Menstrual Cycle Hormones: Estrogen, Progesterone, LH, FSH

Four main hormones run your menstrual cycle: follicle-stimulating hormone (FSH), luteinizing hormone (LH), estrogen and progesterone. The pituitary gland in your brain and your ovaries release them, and their rise and fall shapes your period, ovulation and the days before your next period.

Quick summary: FSH helps follicles grow. Estrogen rises, builds the uterine lining and triggers an LH surge. LH triggers ovulation. Progesterone rises after ovulation and then falls if you are not pregnant, which starts your period. Exact levels vary a lot between people, so think of this as a general pattern.

Meet the four hormones

Hormone	Made by	Main job
FSH (follicle-stimulating hormone)	Pituitary gland	Starts follicle growth in the ovaries
Estrogen	Ovaries (mainly the growing follicle)	Thickens the uterine lining, triggers the LH surge
LH (luteinizing hormone)	Pituitary gland	Triggers ovulation
Progesterone	Corpus luteum (after ovulation)	Thickens and maintains the uterine lining

Hormones across the phases

Menstrual phase: levels are low

If pregnancy has not happened, estrogen and progesterone fall, and the lining of the uterus is shed as your period. The Office on Women's Health describes very low levels of these hormones as the trigger for menstruation. This is the start of your cycle. See the menstrual phase.

Follicular phase: FSH then estrogen

The follicular phase begins on the first day of your period. Cleveland Clinic explains that the pituitary gland releases FSH, which prompts the ovaries to start growing follicles. One follicle becomes dominant and produces more estrogen, which thickens the uterine lining. As estrogen rises, FSH drops and the smaller follicles stop growing.

Ovulation: the LH surge

Rising estrogen triggers a sudden burst of LH, which causes the ovary to release the mature egg. The Office on Women's Health says LH rises about 36 hours before ovulation and peaks about 12 hours before. This surge is what ovulation predictor kits detect. Read more in the ovulatory phase and ovulation signs.

Luteal phase: progesterone takes over

After ovulation, the follicle becomes the corpus luteum, which produces progesterone along with some estrogen (Cleveland Clinic). Progesterone thickens the uterine lining and makes cervical mucus thicker. If there is no pregnancy, the corpus luteum breaks down, hormone levels fall, and your period starts. See the luteal phase.

Do hormones explain how I feel?

Partly, but not entirely. Some effects people commonly report:

• Estrogen rising: Cleveland Clinic links it with clearer skin and a better mood for some people in the follicular phase.
• Before a period: The NHS says hormone changes before a period can cause PMS symptoms such as bloating, breast tenderness, mood swings and irritability.

Remember that sleep, stress, food, health conditions and medication all affect how you feel too. Two people with similar hormone patterns can feel very different.

"Textbook" cycles aren't universal

Diagrams often show a neat 28-day cycle, with ovulation on day 14. In real life:

• Cycles of about 21 to 35 days are common, according to the NHS and Cleveland Clinic. See how long a normal cycle is.
• The Office on Women's Health says the time from ovulation to the next period can range from 7 to 19 days.
• A 2023 review from McMaster University points out that estrogen and progesterone levels differ a lot between women and from cycle to cycle in the same woman, so the standard 28-day model rarely applies exactly.

Eating and training by hormone phase

You may see advice to eat or exercise based on your hormone phases. Research on this "cycle syncing" is limited and early. The McMaster review found little evidence behind it, and the authors say there is no one-size-fits-all approach. Treat hormone-based wellness advice as ideas to test, not facts.

A simple way to remember it

If the details feel like a lot, here is a one-line version for each stage:

• Period: hormone levels are low, and the lining sheds.
• Before ovulation: FSH gets follicles growing, and estrogen climbs.
• Ovulation: an LH surge releases the egg.
• After ovulation: progesterone rises, then drops if there is no pregnancy.

Seeing the cycle as a loop, with each hormone setting up the next step, can make your symptoms feel less random. It also explains why the "before" and "after" ovulation halves of your cycle can feel so different for some people, while for others there is little difference at all.

When to talk to a doctor

Hormone imbalances can show up as changes in your cycle. Contact a doctor if:

• Your periods are irregular or stop (see irregular periods)
• You have excess facial hair, unexplained weight gain or tiredness alongside irregular periods
• You have severe PMS or symptoms that disrupt daily life
• You have not had a period for 3 months or more and are not pregnant

Keeping notes helps. How to track your period and cycle shows what to log.

Where Mochi Moon fits

Mochi Moon, an iPhone app launching in fall 2026, includes a phase guide that explains what is happening in each of the four phases in plain language. It does not measure your hormones, and its predictions are estimates.