Is Estriol Safer than Estradiol?

March 18, 2019

Is Estriol Safer than Estradiol?

Is Estriol Safer than Estradiol?

Estrogen therapy has been used for years to treat pre and postmenopausal women and hormone imbalances. It has been extensively studied and debated in the medical community. Hormone replacement therapy has many benefits for relieving hot flashes, vaginal dryness, and other menopausal symptoms. Most people assume that estrogen comes in one form and acts the same in the body. This assumption isn't correct.

Estrogen comes in three primary forms, produced in different parts of the body.

  •      Estrone (E1)
  •      Estradiol (E2), specifically 17-beta-estradiol
  •      Estriol (E3)

Since estrogen has various chemical structures some people want to know is estriol safer than estradiol? Medical research shows that estriol is the gentlest and most reliable form of estrogen in hormone therapy.

To understand why estriol is safer than estradiol, let's look at each of these types of estrogen and how replacement therapy works.



Levels of bioidentical estrogens fluctuate throughout a woman's cycle and life. Estrone is commonly referred to as the menopause estrogen because levels increase around puberty and menopausal women. Hormone replacement therapy usually doesn't include estrone to improve women's health since high levels cause cancerous cells to grow and increases the risk of breast cancer.


Estradiol is the strongest of the three bioidentical hormones. The hormone is produced in the ovaries and used to treat estrogen deficiency.  Women have an abundance of estradiol, but it decreases as menopause approaches. People then turn to bioidentical hormone therapy using estradiol or synthetic versions. Research shows that bioidentical hormones are safer than synthetic versions since they produce fewer side effects. Commonly used synthetic versions are used in hormonal contraceptives to prevent pregnancy.


Estriol is considered the safer or more efficacious natural hormone. Women produce high amounts of estriol during pregnancy. Estriol grows the lining of the uterus to support a healthy nine months. Due to its weaker form, estriol isn’t commonly used in bioidentical hormone replacement, but a renewed interest has revealed that estriol is safer than estradiol in treating symptoms of menopause. Bioidentical hormones mirror the exact hormones produced in the body, rather than being synthetically created to imitate natural hormones. Synthetic medicines whether in pill form, gels, or creams can have more adverse side effects than bioidentical hormones made from equine estrogen.

Estrogen Hormone Replacement Benefits:

  •      Improves menopausal symptoms (hot flashes, vaginal atrophy, mood swings)
  •      Helps prevent bone loss
  •      Reduces urinary tract infections
  •      Promotes heart health
  •      Prevents heart disease and heart attacks
  •      Healthy and beautiful skin
  •      Increases sexual libido

Research shows that menopausal hormone therapies should include both estradiol and estriol to receive the fullest benefit.

Even though clinical trials show strong benefits for bioidentical hormone therapy using estrogen, other studies have shown harmful side effects and increased cancer risk. It's important to consult with your health care professional to find the right dose and medicine for your needs.

Regardless of where you stand on the bioidentical hormone debate, estriol is safer than estradiol. However, both can provide health and wellness for those suffering from hormonal imbalances or struggling with menopause symptoms.

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