Here's something that might surprise you: not all estrogen is the same. In fact, the type of estrogen that stops hot flashes and clears brain fog is different from the type that helps with vaginal dryness and painful sex. Your body actually makes three distinct types of estrogen, and each one has its own job to do.. Understanding the different types of estrogen is a helpful context for your menopause care. Here's what you need to know.
Q: Is estradiol the same thing as estrogen?
A: Not exactly. Estrogen is the umbrella term. Estradiol is one specific type of estrogen–the main one your body makes during your reproductive years.
Q: How many types of estrogen are there?
A: Your body makes three main types: estradiol (E2), estriol (E3), and estrone (E1). Each one works differently and dominates at different life stages.
Q: Which type controls my period, mood, and hot flashes?
A: That's estradiol (E2), which is the strongest estrogen and the one your ovaries produce most before menopause.
Q: What's estriol used for?
A: Estriol (E3) is much weaker but works really well for vaginal dryness, painful sex, and urinary symptoms. It's also the main estrogen during pregnancy.
Q: Does it matter which type I take for hormone therapy?
A: Yes. Most systemic hormone therapy uses estradiol, the same estrogen your ovaries used to make. For genitourinary symptoms like vaginal dryness, painful sex, or recurrent UTIs, low-dose local vaginal estradiol is typically the first-line treatment.
When doctors talk about "estrogen," they're actually talking about a family of three different hormones. Your body makes all three, but each one takes the lead at different times in your life and handles different jobs.
It's sort of like when someone says they need "vitamins". Vitamin D does something completely different than vitamin B12.Same thing with estrogen. Saying "I need estrogen" is a good start, which type of estrogen you need makes a difference in actually feeling better.
This is the main estrogen running the show from puberty through perimenopause. It's the strongest of the three, about 10 to 100 times more potent than estriol. Estradiol is what's regulating your cycle, keeping your brain sharp, protecting your bones, and maintaining your skin. It's also the one behind your sex drive.
Estriol is much weaker than estradiol when it comes to whole-body effects, but it really shines in one area: your vaginal and urinary tissues. During pregnancy, your body floods with estriol to support the pregnancy. Outside of that, you don't make much of it but it's incredibly useful for treating vaginal dryness and urinary issues.
After menopause, when your ovaries stop churning out estradiol, your body starts converting other hormones into estrone. This happens mostly in your fat tissue. It's weaker than estradiol, so it can't really prevent hot flashes or other menopause symptoms on its own, but it's what your body relies on as a backup.
|
Hormone |
Strength |
Main Time of Life |
What It's Doing |
|
Estradiol (E2) |
Strongest |
Reproductive years |
Running your cycle, protecting your brain and bones, maintaining everything |
|
Estriol (E3) |
Weakest |
Pregnancy (and for local vaginal treatment) |
Supporting vaginal and urinary tissue health |
|
Estrone (E1) |
Medium |
After menopause |
Providing weaker backup estrogen |
When you tell your doctor "my estrogen is low" or "I think I need estrogen," what they're hearing is "my estradiol is low." That's because estradiol is responsible for most of the symptoms women experience during perimenopause and menopause: the hot flashes, brain fog, mood swings, all of it.
So when your doctor prescribes estradiol, they're not giving you something different than estrogen, they're giving you the specific type of estrogen your body needs.
Estradiol is the hormone doing most of the work in your body from your first period until menopause.
In your reproductive system:
Estradiol is what makes your menstrual cycle happen. It builds up your uterine lining each month, triggers ovulation, and keeps everything coordinated. When you're trying to get pregnant, estradiol is essential.
In your brain:
This is huge, and it's something a lot of women don't realize until their estradiol drops. Estradiol helps with memory, focus, and concentration. It also plays a big role in regulating your mood. When estradiol declines in perimenopause, that's when a lot of women start experiencing brain fog or feeling more anxious or depressed.
Throughout your body:
Estradiol is protecting your bones by preventing bone breakdown. It's keeping your skin thick and elastic by supporting collagen production. It's maintaining vaginal lubrication and supporting your sexual response. It's even helping protect your cardiovascular system.
Estradiol works by binding to estrogen receptors throughout your body, proteins that act like locks, with estradiol as the key. When estradiol binds to these receptors, it triggers responses in your cells that affect everything from your menstrual cycle to your mood. Basically, estradiol has been quietly doing a lot of behind-the-scenes work you probably haven't thought about, until it starts declining.
This is where perimenopause and menopause symptoms come in. Estradiol receptors are found throughout the body (brain, bone, heart, vagina, bladder, skin) so when levels start to fluctuate and then drop, you might notice:
Every woman experiences these differently. Some women get hit hard with hot flashes but don't notice much brain fog. Others struggle more with mood and sleep. But they're all connected to declining estradiol.
When clinicians talk about hormone replacement therapy (HRT) or menopausal hormone therapy (MHT), they're almost always talking about estradiol-based therapy. Estradiol (E2) is the most biologically active and potent estrogen produced by the ovaries during your reproductive years, which is exactly why it's the most effective at treating whole-body symptoms.
If you're dealing with hot flashes, brain fog, mood changes, or worried about bone loss, estradiol is what you need. It's the gold standard.
The good news is there are options for how to get estradiol into your system:
For whole-body symptoms:
For vaginal symptoms specifically:
There's more about choosing between these options below, but just know you're not stuck with one option.
Estriol has a very specific and useful role, especially after menopause.
Here's the thing about estriol: it's weak when it comes to systemic effects (affecting your whole body), but it's surprisingly effective when applied locally to vaginal tissue.
During pregnancy, your body makes tons of estriol, it's the dominant estrogen for those nine months. But outside of pregnancy, your body doesn't produce much estriol at all. That's okay, because it can be used therapeutically where it works best.
Estriol is 10-100 times weaker than estradiol when it comes to whole-body effects. This is because estriol binds less strongly to estrogen receptors, the proteins in your cells that respond to estrogen signals. It doesn't have the same strong effects on your brain, bones, or cardiovascular system that estradiol does. And it doesn't stimulate breast tissue or your uterine lining as much as estradiol. For whole-body menopause symptoms, estriol alone isn't going to cut it.
But when you apply estriol directly to vaginal tissue, it works well to restore tissue health without having strong effects throughout the rest of your body.
If you're dealing with any of these, estriol might be exactly what you need:
Vaginal symptoms:
Urinary symptoms:
All of these fall under what doctors now call genitourinary syndrome of menopause (GSM). It's incredibly common, and very treatable. For mild symptoms, estriol can help, but low-dose local estradiol remains the gold standard for moderate to severe cases, with stronger evidence and more predictable results.
When your symptoms are limited to the vaginal and urinary area, estriol offers a gentler approach. It improves the health of vaginal tissue: making it thicker, more elastic, better lubricated, and more resilient. And all this without giving you significant whole-body estrogen exposure.
This can be really appealing if:
Estriol is almost always used vaginally:
It's usually used a few times a week after an initial loading period. Many women find it really improves their quality of life. Sex becomes comfortable again, UTIs stop happening, and they just feel more normal.
Estrone is the estrogen that doesn't get talked about as much, but it's worth understanding. After menopause, it becomes the primary circulating estrogen. It is produced mainly through conversion of androstenedione in fat tissue rather than the ovaries.
After menopause, your ovaries dramatically cut back on estradiol production. To compensate, your body starts converting other hormones (mainly androstenedione from your adrenal glands) into estrone. This happens primarily in fat tissue.
So postmenopause, estrone becomes your most abundant estrogen. But here's the catch, it's significantly weaker than estradiol.
It's not strong enough to prevent symptoms:
Estrone provides some estrogen activity, which is better than nothing, but it's not enough to stop hot flashes, brain fog, or other menopause symptoms. If you're dealing with those, you need estradiol.
Higher body fat means more estrone:
Because the conversion happens in fat tissue, women with higher body fat percentages tend to have higher estrone levels after menopause. When estrone levels get too high, there can be associations with certain metabolic concerns.
Doctors don't typically use it in treatment:
Modern hormone therapy doesn't use estrone as the main hormone. It's just not as effective as estradiol. When doctors prescribe HRT, they choose estradiol because it works better.
Think of estrone as your body's attempt to give you some estrogen support after your ovaries retire. It's doing its best, but it's not a complete solution. If you're having menopause symptoms, estrone alone isn't going to resolve them. You'd need estradiol-based therapy for that.
Now you know there are three different estrogens. The question is: which one do you actually need?
The answer depends entirely on what symptoms you're dealing with. Here's how to think about it.
Hot flashes and night sweats:
These are classic estradiol-deficiency symptoms. Estradiol is the most effective treatment for vasomotor symptoms, nothing works better.
Brain fog, memory issues, trouble concentrating:
Your brain has estrogen receptors everywhere, and they're used to estradiol. When estradiol drops, cognitive symptoms show up. Replacing estradiol can make a huge difference here.
Mood changes | anxiety, depression, irritability:
Estradiol affects neurotransmitters like serotonin and dopamine. Many women find their mood stabilizes when they start estradiol therapy.
Worrying about bone loss:
Estradiol protects your bones by preventing excessive bone breakdown. If you're at risk for osteoporosis, systemic estradiol can help maintain bone density.
Systemic means the estrogen affects your whole body, it gets into your bloodstream and reaches all your tissues. For systemic estradiol, you'd use pills, patches, gels, or pellets.
Vaginal dryness or painful sex:
This is the number one reason women use vaginal estrogen, and it works incredibly well. Whether you use vaginal estradiol or estriol, both can restore tissue health and make sex comfortable again.
Recurrent UTIs:
If you're getting UTIs over and over, especially after menopause, low-dose vaginal estrogen can actually reduce your risk. It helps restore the protective bacteria and the health of urinary tract tissues.
Urinary urgency, frequency, or some types of leakage:
Estrogen deficiency affects your bladder and urethra too. Local estrogen can improve these symptoms.
Local or vaginal estrogen stays mostly in the tissue where you apply it. Very little gets absorbed into your bloodstream, so you're treating the specific area that needs help without giving yourself systemic hormone exposure.
|
What You're Dealing With |
What You Need |
|
Hot flashes, night sweats |
Systemic estradiol |
|
Brain fog, memory issues |
Systemic estradiol |
|
Mood swings, anxiety, depression |
Systemic estradiol |
|
Bone loss prevention |
Systemic estradiol |
|
Vaginal dryness, painful sex |
Vaginal estradiol or estriol |
|
Recurrent UTIs |
Vaginal estradiol or estriol |
|
Urinary urgency or frequency |
Vaginal estradiol or estriol |
Absolutely. Some women need systemic estradiol for hot flashes and brain fog, and also add vaginal estrogen because vaginal tissues often require direct local support beyond what systemic therapy provides. This is completely fine, and actually pretty common.
Yes, and here's why: both work for symptoms, but research shows they carry different risks. Oral estradiol (pills) goes through your liver first, which can increase clotting factors in your blood. Transdermal estradiol (patches or gels) bypasses the liver and is associated with a lower risk of blood clots.
If you have any increased risk for blood clots, transdermal is usually the better choice. BFor clinicians and a lot of women, regardless of their medical history, transdermal is becoming the preferred route because of its safety profile.
Generally, no. Low-dose vaginal estrogen is absorbed so minimally that it doesn't stimulate the uterine lining, so progesterone isn't typically needed. Your blood estrogen levels usually stay in the postmenopausal range even while vaginal tissue gets what it needs. This is different from systemic estrogen, where progesterone is required to protect the uterus if you still have one.
Not necessarily. Menopause is a clinical diagnosis, not a laboratory one. That means that symptoms and clinical context guide treatment more than numbers. That said, when blood work does measure "estrogen," it's almost always measuring estradiol specifically, since that's what correlates with symptoms and helps inform treatment decisions. Estriol and estrone aren't routinely tested unless there's a specific reason.
Chen, P., Li, B., & Ou-Yang, L. (2022). Role of estrogen receptors in health and disease. Frontiers in Endocrinology, 13, 839005. https://doi.org/10.3389/fendo.2022.839005