Last checked September 2026 against 16 sources · Editorial policy
Progesterone side effects
The most common side effects of oral progesterone are drowsiness and dizziness, headaches, breast tenderness, bloating, nausea, mood changes and irregular bleeding or spotting. In Prometrium's 3-year trial, breast tenderness affected 27% of women vs 6% on placebo, and dizziness 15% vs 9%. Most side effects ease within a few weeks to months. Taking it at bedtime helps with drowsiness. Rare serious risks include blood clots and allergy in people allergic to peanuts.
Drowsiness, dizziness, bloating, breast tenderness and mood changes are the most common. Pill and cream side effects, how long they last, and how to reduce them.
Progesterone side effects: expectation vs reality
What people often expect
“Natural, body-identical progesterone shouldn't have side effects”
What the evidence shows
Micronized progesterone is chemically identical to your own, but taken as a pill it still causes side effects. In the Prometrium trial, women on progesterone with estrogen reported more breast tenderness (27% vs 6%), bloating (12% vs 5%) and dizziness (15% vs 9%) than placebo. The good news: many side effects fade as your body adjusts, and some women have none.
Common and serious progesterone side effects
Most common side effects of progesterone
Prometrium's patient information lists headaches, breast pain, irregular bleeding or spotting, stomach cramps and bloating, nausea and vomiting, hair loss, fluid retention and vaginal yeast infections as common side effects. The NHS adds tiredness, dizziness, mood changes, mild rash or itching and acne. Some effects may come from the estrogen taken alongside it.
Drowsiness and dizziness
Progesterone can cause transient dizziness and drowsiness, which is why Prometrium is taken at bedtime. In a few cases, women report blurred vision, difficulty speaking, difficulty walking or feeling abnormal; the label says to tell your provider right away. Don't drive or use machinery if you feel drowsy, and avoid alcohol, which makes it worse.
Learn more →Progesterone 100 mg vs 200 mg side effects
The US trial used 200 mg for 12 days a month with estrogen. At 400 mg for missed periods, dizziness was reported by 24% of women vs 4% on placebo, and breast pain by 16% vs 8%. In continuous HRT, 100 mg is taken daily instead. If side effects persist at any dose, the NHS says your doctor may change the dose or switch to a different progestogen.
Learn more →Progesterone and nausea
Nausea or vomiting affected 8% on Prometrium with estrogen vs 7% on placebo in the 3-year trial, and 8% vs 0% at the higher 400 mg dose. The NHS suggests simple meals and avoiding rich or spicy food, and talking to a doctor if it doesn't go away. Prometrium reaches its peak blood level within 3 hours of a dose.
Mood changes and depression
Depression was reported by 19% of women on Prometrium with estrogen vs 12% on placebo in the 3-year trial. The NHS lists mood changes, including low mood, as a common side effect and suggests talking to your doctor if it doesn't improve, since a different dose or progestogen may suit you better.
Learn more →Bleeding and spotting on progesterone
Spotting or bleeding between periods is common for the first 3 to 6 months of HRT and usually settles. On a sequential schedule, a withdrawal bleed after each course is expected. The NHS says to talk to your doctor if you get heavy or unexpected bleeding after 6 months on HRT.
Learn more →Serious side effects of progesterone
Serious side effects are rare. The label lists blood clots, including stroke, heart attack and pulmonary embolism, and advises urgent care for sudden severe headache, vision or speech changes, or severe chest or leg pain. The NHS adds calf pain or swelling, a sign of deep vein thrombosis, and yellowing skin or eyes, a sign of liver problems.
Progesterone cream side effects
Skin creams deliver much less progesterone into the blood: in a trial of a 32 mg daily cream, blood levels rose only slightly, with no effect on symptoms. OTC creams aren't FDA-approved and don't reliably protect the uterus if you take estrogen. Products vary, and there’s little trial data on their side effects.
Learn more →Oral progesterone side effects by the numbers
From the studies on this page
had breast tenderness on Prometrium with estrogen vs 6% on placebo over 3 years
27%
had dizziness on Prometrium with estrogen vs 9% on placebo
15%
had abdominal bloating vs 5% on placebo
12%
3 to 6 months
The 3-year trial gave 200 mg Prometrium for 12 days a month plus conjugated estrogens and compared it with placebo, so some effects reflect the estrogen too.
How to reduce side effects of progesterone
Take it at bedtime
First stepThe label says to take Prometrium at bedtime because some women become very drowsy or dizzy. The NHS adds taking it at least 2 hours after food.
Related guide →Give it a few weeks
Strong evidenceHeadaches usually last a few days, breast tenderness improves after a few weeks and spotting settles within 3 to 6 months as your body adjusts.
Change the dose or progestogen
Strong evidenceIf headaches, low mood or other effects persist, your doctor may change the dose or switch to another progestogen, such as the hormonal IUD.
Related guide →Painkillers for headaches
Some evidenceThe NHS suggests ibuprofen or acetaminophen for short-lived headaches when starting.
Avoid alcohol and driving when drowsy
First stepAlcohol worsens drowsiness and dizziness; don't drive or use machinery until you know how it affects you.
When progesterone side effects need a doctor
Urgent: Calf pain or swelling, chest pain or sudden shortness of breath
Call 911 or get emergency care. These can be signs of a blood clot.
Urgent: Sudden severe headache or changes in vision or speech
Call your doctor right away or 911; these can be signs of a stroke.
Yellow skin or eyes
Call a doctor now; it can be a sign of liver problems.
Heavy or unexpected bleeding after 6 months
See your doctor to check the uterine lining.
Urgent: Low mood that doesn't lift, or thoughts of self-harm
Talk to your doctor; call or text 988 if you're thinking of harming yourself.
Progesterone side effects: questions women ask
What are the most common side effects of progesterone?
Drowsiness, dizziness, headaches, breast tenderness, bloating, nausea, mood changes and spotting. In Prometrium's trial, breast tenderness (27% vs 6%) and dizziness (15% vs 9%) were more common than on placebo.
Can progesterone cause nausea?
Yes, though it's usually mild. In the 3-year trial, 8% of women on Prometrium with estrogen reported nausea or vomiting vs 7% on placebo. Simple meals and bedtime dosing can help.
What are the side effects of 100mg and 200mg progesterone tablets?
The same as at lower doses, often a bit stronger: drowsiness, dizziness, headaches, breast tenderness, bloating and spotting. 200 mg is the dose used for 12 days a month in sequential HRT.
Related →How long do progesterone side effects last?
Most settle as your body adjusts: headaches within days, breast tenderness within a few weeks, and spotting within 3 to 6 months. If they persist, talk to your doctor about a different dose or progestogen.
How can I reduce the side effects of progesterone?
Take it at bedtime, at least 2 hours after food, avoid alcohol, and give it a few weeks. If side effects persist, ask about a lower dose, a different schedule or the hormonal IUD.
Does progesterone cause weight gain?
Fluid retention and bloating are listed side effects, which can show on the scale. Progesterone itself isn’t usually a direct cause of fat gain, according to Cleveland Clinic.
Related →Who shouldn't take oral progesterone?
Prometrium isn't for people allergic to peanuts, or with unexplained vaginal bleeding, breast cancer, a history of blood clots, stroke or heart attack, or liver disease. The UK capsule also lists soy allergy.
Can progesterone cause depression?
It can affect mood. In the Prometrium trial, 19% reported depression vs 12% on placebo. If low mood appears or worsens, your doctor may change the dose or progestogen.
Does progesterone make you sleepy?
Yes, for many women. Transient drowsiness and dizziness are known effects, which is why capsules are taken at bedtime. In a small trial, 300 mg at night also restored disturbed sleep.
Related →Is micronized progesterone safer than other progestogens?
It may be for some risks. In a large French cohort, estrogen with micronized progesterone was linked to lower breast cancer risk than estrogen with synthetic progestins. Side effects like drowsiness are more typical of progesterone itself.
Related →Do progesterone supplements have side effects?
Over-the-counter progesterone and wild yam creams deliver little hormone, so side effects are uncommon: wild yam cream caused no significant side effects in a trial. They also don't reliably work or protect the uterus, and supplements aren't FDA-approved before sale.
Sources
- Prescribing information: Prometrium (progesterone capsules). Acertis Pharmaceuticals, 2026. DailyMed, US National Library of Medicine.
- NHS. Utrogestan (micronised progesterone): side effects.
- NHS. Utrogestan (micronised progesterone): how and when to take.
- Wren BG, Champion SM, Willetts K, et al. Transdermal progesterone and its effect on vasomotor symptoms, blood lipid levels, bone metabolic markers, moods, and quality of life for postmenopausal women. Menopause. 2003;10(1):13-8.
- US Food and Drug Administration. NASEM study on the clinical utility of treating patients with compounded "bioidentical" hormone therapy.
- NHS. Utrogestan (micronised progesterone): about.
- NHS. Utrogestan (micronised progesterone): common questions.
- National 911 Program. 911.gov.
- Federal Communications Commission. 988 Suicide & Crisis Lifeline.
- Cleveland Clinic. Progesterone: natural function, levels and side effects.
- NHS. Utrogestan (micronised progesterone): who can and cannot take.
- Caufriez A, Leproult R, L'Hermite-Balériaux M, et al. Progesterone prevents sleep disturbances and modulates GH, TSH, and melatonin secretion in postmenopausal women. J Clin Endocrinol Metab. 2011;96(4):E614-23.
- Fournier A, Berrino F, Clavel-Chapelon F. Unequal risks for breast cancer associated with different hormone replacement therapies: results from the E3N cohort study. Breast Cancer Res Treat. 2008;107(1):103-11.
- Komesaroff PA, Black CV, Cable V, et al. Effects of wild yam extract on menopausal symptoms, lipids and sex hormones in healthy menopausal women. Climacteric. 2001;4(2):144-50.
- Wren BG, McFarland K, Edwards L, et al. Effect of sequential transdermal progesterone cream on endometrium, bleeding pattern, and plasma progesterone and salivary progesterone levels in postmenopausal women. Climacteric. 2000;3(3):155-60.
- US Food and Drug Administration. Dietary supplements.
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