Estradiol and Premarin are menopause hormone therapy (MHT) drugs prescribed to relieve several menopause symptoms. Although both are forms of estrogen therapy and their intended purpose is similar, Estradiol is a bioidentical (natural) hormone created to mimic the potency of estrogen produced by the body. Whereas, Premarin is a conjugated equine estrogen – a synthetically manufactured mixture of estrogens derived from pregnant mare’s urine.
While both are considered effective methods of MHT, understanding the differences between bioidentical and synthetic hormones and their various application methods could make all the difference to symptom relief and quality of life during the menopause journey.
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What is Estradiol?
Estradiol is the most potent form of estrogen produced in the female body. To treat menopause symptoms, estradiol is sourced from plants like yams or soy and processed in a lab to resemble the molecular structure of ‘natural’ estradiol.
What is Premarin?
Premarin is a synthetically produced conjugated equine estrogen from a mixture of estrogens found in pregnant mare’s urine. Hence the name Pregnant Mare Urine. Estrogens included in Premarin, such as estrone sulfate and equilin, are not naturally found in the human body.
Both are helpful and effective forms of MHT, depending on the individual’s overall health, needs, and menopause symptoms.
Estradiol vs Premarin: Similarities and Differences
Estradiol and Premarin are both types of estrogen therapy used to treat menopause symptoms and improve quality of life throughout the menopause transition. However, although Estradiol and Premarin have some similarities, they are also different in several ways.
Similarities
- Both provide estrogen to the body to supplement declining estradiol levels
- Both are prescribed for menopause hormone therapy (MHT) to relieve symptoms like hot flashes, vaginal dryness, pain during sex, and mood alterations
- Both are available as forms of systemic or local hormone therapy
- Both are effective in preventing osteoporosis and heart disease after menopause
- Both require a prescription
Differences
- Estradiol estrogen therapy is bioidentical, whereas Premarin is a synthetic hormone.
- Estradiol estrogen therapy is molecularly identical to the estradiol made in the body. While Premarin, as a conjugated equine estrogen, contains estrogens not naturally found in the body, such as estrone sulfate and equilin
- Risk of blood clot with Estradiol is minimal due to its body compatibility, whereas the use of non-human estrogens in Premarin can increase this risk slightly
- Premarin is not available as a patch, gel, spray or vaginal ring and Estradiol is.
Why Estrogen Therapy May Not Be Suitable?
Although safe and effective for most, systemic Estradiol and Premarin may not be recommended for those with a history of breast cancer or certain reproductive cancers.
Local hormone therapy, which treats only genitourinary symptoms of menopause (vaginal dryness, pain during sex, urine leaks, recurring UTIs, and vulvar irritation) is safe for almost everyone.
Local hormone therapy is administered via a vaginal cream, ring, or insert, and systemic hormone therapy includes pills, patches, gels, rings or sprays.
While research shows that estrogen pills can slightly increase the risk of clotting and stroke, transdermal estrogen administered via patches, rings, gels, or sprays poses no additional risk of clotting or stroke because estrogen is absorbed through the skin rather than passing through the liver.
Before starting any form of hormone therapy, it’s important to discuss underlying conditions, medication, or supplements with a menopause expert.
How to Know Which Type of Hormone Therapy is Right for You?
To understand the variables of MHT and which one is right for you, it’s always best to start with an evaluation from a menopause expert. An initial consultation will include questions about your medical history, symptoms, age, menopause journey so far, underlying conditions, and whether you’ve had a hysterectomy.
It’s vital to answer openly and honestly to help the healthcare provider prescribe the most suitable type, dose, and combination of MHT for you.
For those who can’t find a menopause expert in their area, Intimate Rose offers an online consultation with a licensed menopause expert and a personalized hormone treatment plan after a free menopause assessment.
Instead of waiting weeks for an appointment and making regular trips to the pharmacy to collect your prescription, Intimate Rose will deliver your personalized hormone therapy straight to your door.
What Is Estrogen and Why Is It Important During Menopause?
Estrogen is a female sex hormone produced by both males and females, but is more abundant in women. Estradiol, estrone, and estriol are the three types of estrogen produced by the female body (by the ovaries more specifically), estradiol being the most powerful during the reproductive years. In addition to supporting menstruation, pregnancy, and breastfeeding, estrogen also contributes to brain function, heart health, bone density, muscle tone, vaginal health, and skin elasticity.
Once perimenopause begins, estrogen production starts to gradually decline as the reproductive phase of life comes to an end. However, due to its supporting role throughout the body, lower estrogen levels, estradiol in particular, also affect other body systems, such as the brain, bones, heart, muscles, and skin.
These side effects of lower estrogen levels are what we label ‘menopause symptoms’ and they can include, hot flashes, mood swings, heart palpitations, dry skin or vaginal dryness, loss of muscle tone & weight gain, stress, anxiety, and more.
Therefore, MHT, using either bioidentical estradiol or conjugated estrogen, is prescribed to alleviate perimenopause symptoms and improve quality of life throughout the menopause journey.
Women undergoing estrogen therapy whose uterus remains intact will also be prescribed a bioidentical progestin, or synthetic progesterone, to prevent the uterine lining from thickening with estrogen-only therapy. However, those after a hysterectomy will not require progesterone or progestin.
Is MHT Safe?
Yes, contrary to confusing media reports, MHT or hormone replacement therapy (HRT) as it was previously known, is safe and helpful when prescribed in line with each woman’s menopause symptoms & medical history, and routinely monitored by the patient’s healthcare provider.
In addition to easing menopause symptoms such as hot flashes, mood swings, and vaginal dryness MHT also lowers the risk of developing osteoporosis, and heart disease after menopause.
It’s no secret that MHT faced scrutiny in the early 2000s after a study called the Women’s Health Initiative (WHI) suggested that it increased the risk of cancer, heart disease, and stroke for all women. However, further re-evaluations of the WHI study by additional experts found errors in how the study data was interpreted and showed that the implied risks did not apply to all women.
Since then, it has been recognized that one type of MHT does not suit all women, and different combinations, doses, and administration methods have been developed to cater to each woman’s needs. Monitoring each version of MHT also helps to prevent increased risks of cancer, heart disease, and clotting.
In light of this, important criteria now taken into account before prescribing MHT include: age, menopause symptoms, family history, where the individual is on their menopause journey, and whether they’ve had a hysterectomy.
It is therefore recommended that women seeking relief from menopausal symptoms consult with a menopause expert (many GPs lack specialized training for menopause) to determine the correct MHT type, dose, combination, and application method to alleviate their unique symptoms.
What is Bioidentical and Synthetic Hormone Therapy?
The difference between bioidentical and synthetic hormones used in MHT is their molecular structure, source of origin, and potential side effects.
Bioidentical hormones, such as Estradiol, are derived from natural sources (like yams or soy) for their molecular similarities to natural hormones produced in the body. Bioidentical hormone therapy is widely recommended by menopause experts as it is as close to the body’s natural hormones as you can get and appears to have a decreased risk of developing blood clots.
Synthetic hormones do not resemble the molecular structure of natural hormones produced by the body, which can result in additional side effects, including risk of blood clots for some. Additionally, Premarin is not available in as many formulations as estradiol which can be very important in figuring out the best menopausal regimen. Because Premarin contains a mixture of estrogens, this may provide a broader estrogenic effect for some women.
When taking Estradiol or Premarin, noted side effects may include bloating, breast tenderness, nausea, or bleeding.
Conclusion
Although both are forms of estrogen therapy, Estradiol and Premarin are different. Estradiol is available as a bioidentical hormone and replicates the natural estradiol (estrogen) made by the female body. Due to its body compatibility, Estradiol absorption may be easier and safer.
Premarin is a conjugated equine estrogen, sourced from the urine of pregnant mares, and includes forms of estrogen that are not naturally made in the human body. Therefore, absorption may not be as smooth as Estradiol, and side effects can be more significant for some.
Whether you are taking Estradiol or Premarin to reduce menopause symptoms, it’s important to follow up with a healthcare provider for regular check-ups. MHT types and doses can be easily altered, reduced, or increased for an improved and continued quality of life.
References
National Library of Medicine - Hormone Replacement Therapy - https://www.ncbi.nlm.nih.gov/books/NBK493191/
UCLA Health – 2002 HRT Study Comes Under Criticism - https://www.uclahealth.org/news/article/2002-hrt-study-comes-under-criticism
Mayo Clinic - Conjugated Estrogens - https://www.mayoclinic.org/drugs-supplements/conjugated-estrogens-oral-route/description/drg-20075319
News Medical – What Does Estradiol Do? - https://www.news-medical.net/health/What-does-Estradiol-do.aspx
Mayo Clinic - Estradiol (transdermal route) - https://www.mayoclinic.org/drugs-supplements/estradiol-transdermal-route/description/drg-20075306
WebMD – Types of Estrogen Hormone Therapy to Consider - https://www.webmd.com/menopause/which-type-of-estrogen-hormone-therapy-is-right-for-you