In the Women's Health Initiative, hormone therapy reduced hip fracture with a hazard ratio of 0.66, and 0.61 in the estrogen only arm. A 2025 Cochrane review found combined therapy reduced all clinical fractures with a relative risk of 0.78, and estrogen alone 0.73.
Of everything ever claimed for hormone therapy, fracture reduction is among the most solid findings in the entire dataset. It also happens to be the benefit nobody mentions.
Nothing hurts. Nothing shows in the mirror. There is no symptom to send you to a doctor, and that is exactly the problem, because the losing happens quietly and then one day a wrist breaks on a marble floor and the whole thing becomes retrospective.
The window, and why it is so easy to miss
Bone is living tissue, constantly broken down and rebuilt. Estrogen restrains the breakdown. When estrogen falls, the restraint goes and demolition runs ahead of rebuilding.
The timing surprises people. Bone loss begins during the transition, while you are still having periods, and the annual rate appears highest from about one year before the final period through to two years after it.
Which means you are losing it fastest during the years you are still calling it the change, and before any scan is normally offered. By the time a bone density scan is routinely suggested, that window has usually closed.
The number that gets misread
Bone density is measured by a short, low dose scan and reported as a T score, comparing you with a healthy young adult.
- Between -1.0 and -2.5 is low bone mass, often called osteopenia.
- At or below -2.5 is osteoporosis.
- A fracture from a fall from standing height or less diagnoses osteoporosis on its own, whatever the score says.
Here is the counterintuitive part that should change how you read your own result. Women at or below -2.5 have the higher individual risk. But more fractures happen in women whose score sits between -1.0 and -2.5, simply because far more women are in that group.
So a reassuring sounding just a bit of osteopenia is where most fractures are actually coming from. Being told not to worry about that number is not the same as being told your risk is low.
What hormone therapy does here
This is one of the few benefits proven in a large randomized trial rather than inferred, and the trial in question is the same one usually quoted to frighten women.
Beyond the fracture figures above, the PEPI trial randomized 875 women and measured them for three years. Bone density rose by 3.5 to 5.0 percent at the spine and 1.7 percent at the hip in every treatment group, while in the placebo group it fell by 1.8 and 1.7 percent. Observational data agree at scale: in the Million Women Study, over a million women, current users had a lower risk of any fracture with a relative risk of 0.62.
Three honest limits belong with that. Hormone therapy is not first line treatment for established osteoporosis; other medicines have the efficacy and long term data for that. But a woman already taking it for symptoms at an adequate dose usually does not need a separate bone medicine as well. And on stopping, the data genuinely conflict, though most studies show women who have taken estrogen in the past still have higher density than women who never did.
What else actually moves the needle
- Exercise, mostly by preventing falls. A meta analysis of 43 randomized trials in 4,320 postmenopausal women found exercise increased lumbar spine density by 0.85 percent. Small. But a meta analysis of 10 trials found exercise reduced overall fractures from 10.9 percent to 4.8 percent. The fracture benefit is far larger than the density benefit, because most fractures start with a fall.
- Stopping smoking. In female twins discordant for smoking, a pack a day through adult life was associated with 5 to 10 percent lower bone density.
- Calcium and vitamin D as a floor, not a treatment. If your diet already gets you there, supplements add nothing.
- What does not work: vitamin K, folate and B12, isoflavone supplements, fluoride, and whole body vibration platforms. Each has been tested. None is recommended.
A scan does not build bone. But it tells you how much time you have, and it turns an abstract argument into your own number, which is the only version of this that leads to a decision.
When a scan is worth having earlier
Earlier than the standard age based schedule if you have already had a fracture from a minor fall, an early menopause, a family history of hip fracture, low body weight, long term treatment with cortisone type medicines, or a condition affecting absorption such as coeliac disease. It is also the right move before deciding about hormone therapy.
This site runs no scanner and no laboratory. What sits behind the consultation is a network built over a career, so that when a scan or a test is genuinely needed, you are directed to someone who does it properly and the result is read in the context of everything else about you.
If you are inside that window now, this is the moment it is worth acting on. Take it to the specialist and find out where your bones actually stand.