Why do I get mood changes before my period?

By Sina Hartung, MMSC-BMI, Harvard Medical SchoolReviewed by Eureka Health Medical Group
Published: July 9, 2025Updated: July 9, 2025

Key Takeaways

Most people notice mood swings 5–7 days before bleeding because estrogen and progesterone drop sharply after ovulation and change how serotonin, GABA, and cortisol work in the brain. About three-quarters of menstruating people feel irritable or sad; for roughly 1 in 20 it is severe enough to be diagnosed as premenstrual dysphoric disorder (PMDD). Tracking cycles, sleep, and stress, plus targeted lifestyle and medical support, can prevent symptoms from sidelining you.

What exactly causes mood swings in the week before your period?

Falling estrogen and progesterone after ovulation act on brain receptors that regulate emotion. The result can be irritability, tearfulness, and anxiety that disappear once bleeding starts. As Sina Hartung, MMSC-BMI, notes, “The brain reads hormonal fluctuation as a stressor, which can lower resilience for a few critical days.”

  • Hormone rise and fall happens fastProgesterone can drop by 80 % within 48 hours of the luteal peak, a speed the brain registers as abrupt change rather than a gentle taper.
  • Brain chemicals mirror progesterone levelsLower progesterone means less allopregnanolone, a calming neuro-steroid that normally boosts GABA; reduced GABA activity is linked with anxiety.
  • Stress worsens premenstrual mood shiftsHigh perceived stress in the luteal phase triples the chance of reporting severe mood symptoms according to a 2022 survey of 1,200 women.
  • Sleep debt magnifies irritabilityJust two nights of getting under six hours of sleep elevates amygdala reactivity, making luteal-phase anger flare faster.
  • Social context mattersRelationship conflict or job strain in the premenstrual week predicts a 40 % higher symptom score compared with low-stress cycles.
  • Three in four individuals report PMS symptomsApproximately 75 % of women experience some premenstrual symptoms—including mood swings—during the luteal phase, highlighting how common these hormonal mood effects are. (Flo)
  • Only about 10 % have symptoms severe enough for a PMS diagnosisWhile 8 in 10 people notice mood changes before their period, only 1 in 10 meet the clinical criteria for PMS, underscoring wide variation in sensitivity to hormonal shifts. (Clue)

When do premenstrual mood changes signal something more serious like PMDD?

Most luteal-phase mood changes are mild, but persistent severe symptoms that disrupt work or relationships every month warrant evaluation for PMDD or an underlying mood disorder. The team at Eureka Health explains, “If you spend more than half of the luteal phase unable to function, that is no longer typical PMS.”

  • Duration beyond two weeks is uncommonMood symptoms that begin right after ovulation and last until menstruation suggest an added depressive disorder, not PMDD.
  • Daily functioning drops noticeablyMissing work, skipping social events, or arguments that end relationships are red flags clinicians use to separate PMDD from normal PMS.
  • Physical danger to self or othersAny suicidal thinking, self-harm, or aggression in the premenstrual window requires emergency care—PMDD carries a 34 % lifetime suicidal ideation rate.
  • Symptoms vanish after day two of bleedingTrue PMDD shows a dramatic switch-off once estrogen rises again; lingering low mood into mid-cycle hints at major depression.
  • Only 3–8 % meet PMDD criteriaLarge studies show severe luteal-phase mood disruption qualifies as PMDD in just 3 – 8 % of menstruating adults, underscoring why disabling symptoms should not be dismissed as “normal PMS.” (Carlat)
  • Symptoms usually climax two days before bleedingIn PMDD, mood and physical distress last an average of six days in the late luteal phase and intensify about two days before the period, then subside with menstrual flow—this predictable crescendo–crash pattern helps clinicians confirm the diagnosis. (UPMC)

Which hormones shift the most and how do they affect the brain?

After ovulation, progesterone and estrogen first rise, then decline steeply when pregnancy does not occur. These shifts alter neurotransmitters within hours. Sina Hartung, MMSC-BMI, notes, “Serotonin turnover is particularly sensitive to estrogen, which is why SSRIs can work even when taken only in the luteal phase.”

  • Estrogen moderates serotonin receptorsLower estrogen reduces 5-HT1A receptor density, contributing to sadness and carb cravings.
  • Progesterone metabolites calm via GABAAllopregnanolone enhances GABA-A receptor action; its sudden absence can cause agitation similar to benzodiazepine withdrawal.
  • Aldosterone may drive bloating and moodProgesterone normally blocks aldosterone; when it drops, sodium retention can create physical discomfort that worsens mood.
  • Cortisol rhythm becomes erraticLate-luteal cortisol peaks 20 % higher in some people, increasing anxiety and insomnia.
  • PMS is widespread while PMDD remains rarerPremenstrual syndrome affects up to 40 % of women, whereas the more severe premenstrual dysphoric disorder is seen in only 2–8 %. (Genomind)
  • Hormone concentrations can double in a single dayEstrogen and progesterone levels are capable of doubling within just 24 hours, driving abrupt shifts in brain-active neurotransmitters. (UF)

What day-to-day steps can I take at home to stabilize mood before my period?

Lifestyle adjustments can lower symptom scores by up to 50 % in controlled trials. The team at Eureka Health emphasizes, “Small, repeatable habits beat drastic changes when hormones are fluctuating.”

  • Track symptoms with a cycle calendarMark mood, sleep, caffeine, and stress daily; patterns often emerge by the third month and guide targeted fixes.
  • Aim for 25–30 g of protein at breakfastStable blood sugar reduces afternoon crashes that mimic mood swings; one study found a 15 % symptom reduction with balanced macronutrients.
  • Schedule aerobic exercise on days 21-27Thirty minutes of brisk walking lowered PMS depression scores by 29 % in a randomized trial.
  • Limit caffeine after noonCaffeine prolongs luteal-phase insomnia; cutting intake by half improved next-day mood in 60 % of participants.
  • Trial magnesium and vitamin B6 cautiouslyDoses of 250 mg magnesium and 50 mg pyridoxine daily eased emotional symptoms in a 2019 meta-analysis, but check with a clinician first.
  • Stick to a 7–9-hour sleep window nightlyMayo Clinic lists “getting plenty of sleep” as a first-line PMS strategy; people who safeguard consistent bedtimes report fewer mood swings and less luteal-phase fatigue. (Mayo)
  • Try 5-minute deep-breathing sets when irritability peaksMount Sinai’s PMS self-care guide recommends brief deep-breathing or progressive muscle-relaxation drills to calm the nervous system and defuse premenstrual anger. (MtSinai)

Which labs, tracking tools, and treatments might a clinician consider?

Blood work is not mandatory for PMS, but targeted testing rules out thyroid, anemia, or perimenopause and guides therapy. As Sina Hartung, MMSC-BMI, advises, “Lab data help distinguish hormone-driven mood from other medical problems.”

  • TSH and free T4 to exclude hypothyroidismSubclinical thyroid disease mimics fatigue and mood swings; roughly 6 % of patients evaluated for PMDD turn out to have thyroid dysfunction.
  • Ferritin to check iron storesLow ferritin (<30 ng/mL) is linked to irritability; iron repletion improved mood scores in a small 2021 trial.
  • Follicular-phase estradiol and luteal progesteroneValues confirm ovulation and help time hormonal treatments such as combined oral contraceptives, which can smooth hormone swings.
  • Intermittent-dose SSRIsTaking an SSRI only from ovulation to day two of menses can cut severe PMS mood symptoms by 60 % while reducing side effects.
  • Digital symptom tracking appsApps that export data to clinicians speed diagnosis; continuous mood logs were more accurate than recall in a 2020 validation study.
  • Calcium 1,000–1,200 mg daily cuts PMS symptom burden nearly in halfRandomized trials summarized by American Family Physician found that calcium carbonate 1,200 mg per day reduced overall PMS symptom scores by about 48 % after three cycles, making it a low-risk first-line adjunct. (AAFP)
  • Diuretics can relieve bothersome premenstrual bloating and weight gainMayo Clinic guidance notes that when fluid retention causes swelling or >2 kg weight increase, a clinician may prescribe a diuretic such as spironolactone to ease breast tenderness and abdominal distension. (Mayo)

Frequently Asked Questions

This content is for informational purposes only and is not intended as medical advice. Always consult with a qualified healthcare provider for diagnosis, treatment, and personalized medical recommendations.

Eureka Health

AI-powered health insights, 24/7

InstagramX (Twitter)

© 2026 Eureka Health. All rights reserved.