The drug, whose introduction would cost 50 to 80 pounds per year per person, may also help save the NHS hundreds of millions of pounds.
During the tests, it was found to help regrow bones, halve the number of hip fractures, and reduce spine fractures by almost two-thirds in the 8,000 postmenopausal women.
Californian biotechnology company Amgen, which is developing the drug, will announce the results of the international trials at the 30th annual meeting of the American Society for Bone and Mineral Research in Montreal this week.
Osteoporosis charities and medical experts have welcomed the findings.
"There are some treatments available and there is no doubt more people should be on them, but this drug really would be a big help to us," the Telegraph quoted Richard Eastell, professor of bone metabolism at Sheffield University, who led one of the British groups contributing to the Denosumab study, as saying.
"We would like to find something that actually prevents osteoporosis. This might be the drug," he added.
The researchers have revealed that Denosumab stimulates patients' immune systems to block a protein called RANK ligand, which triggers the breakdown of bone strength in osteoporosis sufferers.
Bone cells are regenerated in much the same way as skin cells, they say.
However, the drug does not work in half of middle-aged women, and one in five older men, it does not work, leading to brittle and fragile bones.
According to the researchers, women can regain 40 per cent of bone density by having an injection every six months in a process.
They say that such injections will be cheaper and easier to administer and have fewer side-effects than existing medicines.
The National Osteoporosis Society yesterday cautiously welcomed what is called an "exciting new treatment".
"This drug is not yet licensed for use, but when available, it will add to the choice of drug treatments available for people at risk of breaking a bone because of osteoporosis. However, patient safety is paramount and, as with any new drug to market, risks and side effects will need to be fully assessed," a spokesman for the charity said.