Updated: January 25, 2026

What Is Megestrol? Uses, Dosage, and What You Need to Know in 2026

Author

Peter Daggett

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What Is Megestrol Used For?
What Forms and Strengths Does Megestrol Come In?
What Is the Typical Megestrol Dosage?
How Do You Take Megestrol?
Is Megestrol a Controlled Substance?
Who Should NOT Take Megestrol?

Megestrol acetate (Megace) is a progestin used to treat AIDS-related wasting, breast cancer, and endometrial cancer. Here's everything patients need to know.

Megestrol acetate — sold under the brand names Megace and Megace ES — is a synthetic progestin medication that has been in clinical use since the 1960s. Today it primarily serves two distinct patient populations: people living with HIV/AIDS who are experiencing significant unintentional weight loss, and patients with advanced breast or endometrial cancer. Here's a complete patient-friendly guide to this medication.

What Is Megestrol Used For?

Megestrol has two main FDA-approved uses:

AIDS-related anorexia, cachexia, and unexplained weight loss: The oral suspension formulation (40 mg/mL or the concentrated Megace ES at 125 mg/mL) is FDA-approved to stimulate appetite and promote weight gain in HIV/AIDS patients who are losing significant weight without a clear cause. Megestrol was approved for this indication in 1993.

Advanced breast and endometrial cancer: The tablet form (20 mg and 40 mg) is FDA-approved for palliative management of recurrent, inoperable, or metastatic breast cancer and endometrial carcinoma — cancers that are hormone-sensitive and have spread or cannot be removed surgically.

Off-label, Megestrol is sometimes used for cancer-related appetite loss outside of AIDS, hot flashes related to menopause or hormone therapy, prostate cancer symptom management, and endometriosis or other gynecologic conditions.

What Forms and Strengths Does Megestrol Come In?

Oral tablets: 20 mg and 40 mg. Used for cancer indications.

Oral suspension (40 mg/mL): Standard suspension, sold as generic and brand Megace. Used for AIDS-related cachexia.

Megace ES (125 mg/mL): A concentrated oral suspension. The standard initial dose is 625 mg (5 mL) per day. Not interchangeable with the 40 mg/mL suspension without dose adjustment.

What Is the Typical Megestrol Dosage?

Dosing varies significantly by indication:

AIDS-related cachexia (oral suspension): 400-800 mg/day. Standard suspension: 800 mg/day (20 mL once daily) is the usual starting dose. Megace ES: 625 mg/day (5 mL once daily).

Breast cancer (tablets): 160 mg/day (40 mg four times daily). Therapy should continue for at least 2 months before assessing effectiveness.

Endometrial cancer (tablets): 40-320 mg/day in divided doses, continued for at least 2 months.

Always follow your prescriber's exact instructions. Do not change your dose without medical guidance.

How Do You Take Megestrol?

Tablets: Swallow whole with water. Can be taken with or without food.

Oral suspension: Shake the bottle well before each use. Measure carefully using the measuring cup provided (10 mL and 20 mL markings). Can be taken with or without food. Megace ES can be taken without regard to meals.

Timing: For cancer treatment, allow at least 2 months of therapy before evaluating effectiveness. For appetite stimulation, weight gain may begin within 3-4 weeks but full effect takes longer.

Is Megestrol a Controlled Substance?

No. Megestrol acetate is not a DEA-scheduled controlled substance. Any licensed prescriber can write a prescription for it, and there are no federal limits on refills. However, it is prescription-only and not available over the counter.

Who Should NOT Take Megestrol?

Pregnant women: Megestrol is contraindicated in pregnancy (Category X). A negative pregnancy test is required before starting treatment.

Breastfeeding women: Breastfeeding is not recommended during Megestrol therapy. HIV-positive women should not breastfeed regardless.

Patients with thromboembolic disease history: Use with caution; Megestrol increases clotting risk.

Patients with hypersensitivity: Do not take if allergic to megestrol acetate or any ingredient in the formulation.

For a complete breakdown of side effects and what to watch for: Megestrol Side Effects: What to Expect and When to Call Your Doctor.

If you're having trouble finding Megestrol at your pharmacy, medfinder can check pharmacies near you to see which ones have it in stock.

Frequently Asked Questions

Megestrol acetate has two FDA-approved indications: (1) AIDS-related anorexia, cachexia, and unexplained significant weight loss (oral suspension), and (2) palliative treatment of advanced breast cancer and endometrial carcinoma (tablets). Off-label uses include cancer-related cachexia, hot flashes, prostate cancer, and endometriosis.

Megace refers to the standard 40 mg/mL oral suspension (and tablets). Megace ES is a more concentrated oral suspension at 125 mg/mL, allowing a smaller volume (5 mL = 625 mg) compared to the standard suspension (20 mL = 800 mg). They are NOT interchangeable without a dose adjustment and a new prescription.

Appetite stimulation from Megestrol typically begins within 3-4 weeks of starting therapy. Weight gain may take longer to become noticeable. For cancer treatment, FDA guidelines recommend continuing therapy for at least 2 months before assessing whether the treatment is working.

Yes. Generic megestrol acetate contains the same active ingredient as brand-name Megace at the same strength, dosage form, and route of administration. Generic versions have been available for years and are bioequivalent to the brand. Most patients on Megace can use generic megestrol acetate interchangeably.

Megestrol can be taken long-term, but long-term use at high doses carries risks of adrenal suppression, Cushing's syndrome-like symptoms, hypogonadism, and thromboembolic events. Periodic monitoring by your prescriber is important. Never stop long-term Megestrol abruptly — always taper under medical supervision.

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