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New research: Sleep hormone strengthens bones

A new study by researchers from Aarhus shows that the sleep hormone melatonin improves human bones, and reduces body fat mass in women at risk of osteoporosis.

2015.05.12 | Lotte Fisker Jørgensen

Anne Kristine Amstrup, PhD student from Aarhus University and medical doctor at Aarhus University Hospital

Anne Kristine Amstrup, PhD student from Aarhus University and medical doctor at Aarhus University Hospital

It is well known that the risk of osteoporosis and hip fractures increases with age. But researchers from Aarhus University and Aarhus University Hospital may possibly have found a means that can in future prevent this deterioration of the bones. A research project shows that the sleep hormone melatonin, which is typically used against jet lag, can help to strengthen our bones.

A total of 81 women between the ages of 56-73 participated in the study. During a one-year period, forty of the participants received melatonin  (either 1 or 3 mg) nightly, while the remainder were given placebo.

"Our research showed an increase in bone mineral density or BMD in the femoral neck  among the women who received melatonin, compared to those who received placebo. The increment was up to 2.3% in the group with the highest dose of melatonin, compared to placebo. So our results suggest that melatonin may have a potential effect when it comes to protecting our bones," says Anne Kristine Amstrup, PhD student from Aarhus University and medical doctor at Aarhus University Hospital.

She has headed the research project, which has been carried out in collaboration with research colleagues from Aarhus University and Aarhus University Hospital. The results were recently presented to international researchers at the ECTS-IBMS 2015 conference in the Netherlands. 

Major perspectives

The women did not only improve their bone mineral density. The melatonin treatment also showed other positive effects on the body:

"The women in the test group also lost an average of approximately seven per cent body fat mass. They did not loose weight but there was a trend towards an increased lean mass. And, of course, it is really good news if melatonin also benefits the body in this way," says Anne Kristine Amstrup.

Each year in Denmark, approximately 7,000 elderly adults over the age of 65 suffer hip fractures, which are often caused by osteoporosis. So any future medication against weakening bones would greatly benefit many people.

However, Anne Kristine Amstrup emphasises that larger studies are needed to assess the mechanisms of action including the optimal dose of melatonin, before specific recommendations about melatonin supplements for the elderly can be made. 

Facts about melatonin

  • The body produces melatonin during the night, so that we can sleep.
  • Melatonin can also be produced synthetically. In Denmark it is only available on prescription.
  • The pills are e.g. used to combat jet lag.
  • In USA and a number of other countries melatonin is sold over the counter and used as a dietary supplement.
  • Melatonin has very few side effects.



PhD student Anne Kristine Amstrup

Aarhus University, Department of Clinical Medicine and

Aarhus University Hospital, Department of Endocrinology and Internal Medicine

Telephone: +45 5062 4137


Research, Health and disease, Academic staff, External target group, Health, PhD students, Department of Clinical Medicine, Public/Media