Australian researchers are challenging the notion testosterone is a "male" hormone that is bad for women.

Higher testosterone may actually protect older women from cardiovascular disease, a Monash University study released on Tuesday has found.

Researchers measured blood testosterone, dehydroepiandrosterone (DHEA) and oestrogen levels in thousands of healthy women over 70 with no prior cardiovascular disease events.

Older women with low blood testosterone and DHEA concentrations, but not low oestrogen, were found to have "twice the risk of a cardiovascular event" such as a heart attack or heart failure than those with higher testosterone.

"The apparent protective effects of testosterone and DHEA appeared to emerge early, with the higher three quartiles for each hormone tracking together," the research paper stated.

It is the largest prospective longitudinal study of its kind of women 70 and older and dispels the myth that a higher concentration of testosterone in the blood was associated with an increased risk of cardiovascular disease in older women.

"We need to stop thinking about testosterone as a 'male' hormone that is bad for women. It is an important human hormone for both women and men," study lead Professor Susan Davis said.

"Further research is needed to better understand testosterone action in blood vessels and the heart, including whether treating postmenopausal women with low testosterone protects against cardiovascular disease."

Blood testosterone levels drop by about 25 per cent over the course of a woman's reproductive years.

Before menopause, women's ovaries are the primary source of testosterone circulating in the blood.

However post-menopause, because ovaries stop functioning, blood testosterone is made from the hormone DHEA which comes from adrenal glands.

Studies in women younger than 70 have provided conflicting results, the research said.

Some studies have found higher levels of testosterone in younger women can carry an increased risk of heart disease and death, while others discovered no significant associations between the two.

Previous studies have been limited by deaths being reported many years after blood samples were collected, the paper said.

The study included 5535 Australian women aged at least 70, with no prior cardiac events and a life expectancy of at least five years.

Participants were chosen from 9180 women, who were recruited for an aspirin trial between 2010 and 2014.

The participants were primarily of European descent and as such the findings cannot be generalised to women of other ancestries.