In this article
A hot flash can turn a meeting, a dinner, or a night's sleep upside down. If you are searching for whether HRT helps, you probably want to know three things: does it work, how soon, and is it right for you. Here is what the research measured, in plain English.
What hot flashes and night sweats are
Doctors call hot flashes and night sweats vasomotor symptoms. Each hot flash usually lasts between 1 and 5 minutes, and night sweats are simply hot flashes that happen while you sleep [8]. They can start during perimenopause [1].
They are more than a nuisance. The Menopause Society links them with poorer sleep, irritability, trouble concentrating, and lower quality of life [1]. Hot flashes are usually worst in the first year or two [7], but they can last a long time. In a large US study, frequent hot flashes went on for 7.4 years on average, and for many women more than 10 years [1].
How well HRT works for hot flashes
The Menopause Society calls hormone therapy the gold standard for relief of hot flashes, and the FDA has approved it as first-line treatment for moderate to severe hot flashes from menopause [1].
The best summary of the evidence is a Cochrane review that pooled 24 double-blind, placebo-controlled trials of oral hormone therapy, with 3,329 women in all [2]. Each trial lasted between three months and three years [2]. Here is what it found:
- Frequency: hormone therapy reduced weekly hot flashes by about 75% compared with placebo [2].
- Severity: the hot flashes that remained were also less severe than on placebo [2].
- Dropping out: women on placebo were far more likely to quit a trial because it was not working [2].
- Side effects: any side effect was somewhat more common on hormones, but quitting because of side effects was not significantly more common [2]. The side effects behind most withdrawals were breast tenderness, swelling, joint pain, and mood symptoms [2].
One detail surprises people. Women in the placebo groups also improved, with about a 58% drop in hot flashes from the start of the study to the end [2]. Hot flashes change over time on their own, and expectation plays a part. That is why the reviewers said any hot flash treatment must be tested against a placebo in a blinded trial before you can trust it [2].
The Women's Health Initiative (WHI), a large US trial of 16,608 women aged 50 to 79, asked women about their symptoms after the first year [5]. Among women who had hot flashes when they joined, more of those taking estrogen plus a progestin said their hot flashes had gone away:
- Hot flashes relieved ~86%
- Not relieved ~14%
- Hot flashes relieved ~58%
- Not relieved ~42%
Among women with hot flashes at the start, 85.7% on estrogen plus progestin and 57.7% on placebo reported relief at year one; percentages rounded [5].
The same trial found relief of night sweats in 77.6% of women on hormones and 57.4% on placebo [5]. Keep in mind the WHI used one oral combination pill, and its participants averaged 63 years old [5].
How fast does HRT work for hot flashes?
Trials give a rough picture, not a promise. In a placebo-controlled study of 187 women, a weekly estradiol patch at 0.025 mg a day worked better than placebo for both the number and severity of hot flashes at weeks 4 and 12 [3].
In another patch trial of 214 postmenopausal women with frequent hot flashes, women kept symptom diaries [3]. Across the treatment cycles, weekly hot flashes fell by 67% on the 0.05 mg patch and 72% on the 0.1 mg patch, compared with 18% on placebo [3].
Dose matters for timing. The Menopause Society notes that lower doses, such as oral estradiol of 0.5 mg or less or a 0.025 mg patch, may take 6 to 8 weeks to give enough relief [1]. Everyone responds differently, which is why the labels tell prescribers to adjust the dose based on how you respond [3, 4].
Doses and routes: pill, patch, or cream
Estrogen for hot flashes comes in several forms. Considering the dose, The Menopause Society found no appreciable difference in how well oral and non-oral forms relieve hot flashes [1]. Route can still matter for other reasons, like how it fits your health history, so the choice is shared between you and your clinician [1].
| Form | Where the dose starts | What the label says next |
|---|---|---|
| Estradiol tablet (by mouth) | Usually 1 to 2 mg a day [4] | Adjust to control symptoms, using the lowest dose that works [4] |
| Estradiol patch (on the skin, changed weekly) | 0.025 mg a day [3] | Adjust based on response; try to taper or stop every 3 to 6 months [3] |
Both labels share the same idea: start low, adjust to how you feel, and reassess regularly [3, 4]. The Menopause Society agrees that the need to keep going should be reviewed periodically, based on your symptoms, health, and preferences [1].
Combined estrogen plus progestogen appears slightly more effective for hot flashes than estrogen alone [1]. For more on the skin route, read our estradiol patch guide.
If you still have a uterus
Estrogen alone can be used by women without a uterus [1]. If you still have one, you need a progestogen with systemic estrogen to protect the uterine lining from overgrowth and cancer [1]. Micronized progesterone is one option.
Progesterone on its own has also been studied for hot flashes. The Menopause Society reports that micronized progesterone 300 mg nightly reduced hot flashes and night sweats compared with placebo and improved sleep, though this use is off-label and has no long-term data [1]. Our article on progesterone for sleep covers those studies.
If you can't take estrogen
Hormone therapy is not for everyone. The Menopause Society lists these as reasons not to use oral or skin estrogen [1]:
- Unexplained vaginal bleeding
- Liver disease
- A past estrogen-sensitive cancer, including breast cancer
- Past coronary heart disease, heart attack, stroke, or blood clot
- A personal or inherited high risk of blood clots
If any of these apply, you still have choices. There are non-hormone prescription medicines that can reduce hot flashes [7], and a clinician can talk through which may fit you. Simple habits may help at the margins too, like dressing in layers, limiting caffeine, alcohol, and spicy food, and slow, deep breathing when a hot flash begins [7].
Weighing benefits and risks
For women younger than 60, or within 10 years of menopause, with no reason they should not take it, The Menopause Society says the benefit-risk ratio favors hormone therapy for bothersome hot flashes [1]. Starting later than that, the balance looks less favorable because the absolute risks of heart disease, stroke, blood clots, and dementia are higher [1]. Read the full picture in Is HRT safe?.
There is no set stopping age. Because hot flashes can last for years, The Menopause Society says an arbitrary age-based stopping rule is not clinically appropriate [1].
What happens when you stop
Hot flashes return in about half of women when hormone therapy stops, and experts have not agreed on whether tapering is better than stopping all at once [1]. When the WHI combination pill was stopped, more than half of the women who had hot flashes at the start of the trial reported moderate or severe hot flashes again 8 to 12 months later, compared with about a fifth of the matching placebo group [6].
Treating hot flashes with WarriorBabe Health
A WarriorBabe Health clinician reviews your health history to decide whether hormone therapy makes sense for you. Options include oral estradiol, an estradiol patch, estradiol cream, and a progesterone capsule for women with a uterus. Compare them on our hormone therapy page.
Our hormone products are compounded by a licensed pharmacy and are not FDA-approved. FDA-approved versions of estradiol and progesterone also exist, and your clinician can explain the difference.
Day to dayWhat to do day to day, from the WarriorBabe Show:Can changing my diet help with hot flashes? →Frequently asked questions
How long does it take HRT to stop hot flashes?
It varies. In one patch trial, a low 0.025 mg dose beat placebo for hot flash frequency and severity by week 4 [3]. The Menopause Society notes that lower doses may take 6 to 8 weeks to provide enough relief [1]. If you are not seeing a change, your clinician may adjust the dose.
Is the patch or the pill better for hot flashes?
For relief, they are similar. At comparable doses, The Menopause Society found no appreciable difference in effectiveness between oral and non-oral estrogen [1]. The choice often comes down to your health history and preferences, which you decide with your clinician.
Does HRT help night sweats too?
Yes. Night sweats are hot flashes that happen during sleep [8]. In the WHI, 77.6% of women on estrogen plus progestin reported relief of night sweats after a year, compared with 57.4% on placebo [5].
References
- The 2022 hormone therapy position statement of The North American Menopause Society. Menopause. 2022;29(7):767-794. menopause.org/wp-content/uploads/professional/nams-2022-hormone-therapy-position-statement.pdf
- MacLennan AH, Broadbent JL, Lester S, Moore V. Oral oestrogen and combined oestrogen/progestogen therapy versus placebo for hot flushes. Cochrane Database Syst Rev. 2004;(4):CD002978. pubmed.ncbi.nlm.nih.gov/15495039/
- Bayer HealthCare Pharmaceuticals. Climara (estradiol transdermal system) prescribing information. DailyMed, US National Library of Medicine. dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1e9702c4-f2d7-4ea8-b6e8-7dca31671864
- Estradiol tablets, USP. Prescribing information. DailyMed, US National Library of Medicine. dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=170ec388-d399-4543-8743-208394b38904
- Barnabei VM, Cochrane BB, Aragaki AK, et al. Menopausal symptoms and treatment-related effects of estrogen and progestin in the Women's Health Initiative. Obstet Gynecol. 2005;105(5 Pt 1):1063-1073. pubmed.ncbi.nlm.nih.gov/15863546/
- Ockene JK, Barad DH, Cochrane BB, et al. Symptom experience after discontinuing use of estrogen plus progestin. JAMA. 2005;294(2):183-193. pubmed.ncbi.nlm.nih.gov/16014592/
- MedlinePlus. Menopause. Medical Encyclopedia. US National Library of Medicine. medlineplus.gov/ency/article/000894.htm
- The Menopause Society. Perimenopause. Menopause topics, patient education. menopause.org/patient-education/menopause-topics/perimenopause
This article is for general information. It is not medical advice and does not replace a visit with a licensed clinician who knows your history. Do not start, stop or change a medication without talking to your clinician. If you think you are having a medical emergency, call 911.
