What Hormone Pills Shrink Fibroids? A Comprehensive Guide to Medical Options

October 8, 2025 •

4 min read

According to the National Institutes of Health, up to 80% of women develop uterine fibroids by age 50. When seeking nonsurgical solutions, many women wonder what hormone pills shrink fibroids effectively, and how these medical treatments differ.

Quick Summary

Hormonal medications, including GnRH agonists and antagonists, can temporarily shrink uterine fibroids by reducing reproductive hormone levels. Treatment duration is limited due to potential side effects, and fibroids often regrow after stopping medication, making patient goals critical for choosing treatment.

Key Points

GnRH Agonists Temporarily Shrink Fibroids: Medications like Lupron induce a temporary, reversible menopause-like state, causing fibroids to shrink significantly but requiring limited use due to side effects like bone loss.
Oral GnRH Antagonists Offer Longer-Term Treatment: Newer oral pills such as Myfembree and Oriahnn suppress hormones without the initial surge, often with 'add-back' therapy to manage side effects, allowing for treatment up to 24 months.
Fibroids Often Regrow After Treatment Stops: The shrinkage achieved with GnRH medications is temporary; fibroids typically grow back once the therapy is discontinued, which is an important consideration for patients.
Some Hormone Pills Only Treat Symptoms, Not Size: Medications like hormonal birth control pills and hormonal IUDs can effectively manage heavy bleeding but do not cause fibroid shrinkage.
Selecting a Treatment Depends on Personal Goals: Factors like fertility plans, symptom severity, and overall health are critical for determining the most appropriate medical, surgical, or minimally invasive approach.
Liver Safety Concerns with Other Modulators: Selective progesterone receptor modulators like ulipristal acetate are restricted or not approved in some regions for fibroid treatment due to rare but serious liver injury risk.

The Hormonal Link to Fibroid Growth

Uterine fibroids are non-cancerous growths that develop from the muscle tissue of the uterus. Their growth is heavily influenced by the female reproductive hormones estrogen and progesterone. These hormones cause the fibroids to grow, especially during the reproductive years. This dependency is the key reason why hormone-based medications are used to reduce fibroid size and manage symptoms. After menopause, when hormone levels naturally decline, fibroids often shrink on their own. Therefore, medical therapies are designed to mimic this low-hormone state.

GnRH Agonists: The Menopause-Mimicking Approach

Gonadotropin-releasing hormone (GnRH) agonists are a class of medication that works by inducing a temporary, menopause-like state. They achieve this by suppressing the production of estrogen and progesterone from the ovaries. Common examples of GnRH agonists include leuprolide (Lupron Depot), goserelin (Zoladex), and triptorelin.

How GnRH Agonists Temporarily Shrink Fibroids

Initially, GnRH agonists cause a temporary surge, or “flare-up,” of hormones, which can briefly worsen symptoms. However, continued use leads to a desensitization of the pituitary gland, effectively shutting down the ovarian hormone production. This hypoestrogenic state causes fibroids to shrink significantly, sometimes by as much as 50% after three to six months of treatment.

Key considerations for GnRH agonists:

They are typically administered via injection or nasal spray, not as a pill.
Use is generally limited to a short duration, such as three to six months, due to potential side effects.
Side effects can include menopause-like symptoms, such as hot flashes, vaginal dryness, and mood swings.
Long-term use can lead to significant and irreversible bone loss.
The effect is temporary, and fibroids will often grow back to their original size once treatment is stopped.

GnRH Antagonists: A Newer Oral Option

More recent developments have led to oral GnRH antagonists, which also suppress estrogen and progesterone but do so without the initial flare-up seen with agonists. They are often paired with “add-back” therapy, which involves low doses of estrogen and progestin. This combination manages the hypoestrogenic side effects like bone density loss, allowing for a longer treatment duration.

FDA-Approved Oral GnRH Antagonists

Myfembree: This is a once-daily oral tablet that combines relugolix (a GnRH antagonist) with estradiol and norethindrone acetate. It is approved for up to 24 months of use to manage heavy menstrual bleeding associated with uterine fibroids and has been shown to reduce fibroid size and symptoms.
Oriahnn: Similar to Myfembree, Oriahnn is a capsule combining elagolix (a GnRH antagonist) with estradiol and norethindrone acetate. It is approved to manage heavy bleeding from fibroids and can also be used for up to 24 months.

Comparison of Hormone Therapies for Fibroids


Feature	GnRH Agonists	GnRH Antagonists (e.g., Myfembree, Oriahnn)
Shrink Fibroids	Yes, significantly, but temporarily.	Yes, significantly, but temporarily.
Primary Goal	Pre-operative shrinkage or short-term symptom relief.	Long-term symptom and bleeding control (up to 2 years).
Mechanism	Causes temporary, full menopause-like state.	Blocks receptors to suppress hormones; often includes add-back therapy.
Administration	Injection or nasal spray.	Oral tablets.
Duration	Up to 6 months.	Up to 24 months.
Side Effects	Menopausal symptoms (hot flashes), bone loss.	Reduced menopausal symptoms with add-back therapy, but bone loss risk remains.
Regrowth	Common after treatment stops.	Common after treatment stops.

Other Hormonal Medications for Symptom Management

It is important to distinguish between medications that shrink fibroids and those that only control related symptoms like heavy bleeding. Many common hormonal treatments fall into the latter category.

Birth Control Pills, Patches, or Rings: These can manage heavy bleeding and regulate periods but do not typically shrink fibroids. Some women may even experience slight fibroid growth.
Progestin-Releasing IUDs (e.g., Mirena): This device releases progestin directly into the uterus, thinning the uterine lining and reducing heavy bleeding. It is effective for symptom relief but does not shrink fibroids.
Ulipristal Acetate (Esmya): This selective progesterone receptor modulator was shown to be effective in shrinking fibroids and controlling bleeding but its use is now restricted in the EU and not FDA-approved in the U.S. for this purpose due to reports of serious liver injury.

Choosing the Right Hormone Therapy

Selecting the best treatment depends on several personal factors. A healthcare provider will consider your age, overall health, symptom severity, desire to preserve fertility, and duration of required treatment. While GnRH therapies offer a powerful tool to reduce fibroid size, they are not a permanent solution and are most often used as a bridge to surgery or to manage symptoms temporarily before menopause. For those with milder symptoms or without fertility concerns, therapies focused on bleeding control may be sufficient.

Considerations Beyond Oral Medication

For many women, hormonal pills are just one part of a broader treatment plan. Minimally invasive options are available for those who want a longer-term solution without a major surgery. These include:

Uterine Fibroid Embolization (UFE): This procedure blocks the blood flow to the fibroids, causing them to shrink and die.
MRI-guided Focused Ultrasound Surgery (FUS): High-intensity ultrasound waves are used to destroy fibroid tissue non-invasively.
Myomectomy: Surgical removal of fibroids while leaving the uterus intact.

Discussing these options with your doctor can help you create a personalized treatment plan that aligns with your health goals.

Conclusion

While no hormone pill offers a permanent cure for fibroids, several hormonal medications can effectively shrink them and manage symptoms temporarily. GnRH agonists, such as Lupron, offer a potent but short-term solution, while newer oral GnRH antagonists like Myfembree provide a longer-term treatment option by combining hormone suppression with side effect-mitigating add-back therapy. For some, other hormonal treatments like birth control or hormonal IUDs manage symptoms without impacting fibroid size. The best course of action is always a discussion between a patient and their healthcare provider, considering individual needs and goals. Understanding these medical options empowers women to make informed decisions about their health and treatment journey. For more detailed information on treatment options, you can consult sources like the Mayo Clinic.

Frequently Asked Questions

GnRH agonists, like Lupron, have been widely used to significantly shrink fibroids, often by up to 50% within six months. However, GnRH antagonists in combination therapy, such as Myfembree and Oriahnn, also effectively shrink fibroids while providing longer-term symptom management.

With GnRH agonists, noticeable shrinkage and symptom relief can occur within two to three months of starting treatment. For GnRH antagonist combination therapies like Myfembree, patients may notice changes within four weeks, with full effects appearing later.

No, standard birth control pills, rings, or patches are not designed to shrink fibroids. They can help manage symptoms like heavy bleeding and pain, but some women may find that hormonal contraceptives cause fibroids to grow larger.

GnRH agonists create a temporary, menopause-like state by suppressing estrogen and progesterone. While effective, this can cause significant side effects, most notably bone density loss, which is why treatment is limited to short-term use.

GnRH agonists cause an initial hormone flare-up before suppression, requiring injection and having a shorter treatment window due to side effects. GnRH antagonists, available as oral tablets like Myfembree, block hormones directly without the flare and are combined with 'add-back' therapy to minimize side effects, allowing for longer treatment.

Yes, fibroids typically grow back to their original size once hormone therapy with GnRH agonists or antagonists is stopped. For this reason, these treatments are often used as a temporary solution, a bridge to surgery, or for symptom relief as a patient nears menopause.

Side effects for GnRH therapies can include menopause-like symptoms such as hot flashes, vaginal dryness, mood changes, and bone loss. The severity of these symptoms is often reduced with the 'add-back' therapy used in GnRH antagonist pills like Myfembree.