In this article
You walk into a room and forget why. A colleague's name vanishes mid-sentence. The word you need is right there, and then it isn't. Many women in their 40s and 50s describe this as brain fog, and many wonder whether hormone therapy would clear it. Here is what the research has found, and where it falls short.
What menopause brain fog is
The Menopause Society says 40% to 60% of midlife women report cognitive symptoms such as forgetfulness during the menopause transition [1]. Brain fog shows up as trouble remembering words, names, stories, and numbers [1]. Complaints about concentrating and remembering are common at this stage [2].
Those symptoms can be upsetting, and it is natural to worry about something more serious. The reassuring part: changes in cognitive performance are typically mild and within normal limits, and dementia at midlife is very rare [1].
What studies measured during the transition
The Study of Women's Health Across the Nation (SWAN) followed 2,362 women for four years and tested their processing speed, verbal memory, and working memory [4]. Normally, people score a little higher each time they repeat the same tests, because they learn them. That practice gain stalled in perimenopause: speed scores did not improve in late perimenopause, and memory scores did not climb in early or late perimenopause [4].
After menopause, the learning bounced back to premenopausal levels [4]. The researchers concluded that the cognitive difficulties of the transition may be time-limited [4].
Other menopause symptoms play a part too. The Menopause Society links hot flashes with difficulty concentrating, and poor sleep with memory problems [3]. It also says cognitive function at midlife seems to be influenced by menopause stage [2].
What the hormone therapy trials found
The strongest evidence comes from randomized trials, where women were assigned hormones or a placebo by chance. Three are worth knowing.
| Trial | Who took part | What they took | What happened to thinking and memory |
|---|---|---|---|
| KEEPS-Cog | 693 women, average age 52.6, about 1.4 years past their last period [5] | Oral conjugated estrogens or an estradiol patch, each with cyclic micronized progesterone, or placebo, for up to 4 years [5] | No benefit on cognitive outcomes [5]. About 10 years later, still no difference from placebo [7] |
| ELITE-Cog | 567 women, either within 6 years of menopause or 10+ years after [6] | Oral estradiol 1 mg a day, with progesterone vaginal gel for women with a uterus, or placebo; average 57 months [6] | No benefit or harm on memory, executive function, or overall cognition, in either group [6] |
| WHIMS | 4,532 women aged 65 or older [8] | An older combination pill (conjugated estrogens plus medroxyprogesterone acetate) or placebo [8] | Probable dementia about doubled: 23 more cases per 10,000 women per year [8] |
KEEPS: recently menopausal women
The Kronos Early Estrogen Prevention Study tested hormone therapy in healthy women soon after menopause [5]. Its cognitive arm measured memory, attention, executive function, and language over up to four years, and found no treatment-related benefit on any cognitive outcome [5].
Researchers went back to 275 of these women roughly 10 years after the trial ended [7]. Those who had taken hormones performed similarly to those who had taken placebo [7]. The authors read that as reassurance that short-term hormone therapy in early menopause does no long-term cognitive harm, and also as evidence that it does not improve or preserve cognitive function [7].
ELITE: does timing change the answer?
The Early versus Late Intervention Trial with Estradiol was designed to test the timing idea directly [6]. Starting estradiol within 6 years of menopause did not affect verbal memory, executive function, or overall cognition any differently from starting it 10 or more years later [6]. The authors concluded that estradiol neither benefits nor harms these abilities, regardless of time since menopause [6].
WHIMS: starting late
The WHI Memory Study enrolled women 65 and older [8]. Among those taking the combination pill, 40 were diagnosed with probable dementia, compared with 21 on placebo, over about four years [8]. The pill also did not prevent mild cognitive impairment [8]. These women were well past the menopause transition, so this finding does not describe brain fog in your 40s or 50s, but it is why experts urge caution about starting hormones late.
Where the experts land
The Menopause Society's 2022 position statement says three large randomized trials found neutral effects of hormone therapy on cognition when used early after menopause [3]. Its conclusion: in the absence of more definitive findings, hormone therapy is not recommended at any age to prevent or treat a decline in cognitive function or dementia [3].
Its patient guidance is just as clear: for women who go through natural menopause, hormone therapy is not recommended to improve cognition [2]. One exception the position statement notes is that small trials suggest estrogen may have cognitive benefits when started right after a hysterectomy with removal of both ovaries [3].
Hormone therapy is FDA-approved to treat moderate to severe hot flashes and night sweats, among a few other uses, but not memory or focus [3]. If you are considering it, weigh it for the symptoms it is approved to treat.
Where HRT might still fit
Many women with brain fog also have hot flashes and broken sleep. Hormone therapy is the most effective treatment for hot flashes, and it improves sleep in women with bothersome night sweats by reducing awakenings [3]. Whether that leaves you feeling sharper during the day has not been shown in trials, so treat it as a possible side benefit, not the reason to start.
For safety, The Menopause Society says the benefit-risk balance is favorable for bothersome hot flashes in women younger than 60 or within 10 years of menopause who have no reason they should not take hormones [3]. Read more in Is HRT safe? and HRT for hot flashes.
What may help your brain now
The Menopause Society lists several habits that may benefit memory or help protect against dementia [2]:
- Staying physically and mentally active [2]
- Eating a Mediterranean-style diet [2]
- Not smoking [2]
- Managing heart risk factors like high blood pressure, diabetes, and high cholesterol [2]
And if you notice obvious changes in your memory or thinking, bring them to a healthcare professional [2]. A clinician can help sort out what is going on.
Talking it through with WarriorBabe Health
WarriorBabe Health clinicians can help you sort out which of your symptoms hormone therapy is meant to treat. If hot flashes or night sweats are part of the picture, options include oral estradiol, an estradiol patch, and a progesterone capsule for women with a uterus. See them all on our hormone therapy page.
Our hormone products are compounded by a licensed pharmacy and are not FDA-approved. A licensed clinician decides whether any prescription is appropriate for you.
Frequently asked questions
Is menopause brain fog real?
Yes. Between 40% and 60% of midlife women report symptoms like forgetfulness during the transition [1]. In the SWAN study, women's learning on repeated tests stalled in perimenopause and recovered after menopause [4]. The changes are usually mild and within normal limits [1].
Does HRT improve memory?
Trials in recently menopausal women say no. KEEPS and ELITE found no benefit or harm to memory and thinking from hormone therapy [5, 6], and KEEPS women showed no difference about 10 years later [7]. The Menopause Society does not recommend hormone therapy to improve cognition [2].
Can HRT cause dementia?
Started at 65 or older, an older combination pill doubled the risk of probable dementia in the WHIMS trial, about 23 extra cases per 10,000 women per year [8]. Trials of women starting soon after menopause did not show cognitive harm [6, 7].
References
- The Menopause Society. Perimenopause. Menopause topics, patient education. menopause.org/patient-education/menopause-topics/perimenopause
- The Menopause Society. Mental health. Menopause topics, patient education. menopause.org/patient-education/menopause-topics/mental-health
- 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
- Greendale GA, Huang MH, Wight RG, et al. Effects of the menopause transition and hormone use on cognitive performance in midlife women. Neurology. 2009;72(21):1850-1857. pubmed.ncbi.nlm.nih.gov/19470968/
- Gleason CE, Dowling NM, Wharton W, et al. Effects of hormone therapy on cognition and mood in recently postmenopausal women: findings from the randomized, controlled KEEPS-Cognitive and Affective Study. PLoS Med. 2015;12(6):e1001833. pubmed.ncbi.nlm.nih.gov/26035291/
- Henderson VW, St John JA, Hodis HN, et al. Cognitive effects of estradiol after menopause: a randomized trial of the timing hypothesis. Neurology. 2016;87(7):699-708. pubmed.ncbi.nlm.nih.gov/27421538/
- Gleason CE, Dowling NM, Kara F, et al. Long-term cognitive effects of menopausal hormone therapy: findings from the KEEPS Continuation Study. PLoS Med. 2024;21(11):e1004435. pubmed.ncbi.nlm.nih.gov/39570992/
- Shumaker SA, Legault C, Rapp SR, et al. Estrogen plus progestin and the incidence of dementia and mild cognitive impairment in postmenopausal women: the Women's Health Initiative Memory Study. JAMA. 2003;289(20):2651-2662. pubmed.ncbi.nlm.nih.gov/12771112/
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.
