Does HRT help with hot flushes? About 75% fewer, reviews agree

HRT does help with hot flushes, and the size of the effect is consistent across independent reviews. Oestrogen, taken on its own or combined with a second hormone called a progestogen, reduces how often hot flushes and night sweats happen by about 75% [7]. Doctors group those two complaints together as vasomotor symptoms: the sudden heat, flushing and sweating that come when the body's temperature control goes briefly out of calibration. American studies call them hot flashes. No review has found a more effective treatment for them [7][8][13].

Between 50% and 75% of women get hot flushes, night sweats or both during the menopause transition, and they typically run for more than seven years [7]. That is longer than most people expect. The worst of it is usually the first four to seven years, though for some women the symptoms carry on past a decade [8].

The risks of menopausal hormone therapy are real, and small in absolute terms. Only one set of trials was designed to measure them, and it tested conjugated equine oestrogens, the older oestrogen tablet, with or without a synthetic progestogen called medroxyprogesterone acetate. That tablet raised the rate of stroke and of blood clots in the veins, and the combined version raised breast cancer, each by roughly one extra case per 1,000 women for every year of use [7]. One variant showed no breast cancer increase at all: a low dose of that oestrogen paired with a drug called bazedoxifene in place of a progestogen gave about 2.5 cases per 1,000 women a year, against 2.3 on a dummy tablet [7].

For women under 60 who start within 10 years of their last period, reviews judge the benefit-to-risk balance generally favourable [8]. The alarm raised by the early-2000s trials came largely from women who were over 60, or more than a decade past menopause, when they began [2][8]. Route makes no difference to relief: tablets and skin patches ease hot flushes about equally well [7]. It does make a difference to risk, because oral oestrogen, the older conjugated type in particular, carries more clot and stroke risk than oestradiol, the main oestrogen the ovaries make, absorbed through the skin [13].

Sleep is the murkiest part. Menopausal sleep disturbance is mostly frequent night-time waking and more time spent awake once you have nodded off, and no treatment is approved specifically for it [11]. The broken sleep comes partly from night sweats and partly from hormone and mood changes in their own right, so clearing the flushes helps some women and not others [11].

Hot flushes begin with the ovaries stopping production of oestrogen, but the symptom itself is generated in the brain [5]. Oestrogen acts there as a broad control signal through a network of receptors, and the systems it helps regulate include body temperature, sleep, the day-night clock and sensory processing [9]. That is why the complaints of the menopause transition feel neurological, not gynaecological.

Those functions share circuitry. The same neuronal circuits handle reproduction, body temperature, sleep and mood together [11], so when the oestrogen signal that helps tune them falls away, temperature regulation is one of the systems that drifts [9][11].

The loss is also not smooth, which shapes how the treatment is given. Through perimenopause, the years of irregular periods before they stop for good, oestrogen swings widely instead of simply declining, and the brain's responsiveness to those swings changes as well [2]. Holding the level steady is what helps some linked problems: migraine attacks set off by oestrogen withdrawal improve in a stable oestrogen environment, while progestogens given in cycles rather than continuously can make migraine worse [3].

Oestrogen loss is not the whole story. Reviews of the underlying physiology state plainly that the basis of menopausal symptoms is related to, but not limited to, oestrogen deprivation [10], and one account describes the oestrogen receptor network becoming uncoupled from the brain's energy metabolism during the transition [9]. That gap is part of why replacing the hormone deals with flushes more cleanly than with every other symptom of the transition [11].

The 75% figure comes from reviews pooling trials, not from one clean experiment, and most of the risk numbers rest on a small set of trials from the early 2000s testing one older oestrogen tablet, with or without one synthetic progestogen [1][7]. Newer formulations, oestradiol through the skin and different progestogens, have not been put through trials designed the same way, so their risk is inferred from how they behave in the body, not measured in outcomes [13].

Risk belongs to the specific regimen, not to hormone therapy as a whole. Breast cancer risk looks neutral to favourable with oestrogen alone after a hysterectomy and rises with longer use of combined therapy [13]; clot and stroke risk varies with which progestogen is used [13]. The absolute risk of ovarian cancer stays small, and the evidence on bowel cancer is mixed [13].

The evidence does not apply to everyone:

• women who have had breast cancer - a consensus panel of 18 senior doctors concluded that oestrogen replacement is not recommended after a breast cancer diagnosis because it can raise the chance of relapse [12]
• women over 60, or more than 10 years past their last period, when starting - this is the group the original safety alarm came from, and reviews do not extend the favourable balance to them [2][8]
• women whose menopause followed cancer treatment - what evidence exists is drawn mostly from women over 50 with breast cancer [4]
• anyone hoping for heart protection - cardiovascular prevention is explicitly not an indication [13]

The two sources on cancer survivors do not fully agree, and the disagreement is the honest answer here. One review concludes menopausal hormone therapy seems safe for many patients with cancer, and that vaginal oestrogen, used locally, appears safe for most women with genitourinary symptoms [4]. The breast-cancer-specific panel advises against systemic oestrogen after that diagnosis [12].

Hormone therapy is prescription treatment. Which oestrogen, which route, whether a progestogen is needed, and when to stop are decisions made with a doctor who can weigh your own history [1][15].

Menopausal hormone therapy is mainstream prescription medicine, usually handled by a GP or a gynaecologist, and it is also one of the services longevity clinics list: dozens of the clinics in the Longevinsights directory offer hormone optimisation, which covers menopausal hormone therapy alongside testosterone and thyroid treatment.

A first consultation is mostly conversation. The published clinical algorithms have the practitioner establish why you have come, where you are in the transition, your personal and family history, and then work through hormonal and non-hormonal options as a shared decision [15]. Menopausal status is judged largely from your symptoms and cycle pattern, because hormone levels swing too widely during perimenopause for a single blood test to settle it [2][15]. If you still have a uterus, systemic oestrogen has to be paired with a progestogen or with bazedoxifene to protect the womb lining, so that constraint is clinical, not commercial [1].

Two things to know before the appointment. Vasomotor symptoms are substantially undertreated, so the subject is worth raising yourself if nobody else does [8] - and heart-disease prevention is not a legitimate reason to be started on it [13].