Hormones Across the Menstrual Cycle: Estrogen, LH and Progesterone

About This Chart

Data Visualization Method

• Data: Daily median serum levels of estradiol, luteinizing hormone (LH) and progesterone reported by Stricker et al. (2006). The estrogen line is based on measured estradiol (E2). The chart uses "estrogen" because the term is more familiar to most readers.
• Time axis: The source values are aligned to the day of the LH peak, not to the first day of bleeding. The 28 daily values used here run from 13 days before the peak to 14 days after it. For readability, the LH peak is placed at Day 14 and the series is labeled Day 1–28, the standard teaching frame for the cycle.
• Processing: Each hormone was rescaled independently to a 0–100 range. In that range, 0 is the hormone's lowest daily median in this series and 100 is its highest. The original values (pmol/L, IU/L and nmol/L) are kept in the underlying dataset. Lines are drawn as smooth curves between the daily points.
• Annotations: The Period band (roughly Day 1–5) is a representative guide. The Ovulation line marks the LH peak. The Higher food intake band summarizes a phase-level finding from a separate meta-analysis.
• Chart form: A three-line chart with no numeric y-axis. The height of a line shows where that hormone sits within its own range. It does not show how its concentration compares with the other two hormones.

Creator's Note

Many cycle-hormone graphics are redrawn from earlier illustrations, and some add mood or behavior curves that the research does not support as a single shared pattern. This chart starts from published daily measurements instead. The raw values are preserved, and the data is rescaled only for display.

What the data shows most clearly is sequence rather than size. Estrogen peaks one day before the LH surge. Progesterone stays near the bottom of its range until after the surge, then climbs to its high point around Day 21, where estrogen also rises a second, smaller time. The chart is meant to make that order readable at a glance. How closely any single cycle follows it remains an open question.

Data Sources

• Stricker et al. (2006) — daily median estradiol, LH and progesterone values aligned to the LH peak; the basis for all three hormone lines.
• Tucker et al. (2024) — systematic review and meta-analysis of energy intake across menstrual phases, published in Nutrition Reviews; the basis for the Higher food intake annotation.

Limitations

The lines are group medians, not measurements from one person followed for 28 days. Because each hormone is rescaled on its own, a value of 100 marks each hormone's own peak. It does not mean the three hormones reach the same concentration, and the chart cannot be used to compare their absolute amounts.

The Day 1–28 labels are a reconstruction. The source data is anchored to the LH peak, and the cycle days around that peak are assigned by convention. The Period band is not a bleeding duration measured in the hormone dataset.

The food-intake band comes from a different kind of evidence. The meta-analysis pooled 15 datasets covering 330 participants and found higher average energy intake in the luteal phase than in the follicular phase, a crude difference of about 168 kcal per day. The studies varied widely in how they defined cycle phases and how they measured intake, which was mostly self-reported, and several found no significant difference. The start and end of the band are placed visually. They are not measured days.

What This Chart Doesn't Show

It does not show that cycles last exactly 28 days or that ovulation happens on Day 14. Cycle length, ovulation timing, and the height and timing of each peak vary between people and from cycle to cycle. The chart is a population-level pattern. It is not a clinical reference, and it should not be used to predict fertile days or to interpret individual test results.

It also does not show how the three hormones regulate one another. They are parts of one connected system, and they are drawn as separate lines only for clarity. Annotations for mood and sexual desire were considered and left out, because the available research does not support a single day-by-day pattern that applies to everyone. The food-intake band shows an average tendency, not a cause linked to any one hormone.