Female Hormone Therapy FAQs Estrogen

Hello, I am Lee Dong-hee, director of Wooahan Women's Clinic, an Apgujeong OB-GYN clinic. When I explain menopausal hormone therapy in the clinic, the points patients are most curious about are surprisingly similar. Questions like "Is the pill dangerous," "Is the patch safer," "Does the drug put into the vagina have no systemic effect." The core comes down to one thing: even with the same hormone, the effect and risk change depending on which estrogen, how much, and by what route it is used. In this article, I will unpack frequently asked questions, centered on the type, dose, and route of administration of estrogen, together with academic society recommendations.

The hot flashes, sleep disturbance, vaginal dryness, and joint pain that come in menopause are not simply changes arising from getting older, but systemic changes that appear as estrogen decreases. In particular, vasomotor symptoms (VMS), in which the face flushes and cold sweats break out, are the most common symptoms in menopause and also greatly lower quality of life.

Female hormone therapy is recommended as the most effective treatment to date for these vasomotor symptoms. Both the Korean Society of Menopause and the North American Menopause Society (NAMS 2022) regard hormone therapy as a first-line recommended treatment in women with appropriate indications. However, since its effect and risk change depending on the formulation, dose, route of administration, and starting point, a process of designing it tailored to each individual is needed.

If you are at the point where symptoms are just beginning, reading together when to start menopausal hormone therapy and how long to continue it helps you grasp the whole picture.

It is reported that the risk of venous thromboembolism (VTE) changes depending on the route of administration. Synthesizing observational-study and meta-analysis evidence, oral estrogen is observed to somewhat raise the risk of venous thromboembolism and stroke, whereas transdermal (patch/gel) estrogen is observed not to clearly raise that risk. The NAMS 2022 recommendation also summarizes that the transdermal route and low doses can lower the risk of venous thromboembolism and stroke.

The reason lies in the difference in absorption route. The pill first passes through the liver and affects coagulation factors, but the transdermal formulation absorbed through the skin relatively bypasses this process. So in the clinic, we prioritize the transdermal route for people such as the following.

• Those who are obese or smoke
• Those with a personal or family history of thrombosis
• Those with conditions relatively unfavorable to oral formulations, such as migraine or hypertriglyceridemia

However, I want to emphasize that a considerable part of this evidence is observational studies, and that the judgment changes depending on the individual's underlying conditions and state. The assertion "the patch is unconditionally safe, the pill is unconditionally dangerous" is not appropriate. As seen in the article dealing with contraceptive pills and clot risk, even within the same estrogen class, clot risk differs depending on the type and route.

Low-dose local (vaginal) estrogen is reported to have very low systemic absorption. While being effective for genitourinary atrophy symptoms (GSM) such as vaginal dryness, painful intercourse, and recurrent urinary tract infections, it is observed not to raise the blood estrogen concentration to the point of exceeding the post-menopausal normal range. For this reason, the NAMS 2020 GSM recommendation presents low-dose vaginal estrogen as the first-line treatment for genitourinary symptoms.

Because absorption is low, there is a difference in the safety aspect as well. Unlike systemic therapy, low-dose vaginal estrogen is reported not to meaningfully raise the risk of thrombosis or stroke, and even if there is a uterus, progestogen combination or regular endometrial monitoring is generally not recommended as mandatory. In the clinic, those most reassured by this point are those with a history of breast cancer treatment or those who feel burdened by systemic hormones.

However, there are also clear limits. Vaginal estrogen is effective for local symptoms, but its effect on systemic symptoms such as hot flashes or systemic heat sensation is limited. So if genitourinary symptoms and systemic symptoms are present together, systemic therapy and local therapy are sometimes combined. The specific usage and cautions of local treatment are covered in more detail in the safe use of local estrogen and comparison of vaginal dryness treatment methods.

If you are curious whether hormone therapy is the right approach for you, we will first organize your symptoms and risk factors. Get a consultation on the hormone therapy route

The principle of dose setting is the minimum effective dose. It is a method of starting at the lowest dose within a range that sufficiently controls symptoms, and adjusting while watching the balance of effect and side effects. The NAMS 2022 recommendation also, while considering that low doses can reduce the risk of venous thromboembolism and stroke, recommends deciding the dose, duration, and route needed for symptom control tailored to the individual.

For example, with transdermal estradiol, you start at a low dose at first and then adjust while watching changes in symptoms. Since the dose unit differs for each formulation—gel, cream, patch—even the same "low dose" is adjusted to match the formulation.

There is one point patients often misunderstand here. The question "shouldn't we check with a hormone-level test whether the dose fits well?" In clinical experience, and per many study results, periodically measuring blood hormone levels such as FSH or estradiol during treatment is on the low side in usefulness for dose adjustment. Therefore, in the clinic, we track centered on changes in symptoms and safety rather than on levels.

It is to protect the endometrium. If someone with a uterus uses systemic estrogen alone, it is reported that the endometrium can proliferate excessively and the risk of endometrial cancer can rise. To prevent this, a progestogen agent is administered together, or a combined preparation in which estrogen and progestogen are combined is used.

The NAMS 2022 recommendation advises that, when using systemic estrogen in women who have a uterus, an appropriate progestogen sufficient to protect the endometrium be used together. Conversely, for those without a uterus who have had a hysterectomy, estrogen-only therapy without progestogen combination can be considered.

The type and usage of progestogen are also designed differently for each person. Whether to take it daily or cyclically, and which agent to use, differ depending on the bleeding pattern and individual preference. If you are worried about changes that may occur during hormone therapy, such as breast pain or breakthrough bleeding, looking in advance at breast pain during hormone therapy or menopausal hormone therapy side effects helps you prepare mentally. What examinations are needed before starting is organized in the tests to undergo before hormone therapy.

A revision of the FDA's warning wording has proceeded. In July 2025, the FDA held a public expert panel reassessing the risks and benefits of menopausal hormone therapy, and some experts presented the opinion that the risks of hormone therapy had been exaggerated in labeling all along. After subsequent gathering of opinions and review, in November 2025 the FDA announced that it would phase out the boxed warning on estrogen-containing hormone therapy products.

However, it is not appropriate to take this change to mean "hormone therapy is not dangerous." The core of the revision is that in hormone therapy started at a comparatively young time—within 10 years of menopause or before age 60—the benefits can outweigh the risks, and that it will reflect the risk differences by route, formulation, and starting point more accurately in the label. Also, the endometrial-cancer-related warning for systemic estrogen-only products is maintained as is.

In the clinic, we organize and guide on this trend as follows. Institutional recommendations are becoming more refined not in the direction of unconditionally recommending hormone therapy, but toward prescribing by more finely weighing the individual's risk level and starting point. In the end, what matters is the individualized judgment of "what are my risk factors, and what route and dose are right for me." If you want to see more on this topic, you can also refer together to news of the full reassessment of female hormone therapy.

Estrogen therapy is designed along four axes: type, dose, route, and starting point. If there are risk factors, prioritize transdermal; for genitourinary symptoms, use low-dose vaginal estrogen; and if there is a uterus, also review progestogen combination. Even with the same menopause, for some the patch fits better, for some local treatment, and for some combined therapy.

If menopausal symptoms shake your daily life, rather than searching alone and feeling anxious, we recommend organizing your risk factors and symptoms together. If you are curious about managing menopause overall, refer to menopausal hormone care and menopause screening, and feel free to inquire about any questions. Start a hormone therapy consultation by chat

Written by: Lee Dong-hee Director · Obstetrics and Gynecology Specialist · View medical staff profile

First published November 22, 2025 · Last reviewed May 30, 2026

References: The Menopause Society (NAMS) 2022 Hormone Therapy Position Statement (2022), NAMS Genitourinary Syndrome of Menopause Position Statement (2020), U.S. FDA Menopausal Hormone Therapy Labeling Update (2025)

This article is intended to provide general health information and does not replace individual diagnosis or treatment. If you have symptoms, please consult through a medical visit.