Pharmaceuticals/Chemicals
Progesterone (Oral)
Also called Prometrium · Oral P4
Oral micronized progesterone is often paired with estrogen to protect the womb lining. People also ask about sleep because it can cause drowsiness and has been studied for menopausal symptoms. Those are different reasons for treatment, with different schedules.
Dosage & duration
Two different US oral-label indications; neither is a general sleep prescription.
Prometrium · endometrial protection with estrogen
Product label- Dose
- 200 mg by mouth at bedtime
- How often
- Once nightly for 12 consecutive days in each 28-day cycle
- How long
- Repeating cycles as prescribed, with ongoing review
Label example for postmenopausal people with a uterus receiving daily conjugated estrogen; not every HRT regimen.
Sources: 1
Prometrium · secondary amenorrhea
Product label- Dose
- 400 mg by mouth at bedtime
- How often
- Once nightly
- How long
- 10 days
A distinct label course for absent periods after assessment, not a routine sleep or menopause dose.
Sources: 1
Oral progesterone
Why the schedule matters
-
Womb-lining protection
When a uterus is present, progesterone may be part of the plan alongside systemic estrogen.
-
Nighttime drowsiness
Drowsiness can affect daytime function, even when a capsule is taken at bedtime.
-
Follow the prescribed days
Daily and cyclical plans differ, and the treatment days belong to the full HRT plan.
Why is progesterone added to estrogen?
Systemic estrogen can stimulate the womb lining. Progesterone may be prescribed to counter that effect when a uterus is present. The amount and number of days need to match the estrogen plan, rather than being chosen only for how sleepy a capsule makes someone feel.
Does it help sleep?
Some people experience sedation, and a perimenopause trial found better perceived sleep quality. Its main hot-flush/night-sweat outcome was not statistically significant, so it should not be described as a proven solution for every menopausal symptom. Persistent insomnia deserves its own assessment.
What to notice in everyday use
Bedtime dosing reflects the possibility of dizziness or drowsiness. Do not drive while affected. Unexpected bleeding, intolerable morning sedation or mood changes are reasons to review the plan. The US Prometrium product contains peanut oil; check the exact formulation if allergies are relevant.
Oral and vaginal are different
Changing route changes exposure and product instructions. An oral capsule regimen is not automatically equivalent to a vaginal gel or insert. The relative timing curve does not measure blood levels or test womb-lining protection.
Model details: Progesterone (Oral) · relative timing
Compare timing and buildup for this compound. The values are not blood concentrations or a measure of strength.
Shows a relative timing scenario; absolute blood concentrations are not calibrated.
Timing assumptions and sources
Legacy 22.78 h/1.5 h from a repeated-dose capsule study cannot establish universal per-dose kinetics. The retained 22.78 h slower timescale is an assumption.
One 1 mg input peaks at 1 relative unit after a single dose. Other amounts scale proportionally; overlapping doses add when accumulation is on. Different compounds use separate relative scales.
- Timing half-life used
- 22.78 hours
- Absorption half-life assumed
- 5.695 hours
- Reference amount for the relative scale
- 1 mg
- Absorption half-life is assumed to be one quarter of the slower timescale (5.695 h); it is not a measured absorption parameter.
- A single 1-unit input has a peak of 1 relative unit; scaling and repeated-dose addition are mathematical assumptions. This normalization is independent of the example dose.
- Food, soft vs hard capsule, first-pass metabolites and assay cross-reactivity materially affect measured exposure.
- Baseline progesterone and serum/plasma assay must be specified; no invented 10% F.
- Wang et al 2019: hard and soft micronized progesterone
Utrogestan oral 169.53 and vaginal 12.30 are steady-state observations after 200 mg twice daily 10 days; different products/routes had different PK. Abstract concentration units conflict with tables, so use the tables and original assay context.
- Prometrium label
100 mg daily for five doses: mean Cmax 17.3 ng/mL; this is not a single-dose study.
progesterone-oral-relative-timing-2026-10 · version 1
Common questions
Is progesterone only taken for part of the month?
Some prescribed regimens are cyclical and others continuous. The label example here is a specific cyclical plan; follow the indication-specific prescription.
Can I take it vaginally instead to avoid drowsiness?
Do not assume the oral product, route or dose is interchangeable. Discuss a route change with the prescriber because the treatment evidence differs.
Why do men on TRT discuss progesterone?
Some look for better sleep, libido or less bloating. Reported experiences mix oral, skin and other products, so they cannot establish that oral progesterone solves these problems. The perimenopause sleep study was not a trial in men on TRT, and the product label warns that fluid retention and drowsiness can occur.
Sources Labels, studies and notes behind this guide
Catalog evidence: Human clinical trials. This describes the type of evidence, not a clinical review of every claim.
Summary and fact source checks: 2026-10-07. This records source checking, not medical review of the whole page.
Notes on the quick facts
- Main medical role
- Relevant when a uterus is present; the full HRT plan matters.
- Often taken at night
- Feeling sleepy is not the same as treating every cause of insomnia.
- Schedule matters
- The number of treatment days belongs to the indication and prescription.
- 1. Prometrium — US prescribing information
Label: 200 mg at bedtime for 12 sequential days per28-day cycle with estrogen for endometrial protection; 400 mg at bedtime for 10 days for secondary amenorrhea. Oral route, drowsiness and peanut-oil allergy warnings.
- 2. Prior et al. 2023 — perimenopausal progesterone trial
300 mg nightly versus placebo for three months after baseline. Primary vasomotor-symptom result not statistically significant; perceived sleep quality/night sweats improved. Not proof of universal insomnia benefit.
- 3. Wang et al 2019: hard and soft micronized progesterone
Utrogestan oral 169.53 and vaginal 12.30 are steady-state observations after 200 mg twice daily 10 days; different products/routes had different PK. Abstract concentration units conflict with tables, so use the tables and original assay context.
- 4. Prometrium label
100 mg daily for five doses: mean Cmax 17.3 ng/mL; this is not a single-dose study.
- 5. Oral and vaginal micronized capsule PK study
Randomized open-label study in postmenopausal women; hard and soft capsules had product/route-specific kinetics. Not evidence of universal gel/insert equivalence.
Related compounds and examples
Related compounds
Progesterone (Vaginal)
Vaginal progesterone supports specific fertility treatments, but gels, inserts and capsules are different products. Their milligram amounts and schedules should not be swapped automatically.
Estradiol Topical (EstroGel)
Estradiol gel is used to ease menopausal hot flushes and other low-estrogen symptoms without a pill or injection. The practical choices are the exact pump product, the daily skin routine and whether a separate progestogen is needed.
Estradiol Cypionate
Estradiol cypionate provides estrogen through an injection rather than a daily pill or gel. It is used for low-estrogen symptoms and in feminizing hormone care; the reason for treatment determines the dose and schedule.