There is something no one explains to you in school: your menstrual cycle is not just the 5 days of bleeding. It is a 28-day hormonal system (more or less) with 4 distinct phases, each with its own profile of estrogen, progesterone, FSH and LH.
Those hormones do not only control reproduction. They affect your brain, your energy, your digestion, your sleep and even how you process stress. When you understand which phase you are in, many things that used to feel random start to make sense.
Menstrual phase: the reset
When: Days 1–5 (the first day of bleeding is day 1 of the cycle)
What happens: Estrogen and progesterone are at their lowest point. The uterus sheds its endometrium.
What you feel: Fatigue, cramps, a drop in energy. Your brain produces more prostaglandins (the ones responsible for pain), which is why cramps are real and not something you should just "push through." Many women also report greater emotional sensitivity — that is biological, not dramatic.
What helps: Iron (you lose it through bleeding), magnesium, local heat and guilt-free rest.
Follicular phase: the push
When: Days 1–13 (it overlaps with the menstrual phase at the beginning)
What happens: FSH stimulates the ovarian follicles so they mature. Estrogen starts to rise progressively.
What you feel: Rising energy, better concentration, more motivation to socialize and do new things. If you have ever noticed that you are more productive in the first half of the month, that is estrogen doing its job. Verbal memory and mental fluency also improve.
What helps: This is the best phase to start projects, do high-intensity exercise and have difficult conversations.
Ovulatory phase: the peak
When: Around day 14 (it varies between women and cycles)
What happens: Estrogen reaches its highest peak, which triggers an LH surge that releases the egg. Testosterone levels also rise slightly.
What you feel: Maximum energy, greater confidence, higher libido. Cervical mucus changes texture (more fluid, elastic), which is a physical sign of fertility. Some women feel a slight pain on one side of the abdomen — this is "mittelschmerz," or ovulation pain.
What helps: Your body is at its moment of highest physical and social performance. It is a good time for presentations, interviews or high-intensity exercise.
Luteal phase: the preparation
When: Days 15–28
What happens: The empty follicle becomes the corpus luteum and produces progesterone. If there is no pregnancy, the corpus luteum breaks down, progesterone drops sharply and menstruation begins.
What you feel: The first half (days 15–21) can be fairly stable. The second half is when PMS appears: bloating, mood changes, anxiety, cravings, fatigue, sensitive breasts. All of this is progesterone dropping.
Progesterone has a sedative effect on the brain (it acts on GABA receptors), which is why you may also feel more mental slowness or difficulty concentrating during these days.
What helps: Reducing caffeine and refined sugar (they can worsen symptoms), increasing magnesium, vitamin B6 and calcium. This is not the phase to demand your maximum from yourself — it is the phase to close, rest and prepare for the reset.
How Lua helps you with this
Understanding the phases in theory is useful. Understanding your phases with your data is something else.
Lua records your daily symptoms, your sleep, what you eat and how you feel — and shows you how all of that relates to your current hormonal phase. Over time, it identifies your specific patterns: which phase you sleep worse in, when you have more cravings, which foods worsen your luteal symptoms.
It is not generic prediction. It is intelligence built from your data.
Download Lua and start connecting the dots.