The Difference Between Estradiol and Estrogen

Medically reviewed by Isabel Casimiro, MD PhD

Estrogen is a major sex hormone in people born with a female reproductive system. There are three main forms of estrogen, and estradiol is one of them. Estradiol (medically known as E2) is important for the reproductive systembone health, and weight distribution. It’s considered to be the strongest type of estrogen in the body.

This article discusses estrogen and estradiol, outlining their function and providing tips on coping when levels fluctuate.

<p><a href="" data-component="link" data-source="inlineLink" data-type="externalLink" data-ordinal="1">Anna Mardo</a> / Getty Images</p>

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Function of Estradiol and Estrogen

Estrogen is a sex hormone. It's important for several bodily functions in males and females, including:

  • Sexual development and function

  • Menstrual cycle

  • Bone development

  • Heart health

  • Mood management

The human body produces three different estrogen types, one of which is estradiol (E2). E2 is the major estrogen present in the body during a person's reproductive years. It's vital for many different functions, including the maturity phase of the female reproductive organs and preparing the uterine wall for a fertilized egg to implant.

A small amount of estradiol is converted from another type of estrogen called estrone.

What Is Estrone?

Estrone is one of the three main types of estrogen. Here's how they break down:

  • Estrone (E1) is the main hormone present after menopause.

  • Estradiol (E2) is the main hormone present during the reproductive years.

  • Estriol (E3) is the main hormone present during pregnancy.

Specifically, estrone is produced in the body during the reproductive years and then remains to be the only estrogen present after the point of menopause. It's produced in the adrenal glands, body fat, and ovaries.

Location of Estradiol and Estrogen Production

The ovaries produce estrogen and estradiol. However, estradiol is produced in varying amounts depending on where a person is in their menstrual cycle and reproductive timeline.

Some smaller amounts of estradiol are produced in the adrenal glands, fat cells, breasts, and brain via cholesterol.

In males, estradiol is minimally produced in the testicles.

Why Do Estradiol and Estrogen Levels Fluctuate?

It's normal for hormone levels—in this case, estrogen levels—to rise and fall throughout your lifetime. Normal fluctuation can happen for many reasons, from age and health to stress or diet.

This can be particularly noticeable during specific points, like puberty and menopause. With estradiol, fluctuation occur at the following times:

  • Levels start to increase during puberty.

  • Levels rise and fall during the menstrual cycle.

  • Levels decline slowly as a person ages.

  • Levels decrease the most during menopause (the ovaries stop actively producing estrogen).

But hormone levels can also fluctuate due to a health condition, such as:

What is Ethinyl Estradiol?

A synthetic form of estrogen known as ethinyl estradiol is found in certain types of birth control, commonly in combination oral contraceptives. It can help regulate the menstrual cycle and may also help lower the risk of ovarian and endometrial cancers. Sometimes ethinyl estradiol is also used to help build bone density.

Taking a Blood Test to Confirm Estrogen Levels

blood test can help measure the amount of estrogen in your body. It's commonly used to test for levels of estradiol. This can help:

  • Diagnose an estrogen-related health condition, like menstrual cycle issues or infertility

  • Monitor treatments for infertility, hormone therapy, and some types of cancers

  • Monitor a pregnancy for congenital disabilities or high-risk situations

  • Diagnose a medical condition like thyroid disease or diabetes

Normal estradiol level results will vary based on a person's age and health condition. This typically looks like:

  • 30 to 400 picograms per milliliter (pg/mL) for ovulating females

  • 0 to 30 pg/mL for postmenopausal females

  • 10 to 50 pg/mL for males

How to Balance Estrogen Levels

While some fluctuation in estrogen levels is expected, levels that are too high or too low may need to be balanced. A healthcare provider may recommend a few ways to do this.

Lifestyle changes are often suggested to help even out estrogen levels, depending on the exact cause of the imbalance. Some possibilities include:

  • Maintaining a healthy weight

  • Reducing stress

  • Keeping exercise to a moderate level

  • Limiting alcohol

  • Implementing foods like soy that can help with balancing hormone levels

Medication treatments for addressing estrogen imbalances include:

  • Systemic estrogen therapy, in which estrogen works throughout the bloodstream via oral medication (pills), patches, or sprays.

  • Local estrogen therapy, in which estrogen is applied topically via a cream, vaginal ring, or tablet. This releases smaller doses of the hormone into the bloodstream.

Role of Sex Hormones in Males

Sex hormones are present in both males and females. Though estradiol is more pronounced in females, males also produce smaller amounts of estrogen in their testicles. This makes it key for several functions of male sexual development, including erectile function, sexual libido, and sperm production.

Weighing the Benefits and Risks of Estrogen Therapy

Before starting a prescription estrogen therapy, know that some pros and cons will need to be discussed with a healthcare provider based on your personal and family medical histories.

While an estrogen-only therapy can help address hormone imbalances and other symptoms, it can potentially increase the risk of endometrial cancer when used without another hormone. This type of treatment may also come with a small increased risk of stroke and blood clots from deep vein thrombosis (or DVT) and gallbladder disease.

Systemic oral estrogen therapy may pose more risks than topical estrogen therapy (in patches, sprays, or ring form).


Estradiol (known as E2) is a type of the sex hormone estrogen. Estradiol is the primary estrogen in the female body during childbearing years. While it supports the reproductive system and fertility, estradiol is also helpful in promoting bone and brain health. Estradiol levels usually fluctuate throughout a person's lifetime, though abnormally high or low E2 levels may indicate a health condition or other issue.