Bringing testosterone levels up to normal for women who lose ovarian function owing to early natural menopause or hysterectomy is of no good, shows research.

Before age 40, ovaries stop functioning in about 1 percent of women without some obvious genetic abnormality to blame, bringing on an early menopause.

Called 'primary ovarian insufficiency' or POI, the condition can spell not only infertility and other physical problems but also depression and decreased quality of life.

Adding back lost estrogen and progesterone helps.

But ovaries normally produce testosterone too which has mental and physical effects.

According to a study by the National Institutes of Health Clinical Center in Bethesda, Maryland, adding testosterone for women who lose ovarian function have not yielded consistent results.

In the controlled study, 61 women used placebo patches and 67 women used patches that delivered 150 micrograms of testosterone a day.

After 12 months, testosterone levels were back up to normal for the women who got the treatment.

The researchers saw no detrimental effects of testosterone but they found no significant improvement either in measurements of quality of life, self esteem and mood compared with placebo, said the study published in Menopause, the journal of The North American Menopause Society (NAMS).

"Bringing testosterone back to normal doesn't help these aspects of life, suggesting that it's something other than testosterone that plays a role in mood problems for women with POI," said researchers.

"This study makes an important contribution toward understanding what testosterone can and cannot do," added NAMS executive director Margery Gass.