Researchers looked at 16 different studies to see if taking probiotic supplements (the “good bacteria” pills) could help strengthen bones. They found that probiotics may slightly improve bone density in the lower spine and hip area, especially for women going through menopause. However, the improvements were modest, and the effect wasn’t consistent across all studies. While the results are encouraging, scientists say more research is needed before we can say for certain that probiotics are a reliable way to prevent bone loss.

The Quick Take

  • What they studied: Whether taking probiotic supplements (pills with beneficial bacteria) could improve bone strength and density in adults
  • Who participated: Analysis of 16 different research studies involving mostly postmenopausal women (women past their reproductive years) who were tested for changes in bone density
  • Key finding: Probiotics showed a small but measurable increase in bone density in the lower spine and hip area, but this effect was modest and not consistent across all studies
  • What it means for you: Probiotics may offer a small benefit for bone health, particularly for postmenopausal women, but they shouldn’t be relied upon as a primary treatment for bone loss. Talk to your doctor about whether probiotics might be helpful as part of your overall bone health plan.

The Research Details

Scientists performed a systematic review and meta-analysis, which means they searched through medical databases to find all high-quality randomized controlled trials (the gold standard of research) that tested whether probiotics affected bone health. They looked at studies from three major databases and only included experiments where some people took probiotics while others took a fake pill (placebo) for comparison. The researchers then combined the results from all these studies to see if there was an overall pattern.

They measured bone density using special X-ray machines that can detect very small changes in bone strength. They also looked at blood markers that indicate whether bones are being broken down or built up in the body. By combining data from multiple studies, they could get a clearer picture than any single study could provide.

This approach is important because individual studies can sometimes give misleading results due to chance or differences in how they were conducted. By combining many studies together, researchers can see the bigger picture and determine whether an effect is real and consistent. This helps doctors and patients make better decisions about whether a treatment is worth trying.

This analysis included only randomized controlled trials, which is the highest quality type of research. However, the studies varied quite a bit in how they were done—different people participated, different probiotic strains were used, and studies lasted different lengths of time. This variation made it harder to draw firm conclusions. The results for the hip were less reliable than for the spine because fewer studies looked at hip bone density.

What the Results Show

Probiotics showed a small but statistically significant increase in bone density in the lower spine (lumbar spine), with an average improvement of 0.010 g/cm². This means that on average, people taking probiotics had slightly denser bones in this area compared to those taking a placebo. The hip area also showed improvement, with an average increase of 0.022 g/cm², which is about twice the improvement seen in the spine.

However, the neck of the thighbone (femoral neck) showed no significant improvement from probiotics. This suggests that probiotics may help some parts of the skeleton more than others. The improvements were consistent when researchers looked specifically at postmenopausal women, who made up most of the study participants.

When scientists looked at blood markers that show whether bones are being broken down (CTX) or built up (P1NP), they found no significant changes from probiotic use. This suggests that probiotics may work through different mechanisms than simply speeding up bone formation or slowing bone breakdown.

The research revealed significant variation between studies, meaning that some studies showed much larger benefits from probiotics than others. This variation could be due to differences in the types of probiotics used, how long people took them, the age and health status of participants, and other factors. When researchers removed certain key studies from their analysis, the hip bone density benefit disappeared, suggesting this finding is less stable than the spine results.

This research builds on growing evidence that gut bacteria play a role in bone health. Previous studies had suggested a connection between the microbiome (the community of bacteria in your gut) and bone strength, but it wasn’t clear whether taking probiotic supplements could actually improve bones in real people. This meta-analysis provides the most comprehensive look at this question to date and confirms that there is a small positive effect, though it’s more modest than some earlier studies suggested.

The biggest limitation is that the improvements were very small—the bone density changes were less than 1% in most cases. While statistically significant, it’s unclear whether such small changes would meaningfully reduce fracture risk in real life. Additionally, most studies focused on postmenopausal women, so we don’t know if probiotics work the same way in younger adults or men. The studies used different probiotic strains and doses, making it hard to know which specific probiotics might be most helpful. Finally, most studies were relatively short-term, so we don’t know if benefits continue over years of use or if they fade over time.

The Bottom Line

Based on current evidence, probiotics may offer a modest benefit for bone health in postmenopausal women, but the effect is small. They should not be considered a replacement for proven bone-health strategies like adequate calcium and vitamin D intake, weight-bearing exercise, and medication if prescribed by your doctor. If you’re interested in trying probiotics for bone health, discuss it with your healthcare provider first, especially if you have osteoporosis or are at risk for bone loss. Confidence level: Moderate—the evidence shows a real but small effect.

Postmenopausal women concerned about bone health may find probiotics worth discussing with their doctor. People with osteoporosis or a family history of bone problems should talk to their healthcare provider before starting probiotics. Younger adults and men should know that we don’t yet have strong evidence that probiotics help their bone health. Anyone taking medications should check with their doctor before starting probiotics, as they can interact with some drugs.

If probiotics do help bone health, the benefits would likely take several months to become measurable. Most studies lasted 6-12 months, so you’d need to take probiotics consistently for at least this long to see potential benefits. Don’t expect dramatic changes—any improvements would be gradual and modest.

Want to Apply This Research?

  • Track daily probiotic supplement intake (yes/no) and note the specific strain and dose. Record any digestive changes, energy levels, and overall wellness feelings. While bone density changes require medical imaging to measure, tracking consistency helps ensure you’re giving the supplement adequate time to work.
  • Set a daily reminder to take your probiotic supplement at the same time each day (ideally with food). Pair this habit with other bone-healthy behaviors tracked in the app: daily calcium intake, vitamin D intake, weight-bearing exercise minutes, and sun exposure. This creates a comprehensive bone health routine rather than relying on probiotics alone.
  • Log probiotic use for 6-12 months consistently. Every 3 months, note any changes in digestive health, bloating, or overall wellness. Schedule annual bone density scans (DEXA scans) with your doctor to objectively measure whether your bone health is improving. Use the app to track all bone-health factors together so you can see which combination of habits correlates with the best results.

This research summary is for educational purposes only and should not replace professional medical advice. Probiotics are not approved by the FDA as a treatment for osteoporosis or bone loss. If you have concerns about your bone health, are at risk for osteoporosis, or are considering starting probiotic supplements, please consult with your healthcare provider or a bone health specialist. This is especially important if you are taking medications, have a medical condition, or are pregnant or breastfeeding. The findings presented here represent current research but should not be considered definitive medical guidance.