Micronized Progesterone Explained

The Prometrium label describes improved oral bioavailability through micronization. Bioavailability means how much of a medicine reaches the circulation after administration. Smaller particles help the capsule deliver a usable amount of progesterone; they do not turn it into a different hormone.

Prometrium and Utrogestan are examples of prescription micronized progesterone products. Their local approvals, ingredients, and administration instructions differ. A compounded cream, vaginal preparation, and oral capsule cannot be treated as interchangeable because they all list progesterone.

ACOG includes approved micronized progesterone among bioidentical hormone medicines. A bioidentical prescription can therefore use a manufactured approved product. Custom compounding is a separate decision that should have a specific medical reason.

Systemic estrogen can stimulate the uterine lining. Adequate progestogen protection is usually needed with a uterus to reduce endometrial overgrowth and cancer risk. Oral micronized progesterone is one option, supplied separately or in an appropriate combined medicine.

The US Prometrium label describes 200 mg at bedtime for 12 days of each 28-day cycle for postmenopausal women receiving conjugated estrogen tablets. Other prescriptions may use a different regimen. The estrogen dose, product, clinical situation, and local prescribing guidance affect that decision.

A capsule strength does not establish how many days it should be taken. Ask for a written calendar, the expected bleeding pattern, and instructions for a missed dose. If the estrogen prescription changes, ask whether the progesterone plan also needs review.

Progesterone can cause dizziness and drowsiness. Prometrium advises bedtime dosing and caution with driving or machinery. Some people remain affected the next morning, so report impairment that makes daily activities difficult.

A systematic review of randomized trials found improvements in some sleep measures, predominantly among postmenopausal participants. The pooled findings supported faster sleep onset, while total sleep time and sleep efficiency remained less certain. Some studies also used estradiol or improved vasomotor symptoms, limiting conclusions about progesterone alone.

Drowsiness after a dose and effective treatment of a sleep disorder are separate questions. Persistent insomnia needs assessment of sleep patterns and other causes. Using progesterone solely for sleep is outside the cited US Prometrium indication and should come with an explanation of the evidence and follow-up.

The hormone's similarity to ovarian progesterone does not establish that every regimen is risk-free. Assess the entire HRT prescription, including estrogen route, dose, duration, and personal history. The Prometrium label includes contraindications involving breast cancer, previous clots, stroke or heart attack, liver disease, and unexplained bleeding.

Comparisons between different progestogens are still an area of uncertainty. NICE states that evidence is insufficient to establish whether the breast-cancer risk of combined HRT containing micronized progesterone differs from combined HRT containing other progestogens. A promotional claim of proven lower cancer risk goes beyond that guidance.

Product ingredients also matter. Prometrium contains peanut oil and is contraindicated with peanut allergy. A pharmacist should check the exact formulation and available alternatives when an ingredient is unsuitable.

If side effects make the regimen difficult to maintain, request a review of alternatives. Removing progesterone while continuing systemic estrogen can leave the uterine lining inadequately protected.