Posted on January 13, 2023
Estradiol.
- Main estrogen before menopause
- large amounts produced by developing follicle
- Also made in fat tissue, the lining of the uterus, liver, brain, bone, and muscle
- Level varies significantly through menstrual cycle. 30pg/ml up to 200-300pg/ml
- After menopause levels are 10-25pg/ml
- There are different patterns of estradiol change around menopause: some see a rise and a sharp drop (a common pattern for Caucasian), some see a rise and then a slow drop, for some it is flat (African American), and for others there is a slow decline (Hispanic and Asian women).
Estrone
- Weaker estrogen
- Can be converted into estradiol and vice versa
- Level doesn’t drop as much after menopause as estradiol does
Estriol.
- Seen in the placenta. No role in menopause.
Testosterone
- Made by the follicle, ovary, and adrenals
- Gradual loss with age related changes to adrenal
Progesterone
- Made by corpus luteum.
- Levels decline during menopause transition
Androstenedione
- Made from cholesterol
- Is converted to make estrone or testosterone
- Gradual decline with age
What is bioavailable?
Estrogen and testosterone are the major players as you age, and only the free hormones in the blood can interact with tissues. There is a binding protein called sex hormone binding globulin which increases as you age, leaving less free hormone in the blood. More SHBG means less available estrogen.
Can you test levels and should that guide treatment?
This is a tricky one. Many MDs talk about how hormone levels fluctuate, and they do not think levels help guide therapy for women over the age of 40. To explore this topic further, you can read more of my blogs on menopause.