What are the signs of low progesterone?

Low progesterone often shows up as broken sleep, anxiety or irritability, shorter or heavier cycles, and worse-than-usual PMS — and it's typically the first hormone to drop in perimenopause.

Progesterone is your calming, balancing hormone. It supports sleep (via GABA, the brain's relaxation system), steadies mood, and balances oestrogen's effect on the womb lining. So when it falls, the classic signs are trouble falling or staying asleep (especially that 3–4am waking), new anxiety or a shorter fuse, heavier or more frequent periods, breast tenderness, and heightened PMS. Because progesterone usually declines before oestrogen in perimenopause, these can be the earliest hints the transition has begun — sometimes years before periods change much.

In younger women, low progesterone can also relate to cycles where ovulation didn't happen (you only make meaningful progesterone after ovulating), which is worth knowing if you're trying to conceive.

What to do: track your symptoms against your cycle — a clear pattern (poor sleep and anxiety in the two weeks before your period, for instance) is telling. Support the basics that help: sleep, stress management, and steady blood sugar. If symptoms are disruptive, see your GP — progesterone (often as part of HRT) can restore sleep and calm for many women, and is also used to protect the womb lining if you take oestrogen.