Understanding the Late Luteal Phase

The late luteal phase is the final stretch before menstruation, when both progesterone and estrogen levels fall sharply. These declining hormones affect not just the body, but the brain. Many people notice changes in mood, concentration, and sleep — common signs of the brain responding to hormonal withdrawal.

This phase is often linked to premenstrual symptoms like irritability, low mood, or anxiety. When progesterone falls in the late luteal phase, its calming metabolite allopregnanolone (ALLO) also falls. This rapid withdrawal of ALLO just before menstruation produces short-term changes in GABA signalling in the brain, which can reduce inhibition and heighten neural reactivity in sensitive individuals — linking to symptoms like anxiety, irritability, mood swings, poor sleep, and stress sensitivity (Gao et al. 2023). Alongside this, falling estrogen can reduce serotonin and dopamine activity — neurotransmitters that influence mood and motivation. The result can feel like an emotional dip or mental fog.

Cortisol regulation can also shift, making stress feel harder to manage. This isn’t a personal failing — it’s biology. The brain’s response to these hormonal changes can heighten emotional sensitivity, making self-care and grounding practices especially important.

Recognising the late luteal phase allows for proactive support: gentle exercise, prioritising sleep, magnesium-rich foods, and reducing caffeine or alcohol can all help smooth the transition into menstruation. By aligning with your brain’s needs, this phase can become a time of preparation rather than depletion.