Menstrual Cycle Hormone Levels- A Complete Guide

What Actually Happens to Your Hormones During Your Cycle

Your menstrual cycle is controlled by a finely tuned hormonal orchestra. Four main players—estrogen, progesterone, FSH, and LH—rise and fall in predictable patterns every month.

Most women know something about "hormones" and mood swings, but few understand the actual mechanics. This guide breaks it down without the woo-woo wellness speak.

The Four Hormones That Run Your Cycle

Estrogen

Produced primarily by the ovaries, estrogen does the heavy lifting in the first half of your cycle. It thickens the uterine lining, regulates mood, and keeps vaginal tissues healthy. Levels climb steadily from day one of your period until just before ovulation.

Progesterone

This hormone takes over after ovulation. Its main job is to prepare the uterine lining for a potential pregnancy and keep it stable. If pregnancy doesn't happen, progesterone drops sharply—that drop triggers your period.

FSH (Follicle-Stimulating Hormone)

The pituitary gland produces FSH. It stimulates your ovaries to mature follicles each month. FSH spikes at the start of your cycle and triggers ovulation.

LH (Luteinizing Hormone)

LH surges right before ovulation—it's the hormone that causes the egg to actually release. Tracking LH surges is how ovulation predictor kits work.

Hormone Levels by Cycle Phase

Menstrual Phase (Days 1-5)

Both estrogen and progesterone are at their lowest. The uterine lining sheds, causing bleeding. FSH begins to rise slightly, prepping the ovaries for the next round.

Follicular Phase (Days 6-14)

Estrogen climbs steadily as follicles develop. This is often when women feel most energetic and clear-headed. By day 14 (or thereabouts), estrogen peaks and triggers an LH surge.

Ovulation (Day 14-ish)

The LH surge causes the mature egg to release. Estrogen is high, and you might notice clearer cervical mucus and slightly higher energy. This is your fertile window.

Luteal Phase (Days 15-28)

Progesterone dominates this phase. It rises after ovulation and peaks around day 21-22. If the egg isn't fertilized, progesterone drops around day 26-28, triggering your period.

Average Hormone Levels Overview

Hormone Follicular Phase Ovulation Luteal Phase
Estrogen 30-120 pg/mL 130-370 pg/mL 70-250 pg/mL
Progesterone 0.1-1.5 ng/mL 0.1-1.5 ng/mL 5-20 ng/mL
FSH 3-10 mIU/mL 10-30 mIU/mL 1-8 mIU/mL
LH 2-15 mIU/mL 25-40 mIU/mL 1-12 mIU/mL

Note: These ranges are approximate. Labs use different reference values, and "normal" varies between individuals.

How to Track Your Hormone Changes

You don't need expensive tests to understand your cycle. Here's what actually works:

Basal Body Temperature (BBT) Charting

Measure your temperature first thing in the morning before getting out of bed. After ovulation, progesterone causes a slight temperature rise (0.5-1°F). You'll see a pattern emerge after a few months.

Ovulation Predictor Kits (OPKs)

These detect the LH surge in urine. A positive result means ovulation is likely in the next 12-36 hours. Use them around days 10-14 of a typical 28-day cycle.

Cervical Mucus Tracking

Estrogen causes cervical mucus to become clear, stretchy, and slippery (like egg white) around ovulation. This is one of the most reliable natural signs.

Cycle Apps

Apps like Clue, Flo, or Natural Cycles can help you spot patterns over time. Don't expect perfect predictions—algorithms vary wildly in accuracy.

Signs Your Hormones Might Be Off

Some fluctuation is normal. But these symptoms often point to actual imbalances worth discussing with your doctor:

Common Hormonal Conditions

PCOS (Polycystic Ovary Syndrome)

Afflicts roughly 1 in 10 women. Typically involves higher-than-normal androgen hormones, irregular periods, and often insulin resistance. Diagnosis usually requires ultrasound and blood work.

Hypothyroidism

Low thyroid function slows everything down—metabolism, digestion, and cycle. Often causes longer, heavier periods and fatigue. Blood tests for TSH, T3, and T4 confirm diagnosis.

Perimenopause

Starting anywhere from mid-30s to late 40s, this transition involves wildly fluctuating estrogen. Periods become irregular, hot flashes appear, and sleep often suffers. Lasts an average of 7-10 years.

When to Get Blood Work Done

Standard hormone panels are often ordered on day 3 of your cycle (counting from the first day of bleeding). This captures baseline FSH, estradiol, and often LH.

Progesterone is typically checked around day 21 to see if you've ovulated and whether levels are adequate.

If your doctor is only running one test, push for context. A single number means nothing without knowing where you are in your cycle.

What Actually Helps Balance Hormones

Skip the expensive supplements marketed for "hormone balance." Here's what the evidence actually supports:

The Bottom Line

Your hormones follow a predictable pattern once you learn to read the signs. You don't need to test everything constantly. Tracking your cycle for 2-3 months reveals more than a single blood test ever could.

If something feels genuinely wrong—abnormal bleeding, severe symptoms, or obvious pattern disruption—see a gynecologist or endocrinologist. Not your GP. Someone who actually specializes in reproductive endocrinology.