Osteocalcin is a protein that helps build and maintain bones. Read on to learn more about the osteocalcin test, normal levels, what low and high osteocalcin levels mean, and what you can do to improve your bone health.
The osteocalcin test measures the amount of osteocalcin in your blood.
Osteocalcin is a protein hormone produced in the bones. It binds calcium and helps build and heal bones. Osteocalcin may also help adjust insulin production and blood sugar levels, stimulate testosterone production, and improve muscle strength and brain health [1, 2, 3, 4, 5].
Why Doctors Order It
Osteocalcin blood levels reflect the rate of bone turnover. Therefore, the osteocalcin test is useful for monitoring disorders that affect bone health, such as osteoporosis, primary and secondary hyperparathyroidism, cancer with bone metastasis, and Paget’s disease .
Your doctor can use this test to help diagnose Paget’s disease, cancer accompanied by bone metastases, primary hyperparathyroidism, and renal osteodystrophy. However, this test can’t be used to diagnose osteoporosis.
Your doctor may also order the osteocalcin test to monitor how well bone-building therapy is working.
You shouldn’t take supplements containing biotin or vitamin B7 at least 12 hours before the test. Otherwise, you don’t need to prepare for the test in any special way.
The levels of osteocalcin in your serum (the liquid part of the blood) are usually reported in ng/mL (nanograms per milliliter).
The normal range is around 8 – 32 ng/mL. Levels can vary slightly between labs, due to differences in equipment, chemicals, and methods used.
Some labs give a different range for men, pre- and post-menopausal women.
Low osteocalcin levels usually indicate lower bone turnover.
Causes shown below are commonly associated with low osteocalcin levels. Work with your doctor or another health care professional to get an accurate diagnosis. Your doctor will interpret your value, taking into account your medical history, symptoms, and other test results.
Osteocalcin can be decreased by:
- Underactive thyroid (Hypothyroidism) 
- Underactive parathyroid gland (Hypoparathyroidism) 
- Growth hormone deficiency [9, 10]
- Liver disease 
- Smoking 
- Some drugs, such as glucocorticoids and drugs that slow the progression of bone loss (i.e., antiresorptive agents such as bisphosphonates or hormone-replacement therapy [HRT]) [13, 14]
Increasing Osteocalcin and Improving Bone Health
If your osteocalcin is low, the most important thing is to work with your doctor to find out what’s causing your low osteocalcin and to treat any underlying conditions.
Discuss the additional lifestyle changes listed below with your doctor. None of these strategies should ever be done in place of what your doctor recommends or prescribes!
1) Weight Loss
Lose weight if you are overweight. Obesity has been associated with lower osteocalcin levels .
In a study of 107 older, frail adults, osteocalcin blood levels increased on a calorie restriction diet .
In a study of 49 obese men, osteocalcin blood levels increased after weight loss .
However, in a study of 71 postmenopausal women, there was no link between weight loss and osteocalcin .
Finally, in 178 obese persons, high osteocalcin levels were associated with reduced body fat. However, osteocalcin levels actually decreased after weight loss .
If you’re overweight, even it doesn’t affect your osteocalcin levels, weight loss will improve your overall health, including your bone health .
2) Quitting Smoking
Smoking lowers osteocalcin levels by interfering with the genes that produce osteocalcin. This can lead to difficulties with bone healing, and can loosen teeth and dental implants by weakening bone tissue in the mouth and jaw (alveolar bone) .
Smoking can also decrease osteocalcin levels in saliva, which has been associated with chronic gum inflammation (periodontitis) [21, 22].
Osteocalcin levels are higher in people who are more physically active .
A link between physical activity and higher osteocalcin levels has been found in a study of 54 adolescents .
One hour of exercise, 3 times per week for 12 weeks, increased osteocalcin levels and bone mineral density in 29 women with osteoporosis (with an age range of 71 to 78) .
A study of 11 middle-aged men found that osteocalcin levels increased and remained at higher levels for several hours after a brief period of high-intensity exercise (4 sets of 4 minutes of cycling at nearly peak performance levels). This was also linked to increased insulin sensitivity .
There is also evidence that longer periods of less intense exercise can increase osteocalcin levels. A study involving 31 middle-aged subjects found a significant increase in osteocalcin levels after cycling for an hour, 3 to 4 days per week .
In a study of 39 obese but otherwise healthy young men, those who followed an 8-week program of exercise with four sessions per week had increased osteocalcin and leptin levels .
4) Vitamin K
Vitamin K is necessary to activate osteocalcin in the body. A lack of vitamin K results in a lack of osteocalcin protein in the bones. Vitamin K deficiency is also associated with low bone mineral density and increased risk of fractures [29, 30].
A placebo-controlled study of 40 healthy young men showed that vitamin K supplements increased osteocalcin levels after just 4 weeks. This improved the body’s use of insulin (by reducing insulin resistance) and the maintenance of healthy glucose levels. These results were consistent with other clinical studies involving the use of vitamin K supplements by young males as well as older women and men [31, 32, 33].
An analysis of blood samples from 896 persons suggested that most people do not receive enough vitamin K from their diet. However, vitamin K can be taken as a supplement, to ensure that the body produces enough osteocalcin. The best type of vitamin K to take for this is vitamin K2, particularly the MK-7 type .
However, persons who are taking some types of blood-thinning medication (anticoagulants), such as warfarin, must be careful. There is a significant risk that some of these medications will become less effective if vitamin K is taken as well . Always consult with your doctor before using any supplements!
5) Vitamin D
Vitamin D directly stimulates osteocalcin production .
In a clinical trial of 76 obese but otherwise healthy menopausal women between the ages of 51 and 63, vitamin D supplements in combination with a calorie-restricted diet increased osteocalcin and improved insulin sensitivity, compared to diet alone .
Check your vitamin D levels. If they are low, you may benefit from getting more sun or taking vitamin D supplements. Discuss vitamin D supplements with your doctor.
Dietary zinc intake increased osteocalcin in a study of 66 people with type 1 diabetes .
Zinc supplements increased osteocalcin levels in 22 shorter-than-average children. However, this has not been linked to more growth (height and weight) .
7) Decreasing Glucocorticoids
Glucocorticoids are steroid hormones that inhibit inflammation. They are frequently used to treat asthma and rheumatoid arthritis [38, 39].
However, glucocorticoids may also reduce osteocalcin in the bones, which may increase the risk of osteoporosis in people who take glucocorticoids regularly .
A study found that reducing the dosage of glucocorticoids in 208 patients with rheumatoid arthritis led to improvements in osteocalcin levels and bone metabolism .
Discuss your medications, their dosage, and possible alternatives with your doctor.
High osteocalcin levels indicate higher bone turnover.
Causes shown below are commonly associated with high osteocalcin levels. Work with your doctor or another health care professional to get an accurate diagnosis. Your doctor will interpret your value, taking into account your medical history, symptoms, and other test results.
These can increase osteocalcin levels can be caused by:
- Periods of rapid growth (puberty) 
- Intense physical exercise 
- Bone fractures 
- Osteoporosis 
- Softening of bones (osteomalacia) 
- Vitamin D deficiency 
- Overactive parathyroid gland (hyperparathyroidism) 
- Overactive thyroid gland (hyperthyroidism) 
- Paget disease (a bone remodeling disease) 
- Chronic kidney disease (renal osteodystrophy) 
- Bone cancer and other cancers that metastasize to the bone 
- Excess growth hormone (acromegaly) 
If your osteocalcin is high, the most important thing is to work with your doctor to find out what’s causing your high osteocalcin and to treat any underlying conditions.
Your doctor may suggest vitamin D supplements if you’re deficient .
Skip this part if you are not interested in genetics and haven’t sequenced your DNA.
Two SNPs in the Osteocalcin Gene, BGLAP, have been associated with osteocalcin levels.
The ‘T’ variant of this gene has been associated with higher osteocalcin levels, while the ‘C’ variant is linked to lower osteocalcin levels [51, 52].
In 5,561 older people, the ‘T’ variant of rs1800247 was associated with higher osteocalcin levels in women. In men, those with the ‘T’ variant had a higher risk of bone fractures .
However, in another study with 302 athletes, no relationship was observed between this variant and bone quality. This genetic variant may only be relevant in older people .
In another study of 5,647 people, those with the ‘C’ variant had a lower risk of high blood pressure (hypertension). This may be because osteocalcin improves insulin sensitivity and energy metabolism .
More studies are needed to confirm these associations.
This variant is found close to the osteocalcin gene and may influence its production. In 998 women, the rs1543294 variant was associated with higher osteoporosis-related fracture risk .
Osteocalcin levels can be used to monitor bone disorders and they can help doctors diagnose certain bone disease, along with other bone health markers. This test can also be used to monitor how well bone-building drugs are working.
The normal range of osteocalcin in adults is around 8 – 32 ng/mL.
Abnormal osteocalcin levels can be due to serious underlying issues. If your levels are abnormal, work with your doctor to find out what’s going on and to treat any underlying conditions!
Weight loss, exercise, and supplements such as vitamin K can help improve bone health and increase osteocalcin levels.