bone microarchitecture! 

The only value that was slightly worse than my previous scan of 18 August 2022, was my left femoral neck BMD of 0.728 g/cm2 and a T-score of -1.1 (osteopenia) in 2024, compared to left femoral neck BMD of 0.741 g/cm2 and a T-score of -1.0 (normal density) in 2022. 

For almost a year and a half (3/5/2023 through 8/17/2024), I reduced my daily dosage of strontium citrate from 682 mg of strontium per day to 341 mg 4X per week and 682 mg 3X per week. I resumed the full dosage on 8/18/2024. 

Impression

Based on BMD criteria, the patient has osteopenia. 

Based on the lumbar spine TBS data, the patient has a normal bone microarchitecture compared to the reference population. 

The patient's associated BMD and TBS values suggest a moderate resilience to fracture. 

Follow up with DEXA and TBS: 2 years 

WHO CRITERIA FOR T-SCORES: 

< or = -2.5 = osteoporosis 

< -1.0 and -2.5 = osteopenia

> or = -1.0 = normal density 

TBS scores: 

>1.31: normal bone microarchitecture

<1.31 and >1.23: partially degraded microarchitecture 

<1.23: degraded microarchitecture 

Narrative

EXAM: DXA AXIAL 

INDICATION: Postmenopausal. Risk factors for osteoporosis include [advanced age 

COMPARISON: 8/18/2022 

FINDINGS: 

Spine: Total BMD of the spine L1-4 is 1.129 g/cm2, with a T-score of 0.7 and a Z-score of 3.2. The lumbar spine trabecular bone score (TBS) is 1.521.

Left Femoral Neck: BMD is 0.728 g/cm2, with a T-score of -1.1 and a Z-score of 1.1. 

Left Total Hip: BMD is 0.842 g/cm2, with a T-score of -0.8 and a Z-score of 1.1. 

Right Femoral Neck: BMD is 0.754 g/cm2, with a T-score of -0.9 and a Z-score of 1.3. 

Right Total Hip: BMD is 0.900 g/cm2, with a T-score of -0.3 and a Z-score of 1.5. 

Diffuse increased 10% in the lumbar spine 

FRAX (adjusted for TBS if available) evaluation calculates 10-year probability of fracture: 

Major Osteoporotic: 8.7% 

Hip: 1.7%