Campaigners say draft NHS plans look like condemning some women to a future of "pain and misery" by denying them access to vital osteoporosis drugs.
Osteoporosis sufferers are likely to break bones
The National Osteoporosis Society has criticised National Institute of Health and Clinical Excellence bisphosphonates and strontium ranelate recommendations.
The treatments stop or increase bone density for post-menopausal women.
There are no restrictions on their use at the moment, but NICE has recommended they only be used for women over 75.
Osteoporosis literally means "porous bones" and makes it more likely for them to fracture as they lose their density.
Over 1m women in the UK have been diagnosed with the disease, although experts say many more probably suffer from the condition.
The drugs are used as a precautionary, or primary prevention, measure - to decrease the risk of a bone fracturing if a woman is deemed at risk because of low bone density and other factors such as family history of the disease.
The NICE draft guidance, which is subject to a four-week consultation, is the first time the drugs have been subject to recommendations from the NHS advisory body.
It means to date, post-menopausal women of all ages have effectively had access to the drugs for primary prevention if they were considered at risk.
But the draft recommendations - which are an update on previous draft guidance - say only women over 75 and deemed at risk should get access to them.
NICE is also making recommendations on drugs used once a woman has had fractured bones and diagnosed with fragile bones.
It will mean the under 65s will have better access to scans and women in the 55 to 64 age group will be given access to teriparatide, a much more powerful drug, when they have had three or more fractures. It is currently available only for women over 65.
Angela Jordan, deputy chief executive of the National Osteoporosis Society, said: "These recommendations look set to leave women under 75 without a treatment to prevent the first broken bone.
"Nice is missing a vital opportunity to protect future generations from the pain and misery that broken bones can cause."
NICE public health director Professor Peter Littlejohns said the guidance has been designed to give doctors the "most appropriate and cost effective drugs to prescribe".
"The process that NICE follows is genuinely consultative and we welcome feedback."