Progesterone. Your very own settle and sleep hormone.

If you've been waking at 2am with your heart racing, lying there with a thoughts running wild or feeling more anxious than usual — and you're somewhere in your 40s — there's a good chance that the changing levels of progesterone may have something to do with it. 

But I always like to preface this when talking about hormones - you will hear me say it a million times over. Hormones themselves are NOT the issue. They are simply responding to us, our movements and how we are living now and the cumulation of how we have lived prior. More on this later...

Progesterone is too often filed under "reproductive hormones" and dismissed as something that only matters during pregnancy (its role is to nurture the space in the uterus and to hold the pregnancy). But it's also a brain hormone and a whole body hormone — and one of its most important jobs is keeping you calm, feeling settled and it supports your sleep.

Progesterone is also a pre-cursor to the making of our stress hormone cortisol. So if our stress response system is activated unnecessarily, our body will preference surviving over making progesterone - and then we lose the full impact of this hormone in our body!

Every month, as a result of ovulation, your ovaries produce a surge of progesterone. It's actually quite remarkable how this happens. You've probably felt its effects in the post ovulation phase of your cycle — a more inward feeling is usually how it is described. A subtle sense of ease

But progesterone doesn't just circulate in the bloodstream. It crosses into the brain, where it's converted into a compound called allopregnanolone — a neurosteroid that enhances the activity of GABA receptors. GABA is your brain's primary braking system, the neurotransmitter that tells an overactive nervous system to settle down. Allopregnanolone acts on the same receptors targeted by benzodiazepines like Valium — so when progesterone is plentiful, your brain has access to its own naturally calibrated calming agent.

What many people don't realise is that your brain also makes progesterone directly, independent of the ovaries. When we talk about progesterone's effects on mood, sleep and anxiety, we're talking about something woven into the very fabric of how your brain regulates itself.

During perimenopause and menopause, your entire body is re-wiring, including your nervous system and stress response system. Changing levels of progesterone is an adjustment for the body - and is very personal in how the body experiences this.

During perimenopause, progesterone is usually the first hormone to decline because some cycles tend to be ovulatory and others aren't. Each non-ovulatory cycle means no progesterone surge, no allopregnanolone and less calming support for your nervous system.

The result? We need to adjust to having relied on progesterone and perhaps got away with things because of its incredible support. Our body is saying – now you need to take over by finding a deeper and more inner sense of settlement. This can show up differently for us all, like difficulty falling or staying asleep, waking between 2–4am, increased anxiety, heightened stress sensitivity and a general sense of being wired but exhausted. What's striking is that these symptoms can appear before periods become irregular — and long before most women (or their doctors) connect them to hormones at all.

Therefore, when looking for ‘treatment’ and support, be aware that sleeping pills and anti-anxiety / anti-depressants, etc may not be the answer here and in many cases, may create more issues. If the cause is hormonal, then hormones are the support that is needed. And if hormones are needed, then how can you adjust your life and lifestyle to support your body to adjust and to make it’s own.

When progesterone is required as a treatment option

When progesterone is prescribed as part of HRT, there are two very different options:

Micronised progesterone is chemically identical to what your ovaries produce. Taken orally, it converts into allopregnanolone in the brain — delivering that same calming, sleep-supporting effect as your natural progesterone. Many specialists recommend taking it at night precisely because of this gentle wind-down effect. Research backs this up: women taking micronised progesterone consistently report fewer night wakings, more deep (slow-wave) sleep, and better overall sleep quality.

Synthetic progestins — such as medroxyprogesterone acetate (MPA) or norethisterone — are lab-made hormones that mimic some of progesterone's actions (mainly protecting the uterine lining), but they don't convert to allopregnanolone in the same way. They also bind to other hormone receptors in the body, which can affect mood, fluid retention, and anxiety in negative ways. Large studies have linked synthetic progestins in both contraception and HRT to increased rates of depression and low mood — the opposite of what you're hoping for when you're already struggling.

On safety too, the distinction matters. A large 2022 study found that synthetic progestins combined with estrogen were associated with a higher risk of breast cancer, while micronised progesterone was not — leading researchers to conclude it may be the safer choice.

The bottom line

Progesterone is far more than a reproductive hormone. It's a nervous system ally, a natural sleep architect and your very own a built-in support for settlement. When it drops in perimenopause, the effects, such as disrupted sleep, anxiety, emotional volatility, can feel bewildering and disconnected from any obvious cause. I see this all the time in my clinic room.

If any of this resonates, it's worth having a conversation with a menopause-informed healthcare provider to start with lifestyle adjustments and if needed, being specific about asking for micronised progesterone rather than accepting a synthetic progestin by default. In this case, the detail really does matter.

References:

• Allopregnanolone & GABA mechanism — Liang & Rasmusson (2018), Chronic Stress

• Benzodiazepine-like sleep effects of allopregnanolone — Lancel et al. (2001), Neuropsychopharmacology

• Brain-synthesised progesterone — Schumacher et al. (2022), Frontiers in Neuroendocrinology

• Progesterone as brain neuromodulator — European Society of Medicine (2025)

• Sleep disorder prevalence in perimenopause/postmenopause — Jehan et al. + Gold et al. (SWAN study)

• Micronised progesterone sleep meta-analysis — Nolan, Liang & Cheung (2021), JCEM

• Phase III RCT of micronised progesterone — Prior et al. (2023), Scientific Reports

• Synthetic progestins & depression — Skovlund et al. (2016), JAMA Psychiatry

• Breast cancer risk: progesterone vs progestins — Asi et al. (2016) meta-analysis

• E3N cohort breast cancer data — Fournier/Stute et al.

• Sleep & menopause review — Baker et al. (2018), Nature and Science of Sleep