Last week, I saw a 51-year-old woman in the clinic with fatigue, mood changes, body aches, poor sleep and bouts of night sweats. Routine tests were normal. “Doctor, there is something wrong with me, but no one seems able to diagnose it,” she said. Her periods had stopped a year earlier. It was clear that she might benefit from estrogen replacement. The real question was whether she should receive it, and whether it would be safe.
That question is worth asking more often, because estrogen is one of medicine’s most misunderstood hormones. Most people still think of it simply as a female sex hormone, but that narrow label hides its wider importance. Estrogen shapes puberty, menstrual function, fertility, bone strength, brain health, skin, and even the heart and blood vessels. The term itself was coined in 1906, from Greek roots referring to desire and production.
Estrogen first enters everyday conversation at puberty, when it helps the breasts develop, brings on menstrual cycles, and supports the reproductive system.
It also influences how body fat is distributed and how bones grow. Later in life, it continues to act far beyond reproduction, helping maintain bone density, influencing mood, and supporting the lining of the genital and urinary tract.
Like all hormones, estrogen is a chemical messenger that acts far from its main source. In women, the ovaries are the principal producers, but the adrenal glands and body fat also contribute small amounts. In men, too, estrogen is made in modest quantities when enzymes convert androgens such as testosterone into estrogen; this matters particularly for bone health.
Estrogen levels are not fixed. They rise during puberty and decline as menopause approaches. They rise during ovulation to prepare the body for pregnancy and rise again during pregnancy, peaking in the third trimester, only to fall dramatically after childbirth.
During pregnancy, estrogen plays multiple roles: It promotes foetal development, growth of the uterus, blood flow to the placenta, and breast development.
Menopause, what my patient was going through, marks the time when ovarian estrogen production declines. With that fall comes a familiar cluster of symptoms — hot flashes, night sweats, sleep disturbance, vaginal dryness, painful intercourse, low mood and urinary complaints.
The long-term consequence that often receives less attention is bone loss. Estrogen helps keep calcium in bone; when estrogen falls, bone breakdown accelerates, increasing the risk of osteoporosis and fractures.
Estrogen deficiency can also occur before natural menopause. It may follow removal of the ovaries, certain cancer treatments, premature ovarian insufficiency, or severe stress on the body from extreme weight loss, excessive exercise or chronic illness. In these settings, the hormonal effects can be even more abrupt and disruptive than after natural menopause.
The idea of using estrogen to ease menopausal symptoms is not new. In the late 19th century, studies using ovarian tissue from cows suggested relief in women with menopausal symptoms and sexual dysfunction. Later, estrogen was extracted from the urine of pregnant women and then from the urine of pregnant mares, which became the source of Premarin, a preparation that is still used in clinical practice.
For women with troublesome hot flashes or vaginal symptoms, estrogen therapy can be highly effective. Local vaginal estrogen is usually enough for dryness and urinary discomfort, while systemic therapy — tablets, patches or gels — is used when symptoms are broader and affect daily life. Hormone therapy remains the most effective treatment for vasomotor symptoms, and local therapy is preferred when symptoms are limited to the genitourinary tract.
This brings us to the difficult question: If estrogen helps so much, why not prescribe it to every woman at menopause? The answer is that every medical intervention has potential side effects, and estrogen is no exception. The main concerns are breast cancer risk in certain settings, blood clots and, with some formulations, stroke.
Risk depends on age, timing, formulation and route of administration; transdermal estrogen is generally associated with a much lower clot risk than oral therapy.
Timing matters. Hormone therapy tends to be most favourable within five-to-10 years of menopause onset, when symptom benefit is greatest and the risk-benefit balance is usually better. Starting later, particularly after age 60 or after a long gap from menopause, is generally not recommended unless there is a compelling reason and careful supervision.
There are also situations where estrogen therapy should be avoided or approached with caution. A history of breast cancer, unexplained vaginal bleeding, active liver disease, prior blood clots, stroke, heart attack or certain heart conditions can change the balance of risk. In women with a uterus, estrogen must also be paired with a progestogen to protect the lining of the uterus.
For bone health, the message is equally important. Estrogen preserves bone health, but not every menopausal woman needs it. Lifestyle measures, adequate calcium and vitamin D, weight-bearing exercise and fracture-risk assessment remain essential. In women at high fracture risk, osteoporosis medicines may be added rather than estrogen alone.
My patient’s story is a common one, and a reminder that menopause is not merely the absence of periods. It can be a period of real physiological change, with symptoms that are easy to dismiss and easy to miss. A careful history, thoughtful examination and appropriate tests often reveal that the problem is not “in the mind” at all, but in the endocrine transition itself.
A better way to think about estrogen is not as a hero or a villain, but as a powerful biological signal whose benefits and risks depend on context. Used wisely, it can relieve symptoms, protect bone and improve quality of life. In that sense, estrogen therapy may improve “healthspan” more than lifespan. The goal is not to give hormones to everyone, but to give the right treatment to the right woman at the right time.
Ambrish Mithal is chairman and head of endocrinology and diabetes at Max Healthcare. The views expressed are personal
