New research links HRT with lower dementia risk in some women—but it does not prove prevention. Here’s what the evidence shows and how to build brain reserve now.
I’ve scrolled past the same headline about six times this week: women on HRT have lower rates of dementia. Every time, that little flicker goes off—finally, more proof. Then the doctor in me taps the brakes.
This one’s coming out of the UK Biobank, which is real, high-quality data. But it’s landing in a feed full of influencers telling you HRT prevents Alzheimer’s, full stop. That’s not what this study says. It’s not what any study says. Yet.
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Here’s where I actually land, and what I tell my patients: if you have a family history of dementia and real risk factors, you should be doing everything you can to protect your brain—starting in your 20s and 30s, not waiting for a diagnosis in your 60s. HRT is part of that picture for me. It is not the whole picture, and it is not proven for this specific use yet.
If dementia runs in your family and you want to actually map your risk—not the headline version—that’s exactly the conversation we’d have at Parsley →
So this week: what the new research actually says, what it doesn’t, and the protocol I’d run regardless of how the HRT-and-dementia question eventually shakes out.
⚡ Forward this protocol
Two things matter more than anything else for dementia risk, and neither of them is a headline.
The Metabolic Brain Check:
👉 Forward this to the friend who just texted you the HRT-dementia headline.
❌ The overclaim: HRT prevents Alzheimer’s. That’s influencer talk—not what any study has proven.
✅ What the UK Biobank study actually found. Researchers followed 183,450 postmenopausal women for 13.3 years. HRT use was linked to a 10% lower risk of all-cause dementia overall1—but that benefit was concentrated almost entirely in specific subgroups: surgical menopause (26–32% lower risk), starting HRT at ages 51–56 (23% lower risk), shorter lifetime estrogen exposure. Women with natural menopause as a whole group? No significant benefit.
❝ It’s a subgroup finding, not a population-wide effect—and it’s observational, not a randomized trial.
✅ The autopsy data is more specific—and comes with a catch. A Neurology study of nearly 3,000 autopsied brains found estrogen-only HRT users had 35% lower odds of Alzheimer’s pathology and 39% lower odds of a dementia diagnosis.2 Except these women started estrogen-only HRT after age 70—not in their late 40s/50s the way we prescribe it today. A newer, bigger systematic review of over 1 million women found “no clear evidence” HRT changes dementia risk either way.3 Translation: not settled.
✅ That “120 million medical records” stat going around? It’s a poster, not a published study. Researchers presented data from a 120-million-patient EHR database at The Menopause Society’s 2025 meeting, showing women who started estrogen during perimenopause for 10+ years had roughly 60% lower odds of breast cancer, heart attack, and stroke versus non-users.4 It’s a real, striking number—and it hasn’t been peer-reviewed. The researchers’ own caution: perimenopausal starters are younger and healthier to begin with, which alone could explain some of the gap (“healthy user bias”). Women who started after menopause saw a smaller benefit—and a 4.9% higher stroke risk. This is early data worth watching, not proof.
Where your risk actually starts. Women’s lifetime Alzheimer’s risk really is about double men’s—1 in 5 for women vs. 1 in 10 for men, by age 45.5 Some of that gap is longevity, but not all of it—which is exactly why this research area matters so much for women specifically, and why the headlines land so hard.
Dementia has a massive metabolic component. Insulin resistance and blood sugar dysregulation accelerate hard after menopause, and both are on the list of dementia’s modifiable risk factors—the 2024 Lancet Commission estimates 45% of dementia cases could be delayed or prevented by addressing 14 of them.6 HRT may end up being one piece of that picture. It’s not dementia insurance on its own.
If I had a family history of dementia—and honestly, even without one—this is the protocol I’d run. Most of it pays off starting in your 20s and 30s.
Target A1c ≤5.4%, fasting insulin under 5 µIU/mL. This is about the slow insulin resistance some researchers now call “type 3 diabetes” for its direct line to Alzheimer’s pathology—not just avoiding diabetes.
Skeletal muscle absorbs roughly 80% of the glucose you eat via insulin-stimulated uptake.7 More muscle, more places for blood sugar to go.
A 2025 Framingham analysis found high-intensity activity in midlife was linked to a 41% lower dementia risk—45% for consistent intensity in your 60s-80s.8 Zone 2 alone didn’t move this number. Intensity did.
A 2026 study of nearly 2,000 adults found the highest lifetime cognitive enrichment was linked to a 38% lower Alzheimer’s risk.9 Work you find genuinely engaging, in particular, tracks with lower dementia rates the longer you stay in it.
A 2026 study of 130,000+ people linked moderate coffee and tea intake to slower brain aging and lower dementia risk.10 Caffeine, antioxidants, or both—not fully worked out yet.
The dementia case isn’t proven. The case for bone density, metabolic, and cardiovascular support is—especially starting within 10 years of menopause.
The goal: you’re not trying to out-supplement a dementia diagnosis at 70. You’re building brain reserve now, so whatever the HRT research eventually proves, you’re already covered on everything else that matters.
When I was in college, my grandmother died of metastatic colon cancer. She died far too young, in her 70s, because she didn’t get proper screening—a colonoscopy—in time. She’d also spent decades eating the SAD (Standard American Diet) and smoking cigarettes, both top risk factors for colon cancer.
So it meant a lot to me last week when I got my first-ever colonoscopy. I did a Cologuard test three years ago—the noninvasive stool test that catches roughly 98% of colon cancers—and it came back clear. But I wasn’t going to rely on that indefinitely. The thing about a colonoscopy is that it’s not just a screening, it’s an intervention: if they find a polyp, they can remove it on the spot. Even removing benign polyps matters, because benign ones can turn cancerous over time.
According to the doctor who did the procedure, they removed one benign-looking polyp and everything else was clear. But even having a polyp at all gives me pause. I eat extremely well, don’t smoke and never have, drink alcohol only moderately, exercise, keep my toxin burden low, and get adequate fiber. My blood sugar and metabolic health—another major cancer risk factor—are optimal. It just goes to show: you don’t know until you look. A Cologuard test wouldn’t have caught or removed that polyp.
Longevity is lean muscle mass, creatine, sauna, supplements, HRV, and HRT—yes. But it’s also good old-fashioned preventive care, taken seriously instead of avoided.
There’s a lot our U.S. medical system gets wrong, and even more it outright misses, when it comes to our health. That’s exactly why we need functional medicine to become the standard of primary care. But there are things the system does really well to keep us alive and thriving—colonoscopies, Pap smears, and blood tests among them. If you’re due, this is your bat signal to get on it. Your healthspan will thank you.
I’m not waiting for a randomized trial to check my own numbers. My annual longevity labs with Parsley cover A1c, fasting insulin, and a full hormone panel in one draw.
Book yours here →
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