Despite the positive effects of hormone replacement therapy, in 2002 the Women’s Health Initiative (WHI) Study reported that hormone therapy for women was related to a 24% increased risk for invasive breast cancer, with no major beneficial effects against cardiovascular disease, stroke, and thromboembolic diseases. Within three months of the publication of this report, 63% of women stopped taking hormone replacement therapy.

The problem was that the WHI study used oral conjugated equine estrogen and synthetic progesterone in women long after menopause onset (the average age of participants was 63 years). For women aged 50 to 59 years in the WHI study, hormone therapy did not increase cancer or cardiovascular deaths after a median of 18 years’ follow-up compared with women not taking hormones. With estrogen alone, mortality related to breast cancer, Alzheimer’s disease, or dementia was reduced!

Nonetheless, the fear of breast cancer from hormone replacement therapy became so widespread that misinformation is still common 20 years later. And worse, most physicians practicing today received little if any training on menopause or menopause hormone therapy. This situation has resulted in a lack of credible health information for women at midlife. For an overview, see this in-depth New York Times article.

Fortunately, menopause and hormone therapy have gained more attention in recent years and misinformation is slowly being replaced. As evidence of this change, the US FDA initiated removal of the misleading “black box” warnings on hormone replacement therapy products in late 2025.

Many people who think of testosterone as a “male” hormone are surprised to find that women normally produce 3-4 times more testosterone than estrogen! Testosterone is linked to sexual desire and arousal, but also to mood, energy level, and general wellbeing. Testosterone acts on androgen receptors found in the brain, heart, blood vessels, bones, muscles, breasts, skin, bladder, and vagina. It works with estrogen to maintain bone and muscle mass. Testosterone level decreases over a woman’s lifespan, not just at menopause.

Despite its importance, testosterone deficiency in women has received very little research attention and few products address female testosterone replacement. In all countries (other than Australia and S. Africa), there are no licensed testosterone products available for women. Usually, a smaller dose of an approved transdermal male formulation (prescribed off-license) is recommended. But many physicians do not support treating testosterone deficiency in women. This all stands in sharp contrast to the attention paid to “Low T” in men.

Some believe that supplementing with testosterone causes side effects such as excess hair growth, breast cancer, or cardiovascular disease. But testosterone therapy aims to treat a deficiency, while keeping levels within the physiological range, which should not result in “masculinization.” Research on testosterone therapy in women is limited, but shows promise in improving sexual function and urinary tract health, as well as benefiting bone density, muscle mass, mood, energy, and cognitive function. Studies of transdermal testosterone have not found increased incidence of heart disease, stroke, venous thromboembolism, cardiovascular death or increased blood sugar or blood pressure. More frequent administration, as with daily transdermal testosterone cream or gel, may also have lower serum testosterone fluctuation compared to less frequent applications such as testosterone pellets.

Testosterone has not been associated with increased cancer risk and may even reduce the chance of developing breast cancer. Some research also reports that testosterone can have anti-cancer effects when used with traditional breast cancer treatments (see Hormones after breast cancer section below).

The International Society for the Study of Women’s Sexual Health provides standards for prescribing testosterone to women. Transdermal application is likely the safest and most studied, but it is available as pellets and injections as well. Keep in mind that until the FDA and other regulatory bodies approve testosterone products for women, you will likely rely on compounding pharmacies for testosterone.

The best action you can take is to arm yourself with accurate information about menopause and hormone therapy. There are good resources that can be helpful to understand the facts about menopause and research on hormone replacement. See Additional Resources below for more information.

Discuss menopause and hormone treatment with your physician, keeping in mind that you may have to search for a physician who has training and experience in this area. In the U.S., you can check the The Menopause Society’s website for trained providers.

Don’t assume that menopause hormone treatment is out of the question if you have been diagnosed with breast cancer. It’s critical to evaluate your risks vs the benefits of hormone replacement therapy with your physician.