Research brief · 2026-09-09
Do GLP-1s Affect Bone Density?
Semaglutide, tirzepatide and liraglutide are prescription medications, and rapid weight loss from any cause can cost bone. So whether these drugs affect bone density is a fair question. The honest answer is that the published meta-analyses disagree with each other, and most of the evidence was not gathered in the people asking.
A 2025 systematic review and meta-analysis by Tan, Liu and Tang in Acta Diabetologica pooled 25 randomised trials of GLP-1 receptor agonists in people with type 2 diabetes. It found bone mineral density modestly improved at the lumbar spine, femoral neck and total hip compared with control groups, with bone-formation markers moving in a favourable direction. Fracture risk was not significantly different, with a relative risk of 0.80 and a confidence interval that crossed one.
A 2024 meta-analysis by Kim and colleagues in Diabetes/Metabolism Research and Reviews applied stricter inclusion criteria and ended up with seven randomised trials. It found no significant change in bone density at any site. It did find a rise in CTX, a blood marker of bone breakdown, which is the same marker that fell in the first analysis. Different trial sets and different methods produced opposite directional conclusions on the same drug class, and neither review could resolve the contradiction.
The most direct trial evidence comes from Denmark. Jensen and colleagues, in JAMA Network Open in 2024, reported a secondary analysis of a trial in which 195 adults with obesity lost weight on a low-calorie diet and were then randomised to a year of exercise, liraglutide, both, or placebo. Bone density in the combination group was unchanged from placebo. But liraglutide alone lost significantly more bone at the hip and spine than exercise alone, despite comparable weight loss. The authors read this as evidence that mechanical loading from exercise, not the drug, protected bone during weight loss.
The gaps are large. Nearly all the meta-analysed trials enrolled people with diabetes, at doses set for blood sugar rather than obesity, for months rather than years. The only trial dedicated to older adults, a 2025 pilot by Dinkla and colleagues in Frontiers in Aging, enrolled 20 people with an average age of 72.7 for 20 weeks and found no significant difference in bone density; its authors were explicit that it was too small to draw conclusions. Bone remodels slowly, and two years of fracture data may not be long enough. Anyone with osteoporosis or concerns about bone health should discuss these medications with a physician.
Sources
- Tan Y, Liu S, Tang Q. Effect of GLP-1 receptor agonists on bone mineral density, bone metabolism markers, and fracture risk in type 2 diabetes: a systematic review and meta-analysis
- Acta Diabetologica 2025
- Kim HJ, et al. Effects of Glucagon-Like Peptide-1 Receptor Agonist on Bone Mineral Density and Bone Turnover Markers: A Meta-Analysis
- Diabetes/Metabolism Research and Reviews 2024
- Jensen SBK, et al. Bone Health After Exercise Alone, GLP-1 Receptor Agonist Treatment, or Combination Treatment: A Secondary Analysis of a Randomized Clinical Trial
- JAMA Network Open 2024
- Dinkla L, et al. Bone mineral density and turnover response to GLP-1 receptor agonists in older adults with overweight/obesity and prediabetes/type 2 diabetes: a 20-week pilot trial analysis
- Frontiers in Aging 2025
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