Hormone Therapy
Progesterone Therapy: Uses, Safety, and Why It Matters
Medically reviewed by HealthRX.com Medical Team · Last reviewed
Why do you need progesterone with estrogen?
Estrogen stimulates growth of the uterine lining. Given alone to a woman who still has her uterus, it can cause the lining to overgrow, raising the risk of endometrial hyperplasia and uterine cancer. Adding progesterone opposes this and protects the lining.
The FDA label for micronized progesterone states this directly and recommends adding a progestogen to reduce that risk. A woman without a uterus generally does not need progesterone and can use estrogen alone. [7]
Micronized progesterone versus synthetic progestins
Micronized progesterone is identical to the body's own progesterone and is FDA approved. Synthetic progestins, such as medroxyprogesterone, are different compounds with progesterone-like activity. Both protect the uterine lining, but micronized progesterone has a more favorable profile for the breast.
How is progesterone taken?
Micronized progesterone is usually taken once daily at bedtime, because it can cause dizziness or drowsiness. In a continuous combined regimen it is often about 100 mg daily; in a cyclic regimen it is about 200 mg for 12 to 14 days each month.
| Regimen | Typical use | Notes |
|---|---|---|
| Continuous combined | About 100 mg daily | Taken with daily estrogen |
| Cyclic | About 200 mg for 12 to 14 days monthly | Taken part of each month |
Is progesterone safe?
Micronized progesterone is generally well tolerated. The most common effects are drowsiness and dizziness, which is why it is taken at bedtime. One label-level caution matters: the Prometrium brand contains peanut oil, so it should be avoided by people with a peanut allergy.
- Common effects: drowsiness, dizziness, breast tenderness, bloating.
- Contains peanut oil in the Prometrium brand; avoid with peanut allergy. [7]
- Used with estrogen as part of a full hormone therapy plan reviewed by a clinician.
How does Progesterone compare with other peptides?
| Micronized progesterone | Synthetic progestins | |
|---|---|---|
| Structure | Identical to natural progesterone | Different compounds |
| Endometrial protection | Yes | Yes |
| Breast profile | More favorable | Varies |
| FDA approved | Yes | Yes |
Frequently asked questions
Do I need progesterone if I take estrogen?
If you still have your uterus, yes. Estrogen alone thickens the uterine lining and raises the risk of endometrial hyperplasia and uterine cancer. Progesterone protects the lining. If you have had a hysterectomy, you generally do not need it.
Is micronized progesterone better than a progestin?
Both protect the uterine lining. Micronized progesterone is identical to the body's own hormone and has a more favorable breast profile than some synthetic progestins, which is why many clinicians prefer it. Your provider can advise what fits you.
Why is progesterone taken at night?
Micronized progesterone can cause dizziness or drowsiness, so it is usually taken at bedtime. Many people find this timing also helps with sleep during the menopause transition.
Is progesterone bioidentical?
Micronized progesterone is identical to the progesterone your body makes and is FDA approved, so it is a bioidentical option that does not require compounding. Bioidentical and FDA approved are not opposites.
Are there any allergy warnings?
Yes. The Prometrium brand of micronized progesterone contains peanut oil, so it should be avoided by anyone with a peanut allergy. Tell your prescriber about any allergies.
Citations
- Gompel A. Micronized progesterone and its impact on the endometrium and breast vs. progestogens. Climacteric. 2012;15(Suppl 1):18-25.
- Progesterone (Prometrium) capsules, FDA Prescribing Information (DailyMed).
This guide is educational and is not a substitute for individualized medical advice. Progesterone is prescription-only and requires evaluation by a licensed provider.