Hot flashes and night sweats: what is happening and which treatments can help

At a Glance

• Hot flashes are linked to a change in temperature regulation in the brain, under the influence of fluctuating and declining estrogen levels.
• They can begin during perimenopause, while menstrual periods are still present and sometimes regular.
• Their duration is often longer than many people expect: several women experience them for seven years or more.
• Some differences have been observed across ethnoracial groups, but they cannot be explained by biology alone.
• Hormone therapy remains the most effective treatment when it is appropriate.
• Several evidence-based nonhormonal options are also available.

A sudden rush of heat rising to the face and upper body. Sweating that appears without warning. Waking in the middle of the night with damp clothes or sheets.

Hot flashes and night sweats, also called vasomotor symptoms, are among the most common manifestations of the menopause transition. They affect an estimated 70 to 80% of women, but their frequency, intensity, and impact vary considerably. For some, they remain occasional. For others, they disrupt sleep, work, concentration, mood, and quality of life for several years.

They are neither imaginary nor simply caused by "being too warm." They result from real changes in the brain mechanisms that regulate body temperature.

What is a hot flash?

A hot flash is a sudden sensation of heat, usually felt in the face, neck, chest, or upper body. It may be accompanied by flushing, sweating, palpitations, brief anxiety, or a feeling of cold when the episode ends.

Most last a few minutes, but their frequency can range from a few episodes a month to several episodes a day.

When they occur during sleep, they are generally called night sweats. Some women are awakened by the sensation of heat itself. Others realize an episode has occurred only when they wake up with damp clothing or bedding.

Night sweats can fragment sleep repeatedly. Even when awakenings are brief, their accumulation can contribute to fatigue, irritability, difficulty concentrating, and the feeling of never fully recovering.

Why do hot flashes occur?

It is often said that hot flashes are simply caused by an "estrogen deficiency." That explanation is incomplete.

During perimenopause, estradiol levels do not necessarily decline in a steady way. They can fluctuate markedly, with unpredictable rises and falls. Over time, ovarian estrogen production becomes less consistent, then declines further after menopause.

These changes influence a network of neurons in the hypothalamus, a brain region involved in temperature regulation. This network includes the so-called KNDy neurons, which use kisspeptin, neurokinin B, and dynorphin as chemical messengers. When estrogen exposure decreases, the activity of this system changes, particularly neurokinin B signaling.

The brain then appears to tolerate a narrower temperature range than before. A very small rise in core temperature, which would normally go unnoticed, can be interpreted as an urgent need to lose heat.

The body then rapidly triggers its cooling mechanisms:

• blood vessels near the skin dilate;
• heat rises to the face and upper body;
• sweating increases;
• heart rate may accelerate;
• a feeling of cold or shivering may follow as temperature falls again.

The newer medications that block certain neurokinin receptors were developed directly from this more precise understanding of the pathophysiology.

How long can the symptoms last?

Hot flashes can appear several years before the final menstrual period. They therefore do not begin only once menopause is confirmed.

According to INESSS, the clinical manifestations linked to perimenopause and postmenopause persist on average for four to seven years, but may last fifteen years or longer in some women. Among these, vasomotor symptoms are among the most common.

In the U.S. SWAN study, which followed women from different ethnoracial groups through the menopause transition, the median total duration of frequent hot flashes was 7.4 years. In women whose symptoms had begun before the final menstrual period, the duration was generally longer.

These figures are population averages, not individual predictions. One woman may experience symptoms for a few months, while another continues to have them for many years.

There is therefore no need to wait in the hope that they will disappear quickly when they are already interfering with sleep, daily functioning, or quality of life.

Why are some women more affected than others?

The frequency and persistence of hot flashes are influenced by several factors. Studies have observed associations with:

• earlier onset of symptoms in the menopause transition;
• smoking;
• higher stress levels;
• symptoms of anxiety or depression;
• certain differences in body composition;
• social and economic conditions;
• overall health status;
• the way symptoms are perceived, interpreted, and reported.

These associations do not mean that a woman is responsible for her symptoms or that she could necessarily make them disappear by changing her habits.

Are there differences by ethnoracial origin?

Differences have been observed among the groups studied, particularly in U.S. cohorts.

In the SWAN study, Black women reported, on average, more frequent and more persistent symptoms. The median duration of frequent vasomotor symptoms reached about 10.1 years among Black participants, compared with shorter durations in the other groups studied.

These findings must nonetheless be interpreted with nuance.

Racial and ethnic categories do not represent homogeneous biological groups. The observed differences cannot be reduced to a genetic or hormonal explanation. They may reflect a complex interaction among several factors:

• exposure to chronic stress;
• experiences of discrimination;
• socioeconomic inequalities;
• working and housing conditions;
• comorbidities;
• smoking and other exposures;
• cultural differences in recognizing and reporting symptoms;
• access to appropriate assessment and treatments.

SWAN researchers notably emphasize that structural racism and inequalities accumulated over the life course may contribute to the health gaps observed between Black and White women.

Most of these data also come from the United States. They cannot be automatically applied to all women or to the Quebec population. They nevertheless underscore the importance of not dismissing symptoms and of taking social, cultural, and individual context into account in clinical assessment.

Is it always perimenopause or menopause?

Typical hot flashes that appear during the menopause transition can often be recognized from age, changes in menstrual cycles, and associated symptoms. In women aged 45 and older, hormone blood tests are generally not needed to establish that the symptoms are related to the menopause transition.

A more thorough evaluation may nonetheless be warranted when the episodes:

• begin at an unusually young age;
• appear suddenly after a long symptom-free period;
• are accompanied by fever, unexplained weight loss, or significant malaise;
• are associated with persistent palpitations, tremor, or other unusual symptoms;
• occur after a medication is started or changed;
• do not match the usual picture of a vasomotor symptom.

Certain medical conditions, medications, alcohol, infections, thyroid disorders, or other causes can produce sensations of heat or night sweats. The goal is not to multiply tests in every woman, but to recognize situations in which another explanation deserves to be explored.

What options can reduce hot flashes?

Treatment depends above all on how frequent the symptoms are, how intense they are, and how much they affect daily life.

A woman who has an occasional mild hot flash does not necessarily need treatment. By contrast, symptoms that interrupt sleep, complicate work activities, or require several clothing changes a day may justify a more active approach.

When hormone therapy is being considered, INESSS recommends an individualized decision that takes into account medical history, risk factors, preferences, treatment goals, and effects on quality of life.

Comfort measures

Some simple strategies can make episodes more tolerable:

• wearing layers that are easy to remove;
• using a fan;
• keeping the bedroom cool;
• choosing breathable bedding;
• keeping a change of clothes nearby;
• noticing whether alcohol, hot drinks, or spicy foods regularly trigger episodes.

These measures can improve comfort, but they do not necessarily change the brain mechanism responsible for the symptoms. Studies have not consistently shown that cooling techniques or general trigger avoidance reduce the frequency or intensity of hot flashes.

There is therefore no need to impose a long list of prohibitions. It is generally more useful to identify the triggers that seem reproducible for a particular person.

Hormone therapy

When appropriate, menopausal hormone therapy remains the most effective treatment for hot flashes and night sweats.

Treatment usually relies on a systemic estrogen. In a woman who still has her uterus, a progestogen generally needs to be added to protect the endometrium. After hysterectomy, estrogen alone can usually be used.

Within the INESSS framework, the choice of treatment should take into account, among other things:

• age and stage of the menopause transition;
• whether or not the uterus is present;
• personal and family history;
• cardiovascular and thromboembolic risk;
• migraines;
• smoking;
• blood pressure;
• the patient's preferences;
• other symptoms that need treatment.

In women with certain thromboembolic or cardiometabolic risk factors, such as obesity, smoking, migraines, hypertension, dyslipidemia, or type 2 diabetes, transdermal estradiol may be preferred because it avoids first-pass metabolism through the liver.

Treatment is generally started at a low dose, then adjusted according to response and tolerability. About six to eight weeks may be needed to properly assess the effect of a given dose. The goal is not to use the smallest possible dose automatically from the outset, but to find the lowest dose that adequately controls symptoms, then to reassess needs periodically.

Hormone therapy is not suitable for every woman, however. A history of certain hormone-dependent cancers, thrombosis, stroke, cardiovascular or liver disease, as well as unexplained uterine bleeding, may change the options or require specialist assessment.

The presence of a risk factor does not always mean that hormone therapy can never be considered. It means rather that the decision requires a more individualized analysis of benefits, risks, route of administration, and alternatives.

Prescription nonhormonal treatments

Nonhormonal treatments may be considered when a woman:

• does not wish to use hormone therapy;
• has a contraindication;
• experiences adverse effects;
• obtains insufficient relief;
• prefers an option that also targets another problem, such as anxiety, depression, or neuropathic pain.

They are not all equivalent, and their efficacy is generally more modest than that of hormone therapy. Some can nonetheless provide meaningful relief.

SSRIs and SNRIs

Certain selective serotonin reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors can reduce the frequency and intensity of vasomotor symptoms.

Depending on the medication chosen, they may be particularly relevant when a woman also experiences anxiety, low mood, or certain pain symptoms. A diagnosis of depression is not required for one of these medications to be used for hot flashes.

Possible adverse effects include nausea, sleep changes, sexual effects, or blood-pressure changes, depending on the product. In women taking tamoxifen, some medications—particularly paroxetine and fluoxetine—can interfere with its metabolism and are generally not first choices.

Gabapentin

Gabapentin can reduce vasomotor symptoms and may be especially useful when night sweats and awakenings are the main concerns.

Because it can cause drowsiness, dizziness, or unsteadiness, evening dosing may sometimes be considered. Those same effects can, however, limit its use in some people.

Oxybutynin

Oxybutynin, a medication also used for overactive bladder, can reduce hot flashes in some women.

It can, however, cause dry mouth, constipation, blurred vision, or other anticholinergic effects. Longer-term use requires more caution, particularly with advancing age or when there are cognitive concerns. It is therefore not necessarily a first-line option despite its possible efficacy.

Neurokinin receptor antagonists

This newer class of medications acts directly on the brain circuits involved in temperature regulation. It does not contain hormones.

Two medications in this class are now authorized in Canada for the treatment of moderate or severe vasomotor symptoms associated with menopause:

• fezolinetant (Veozah), an NK3 receptor antagonist, authorized by Health Canada in December 2024;
• elinzanetant (Lynkuet), an NK1 and NK3 receptor antagonist, authorized in July 2025.

Phase 3 trials have shown that these medications can reduce the frequency and intensity of vasomotor symptoms. Improvements in sleep and quality of life have also been observed in some trials.

Their profile differs from that of hormone therapy, but "nonhormonal" does not mean free of risks or monitoring requirements.

Fezolinetant requires particular attention to liver health and blood tests in accordance with its product monograph. Elinzanetant may be associated with drowsiness, dizziness, fatigue, or digestive symptoms and may interact with certain medications. Market authorization does not guarantee uniform pharmacy availability; cost, insurance coverage, and real-world access to the treatment can vary and should be considered.

Because these medications are relatively new, very long-term clinical experience remains less extensive than for several older treatments.

Clonidine

Clonidine has previously been used for hot flashes. Its efficacy is limited, however, and its adverse effects—including dry mouth, dizziness, drowsiness, and drops in blood pressure—reduce its usefulness.

It is no longer among the nonhormonal options recommended as a priority by The Menopause Society.

Psychological approaches

Cognitive behavioural therapy does not necessarily make hot flashes disappear, but it can reduce distress, interference with daily activities, and the sense of being overwhelmed by symptoms.

Its aim is not to suggest that hot flashes are psychological. Rather, it helps reduce certain mechanisms that amplify their impact, such as anxious anticipation, hypervigilance, or catastrophic thinking.

When night sweats have contributed to persistent insomnia, cognitive behavioural therapy specifically designed for insomnia can also be useful. Even after night sweats improve, the brain may have developed waking habits or significant worry about sleep. It may then be necessary to treat both the vasomotor symptoms and the insomnia.

Structured clinical hypnosis also has some favourable evidence, but access and the availability of adequately trained professionals can be limited.

Physical activity, weight, and lifestyle habits

Physical activity remains important for cardiovascular health, muscle, bone, sleep, mood, and long-term health.

It should not, however, be presented as a reliable treatment for hot flashes. The evidence does not consistently show that exercise, yoga, breathing techniques, or meditation directly reduce their frequency.

Weight loss may improve symptoms in some women living with excess weight, but results are variable. This possibility should be discussed without blame and in the broader context of health, medications, sleep, body-composition changes, and personal preferences.

What about natural products?

Several products are marketed for menopause symptoms, including:

• black cohosh;
• soy isoflavones and extracts;
• red clover;
• herbal blends;
• pollen-based supplements;
• cannabinoids;
• various products presented as "hormone balancers."

Overall, the studies are heterogeneous and do not demonstrate sufficiently consistent efficacy to recommend these products as first-line treatments for vasomotor symptoms.

Quality, concentration, and purity can also vary from one product to another. Some supplements may interact with medications or be unsuitable in the presence of liver disease, a history of cancer, or another medical condition.

This does not mean that no woman will feel improvement. It means that benefits are less predictable and that the word "natural" guarantees neither efficacy nor safety.

Soy foods can absolutely be part of a nutritious diet. They simply should not be presented as a treatment whose efficacy against hot flashes is comparable to that of proven medical options.

How to choose the most appropriate treatment?

There is no single right option for every woman.

The choice may depend on:

• the frequency and intensity of symptoms;
• their impact on sleep and quality of life;
• age and when they appeared;
• whether the uterus is present;
• the need for contraception;
• medical history;
• medications already in use;
• associated symptoms, such as anxiety, pain, or urinary problems;
• preferences regarding hormones;
• adverse effects the person wishes to avoid;
• cost, access, and coverage of the treatment.

In some situations, hormone therapy will be the most effective and coherent option. In others, an SSRI, an SNRI, gabapentin, a neurokinin antagonist, or another approach will be preferable.

The first treatment tried is not always the final one. It may be necessary to adjust the dose, change the route of administration, or try another option.

A reassessment after about six to eight weeks generally makes it possible to check:

• whether episodes are less frequent or less intense;
• whether sleep has improved;
• whether adverse effects are acceptable;
• whether the treatment is being used correctly;
• whether the patient's goals are being met.

Key Takeaways

Hot flashes and night sweats result from a change in temperature regulation in the brain. They are not a lack of willpower, poor stress management, or something that simply has to be endured.

They can last several years, and the experience differs considerably from one woman to another. The data also show average differences across ethnoracial groups, but these reflect a complex set of biological, social, environmental, and structural factors.

Hormone therapy remains the most effective treatment when it suits the clinical situation. Proven nonhormonal options also exist, including older medications, psychological approaches, and newer treatments targeting neurokinin receptors.

The most appropriate option is the one that takes into account symptoms, overall health, risks, preferences, and the person's priorities.

Looking Ahead

To better understand the place of hormone therapy, its benefits, and its risks, see our article "Hormone therapy: myths and facts".

The article "Hormone therapy: what's the difference between bioidentical and synthetic hormones?" goes further into differences in origin, molecular structure, and routes of administration.

Disclaimer

This article presents general educational information. It does not replace a clinical assessment or the advice of a healthcare professional.

References and Further Reading

1. Avis, N. E., Crawford, S. L., Greendale, G., Bromberger, J. T., Everson-Rose, S. A., Gold, E. B., Hess, R., Joffe, H., Kravitz, H. M., Tepper, P. G., & Thurston, R. C. (2015). Duration of menopausal vasomotor symptoms over the menopause transition. JAMA Internal Medicine, 175(4), 531–539. https://doi.org/10.1001/jamainternmed.2014.8063

2. Harlow, S. D., Burnett-Bowie, S.-A. M., Greendale, G. A., Avis, N. E., Reeves, A. N., Richards, T. R., & Lewis, T. T. (2022). Disparities in reproductive aging and midlife health between Black and White women: The Study of Women's Health Across the Nation (SWAN). Women's Midlife Health, 8, 3. https://doi.org/10.1186/s40695-022-00073-y

3. Institut national d'excellence en santé et en services sociaux. (2026). Prise en charge des manifestations cliniques liées à la ménopause par l'hormonothérapie : outil d'aide à la prise en charge. Gouvernement du Québec. https://www.inesss.qc.ca/fileadmin/doc/INESSS/Rapports/Usage_optimal/Hormonotherapie/INESSS_Hormono_Outil_prise_charge_FRANCAIS_VF.pdf

4. Institut national d'excellence en santé et en services sociaux. (2026). Prise en charge des manifestations cliniques liées à la ménopause par l'hormonothérapie : rapport en soutien. Gouvernement du Québec. https://www.inesss.qc.ca/fileadmin/doc/INESSS/Rapports/Usage_optimal/Hormonotherapie/INESSS_Hormonotherapie_GN.pdf

5. Lederman, S., Ottery, F. D., Cano, A., Santoro, N., Shapiro, M., Stute, P., Thurston, R. C., English, M., Franklin, C., Lee, M., & Nappi, R. E. (2023). Fezolinetant for treatment of moderate-to-severe vasomotor symptoms associated with menopause (SKYLIGHT 1): A phase 3 randomised controlled study. The Lancet, 401(10382), 1091–1102. https://doi.org/10.1016/S0140-6736(23)00085-5

6. Panay, N., Joffe, H., Maki, P. M., et al. (2025). Elinzanetant for the treatment of vasomotor symptoms associated with menopause: A phase 3 randomized clinical trial. JAMA Internal Medicine, 185(11), 1319–1327. https://doi.org/10.1001/jamainternmed.2025.4421

7. Pinkerton, J. V., Simon, J. A., Joffe, H., et al. (2024). Elinzanetant for the treatment of vasomotor symptoms associated with menopause: OASIS 1 and 2 randomized clinical trials. JAMA, 332(16), 1343–1354. https://doi.org/10.1001/jama.2024.14618

8. Health Canada. (2024). Summary Basis of Decision – Veozah. Government of Canada. https://dhpp.hpfb-dgpsa.ca/review-documents/resource/SBD1740491309253

9. Health Canada. (2025). Summary Basis of Decision – Lynkuet. Government of Canada. https://dhpp.hpfb-dgpsa.ca/review-documents/resource/SBD1760450740287

10. Schaudig, K., Wang, X., Bouchard, C., et al. (2024). Efficacy and safety of fezolinetant in individuals with moderate-to-severe vasomotor symptoms considered unsuitable for hormone therapy: A phase 3b randomised controlled trial. BMJ, 387, e079525. https://doi.org/10.1136/bmj-2024-079525

11. The North American Menopause Society. (2023). The 2023 nonhormone therapy position statement of The North American Menopause Society. Menopause, 30(6), 573–590. https://doi.org/10.1097/GME.0000000000002200