The Menstrual Cycle: Hormones, Ovulation, and What You Might Feel
"Hormonal" gets used as a dismissal a lot — but the hormone shifts across your cycle are real, well-mapped, and predictable enough that most of what you feel physically and emotionally has a name and a cause. Here's the actual pattern, phase by phase.
Last updated August 2026
Menstrual
Days 1–5In the ovary
Last cycle's corpus luteum has broken down, hormones bottom out, and a new group of follicles is just starting to grow.
What you might feel
Cramping and lower energy are common as the uterine lining sheds. A lot of people feel more inward or low-key during this window — that tracks with hormones being at their lowest point of the cycle, not just "in your head."
Follicular
Days 5–13In the ovary
FSH stimulates a group of follicles to grow; usually one pulls ahead and becomes dominant.
What you might feel
Estrogen climbs steadily through this window, and energy, mood, and often libido tend to climb with it — many people feel their best here.
Ovulatory
~Day 14In the ovary
The dominant follicle ruptures and releases an egg — ovulation. Estrogen peaks the day before, which is what triggers the LH surge that actually causes the release.
What you might feel
Often the highest energy and libido of the cycle. Some notice a brief one-sided pelvic twinge around this time (called mittelschmerz) — usually harmless, worth mentioning if it's ever severe.
Luteal
Days 15–28In the ovary
The ruptured follicle becomes the corpus luteum, producing progesterone. If there's no pregnancy, it breaks down around day 22–24, and hormones fall sharply in the final days — that drop is what triggers the next period.
What you might feel
That end-of-phase hormone drop is what drives PMS-type symptoms for a lot of people — mood changes, bloating, breast tenderness, irritability — usually in the final few days before the next period starts.
The short version
A cycle has four phases: menstrual, follicular, ovulatory, and luteal. Two hormones drive most of it — estrogen, which rises through the first half of the cycle, and progesterone, which only shows up after ovulation. The chart and phase breakdown below walk through what's happening in your ovaries and what you might feel at each point.
The 28-day cycle shown here is a reference point, not a rule — anywhere from about 21 to 35 days is typical, and the luteal phase (after ovulation) tends to be the more fixed part at roughly 12–14 days, while the follicular phase (before ovulation) is what usually varies cycle to cycle and person to person.
Why the luteal phase (not "before your period") is when PMS hits
PMS-type symptoms — mood changes, bloating, breast tenderness, irritability — cluster in the last several days of the luteal phase, right as progesterone (and estrogen) drop sharply on their way to triggering the next period. That drop, not "your period coming," is the actual trigger — which is also why PMS symptoms ease once bleeding starts and hormones have already bottomed out.
If mood symptoms in that window are severe enough to disrupt your life most cycles — not just uncomfortable, but disruptive — that's worth naming as PMDD (premenstrual dysphoric disorder) rather than "just PMS," since PMDD has real treatment options. Our Mental Health Check-In can help sort out whether what you're describing fits that pattern.
What ovulation actually requires
Ovulation isn't automatic — it depends on the whole hormonal sequence happening in the right order: FSH recruiting follicles, one becoming dominant, estrogen rising enough to trigger the LH surge, and the LH surge actually causing release. Anything that disrupts that sequence (very low body weight, very high stress, thyroid dysfunction, PCOS, perimenopause) can delay or skip ovulation for a cycle, which is part of why cycle length varies even in people who are generally regular.
Worth discussing with your provider
Educational information only — general patterns that vary by person. This is not medical advice, a diagnosis, or a substitute for care from your own clinician.
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