Why PMS Starts in the Brain — Not Just Your Hormones

While hormone fluctuations are part of the picture, it’s the brain’s response to those hormones that often determines PMS symptom severity.

Let’s unpack that.

Hormones Aren’t Always the “Problem”

Throughout the menstrual cycle, estrogen and progesterone naturally rise and fall. These changes are expected, they’re not a “dysfunction” in themselves. However, some people are more sensitive to these shifts. Their brains, particularly the emotional and stress-regulating centres, react more strongly. This is where the hypothalamus and amygdala come in.

The Amygdala: The Brain’s Emotional Processing Hub

The amygdala plays a key role in how we respond to stress, threats, and mood-related signals. In people with PMS or PMDD, research suggests the amygdala is more reactive to normal hormonal changes, especially the drop in calming neurosteroids like allopregnanolone (a metabolite of progesterone). This can heighten emotional responses, anxiety, or mood swings — even when hormone levels themselves are within a normal range.

The Hypothalamus: The Brain’s Hormonal Control Centre

The hypothalamus sits in the brain and acts as the command centre for hormone regulation. It communicates with the pituitary gland, which sends signals to the ovaries to produce estrogen and progesterone.

If the hypothalamus is stressed or dysregulated - due to poor sleep, blood sugar instability, nutrient deficiencies, trauma, or chronic stress - the entire HPO (hypothalamic–pituitary–ovarian) axis can become imbalanced. This can lead to:

• Altered hormone production

• Poor ovulation (leading to low progesterone)

• Heightened stress responses to normal hormone changes

So, Is PMS a Brain Problem or a Hormone Problem?

It’s both. But in many cases, the brain’s interpretation of hormone shifts is the root cause.

Research into PMDD (a severe form of PMS) shows that women with PMDD don’t necessarily have higher or lower hormone levels. Instead, they have increased sensitivity in the brain - particularly in areas like the amygdala - to normal hormonal changes, especially the drop in progesterone and its calming neurosteroid metabolite, allopregnanolone.

What Can Dysregulate the Hypothalamus?

• Stress and cortisol dysregulation

• Poor sleep quality

• Inflammation or chronic illness

• Blood sugar imbalances

• Nutrient deficiencies (especially magnesium, B6, zinc, and essential fatty acids)

• Lack of ovulation (e.g. due to under-eating or overexercising)

To support someone with PMS, we’re not just “balancing hormones.” We’re supporting brain chemistry, stress resilience, and hypothalamic function by:

• Supporting ovulation with diet, protein, zinc, and B vitamins

• Reducing stress to restore HPO axis communication

• Enhancing GABA activity (through magnesium, taurine, or adaptogens)

• Addressing blood sugar and sleep

Testing Progresterone Why Testing Progesterone with DUTCH Gives a Clearer Picture — Especially for PMS & PMDD

When you’re dealing with PMS, PMDD, or hormone-related mood shifts, it’s not just about how much progesterone you have - it’s about what your brain is doing with it.

Progesterone’s Calming Effect Comes From a Metabolite

Once your body makes progesterone (after ovulation), it doesn’t just float around — it gets converted into other compounds, including a calming brain chemical called allopregnanolone. This calns your nervous system through GABA receptors.

In some women, especially those with PMDD or severe PMS progesterone levels are normal but they don’t convert enough into allopregnanolone, or their brain is extra sensitive when it drops off before a period. This can trigger anxiety, mood swings, insomnia, and sensory overload.

When testing progesterone with a blood test, you’re only getting part of the picture.

In blood (serum) testing, progesterone levels fluctuate dramatically throughout the day - sometimes jumping from 2 to 40 ng/ml in minutes. A single blood test can’t reliably show whether you’re producing enough progesterone. That’s why a low serum result is inconclusive, not diagnostic. In contrast, with urine testing (like the DUTCH test), the urine accumulates over hours, giving you a more stable, averaged reading of hormone activity.

Most blood tests also only measure one progesterone metabolite, beta-pregnanediol. The DUTCH test measures both the alpha and beta breakdown pathways. This is crucial because some women, like those with PCOS, tend to metabolise progesterone through the alpha pathway, while others, such as those with hypothyroidism, lean more toward the beta pathway. Measuring both provides a fuller, more accurate picture of your hormone health.

The DUTCH Test (Dried Urine Testing for Comprehensive Hormones):

• Measures progesterone metabolites, including allopregnanolone

• Captures an average over several hours (unlike blood, which reflects just a single moment)

• Provides insight into how your body processes hormones, not just how much you have

For example:

• You might find that your progesterone levels are normal, but if your calming metabolites, like allopregnanolone, are low, it could explain symptoms like anxiety or mood swings.

Through functional testing, targeted nutrition, and lifestyle changes, we help women achieve symptom-free cycles and optimal hormonal health. If you’re ready to get to the root cause of your PMS and take control of your health, book a consultation today.