You may have heard of blood tests called P1NP and CTX that measure “bone turnover”. This explains what they can and cannot tell you — especially if you are making lifestyle changes for your bones around the menopause.
They measure how fast your bone is being renewed right now. Bone is living tissue that is constantly broken down and rebuilt. CTX is a marker of the breaking-down side; P1NP a marker of the building-up side. Importantly, they measure the speed of renewal — not how much bone you have. Only a DXA scan measures the amount of bone.
Checking that an osteoporosis medicine is working. Because they change within weeks rather than the years a scan needs, they are useful for one job: confirming that a bone medicine is having its effect, and that it is being taken correctly. That is what they were designed and tested for.
They are very changeable. CTX in particular swings with the time of day and drops sharply after eating, so the blood must be taken in the morning, before food, at the same laboratory each time. Levels also shift after a recent fracture, with kidney function and with the seasons. A change has to be quite large — roughly a quarter to a third — before it means anything real.
Honestly, not reliably for one person. The improvement in bone from diet and exercise is usually small — often smaller than the test’s own natural wobble. So in an individual it is very hard to tell a real change from background noise, and a small swing can give false reassurance or false alarm. These markers are far better suited to research studies and to medicine monitoring than to tracking your own progress.
P1NP and CTX are reliable for one main job: checking whether an osteoporosis medicine is working and being taken. For telling an individual woman whether her diet and exercise are helping her bones, their natural wobble usually drowns out the small signal — so they are not a dependable personal scorecard. If you have them done, do them properly and read them with your doctor.
This is a summary report from the IIMHE Educational Directorate and is not individual medical advice. Do not start, stop or judge any treatment on the basis of a single blood marker — discuss testing and results with your primary care physician or a bone specialist. · IIMHE, June 2026
2nd February 2026 @ 20:00 GMT
Nutrition and musculoskeletal health
Given by: Dr Kimberley Zambito, Orthopaedic Consultant
Hosted by: Dr Nick Birch
Throughout 2026 and beyond, IIMHE (the International Institute of Musculoskeletal Health Education), in partnership with OsteoscanUK, will host a series of engaging educational webinars, open to anyone interested in bone and musculoskeletal health.
