Boston ? Long-term use of hormone replacement therapy, already shown to be bad for older women’s physical health, is found to be no panacea for their memory or mental outlook either.

In a challenge to popular belief, a large new study finds that estrogen and progestin pills fail to make older women feel better by improving their memory, sleep and sex lives.

The new results suggest this is nothing more than a placebo effect. The researchers conclude the pills are still an effective treatment for short-term relief from hot flashes and night sweats, but nothing else.

“The average woman will not experience an improvement in her quality of life by taking this pill,” said Jennifer Hays of Baylor College of Medicine, a psychologist who directed the analysis.

The results released Monday are another impressive reversal for what, until recently, was one of the most universally accepted treatments in medicine. Women typically begin taking combinations of estrogen and progestin to ease hot flashes and other miseries of menopause. But many keep taking them, often into their 60s and 70s, believing the drugs are good for their health and well-being.

Last year, however, data from the same study found the pills do more harm than good to women’s physical health. While hormone replacement decreases hip fractures and colon cancer, it slightly increases the chance of heart attacks, strokes and breast cancer.

Despite those findings, many women vowed to stick with hormone replacement because they felt it helps their memory and mood and generally made them think and feel better. The new report rejects that contention, too.

“There is a myth that hormone therapy improves quality of life, even in women without menopausal symptoms. This study dispels the myth,” said Dr. JoAnn Manson of Harvard’s Brigham and Women’s Hospital in Boston.

Experts now say the hormones’ only acceptable use is for the short-term relief of severe menopausal symptoms. For otherwise healthy women in their early 50s, the risks of this treatment are small and the benefits worthwhile. Last week, the Food and Drug Administration approved a new low-dose variety but urged it be taken for the shortest possible duration.

“There is no place for this treatment in women who are not having hot flashes. That simplifies matters a lot,” said Dr. Deborah Grady of the University of California, San Francisco, who was not involved in the study.