Why Progesterone Can Calm One Woman and Make Another Worse: The Overlooked Connection Between Trauma, Allopregnanolone, Mast Cells, and Women's Brain Health

Something I hear frequently from women I work with is the frustration of receiving a diagnosis, being prescribed a hormone or medication, and then experiencing symptoms that nobody seems able to explain. Most of my clients are women, and I have learned how important it is to listen when someone tells me that a treatment intended to help her is actually making her worse. One example I have encountered is progesterone. It is often described as a calming hormone that can support sleep, emotional stability, and potentially mast-cell regulation. Yet some women experience increased anxiety, agitation, insomnia, or worsening neurological symptoms when taking it. I have been looking into this for quite some time, and I believe part of the explanation may involve something we do not discuss enough: the relationship between neurosteroid metabolism, GABA-A receptor sensitivity, previous trauma, and the nervous system’s ability to adapt to hormonal changes.

To understand this, we need to look at what happens to progesterone inside the body. Pregnenolone is an upstream precursor used to produce progesterone and several other steroid hormones. Progesterone can then be converted by 5α-reductase into 5α-dihydroprogesterone, which is further converted by 3α-hydroxysteroid dehydrogenase into allopregnanolone. This is a particularly interesting molecule because it acts as a neurosteroid, meaning it can directly influence how neurons communicate. Allopregnanolone enhances the activity of GABA-A receptors, which are involved in controlling neuronal excitability. GABA is our primary inhibitory neurotransmitter, and when it activates GABA-A receptors, it generally allows chloride ions to move across neuronal membranes in a way that reduces the likelihood of excessive neuronal firing. Allopregnanolone makes this inhibitory signaling more effective, which helps explain why progesterone can feel calming for some women.

However, having more allopregnanolone does not automatically mean having a calmer nervous system. This is where I have become particularly interested in the receptors themselves. GABA-A receptors are made of different protein subunits, including α, β, γ, and δ subunits, and their composition determines how they respond to GABA and neurosteroids. Some receptors are located at synapses, where they respond to brief releases of GABA, while others are found outside synapses and provide a more continuous background level of inhibition. These receptors are constantly adapting. Prolonged changes in neurosteroid exposure can alter receptor expression, subunit composition, and sensitivity. Certain receptor populations may decrease while others increase, potentially changing how the brain responds to the same concentration of allopregnanolone. In susceptible individuals, neurosteroid exposure may even produce paradoxical effects on mood. This is why I believe we need to investigate receptor adaptation rather than assuming progesterone will always produce the same neurological response.

Another important part of my thinking involves trauma and chronic stress. When someone experiences prolonged psychological stress or trauma, the brain’s stress-response system can undergo lasting adaptations. The hypothalamic-pituitary-adrenal axis, which regulates cortisol and other stress responses, may become dysregulated. At the same time, stress-related changes in neurosteroid synthesis, GABA signaling, and neuronal excitability can influence the brain’s ability to regulate fear, anxiety, and emotional responses. One particularly interesting possibility is that alterations in the enzymes responsible for neurosteroid synthesis may reduce allopregnanolone availability in certain individuals, even when progesterone itself is not particularly low. Repeated changes in stress signaling may also influence GABA-A receptor function and sensitivity. Trauma does not necessarily downregulate all GABA-A receptors, but it may alter the overall inhibitory system in ways that make someone respond differently to subsequent hormonal fluctuations.

This is why I believe a woman’s history can be biologically relevant to her response to progesterone. Imagine two women with similar progesterone levels. One has a nervous system that adapts effectively to changing neurosteroid concentrations. The other has experienced chronic stress, trauma, disrupted sleep, or prolonged inflammatory symptoms that may have influenced her neurosteroid signaling and inhibitory circuitry. Although their hormone levels appear similar, their neurological responses may be completely different. The difference may not be how much progesterone they have, but how effectively their nervous systems interpret and respond to its downstream signals.

This becomes especially interesting during pregnancy and after childbirth. During pregnancy, progesterone and allopregnanolone concentrations rise dramatically, exposing the maternal brain to a very different neurochemical environment. The nervous system must adapt its GABA-A receptor activity as these concentrations change. After childbirth, progesterone and allopregnanolone decline rapidly, removing much of the neurosteroid exposure that was present throughout pregnancy. What interests me is that nearly every woman experiences this hormonal withdrawal, yet only some develop postpartum depression. From my understanding, one important difference may involve how effectively GABA-A receptors and the broader inhibitory nervous system adapt to the sudden withdrawal of allopregnanolone. If receptor expression and sensitivity do not adjust appropriately, the balance between inhibitory and excitatory signaling may become disturbed. This could contribute to anxiety, emotional instability, sleep disturbances, and depressive symptoms in susceptible women. I do not believe postpartum depression is caused by a single mechanism, but neurosteroid sensitivity may help explain why normal hormonal changes become problematic for some women and not others.

This also explains why I have been looking closely at the glutamate–GABA–glutamine cycle. Glutamate is the brain’s primary excitatory neurotransmitter, while GABA provides much of the inhibitory balance. Astrocytes, which are specialized cells supporting neurons, help prevent excessive glutamate accumulation by removing it from the extracellular environment through transporters such as EAAT1 and EAAT2. Inside astrocytes, glutamate can be converted into glutamine by glutamine synthetase. Glutamine is then transferred back to neurons, where it can be converted into glutamate and subsequently into GABA through glutamate decarboxylase. This recycling process is essential for maintaining neurotransmitter balance and depends on mitochondrial metabolism and adequate cellular energy.

The reason I find this important is that allopregnanolone influences how effectively GABA-A receptors respond, but it does not directly correct problems with glutamate clearance or neurotransmitter recycling. If astrocytes are struggling to regulate extracellular glutamate, or if neuronal energy metabolism is compromised, the balance between excitation and inhibition may become more vulnerable. Changes in GABA-A receptor sensitivity could potentially amplify that vulnerability. This does not mean that impaired glutamate recycling is necessarily present in women who react poorly to progesterone, but it is another biological system I believe deserves investigation.

Then there is the mast-cell component, particularly the MRGPRX2 receptor, which I have also been exploring for some time. Mast cells are not simply involved in allergies. They communicate with sensory nerves and participate in neurogenic inflammation. When sensory neurons release substance P, this neuropeptide can activate MRGPRX2 on certain mast cells, triggering intracellular calcium signaling and the release of mediators such as histamine and tryptase. These mediators can further stimulate nearby sensory nerves, potentially increasing pain, burning sensations, itching, and other inflammatory responses. Tryptase can also activate PAR2 receptors on sensory neurons, creating a feedback loop in which nerve activation encourages mast-cell activation, and mast-cell activation further sensitizes the nerves.

What interests me is the possibility that women with hormonal sensitivity and mast-cell-related conditions may have several overlapping systems influencing their symptoms. One involves neurosteroid signaling and GABA-A receptor adaptation, another involves glutamate regulation and neuronal excitability, and another involves peripheral mast-cell and sensory-nerve communication. These pathways do not necessarily cause one another, and a direct connection between allopregnanolone sensitivity and MRGPRX2-driven mast-cell activation has not been established. Nevertheless, understanding their potential interactions may help us ask better questions about why hormonal transitions feel so destabilizing for certain women. We also need to distinguish neurological sensitivity from genuine progesterone or progestogen hypersensitivity, which is a separate clinical phenomenon.

This is one of the reasons women’s health has become such an important area of my work. I have been deeply interested in understanding hormonal transitions, postpartum depression, PMDD, trauma-related changes in the nervous system, mast-cell disorders, and the relationship between neuroinflammation and metabolism. I do not think women’s health should be reduced to whether estrogen or progesterone is simply too high or too low. Hormone concentrations matter, but so do receptor sensitivity, enzyme activity, cellular metabolism, immune signaling, and the nervous system’s capacity to adapt.

I cannot personally experience what a woman goes through during pregnancy, childbirth, postpartum recovery, or the many hormonal transitions throughout her life. But I can listen carefully, take her experiences seriously, and continue investigating the mechanisms that may explain why her body responds differently.

Because when one woman feels significantly better with progesterone and another feels considerably worse, I don’t think the second woman’s experience should be dismissed or automatically attributed to anxiety.

I think it should encourage us to look deeper into her biology. And that, to me, is where a more individualized understanding of women’s health begins.