The short answer
Micronized progesterone is body-identical progesterone in oral capsules, sold as Prometrium and generics. In menopause care its FDA-approved role is protecting the uterine lining in people with a uterus who take estrogen. It is commonly taken at bedtime because it can cause drowsiness. Prometrium capsules contain peanut oil and are contraindicated in people with peanut allergy.
Safety essentials
Prometrium's revised label (DailyMed, July 2026) no longer has a boxed warning. In November 2025 the FDA asked makers of menopausal hormone therapy to remove boxed-warning language about cardiovascular disease, breast cancer, and probable dementia, while keeping the endometrial cancer warning for systemic estrogen-alone products. That is a class-level request: each product's warning changes only when its own label is revised. On February 12, 2026 the FDA approved the first six revised labels (Prometrium, Divigel, Cenestin, Enjuvia, Estring, and Bijuva).
The Prometrium label lists these contraindications: allergy to its ingredients (the capsules contain peanut oil), abnormal genital bleeding of unknown cause, known, suspected, or past breast cancer, active or past blood clots, active or past stroke or heart attack, and liver disease. Drowsiness and dizziness are common; avoid driving until you know how it affects you.
Current label check
The medication-specific claims on this page were checked against these current product labels on 2026-10-03.
| Product label | Label date | Boxed warning on that label |
|---|---|---|
| Prometrium (progesterone) capsules | 2026-07-23 | None (revised label) |
Established evidence
What is micronized progesterone?
Micronized progesterone is progesterone ground into tiny particles and suspended in oil so it can be absorbed by mouth. It is chemically identical to the progesterone made by the ovaries. Prometrium is the original brand; generic micronized progesterone capsules are widely available and equivalent.
Established evidence
FDA-approved uses
- Prevention of endometrial hyperplasia in postmenopausal women with a uterus who are receiving conjugated estrogens tablets (in practice it is also paired with other estrogens, which is outside that exact wording)
- Secondary amenorrhea
Limited human evidence
Progesterone vs progestin
Progestins are synthetic molecules that act on progesterone receptors, such as medroxyprogesterone acetate, norethindrone acetate, and levonorgestrel. All can protect the uterine lining at the right dose, but they differ in effects on mood, bleeding patterns, lipids, and possibly breast tissue.
French observational studies (E3N) associated estradiol plus micronized progesterone with lower breast cancer risk over the first five years than estrogen with some synthetic progestins. These are observational data, not randomized trials, and The Menopause Society describes the evidence as limited.
| Feature | Micronized progesterone | Synthetic progestins |
|---|---|---|
| Structure | Identical to human progesterone | Synthetic, receptor-active molecules |
| Common forms | Oral capsule | Tablets, patches combined with estrogen, IUD |
| Sedation | Common, often helpful at bedtime | Uncommon |
| Peanut allergy | Prometrium contraindicated | Not applicable |
Related progesterone products
Several products that used to have separate pages on this site are summarized here because they share an ingredient or purpose.
| Product | What it is | Approved use |
|---|---|---|
| Prometrium / generic | Oral micronized progesterone | Endometrial protection with estrogen; secondary amenorrhea |
| Crinone | Progesterone vaginal gel | Fertility treatment support; 4% gel for secondary amenorrhea. Not a menopause product |
| Endometrin | Progesterone vaginal insert | Luteal support in assisted reproduction. Not a menopause product |
| Bijuva | Estradiol plus progesterone capsule | Moderate-to-severe hot flashes in people with a uterus |
| Activella, CombiPatch, Climara Pro, Prempro/Premphase | Estrogen plus a synthetic progestin, not micronized progesterone | See the combined hormone therapy guide |
How it is taken
In menopause regimens, micronized progesterone is taken either every night (continuous) or for part of each month (cyclic), as chosen by the prescriber. Continuous regimens aim for no periods after an adjustment phase; cyclic regimens usually produce a monthly bleed.
Established evidence
Common side effects
- Drowsiness and dizziness
- Breast tenderness
- Bloating
- Headache
- Mood changes in some people
- Irregular bleeding early in treatment
Limited human evidence
Does progesterone help sleep?
Progesterone metabolites act on GABA receptors, which explains the drowsiness. Small trials suggest improved sleep quality in some postmenopausal people, but progesterone is not FDA approved as a sleep medicine and should not be used alone for that purpose without clinical guidance.
Questions to ask a healthcare professional
- Continuous or cyclic progesterone for me?
- Is an IUD or combined product a better option?
- What bleeding pattern is expected, and when should bleeding be checked?
Questions, answered
What people ask about Prometrium
Is Prometrium the same as progesterone?+
Yes. Prometrium is a brand of oral micronized progesterone; generics contain the same ingredient.
Do I need progesterone if I had a hysterectomy?+
Usually not. Its main menopause role is protecting the uterine lining, so people without a uterus generally use estrogen alone.
Why is progesterone taken at night?+
It commonly causes drowsiness and dizziness, so bedtime dosing reduces daytime effects.
Is progesterone safer than progestins?+
Observational data suggest possible differences in breast cancer risk, but randomized evidence is limited. Both can protect the uterine lining.
Does Kindr Health offer progesterone?+
This page is educational. Whether any treatment is appropriate is decided by a licensed professional.
Kindr Health does not claim to offer Prometrium on this page. Availability and prescribing are not implied.
A broader care pathway
Explore menopause care
Learn how Kindr Health care pathways work. An educational page is not a statement that this medication is available or appropriate for you.
SOURCES & REFERENCES
Every clinical claim on this page is sourced.
- Prometrium prescribing information (current label) (2026) — DailyMed, U.S. National Library of Medicine. dailymed.nlm.nih.gov/dailymed/search.cfm?labeltype=all&query=Prometrium
- FDA initiates removal of boxed warnings from menopausal hormone therapy products (2025) — U.S. Department of Health and Human Services / FDA. www.hhs.gov/press-room/fact-sheet-fda-initiates-removal-of-black-box-warnings-from-menopausal-hormone-replacement-therapy-products.html
- FDA approves labeling changes to menopausal hormone therapy products (first six labels) (2026) — U.S. Food and Drug Administration. www.fda.gov/news-events/press-announcements/fda-approves-labeling-changes-menopausal-hormone-therapy-products
- The 2022 hormone therapy position statement of The North American Menopause Society (2022) — The Menopause Society (Menopause journal). pubmed.ncbi.nlm.nih.gov/35797481
- Unequal risks for breast cancer associated with different hormone replacement therapies (E3N cohort) (2008) — Breast Cancer Research and Treatment. pubmed.ncbi.nlm.nih.gov/17333341
This resource is educational and does not replace individualized medical advice. Do not start, stop, or change a prescription without guidance from a licensed healthcare professional.