What is the Difference Between Estriol and Estradiol? | PYHP 036

Our bodies make three different forms estrogens:

• Estrone (E1)
• Estradiol (E2)
• Estriol (E3)

Estrone is usually considered an unhealthy estrogen.  It is still bioidentical, but you do not want loads of estrone around when you are balancing the hormones.  Estrone is common in young girls when they first get their periods and after menopause.  Estrone metabolites can raise the risk for cancer.  This is why you do not want a high level of estrone, which can also cause moodiness, feeling munchie, puffy and grumpy.  With bioidentical hormone replacement therapy (BHRT), we do not use estrone for the above reasons mentioned.

Estradiol is the strongest of the three bioidentical estrogens.  Estradiol is common in conventional hormone replacement in the form of oral, patches or transdermal.  Premarin and Prempro are not estradiol and are not bioidentical.  Because estradiol is the strongest of the estrogens, it has pros and cons to use.  

Pros of Estradiol:  

• Great for keeping bones strong
• Eliminating hot flashes and night sweats
• Neuroprotective for the brain
• Great for short-term memory and memory recall
• Helpful for libido and sex drive

Cons of Estradiol: 

• Estradiol likes to grow things.   (i.e. grow the lining of uterus, which can cause a risk of uterine cancer)
• Can cause spotting, bleeding, periods
• Grow breast tissue
• Cause breast tenderness
• Enlarge breasts which can be a risk factor
• Moody (weepy, irritable, anxious) 
• Can be similar to a 24/7 feeling of PMS
• Weight gain

Many women report gaining on average 6 to 8 lbs when taking conventional estradiol hormone replacement.  It is primarily in the breasts and stomach.
   
So how do we get the positive benefits of estradiol without the negative side effects? The best way to properly balance estradiol is to take estriol with it.

Estriol (E3):

Estriol is the gentlest form of estrogen.  Some people refer to it as the weakest form, but I think that is a misnomer.  When you combine estriol with estradiol you can get the beneficial effects of estradiol and estriol, without the negative side effects of estradiol.

Also, estriol is excellent for the skin and mucous membranes.  Often, we use estriol for vaginal dryness during menopause.  It is very beneficial for vaginal atrophy and pain with intercourse without any adverse effects.  We also use it for wrinkles and skin integrity.  Applying estriol topically can increase collagen and hydrate cells, which makes it especially great for reducing wrinkles.

Unfortunately, estriol is not available commercially.  You are not going to get estriol hormone replacement from your primary care doctor or gynecologist.  You are not going to get estriol from your big box pharmacy.  

However, Functional Medicine doctors that specialize in bioidentical hormone replacement will be very familiar with estriol and estradiol.  We use a combination of estriol and estradiol, which is known as Biest for hormone replacement.  Biest and estriol are both available from compounding pharmacies.  With compounding pharmacies, we can prescribe almost any dosing of Biest that we want based on the particular needs of the patient.  

Hopefully, this has been informative and helpful to you. If you have any questions or personal stories, please feel free to email us at [email protected].