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E & P

This post is dedicated to learning about these two hormones, the roles they play within our body, and what may happen if they become imbalanced.



Estrogen is one of our main sex hormones and it comes in 3 different forms:

  • Estrone (E1): is mostly a storage form or a metabolite form. It is the most common form of estrogen found in post-menopausal women.

  • Estradiol (E2): is our MAIN form of estrogen. It is made mostly by our ovaries but also by our adrenal glands (see how important these little guys are) and our fat tissue. Estradiol is the estrogen that fluctuates with our menstrual cycle.

  • Estriol (E3) : this form of estrogen is mainly present during pregnancy when made from the placenta. It can also be made in the liver from E1 and E2.

Estrogen receptors are found pretty much EVERYWHERE : brain, lungs, breast, liver, bladder, bones, joints, gastrointestinal tract, ovaries and uterus

So what does estrogen do for us?

  • Reproductive function : stimulates the growth of our reproductive organ and regulates our menstrual cycle

  • Bones : keeps our bones healthy and strong

  • Brain : keeps our mood elevated via increasing serotonin. Fluctuations in estrogen during our cycle can lead to fluctuations in our mood (see... we aren’t crazy!)

  • Heart: keeps our heart healthy and is protective from cardiovascular diseases

  • Skin : receptors in the skin allow estrogen to play a role in skin elasticity and strength

Estrogen is powerful and important.



Progesterone is produced mostly in the ovaries during ovulation and therefore dominates in the second half of our cycle (after ovulation).

Do any of you use your basal body temp to track ovulation? Well this increase in temp is due to progesterone

What does progesterone do for us?

  • Reproductive function : during our cycle progesterone helps prepare our body for pregnancy as well as maintain pregnancy if achieved

  • Brain: progesterone has protective effects in the brain including anti-inflammatory and anti-oxidant effects. It is being studied for its use in traumatic brain injuries which is SO cool (but for another post)

  • Skin : receptors in the skin allows progesterone to play a role in skin elasticity and strength

Like Estrogen, Progesterone wonderfully important too.



Now that we have gone through more about E & P we can place them in the context our our cycle

Our cycle has two phases: follicular phase and luteal phase

Phase 1: Follicular Phase

Days 1-14

Now this is going to be mind blowing: but our period (menses) is actually the beginning of our cycle (the first week or so) as opposed to the last week like we usually think. During this time both estrogen and progesterone are falling to their lowest and we are losing part of the lining of our uterus.

After this we are ready to begin trying for pregnancy again

Estrogen starts to increase more and more, our egg follicles are developing more and more, and the lining of our uterus is thickening more and more. There are two other hormones that play a role in this phase: LH and FSH

FSH is follicle stimulating hormone and therefore stimulates our egg follicles to develop and get ready for ovulation

LH is luteinizing hormone and it stimulates ovulation or the release of the egg from the ovary



we get a spike in Estrogen and an even bigger spike in LH. This signifies ovulation and the transition from follicular phase to luteal phase.

Just before, during, and just after ovulation is when our chance at pregnancy is at it's highest


Phase 2: Luteal Phase

Day 14 - 28

After ovulation E & P switch roles

Estrogen levels fall while progesterone levels continue to go up and up

This is because progesterone is released from the "corpus luteum" which is only formed after ovulation. You can think of the corpus luteum as the shell surrounding the egg before it got released (kinda weird I know). After the egg is released during ovulation these cells stick around to produce progesterone.

Progesterone's main role is to prepare our uterus for pregnancy. That is why you can see our uterine lining not only thickening but increasing in blood supply and secretions while progesterone is on the rise.

BUT if there is no pregnancy achieved, then progesterone (and estrogen) start to fall and HELLO it's our time of the month...

= Luteal Phase ends and we are back at the Follicular phase

That sums up our menstrual cycle


When talking about E & P there is one MAJOR concept we like to discuss...BALANCE !

When we talk about estrogen excess and deficiency, it is usually an imbalance of estrogen relative to progesterone. This post is about what occurs if E & P becoming imbalanced.

The most common case of this is referred to as : Estrogen dominance

Estrogen dominance

Estrogen dominance refers to too much estrogen RELATIVE to progesterone (too little progesterone).

Remember how we talked about how the second half of the cycle is progesterone’s time to shine? Often times symptoms that occur during this part of the cycle can signify that estrogen is in excess and progesterone is in deficiency .

How can estrogen become dominant?

  • stress : is our hormone cascade getting shifted away from progesterone and towards cortisol?

  • poor diet: are we getting the right precursors? is our body in a thriving state?

  • birth control: goal is to prevent ovulation and without it we don’t make as much progesterone

  • our microbiome: certain bacteria can allow for recirculation of estrogen in our body

  • lack of ovulation

  • xeno-estrogens: substances we use in everyday life that cause hormone disruption in our bodies : pesticides, soaps and cosmetics, plastic bags and water bottles

Signs and symptoms:

  • irregular periods

  • heavy bleeding

  • weight gain

  • fibrocystic breasts

  • brain fog

  • mood swings

  • anxiety

  • depressed mood

  • decreased libido

  • food cravings

  • fatigue


Since we talked about what occurs during estrogen excess I felt like we should also discuss estrogen deficiency. This can also involve an E & P imbalance but is less common and less overt.

Estrogen deficiency

One of the main ways this occurs: communication breakdown

The signal for our body to make estrogen actually comes from something called our pituitary gland. Our pituitary gland releases two hormones called FSH and LH that basically tell our ovaries: “hey, secrete some estrogen”. Without this communication, we can end up with estrogen deficiency.

How can this happen?

Ever heard of an HPG axis? Otherwise known as Hypothalamic-pituitary-gonadal axis, which refers to the teamwork of all three of these components. The hypothalamus is part of the brain, the pituitary gland sits just below it and our gonads are of course, our ovaries.

If one component of this axis or many components aren’t working well together as a team then we can end up with dysfunction including estrogen deficiency.

Lifestyle factors that can affect this pathway and decrease estrogen:

  • over-exercising

  • eating disorders

  • high stress

  • as we age, our ovaries also stop responding as well

Symptoms of low estrogen:

  • absent periods

  • irregular periods

  • increased UTIs

  • hot flashes

  • breast tenderness

  • decreased vaginal lubrication

  • headaches and migraines

  • depression

  • trouble concentrating

  • fatigue

  • dry skin

  • insomnia

Menopause is an interesting case because it is low estrogen.. however there is can also be an estrogen dominance picture. How you might ask? Because although estrogen drops by as much as 60%, progesterone drops by about 90%. This can leave us with a higher estrogen to progesterone ratio = estrogen dominance symptoms.


So how can you find out if your E & P are in balance?

There are various ways to test your hormone levels – this includes through a blood test or saliva and urine samples. They all have their pros and cons but can be very beneficial in identifying an imbalance and providing guidance on where to focus.

If you just read through this whole post and thought wow this is me...

I have good news for you: there are many ways in which we can support our body and try and correct the balance between estrogen and progesterone.

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