Osteocalcin dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
The bone hormone said to control muscle, blood sugar and testosterone in mice. Then in 2020, two separate labs made new mice without osteocalcin and found none of that. In people, as far as genetics can tell, the arrow points the other way: diabetes lowers osteocalcin.
Evidence grade for Osteocalcin: Preliminary. The rule: studied in people, but no published study has had people take it. The sum on this page: 2 human studies where nobody was given it. A grade counts how much has been done to people, not whether it works.
- People given it
- 0
- Human studies
- 0
- Found nothing
- 0
Dose
No human dose established
No published study on this page has given this compound to people and reported a result.
2 human studies where nobody was given it
No first-hand reports gathered yet. That is a gap in what we have collected, not a finding that nothing has been reported.
Goal pages: Fat loss and metabolism, Muscle and strength, Hormones and growth hormone, Gut health
In plain English
In plain English, from Aaron
This is how I would explain it to a friend. The evidence, with the numbers, is further down the page.
Osteocalcin is a protein your bones make. Doctors measure it as a sign of bone building. It was once thought to be a hormone that helps muscle, blood sugar and testosterone. Newer mouse studies did not back that up. It is not sold as a product.
What people take it for
- People do not take it. They take vitamin K2 because of the osteocalcin story.
- They see it as a bone-to-muscle signal that exercise switches on.
What studies in people showed
Nobody has given osteocalcin to a person. A genetics study of 5,169 people in China found diabetes lowers osteocalcin, not the other way round. In women over 70, the share of one form tracked with leg strength. The amount did not. In 2020, two labs made new mice without osteocalcin. Their bones were weaker. Their blood sugar, testosterone and muscle were normal.
What people report
Reports, not study results
The good
- We have not collected user reports on this one. Nobody sells it.
The bad
- Vitamin K2 is sold on this story, but K2 lowers the form the story says is active.
Where these come from: The bad line is from the notes on this page. We have not collected user reports on this one, because nobody sells it.
My bottom line
Exercise helps bone and muscle. You do not need a bone hormone story to explain that. Lift, walk, and let your doctor read your bone markers.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
Measured in people
Goals Osteocalcin has been tested for in people, biggest studies first. We count only what the studies on this page say, so the real numbers may be higher.
- Blood sugar and insulin5,169 people · 1 study
- Liver fat and liver health5,169 people · 1 study
Animal and lab work, not yet tested in people
Real results, but from animals or cells, not people. What works in a mouse often does not work the same way in a person. Nobody can patent this, so nobody would ever earn back the cost of a study in people. That is usually why there is none. The record on this one is set out below.
- Keeping or building muscle1 animal or lab study
- Testosterone and male hormones1 animal or lab study
32 of the 36 indexed goals have no study of any kind behind Osteocalcin
No study in people, animals or cells on this page reports a result for these. That does not prove Osteocalcin does nothing for them. It does mean anything you have heard about Osteocalcin and one of these did not come from a study cited here.
Show full evidence
What is Osteocalcin?
The bone hormone said to control muscle, blood sugar and testosterone in mice. Then in 2020, two separate labs made new mice without osteocalcin and found none of that. In people, as far as genetics can tell, the arrow points the other way: diabetes lowers osteocalcin.
Osteocalcin is the most common protein in bone after collagen. Bone-building cells make it, and vitamin K is needed to finish it. From the mid-2000s it seemed to be much more: a hormone sent out by bone. Mice without osteocalcin were reported to handle sugar badly and to be infertile. A 2016 paper in Cell Metabolism reported that osteocalcin signalling in muscle fibres was needed, and enough on its own, for mice to adapt fully to exercise. Bone talking to muscle during exercise was the most appealing version of the exercise signal story.
Start with the people. No one has ever been given osteocalcin, so the human evidence is only measurements. A 2021 study measured osteocalcin in 5,169 people in China. Higher levels went with better blood sugar and other metabolic markers, as the hormone story predicts. But when the researchers used genetics to test which way cause and effect ran, the answer was that type 2 diabetes lowers osteocalcin, not that osteocalcin protects against diabetes. The only link to muscle in people comes from women over 70 in a vitamin D study, looked at afterwards. The share of osteocalcin in one form, but not the amount, tracked with hip and thigh strength.
Then the mice were remade. In May 2020 two labs published side by side in PLoS Genetics. A Japanese team deleted both mouse osteocalcin genes. They found osteocalcin was needed to line up the mineral crystals in bone, and so for bone strength. But it had nothing to do with blood sugar, testosterone or muscle mass. A US team, working separately, used gene editing to make mice with no osteocalcin in the blood. They found no difference from normal littermates in blood sugar or male fertility. Their paper says plainly that they cannot explain why the older mouse strain showed hormone effects.
How does Osteocalcin work?
Osteocalcin is a small protein made by bone-building cells. Its proven job is structural. It lines up bone's mineral crystals along the collagen fibres. Without it, bone gets weaker even though there is the same amount of it. The proposed hormone job is the part that failed to repeat in the new mouse strains. The idea was that when bone is broken down, an unfinished form of osteocalcin is released and acts on a receptor called GPRC6A in the pancreas, the testes and muscle. The authors who found no effect say they cannot explain the difference. It might come from the way the original mice were made affecting nearby genes, from the mouse breed, or from how the mice were kept.
What have studies in people found about Osteocalcin?
All the human data are measurements or genetics. Nobody has given osteocalcin to a person, so there is no human treatment evidence at all.
- A genetics study in East Asian groups, including 5,169 people in China: the cause and effect it supports is type 2 diabetes lowering osteocalcin, not osteocalcin improving blood sugar control.
- Women over 70, looked at after a vitamin D study: the share of osteocalcin in its unfinished form tracked with hip and thigh strength. The actual amount did not.
- Osteocalcin in the blood is a widely used marker of bone building, and it does track bone turnover well. That is a different claim from the hormone story.
- No study has given osteocalcin, or any form of it, to a person.
What this does not tell you: Osteocalcin levels move with bone turnover. Bone turnover moves with exercise, age, vitamin K and vitamin D levels, and metabolic disease. So a snapshot link between osteocalcin and muscle strength or blood sugar tells you almost nothing about cause. The genetics method helps with direction, but it rests on gene spots that explain only a small share of the differences between people, and it was run in East Asian groups. Nothing in the human research tests whether raising osteocalcin does anything.
The state of the research
This is a textbook case of a striking mouse result shrinking when others try to repeat it. It is worth reading carefully, because the same pattern turns up across exercise signal biology.
The original hormone findings all came from one line of mice, made with an older gene method. Two separate teams, publishing in the same journal on the same day in May 2020, made new mice without osteocalcin by different methods. They found the bone effect but none of the hormone effects. Both papers are careful. Both say the difference is unexplained. One team gave its mouse strain to a public mouse bank so anyone can test it. Possible reasons include the original method disturbing nearby genes, the mouse breed, and how the mice were kept.
What survived is not nothing. Osteocalcin turned out to be needed for lining up bone's mineral crystals, which gives bone its strength. That is a real and useful finding about bone quality. What did not survive is the part supplement and biohacking writing repeats: that osteocalcin is the bone hormone that drives muscle gains, testosterone and blood sugar.
The human data never tested that claim. They measured links. The one genetic analysis able to speak to direction suggests metabolic disease lowers osteocalcin, not the other way round. Nobody sells osteocalcin, because it cannot be taken by mouth and has never been given to a person. But vitamin K supplements are sold on the story about the unfinished form of osteocalcin, and that story rests on exactly this research.
The evidence, in charts
Fig. 1a · how many people
5,169people, across 1 study in people cited here
| Study | People | Share |
|---|---|---|
| Journal of Bone and Mineral Research 2021 | 5,169 | 100% |
The whole total is one study of 5,169. Counts are the number of people each study on this page says it signed up. That includes studies that only watched people and gave nobody the compound. 1 more study in people gives no headcount and is not counted here. Studies still signing people up are left out, and only studies cited on this page are counted.
Fig. 1b · evidence mix
2 of 5 sources here are studies in people. The rest are not.
- Study in people · done in people240%
- Animal study · done in animals360%
Counted from the list of sources on this page. It counts only what we cite, so there may be more studies out there. A review counts once, however many studies it sums up.
Fig. 2 · evidence over time
The studies cover 4 different years, 2014 to 2021, counted from the list of sources on this page.
Fig. 3 · legal status at a glance
US
Not approved
UK
Not approved
AU
Not approved
CA
Not approved
Not approved in any of the four countries shown. This is what the law says, not a verdict on the science. See Legal status below for the full text and any notes.
Fig. 4 · how much does what
Nobody has tested different amounts in people
This chart would show how the effect changes as the amount goes up. For this compound, nobody has measured that in people. So we leave it empty. We will not borrow an animal chart and pretend it works the same in people.
Fig. 5 · what the molecule is
- Kind of compound
- Peptide
- Molecule weight
- About 5.8 kDa; the mature human protein is a 49 residue peptide
- Half-life
- Stated in words, not a numbersee the exact wording below
- Chain length
- None on file
Half-life as stated on file: Not stated here. Circulating osteocalcin is cleared quickly and the assays used across the literature measure different fragments, so a single figure would be misleading.
No amino acid sequence is on file for Osteocalcin, so none is drawn rather than guessed from a name.
The studies we cite
- Study in people2014Undercarboxylated osteocalcin, muscle strength and indices of bone health in older women
A hint, dug out of a trial run for another purpose. Women over 70 taking part in a vitamin D trial had their osteocalcin measured. The ratio of one form to the total tracked with stronger hips and thighs. The raw amount of that form did not. Nobody was given osteocalcin, and this was not what the trial was built to look at. It is a pattern in stored data, so it cannot show that osteocalcin makes muscles stronger.
Post hoc analysis of a randomised vitamin D trial in women over 70. The ratio of undercarboxylated to total osteocalcin, but not the absolute undercarboxylated concentration, was positively associated with hip flexor, hip abductor and quadriceps strength (all p < 0.05). Association, in an analysis that was not the trial's purpose.
- Study in people2021Type 2 Diabetes Is Causally Associated With Reduced Serum Osteocalcin: A Genomewide Association and Mendelian Randomization Study
The arrow points the other way. Osteocalcin was measured in 5,169 people in China, and lower levels went with higher blood sugar, insulin resistance, triglycerides, liver fat and weight. That is exactly what the bone hormone story predicts. Then the researchers used genetics to test which way the causation runs, and the genes say type 2 diabetes lowers osteocalcin rather than low osteocalcin causing diabetes. Nobody was given anything. This is the most important caveat on the page.
5,169 Chinese participants with measured osteocalcin, plus bidirectional two-sample Mendelian randomisation against Biobank Japan and East Asian diabetes GWAS. Osteocalcin correlated with lower glucose, insulin resistance, triglycerides, liver fat and BMI, but the causal analysis supported type 2 diabetes lowering osteocalcin (causal effect -0.03, -0.05 to -0.01, p = 0.006 and p = 0.001 in two datasets), not the reverse.
- Animal study2016Osteocalcin Signaling in Myofibers Is Necessary and Sufficient for Optimum Adaptation to Exercise
In mice. The paper that made osteocalcin an exercise signal. It reported that osteocalcin signalling in muscle fibres was needed, and enough on its own, for mice to adapt fully to exercise. There was no human treatment.
The mouse paper that made osteocalcin an exerkine. Osteocalcin signalling in muscle fibres was reported as necessary and sufficient for optimum exercise adaptation in mice. No human intervention component.
- Animal study2020Osteocalcin is necessary for the alignment of apatite crystallites, but not glucose metabolism, testosterone synthesis, or muscle mass
In mice. A new strain made without osteocalcin had normal bone amount, blood sugar, testosterone and muscle mass. What was off was the lining up of bone's mineral crystals, and the bones got weaker. The authors conclude osteocalcin does not act as a hormone.
A new osteocalcin-deficient mouse made by deleting Bglap and Bglap2. Bone quantity, glucose metabolism, testosterone synthesis and muscle mass were all normal. What was abnormal was the crystallographic orientation of bone apatite, and bone strength fell as a result. The authors conclude osteocalcin does not function as a hormone.
- Animal study2020An osteocalcin-deficient mouse strain without endocrine abnormalities
In mice. A separate team made mice with no osteocalcin in the blood. Bone makeup changed a little, but bone mass, bone strength, blood sugar and male fertility matched normal mice. The authors cannot explain the older strain's hormone effects, and gave their mice to a public bank so others can check.
An independent CRISPR double knockout with no immunodetectable circulating osteocalcin. Collagen maturity and carbonate to phosphate ratio changed in cortical bone, but bone mass, three-point bending strength, serum glucose and male fertility did not differ from wild-type littermates. The authors state they cannot explain the absence of the endocrine effects reported in the older strain, and donated the line to Jackson Laboratories so others could check.
Where to buy Osteocalcin
No seller we track lists Osteocalcin yet. We read sellers’ public product lists every week, and this section fills in as soon as one does. Every seller, graded
Common questions
Has Osteocalcin been tested in people?
Not in a completed trial cited here. 2 human studies where nobody was given it. The bone hormone said to control muscle, blood sugar and testosterone in mice. Then in 2020, two separate labs made new mice without osteocalcin and found none of that. In people, as far as genetics can tell, the arrow points the other way: diabetes lowers osteocalcin.
What is the Osteocalcin dosage?
No human dose established. No published study on this page has given this compound to people and reported a result. 2 human studies where nobody was given it
Is Osteocalcin FDA-approved?
Not a drug. Osteocalcin is a protein the body makes. Medical labs measure it as a sign of how fast bone is being rebuilt. No osteocalcin product is approved anywhere, and none has been given to a person in a trial.
Does exercise raise osteocalcin and build muscle through it?
Exercise does raise osteocalcin, because it speeds up bone turnover. The claim that osteocalcin then acts on muscle to cause the gains comes from mice. And two new mouse strains without osteocalcin, made in 2020, had normal muscle mass. There is no human treatment evidence for a bone-to-muscle pathway.
Should I take vitamin K2 to increase undercarboxylated osteocalcin?
Vitamin K2 does the opposite. It finishes osteocalcin, which lowers the unfinished share. The hormone story says the unfinished form is the active one. The two claims are often sold together, and they contradict each other.
Is a high osteocalcin blood test a good sign?
It is a bone turnover marker. High values mean a lot of bone building, which is expected in growth, in healing, and in conditions with a lot of bone remodelling. It is not a fitness or metabolic health score. The clinician who ordered it reads it alongside other bone markers.
Can you buy osteocalcin?
No, not in any form that would work. It is a protein that has never been given to a person in a study, and there is no approved product anywhere.
So was the mouse work wrong?
The fairest summary is that it did not repeat in mouse strains made separately, and the authors who could not repeat it say openly that they cannot explain why. The structural role of osteocalcin in bone quality held up. The hormone role did not.