What Oestrogen and Progesterone Do Beyond the Cycle

The Women's Health guide covers the menstrual cycle, contraception, and menopause in full practical depth — this section is narrower: the underlying hormonal mechanism itself, relevant to both sexes.

What These Hormones Actually Do

Oestrogen and progesterone are produced primarily by the ovaries in women (with smaller amounts from fat tissue and the adrenal glands in both sexes), and they do far more than regulate the reproductive cycle — oestrogen supports bone density, cardiovascular health, and skin and connective tissue integrity; progesterone has calming, sleep-supportive effects for many women and plays a critical role in preparing the uterine lining for potential pregnancy each cycle.

The Body Fat Connection Works Both Ways

As covered in Section 2, fat tissue actively produces oestrogen via aromatase — which means very low body fat can suppress oestrogen enough to disrupt the menstrual cycle entirely, including amenorrhea (periods stopping) and RED-S, both covered in full in the Women's Health guide, while very high body fat can push oestrogen levels too high, which is itself associated with its own set of health risks. Both directions represent a genuine hormonal imbalance, not just an aesthetic or fitness consideration.

In Men

Oestrogen matters in men too, in smaller amounts — it supports bone density and modulates libido, and both excessively low and excessively high levels (the latter often from excess aromatisation of testosterone, per Section 2) cause problems. This is part of why oestradiol is worth including on a hormone panel for men, not just women, despite the common assumption that it's an exclusively female concern.