Hormones and Their Impact on Your Cycle

Hormones regulate the menstrual cycle in fascinating ways. From the rise of estrogen in the first half of the cycle to ovulation and then the increase in progesterone during the second phase, each hormone plays an essential role. In our articles you will learn how hormones influence your cycle, your mood, your energy, your fertility and overall health.

The female cycle is regulated and influenced by a finely tuned interplay of various hormones.

Hormonal Influence

Those who understand their cycle can intentionally align nutrition, mood, and fitness with hormonal changes to their advantage.

Hormones & Fitness

The thyroid is a central regulatory organ for the human metabolism. Its importance for the female cycle and fertility is often underestimated.

Thyroid & Its Influence

The Most Important Hormones in Your Cycle

FSH (Follicle-Stimulating Hormone) triggers the maturation of follicles in the ovaries. LH (Luteinizing Hormone) triggers ovulation itself – the LH surge is the starting signal. Estrogen rises during the follicular phase, improving mood and energy levels while preparing the uterine lining. Progesterone takes over after ovulation, stabilizes the uterine lining and raises basal body temperature – the shift that Daysy measures every single morning.

How Hormones Affect Your Basal Body Temperature

The rise in progesterone after ovulation causes a measurable temperature increase of 0.2 to 0.5°F (0.2 to 0.5°C). Daysy detects this shift precisely and confirms that ovulation has taken place. No temperature rise means no ovulation and no ovulatory cycle.

Hormonal Fluctuations and How They Show Up

Mood changes before your period, energy highs during the follicular phase, fatigue in the luteal phase – all of this is hormonally driven. Understanding your cycle means recognizing that these shifts are not random. They follow a clear biological logic, and once you see the pattern, everything starts to make sense.

What Happens After Stopping Hormonal Birth Control?

When you stop taking hormonal contraceptives, your body needs time to find its natural rhythm again. Daysy learns your individual cycle from day one and guides you through this transition with daily feedback, so you always know where you stand, even when your cycle is still recalibrating.

In the hormone section on the Daysy website you'll find evidence-based articles that make complex biology easy to understand.

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