Estriol is one of three estrogens that our bodies make.  It is the gentlest of the estrogens and has great uses for anti-aging and bioidentical hormone replacement.  
The three estrogens we make are Estrone, Estradiol, and Estriol. Estrone and estradiol are much stronger than estriol.  Here is a quick synopsis of estrone, estradiol, and estriol. Then I will go on to explain what and how estriol is used.
 
Estrone: This is more of an undesirable estrogen because it can create negative effects.  The goal is to have estrone at a lower ratio compared to estradiol and estriol. Some Common adverse effects of high levels of estrone are sugar cravings, weight gain, irritability and mood swings.  Higher levels of estrone can promote higher levels of undesirable metabolites such as 2OH-estrone and 4OH-estrone. Higher levels of these metabolites can contribute to reproductive cancers, particularly breast.  Estrone is more prominent in teens and is elevated until their bodies start cycling properly as they get older. Estrone is produced by our fat tissues and can convert into estradiol, which is the strongest form of estrogen in our bodies.   

Estradiol: Estradiol as mentioned above, is by far the strongest of the three estrogens.  There is a good side and a bad side to estradiol. Estradiol has so many benefits for the body.  In excess because of its potency, estradiol can have many side effects. Estradiol is awesome for bone density. This is why so many women can fall prey to osteoporosis once they hit perimenopause and postmenopausal when the estradiol drops.  Estradiol is helpful in the cardiovascular system helping raise HDL (high-density lipoproteins), the beneficial cholesterol. It is also beneficial for memory and recall. Which is why in menopause so many women complain about their short-term memory.  As I mentioned, estradiol can be very potent. Estradiol likes to “grow things.” High levels of estradiol can exacerbate or promote uterine fibroids and fibrocystic breasts. Elevated levels of estradiol can cause weight gain, moodiness, PMS, heavy periods.          

Estriol: Estriol is the weakest or most gentle of the estrogens.  Estriol circulates in low levels of the bloodstream in menstruating females.  It becomes much higher during pregnancy. Estriol is especially helpful for skin integrity and mucous membranes.  It is helpful in hormone replacement to balance estradiol side effects. Estriol can also be used in BHRT for women that cannot tolerate the strong potency of estradiol.

Estrone, estradiol and estriol, the three main estrogens all stimulate the many estrogen receptors in our bodies.  As mentioned above estrone converts to estradiol. Having elevated levels of estrone can promote high levels of estradiol.  Estriol, on the other hand, does not convert to estradiol. Having higher levels of estrone or estradiol can promote Estrogen Dominance.  

If you would like to read more about Estrogen Dominance, check out our blog: ‘What Does Estrogen Dominance Feel Like?’. Estrone stimulates the estrogen receptor moderately, while estradiol has a very strong effect on the receptor.  Estriol, like the other estrogens, stimulates estrogen receptors. But it does so more weakly than estrone and estradiol. For example, imagine a door is the “estrogen receptor.” Estrone will approach the door and knock firmly on the door to get someone inside to open it.  

Estradiol is the strongest stimulator of estrogen receptors. So estradiol will pound on the door with a sledgehammer to get someone to open up. Back to estrone for a moment. If the door is not opened quickly enough for estrone, she gets a little tricky. Estrone will morph like a werewolf into estradiol and then go blow that door down.  Estriol is a weak stimulator of the estrogen receptors, will gently, quietly knock on the door. The interesting part here is, estriol while being a weak stimulator can provide a strong of an impact on the receptors. Meaning, say there is no estrogen/estradiol around due to menopause or total hysterectomy. Then estriol can stimulate the receptors gently providing estrogen stimulation to the body.  Now imagine there is a lot of estradiol and estrone around (as in Estrogen-Dominance). Estriol can go hang out at the door knocking softly while blocking the potent effects of estradiol and estrone. Even though it is the gentlest of the estrogens, doesn’t mean estriol is not effective for BHRT.

How to Take Estriol?
There are many ways to administrate estriol.  There are capsules, sublingual troches, creams, gels, vaginal suppositories.  You are not going to be able to get estriol from your local big pharmacy. Estriol can be found through compounding pharmacies.  Estriol is available online without a prescription. I am not familiar with the online brands. As I like to prescribe estriol from the compounding pharmacy, to keep track of exact doses, fillers, excipients, and forms of administration.  Below as I explain the uses of estriol, I will delve into some of the forms of administration for each application.

What is Estriol Used For?
Estriol is used for bioidentical hormone replacement (BHRT).  Estriol can be helpful for women going through symptoms of perimenopause and menopause.  Estriol is very beneficial for skin integrity and mucous membranes. It also stimulates estrogen receptors causing a gentle reaction for stimulating estrogen activity.  Based on this estriol has quite a few uses for women that I am going to describe below.

Vaginal Atrophy:  After menopause, the ovaries cease to produce estrogen.  This is a natural transition of life. But one of the most common complaints I hear about is pain with intercourse.  The vaginal cells need estrogen to mature. Without estrogen, the vaginal cells are what is called, parabasal cells. These are immature vaginal cells.  Commonly on a pap smear in a postmenopausal female, the report will read, predominantly parabasal cells. This causes pain with intercourse, sometimes even bleeding with intercourse because the tissues are so fragile. I have had women that cannot have penetration because of vaginal atrophy.

Conventionally gynecologists or your primary care will give you estradiol to apply topically to the vaginal cells. As mentioned above, estradiol is quite strong.  Usually, when given estradiol for vaginal atrophy, the estradiol will enter the bloodstream, stimulating more than just the vaginal cells with estrogen. Using estriol only for the vaginal tissues is much more effective for vaginal atrophy than estradiol.  Estriol is more specific for mucous membranes such as the vaginal tissues. And because it is so gentle, you can use a dosage that is helpful for the vaginal tissues, but it does not go into the bloodstream. There are many instances to use estriol for postmenopausal vaginal atrophy.  

For example, I would like to tell you about a patient of mine, Iris.  Iris had a hysterectomy at the age of 35 for bleeding and cysts and “female issue” as she put it.  It was commonplace 20+ years ago to simply remove the uterus and ovaries for any female condition. Currently, that might hold true in some circles, but most surgeons are not quite as scalpel ready as they were years ago.  Iris was 50 years old and had never taken hormones since her total hysterectomy (ovaries and uterus) fifteen years ago. Recently, Iris had met a man, and they had a real connection. Iris was over the moon in love and ready to spend her life with Jon.  But Iris admitted that she had concerns about intimacy. She told me that they had “tried, but it didn’t work.” While the average age of menopause is 51.5 years of age, Iris technically went through menopause at 35.

There was a lack of hormones for the past 15 years Iris would have otherwise made from her ovaries.  Needless to say, the lack of estrogen had caused quite a bit of vaginal atrophy. I was working with her for her osteoporosis and general health. Estradiol is amazing for bones, so the lack of estrogen for the last 15 years had caused Iris to become osteoporotic. But she was concerned because she wanted to have a sex life with Jon.  This might be TMI, but because of the lack of estrogen all these years, Iris could not have penetration due to the atrophy.

Iris’ gynecologist gave her Premarin to use vaginally.  She tried it once but didn’t want to take it because she did not want to take hormones or anything made from a horse’s urine.  That is her choice and not everyone, due to personal or family history may not be a candidate for hormone replacement. What worked for Iris and also helped make her feel comfortable “using hormones,” was estriol.  I had Iris apply a topical estriol cream nightly to her vaginal tissues for two weeks. Once that softened the tissues enough, I then had her use estriol vaginal suppositories. After eight weeks of treating with estriol Iris was able to have intercourse with Jon.  During this time, I still tested her blood to make sure the estriol and estrogen levels bloodstream were nonexistent. After that to keep the vaginal atrophy at bay, she used the estriol intermittently. To this day, both Iris and Jon make me blush, teasing that they are like a couple of teenagers.                        

Face, Neck, Decolletage:  Estriol is amazing for skin integrity.  Estriol has a better impact on the skin than estradiol.  Estriol helps to promote collagen growth in the skin. And estriol also helps the cells in the skin retain moisture keeping them plump.  With that said, I love to use estriol for wrinkles and the skin of the face, neck and upper chest. Applying a low dose to the skin can help build the collagen and plump up the cells to reduce wrinkles.  I commonly banter with patients, that estriol is so versatile, you can use it “up north and down south,” as in the case of Iris. Many pharmacies make their own combination estriol with a cream base to apply it to your face, neck, and decolletage. We all have different skin types and sensitivity, mixing a small amount of estriol with your favorite skin cream is great for wrinkles and anti-aging.  

Crooks of arms and upper knees:  When I was a young, naive girl of 19, an older friend of mine that worked with me at a local department store gave me some sage advice.  She said, in aging, the first to go was your knees. I was 19 and at the time more concerned with my thighs than my knees. But in my 40’s, I now know what she is talking about, the knees start to fall.  Applying just a small amount of estriol to the upper knees is an excellent way to battle gravity. After you apply estriol to your upper knees, what remnants are on your fingers you can rub on the crooks of your arms by your elbows.  If you are in your 40’s or beyond, then you know exactly what I am talking about.

Libido and vaginal sensitivity:  As mentioned above, estriol is fantastic for vaginal atrophy or dryness.  But applying estriol to the vaginal tissues can help with sensitivity and libido.  There is an enormous number of nerve endings in the vaginal area around the clitoris.  Estrogen helps to mature the cells in the vagina. The lack of estrogen in menopause or perimenopause can cause the cells to shrink, causing less stimulation during intimacy.  Many perimenopausal and menopausal women tell me that they have a hard time achieving an orgasm. Or that it “takes forever’ to have an orgasm. And when they do, it just is not as intense as it used to me.  

They also report that during any type of sexual activity they don’t feel as stimulated as they used to be.  Estriol can help mature the vaginal cells so that the stimulation and sensitivity is more intense. By maturing the vaginal cells, it helps with blood flow to the area when aroused.  Estriol is only applied 2-4 times a week to help with vaginal tissues. And I always tell my patients, if for some reason you apply the estriol to your vaginal tissue and then spontaneously have sex right after.  I promise you that is that tiny bit of estriol gets on your male partner, nothing will happen.

Urinary stress incontinence: Estriol is great for improving the tonicity of skin tissues.  Urinary stress incontinence is a very common aggravating issue with a lot of women. There are many reasons for urinary incontinence.  It can be from the bladder has fallen, or the uterus is pressing on the bladder. Commonly with urinary incontinence, the urethra is soft and lax.  The urethra is the tube the connects the bladder to the outer world. I liken the urethra to the elastic waistband of your underwear. If the waistband is lax and loose, then you are always pulling it up.  If the urethra is lax, it cannot hold urine in the bladder as well. Coughing, laughing or exercise and cause a little leakage. If the urethra is loose, women report, if they need to urinate, find a bathroom right away.  There is an urgency to use the bathroom right away if you need to urinate. Estriol is great to help tonify the urethra. Estriol can tighten and strengthen the urethra for urinary incontinence.

Balances Estradiol:  As mentioned above estriol can help rein in the negative effects of estradiol.  Estradiol is the most common form used to hormone replacement. But because of the potency of estradiol, there can be many side effects associated with it.  By implementing estriol with estradiol for BHRT, you can reduce the negative side effects of estradiol. But at the same time maintaining the highest effectiveness of hormone replacement.  With compounding pharmacies, you can combine estriol with estradiol in any ratio. The most common ratio of estriol to estradiol is 80:20. Meaning there is 80% estriol to 20% estradiol in the combination.  But you can do 50:50 ratios, which I use in patients that have had previous conventional hormone therapy or those that need a stronger form of hormone replacement. Or even a 90:10 ratio in those that need just a small amount of estradiol.

Hormone-Sensitive Females:  Some women just cannot tolerate estradiol.  No matter how low the estradiol dose, some women still have unwanted symptoms.  This makes them a perfect candidate to use estriol for menopausal symptoms and BHRT.  For instance, my patient Abby, could not tolerate estradiol. Her gynecologist had put her on an estradiol patch, estradiol tablets, estradiol gels and she could not take any of them.  She would get symptoms of estrogen-dominance, such as weight gain, heavy tender breasts, moody, acne, sugar cravings and trouble sleeping. When she can to see me, I put her on a “biest” cream: which had 80% estriol and 20% estradiol.  

I moved the dose of biest up and down, and she still felt terrible. She would have symptoms of estrogen dominance such as breast swelling and tenderness. On the biest, Abby’s weight would continue to climb. When I lowered the biest, she still had huge breasts and multiple hot flashes.  Even changing the ratio of biest for 90% estriol and 10% estradiol, she still had symptoms of high and low estrogen at the same time. It wasn’t until I put her on estriol only that she felt better. As soon as I did an estriol only cream, Abby lost 12 pounds, hot flashes and night sweats ceased, and she felt as she called it, “normal.”  

When people think of bioidentical hormone replacement, they think estrogen.  But we make estrone, estradiol, and estriol as our “estrogen.” I think it is important to stress that these estrogens are not similar, but far different from each other.  Estrone is unwanted and mainly made in teenagers. Estradiol is super strong and has both good and bad sides to it. Estriol, on the other hand, is gentle. But don’t be fooled by estriol thinking it is weak.  It can be used alone for vaginal atrophy and skin integrity. Or it can be combined with estradiol to offset the potency and side effects of estradiol. In some cases, estriol alone is sufficient enough for BHRT.  Either way, estriol is extremely versatile and should be considered an unsung hero for BHRT.

Hopefully, this gave you a better understanding of some of the potential uses for estriol. If you have any questions, please leave a comment below, or send an email to [email protected]