What is estrogen and progesterone?

Estrogen, like all hormones, is a chemical messenger. It tells your body when to start and stop processes affecting your sexual and reproductive health. These processes cause important changes in your body.

Estrogen levels rise during puberty. The increase leads to secondary sex characteristics like breasts and changes in overall body composition (like curves).

Along with hormones made in your brain (FSH and LH) and progesterone, estrogen plays an important part in your menstrual cycle. These hormones coexist in a delicate balance to keep your periods regular. Estrogen plays a role in ovulation (when your ovaries release an egg) and thickens the lining of your uterus (endometrium) to prepare it for pregnancy.

Estrogen peaks in the days leading up to ovulation. This is your most fertile period. At the same time, estrogen thins your cervical mucus, a fluid sperm has to swim through to reach and fertilize an egg. These estrogen-induced changes make it easier for you to become pregnant if you have intercourse.

Regardless of where you are in your menstrual cycle, the presence of estrogen makes it more comfortable to have intercourse. It keeps your vaginal walls thick, elastic and lubricated, reducing pain associated with penetrative sex.

Estrogen levels drop during perimenopause, the time right before menopause. Perimenopause may last several years before menopause. Menopause officially begins when you don’t have a period for 12 months. It usually happens around age 51. With menopause, your estrogen levels drop and you no longer ovulate. The decrease in estrogen may lead to symptoms like vaginal dryness, mood changes, night sweats and hot flashes.

The primary estrogen in your body changes from estradiol (E2) to estrone (E1) during menopause.

Estrogen affects the reproductive health of people who are assigned male at birth (AMAB), too. In cisgender men, transgender women and nonbinary people with penises, estrogen impacts sex drive and the ability to get an erection and make sperm.

Too little estrogen can lead to a low sex drive. Too much of it can cause infertility and erectile dysfunction. Excessive estrogen can cause gynecomastia, or enlarged breasts.

If you’re assigned male at birth and concerned about your estrogen levels, speak with an endocrinologist or a functional medicine specialist for help.

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:

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.

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:

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, research suggests progesterone is necessary for:

Table of contents

You can think of hormones as chemical messengers that regulate the systems in the body. [1] They send signals to those systems to tell them when it’s time to get a move on, coordinating all sorts of changes and effects. As a human, you have over 50 different hormones—and two of these hormones are estrogen and progesterone.

Estrogen and progesterone are best known for their effect on the sexual development of women and people assigned female at birth. However, these hormones also impact many other systems in the body. [2] As a result, men and intersex individuals need some estrogen and progesterone, too.

To understand the roles estrogen and progesterone play within the body, it can help to define these two hormones and break down their differences. We’ll also explore their part in regulating female fertility and menstruation.

Estrogen is a sex hormone that most people start producing during puberty. [3]

Females produce most of their estrogen within their ovaries. Some of their estrogen is also created within the adrenal glands, fat tissue, and brain. During pregnancy, the placenta secretes some estrogen, too. [3]

Females naturally produce three types of estrogen, whereas males only produce two. The three types of estrogen are: [3]

The functions of estrogen vary, depending on sex, age, and pregnancy status. In women and people assigned female at birth, estrogen’s primary roles are to: [3]

In men and people assigned male at birth, estrogen helps regulate libido, erectile function, and sperm production. [3]

Estrogen also has non-reproductive functions. Whether you’re a male, female, or intersex, estrogen can impact your: [3]

As you can see, estrogen has a wide range of essential functions. For this reason, it’s important to maintain healthy levels of estrogen for your sex and age. If estrogen becomes too low or too high, you can develop certain health issues. [3]

Estrogen naturally decreases in females as they approach menopause. [3] Some females may also see a drop in estrogen in response to certain health issues. No matter what the cause is, low estrogen in females is often characterized by: [3]

In males, low estrogen levels may lead to a lower sex drive, bone loss, and the development of excess abdominal fat. [5]

While you don’t want estrogen levels to be too low, you don’t want them to become too high, either. If estrogen levels exceed progesterone levels, you may develop a condition known as estrogen dominance. [6]

Some potential signs of estrogen dominance in females include: [6]

Males with estrogen dominance may experience infertility, erectile dysfunction, or gynecomastia (enlargement of the breasts). [6]

Estrogen dominance can develop naturally in response to insulin resistance, excess stress, or intestinal dysbiosis. [7] You can also take in too much exogenous estrogen from hormonal contraceptives, hormone replacement therapy, certain foods, or exposure to synthetic xenoestrogens.

Like estrogen, progesterone is a sex hormone that’s found in female, male, and intersex bodies in varying degrees. [8] Progesterone is derived from cholesterol.

Females produce most of their progesterone in the corpus luteum, which is a temporary endocrine gland that arises after ovulation. [2] Some female progesterone is also secreted in the ovaries and adrenal glands. During pregnancy, the placenta takes over a portion of progesterone production.

Males produce progesterone in their testes and adrenal glands.

Like estrogen, progesterone has both reproductive (sex-specific) and non-reproductive functions.

In females and people assigned female at birth, progesterone can: [2]

If a female doesn’t become pregnant after ovulation, the corpus luteum goes away, causing progesterone levels to drop and menstruation to begin.

If a female does become pregnant, progesterone helps to: [2]

In males and people assigned male at birth, progesterone plays a role in semen production. [9] It also serves to combat the development of estrogen dominance.

In people of all sexes, progesterone can help regulate a variety of systems. Most notably, this hormone can impact brain function, bone health, and the cardiovascular system. [10]

Like estrogen, low progesterone can impact menstruation, libido, fertility, and weight management in women. [11]

Low progesterone may present serious problems when it comes to pregnancy. Since progesterone is crucial for a healthy pregnancy, low levels are associated with an increased risk of miscarriage or premature birth.

In males, low progesterone levels may result in estrogen dominance and the associated symptoms discussed earlier.

As you can see, estrogen and progesterone work together to support healthy reproduction. They also play a role in several other important processes within the body.

Despite their similarities, estrogen and progesterone have some key differences in how they operate within the body. These include the impact they have on:

Estrogen and progesterone are both equally important for the healthy functions of the body. If they’re at proper levels, these two hormones can support your optimal health and wellbeing.

The only time this question may be relevant is in regards to hormonal contraception. For some people, hormonal contraceptives with both estrogen and progestin may work better. But others may prefer to take a progestin-only pill.

All hormonal contraceptives may cause some side effects. For instance, combination pills may be more likely to cause headaches, nausea, libido disruptions, breast tenderness, abdominal cramping, and blood clots. In contrast, progestin-only pills may be more likely to cause follicular ovarian cysts and acne. [16]

Both types of birth control pills can cause breakthrough bleeding, especially during the first few months of a new birth control prescription.

You can ask your healthcare provider which type of birth control is better suited for you based on your unique health factors and family history.

By now, it should be clear that everyone needs a certain amount of progesterone and estrogen in their bodies—females, males, and intersex people alike.

But what if you experience a hormone imbalance? If if you’re concerned that your estrogen or progesterone levels aren’t where they should be, you have options. You can have your hormone levels checked at a healthcare provider or by taking an at-home health test. This is a crucial step if you want to learn how to increase estrogen naturally. Then, they can suggest hormone therapy or hormone replacement options to help you reach a healthy estrogen and progesterone level.

Are you curious about your hormone levels or how to test estrogen levels at home? If you’re experiencing menstrual irregularity, issues becoming pregnant, or any of the other symptoms we discussed above, you may want to have your hormone levels checked.

At Everlywell, we offer an easy at-home Women's Fertility Test. This test checks five key fertility hormones, including estradiol, luteinizing hormone, follicle-stimulating hormone, thyroid-stimulating hormone, and total testosterone. Once you send in your blood sample (collected with an easy finger prick), we test it at one of our CLIA-certified labs and have one of our independent board-certified physicians review your results.

Are you ready to gain insight into your hormonal health? Order your Everlywell Women’s Fertility Test today.

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What is a Follicle on the Ovary?

Progesterone and estrogen are the two most important hormones in the female body. These are steroid hormones that are responsible for various female characteristics in the body. The ovaries are a pair of ova-producing organs (that is, they produce egg cells) that maintain the health of the female reproductive system.