Why Calcium and Vitamin D Alone Don't Lower Your Fracture Risk

What did the largest calcium and vitamin D analysis ever run find?

Zhao and colleagues published the analysis in JAMA in 2017. It pooled 33 randomized trials and 51,145 community-dwelling adults over 50, making it the biggest fracture analysis of these two supplements ever assembled. The result surprised a lot of people who had spent decades being told to simply take more calcium.

None of the three approaches significantly lowered hip fracture risk. Calcium alone carried a relative risk of 1.53, statistically no different from placebo. Vitamin D alone came in at 1.21, also not significant. Calcium and vitamin D combined, the standard advice given in nearly every doctor's office, landed at 1.09, still not significant. The null result also held for nonvertebral, vertebral, and total fracture, not just the hip.

What makes this hard to dismiss is what the authors checked next. The result held regardless of the dose used, the sex of the participant, whether someone already had a fracture history, how much calcium was already in their diet, and their starting vitamin D level. The authors' own conclusion was blunt. Their findings, they wrote, "do not support the routine use of these supplements in community-dwelling older people."

Why this is written as "adults," not "women"

Neither trial in the pool was restricted to women, and neither enrolled only people who were already deficient. This is a population-wide finding about supplementing on top of an already-adequate baseline, not a statement about what happens in someone who is genuinely short on calcium or vitamin D. We are careful about that distinction throughout this piece, because it is the honest one.

Did the government's own vitamin D trial find anything different?

No. LeBoff and colleagues ran the VITAL trial, published in the New England Journal of Medicine in 2022, specifically to test vitamin D on its own against real fractures in a large, well-controlled group. It randomized 25,871 adults to 2,000 IU of vitamin D3 daily or placebo. Participants were not selected for deficiency, low bone mass, or a prior osteoporosis diagnosis, so this was a test of everyday supplementation, the exact scenario most people are in.

The paper's own sentence says it plainly. "Vitamin D3 supplementation did not result in a significantly lower risk of fractures than placebo."

Two trials. Seventy-five thousand people combined. Neither found a fracture benefit from adding more of the two nutrients most associated with bone health.

Why doesn't more calcium fix a body that has stopped listening to it?

Bone is not a static warehouse of mineral that simply needs restocking. It is living tissue, constantly being broken down and rebuilt by two cell types working in balance, osteoclasts that clear old bone and osteoblasts that lay down new bone. Before menopause, estrogen keeps that balance tilted toward rebuilding. After estrogen falls, the signal that tells osteoblasts to keep building weakens, and the clearing side starts winning by default.

Adding more calcium to that system is a little like restocking a warehouse whose loading crew went home. The material sits there. Nothing tells the body to actually use it for construction rather than simply pass it through.

A few things determine whether extra calcium ever becomes new bone rather than passing straight through the body:

• Whether the hormonal signal that activates osteoblasts is still present
• Whether the existing collagen scaffold bone is built on is intact enough to mineralize onto
• Whether inflammation in the joint and bone environment is high enough to interfere with normal remodeling
• How much of the calcium taken is actually absorbed in the gut, versus excreted unused
• Whether vitamin D levels are adequate enough to matter at all, which for most people not already deficient, they already are

Why vitamin D alone can't replace the signal either

Vitamin D's real job is helping the gut absorb calcium efficiently. It is a delivery cofactor, not the construction signal itself. Someone who is not deficient already has enough of that cofactor working. Adding more vitamin D on top of an adequate level does not create a new rebuilding instruction, which is consistent with why the VITAL trial, run in a largely non-deficient population, came back null.

What did the shilajit trial measure instead?

Pingali and colleagues ran a 48-week, double-blind, randomized controlled trial in 60 postmenopausal women. This is the detail most summaries miss. Baseline DEXA scans showed osteopenia at the lumbar spine, a T-score of negative 2.0, and the paper's own results section labels the femoral neck reading, negative 2.5, as osteoporosis. These were not healthy volunteers taking a supplement for insurance. They were women with measurably thinning bone at two sites.

Shilajit increased bone mineral density at both the spine and the hip in a dose-dependent way, meaning higher doses moved the number further. The placebo group kept losing density across the same 48 weeks. By the six-month mark, every single woman in the treatment group had reversed her hip osteoporosis finding. No serious side effects were reported.

The trial tracked several outcomes across the 48 weeks:

• Bone mineral density at the lumbar spine
• Bone mineral density at the femoral neck, the hip measurement that carried the osteoporosis reading
• Whether the improvement scaled with the dose given
• Adverse events, of which there were none serious enough to report
• How the placebo group's bone density changed over the same window, which is what makes the comparison meaningful

This was not a fracture-prevention trial. It measured the density number a DEXA scan actually reports, over a much shorter window than the multi-year fracture trials above, in a much smaller group. It answers a different, narrower question. Can already-thinning bone turn around? In this one trial, the answer was yes.

How does a rebuilding signal compare to a mineral supply, side by side?

Reading this table straight, the two supplement categories were tested for two different things. Calcium and vitamin D were tested against real fractures over years, in tens of thousands of people, and came back null. Shilajit was tested against the density number itself, over months, in a much smaller trial, and moved it. Neither fact cancels the other out. They are simply answers to different questions, and the honest version says so.

What should you actually look for in a bone supplement?

The research above points toward a specific set of questions worth asking before adding anything new to a bone routine, rather than assuming more of what you already take will move the number.

• Does it address the hormonal signaling behind bone remodeling, or only the raw material
• Was it tested in a randomized, placebo-controlled trial, not just an open-label pilot
• Was the population studied similar to your own situation, postmenopausal, already showing density loss
• Does the company publish third-party lab testing for heavy metals on every batch
• Is the sourcing traceable to a specific place, rather than a generic, unnamed origin

Optimum Shilajit is sourced from the Altai mountains, purified, and lab tested for heavy metals on every batch, with the report published for anyone to read. It is built around the Pingali trial above, and around the honest reading of what that trial does and does not show. Optimum Shilajit is the product this research supports.