Did you know your body is full of chemical messengers that help regulate your various organs and body systems? There are at least 50 such chemicals, called hormones, in the human body. Their levels and when they’re present can affect your growth, reproductive system, metabolism, and more.
Hormonal imbalances (when hormone levels are higher or lower than typical for your sex and age) can have serious effects on how your body develops and functions.
Hormone levels and presence vary across our lifetimes, and there are some sex differences as well. Two kinds of hormones that most bodies have some levels of are estrogen and progesterone.
These hormones are mostly associated with female sexual development and play important roles here. But all bodies, including males and people who are intersex, produce these hormones.
Read on to learn more about the roles of estrogen and progesterone, and how we might maintain our best hormonal balance.
In this article, we use “male” and “female” to refer to someone’s sex as determined by their chromosomes, and “men” and “women” when referring to their gender (unless quoting from sources using nonspecific language).
Sex is determined by chromosomes. Gender is a social construct that can vary between time periods and cultures. These aspects are acknowledged to exist on a spectrum, both historically and by modern scientific consensus.
Estrogen and progesterone based hormone treatments are used by trans and cis women alike.
Both these hormones are important in all human bodies.
It’s beneficial for all human bodies to produce estrogen in some form, but the exact types will depend on your sex:
- Female bodies typically produce estrone, estradiol, and estriol.
- Male bodies typically produce estrone and estradiol.
- Intersex bodies may produce any combination of estrone, estradiol, and estriol.
In female bodies, the ovaries mainly produce estrogen. Fat tissue, adrenal glands, and the brain can make it too. In males, fatty tissues typically produce estrogen. Enzymes can also convert it from excess testosterone.
Estrogen has several functions but is best known for its essential role in female growth and reproductive development. It helps maintain the menstrual cycle and facilitate the preparation of the uterus for anticipated and actual pregnancy.
Estrogen is also necessary for all human bodies to ensure proper bone growth and health, optimize brain function, and regulate mood.
All people also have varying levels of progesterone in their bodies. Like estrogen, progesterone is often linked to its presence and effects on female bodies, but it’s also found in male and intersex bodies.
Progesterone is a steroid hormone that plays a key role in preparing all human bodies for reproduction. In females and some intersex people, most progesterone is produced by the corpus luteum. It’s a temporary gland that emerges in the second half of the menstrual cycle after ovulation.
Sometimes, doctors prescribe synthetic progesterone (progestin) for:
- menopause symptoms
- irregular periods
- birth control
Increased levels of progesterone signal the female body to thicken the lining of the uterus to accept a fertilized egg. If an egg is fertilized, the body continues to produce progesterone throughout pregnancy to support the developing fetus.
Progesterone is also necessary to prepare the breasts for milk production.
Levels of progesterone that are too low can have significant effects on:
- overall health
Like estrogen, progesterone has far-ranging effects on male, female, and intersex bodies. In males, an increase in progesterone typically leads to an increase in the body’s estrogen levels.
Besides playing a role in sexual development,
- maintaining fat tissue
- stimulating weight gain and appetite
- maintaining optimal central nervous system and kidney function
- regulating behavior
- regulating the immune, cardiovascular, and respiratory systems
- maintaining bone health
Take a look at the chart below to compare the differences and similarities of estrogen and progesterone.
|cancer (breast and uterine)||High levels of estrogen are associated with an increased risk of certain cancers.||Synthetic progesterone (progestin) has been linked to increased breast cancer risk.|
|mental health||Estrogen treatments have been known to lower the risk of depression in postmenopausal women.||Progesterone is thought to play a role in regulating behavior.|
|menstrual cycles||Low and high levels of estrogen are linked to menstrual problems.||Low levels of progesterone have been linked to menstrual problems.|
|menopause and premature menopause||Low levels of estrogen are linked to menopause and premature menopause.||Low levels of progesterone are linked to menopause and premature menopause.|
|pregnancy||Estrogen is necessary for preparing the body for pregnancy.||Progesterone is necessary for maintaining a pregnancy.|
|conception||Estrogen is necessary for conception in a female or intersex body.||Progesterone is necessary for conception in a female or intersex body. In males, progesterone is necessary for the production of semen (sperm).|
|weight gain||High levels of estrogen are linked to weight gain.||High levels of progesterone are linked to weight gain.|
|bone health||Low levels of estrogen are linked to poor bone health.||Low levels of progesterone are linked to poor bone health.|
|brain function||Low levels of estrogen are linked to diminished brain function.||Low levels of progesterone may impair central nervous system function.|
|puberty and secondary sexual characteristics||Low levels of estrogen are linked to a lack of development of female secondary sex characteristics. High levels are linked to the development of female secondary sex characteristics.||In females and some intersex people, progesterone plays a key part in the menstrual cycle. In males and other intersex people, its presence triggers the production of estrogen.|
Today, there are many birth control options on the market.
When it comes to birth control pills, there are two main options. One contains both estrogen and progesterone, and the other contains only progesterone.
The combination estrogen-progesterone pill works by stopping your body from ovulating each month. The progesterone-only pill works by thickening the mucus at the entrance of your uterus to prevent sperm from passing through to fertilize an egg.
If you’re taking birth control pills, you can expect
Which side effects you may experience depend on the type of pills you have been prescribed and your body’s natural levels of hormones.
The most common side effects of combined estrogen-progesterone pills include:
- breakthrough bleeding between periods
- abdominal cramps
- breast tenderness
- increased vaginal discharge
- decreased libido
- slight decrease in bone mineral density
- increased risk of blood clots and cardiovascular issues
The most common side effects of progesterone-only pills include:
- unscheduled or irregular menstrual bleeding
- acne flareups
- increased risk of follicular ovarian cysts
Avoid taking combination birth control pills if you smoke cigarettes and are over age 35, or if you have experienced:
- blood clots
- breast cancer
- cardiovascular problems
- high blood pressure
- migraine episodes with auras
- severe diabetes or liver disease
Avoid taking the progesterone-only pill if you’ve had:
- breast cancer
Both estrogen and progesterone naturally diminish in the body over time.
Females and intersex people who are going through menopause may experience difficult side effects during menopause, such as hot flashes, vaginal dryness, and mood changes.
However, estrogen-only or estrogen-progesterone therapy can help alleviate some menopause symptoms and also reduce the risks of osteoporosis for people with bone loss.
The risks of taking hormone replacement therapy (HRT) are similar to those associated with taking birth control pills.
During menopause, taking estrogen without progesterone can increase the risk of endometrial cancer. When your body no longer sheds its endometrial lining (having your period), cells can build inside your uterus. Progesterone helps by thinning the lining of the uterus, reducing the risks of cell overgrowth and cancer.
However, if you’ve had a hysterectomy, it’s safest to take estrogen alone. It has fewer long-term risks than the combination therapy.
Transgender women and gender nonconforming or intersex people
Both estrogen and progesterone can lead to the development of female secondary sex characteristics, including in transgender women. It can also help to improve their bone health.
When administered as a part of gender affirming hormone therapy, your doctor may also prescribe a medication that blocks the function of testosterone (the key hormone in male sexual development) to increase the feminizing effects on the body.
While gender affirming hormone therapy can help alleviate gender dysphoria and improve one’s quality of life, it carries the usual risks of taking estrogen and progesterone.
Estrogen cream vs. progesterone creams
Hormone therapies, for trans and cis women alike, may be recommended in the form of creams applied to the genitals or the skin. These creams are most frequently used to treat vaginal dryness during menopause.
The National Women’s Health Network states that estrogen and progesterone creams are safe to use for menopause treatments. They’ve been shown to be one of the safest ways to treat some menopause symptoms.
However, this style of treatment is fairly low dosage, and less research exists on their higher dosage use in trans women.
Because there’s a known increased risk of breast cancer with these medications, make sure to discuss any needed changes in your screening routine with your doctor.
In the body, the hormones estrogen and progesterone can be seen as “talking to” each other. Progesterone’s function influences estrogen’s levels and vice versa.
Estrogen dominance is a state of increased levels of estrogen relative to progesterone. It occurs when the body makes too much estrogen or metabolizes it differently. Serious conditions are associated with estrogen dominance, such as:
Estrogen dominance is linked to progesterone deficiency in female bodies. Female bodies with estrogen dominance most commonly experience changes in menstruation as a side effect.
Progesterone dominance can lead to:
- the development of “feminized features”
- increased risk of cardiovascular problems
Estrogen and progesterone have reputations as hormones important in female sexual reproduction. But they are much more than that. They regulate the development of the bones, brains, and body systems in all bodies.
These hormones can be useful when used as therapies for birth control, gender affirming therapy, menopause treatment, and more.
The best advice for safely taking hormones of any kind is to closely follow your doctor’s recommendations and keep an open line of communication about any changes to your body.