Precision Medicine for Women: Why Personalized Health Strategies Are Gaining Importance

Expert Interview with Dr. med. Simone Koch

About the author: Gynaecologist Dr med. Simone Koch focuses on individualised measures that are far removed from standard concepts when it comes to women's health, well-being and performance. In her online academy, she advises doctors and health experts, writes specialist articles and regularly appears as a speaker.

The Invisible Interplay of Hormones

1. Dr. Koch, in public perception, hormones are frequently viewed in isolation. Why is this approach too short-sighted in your opinion, and how closely is this hormonal network actually linked to metabolism, the nervous system, and immune function?

Dr. Koch: When I look at an isolated hormone level, it tells me almost nothing on its own. Hormones work in a feedback loop in which every factor influences the others, which is why looking at a single value in isolation so often leads down the wrong path. An example I see daily: when estrogen drops during perimenopause, insulin sensitivity deteriorates by up to forty percent, the thyroid converts less active free T3, and at the same time, the immune balance shifts toward pro-inflammatory signaling molecules like IL-1, IL-6, and TNF-alpha. So, a single declining value pulls metabolism, the nervous system, and the immune defense along with it.

At the molecular level, this interconnection is even demonstrable. Thyroid hormones and sex hormones share common coactivators at the nuclear receptor family. In other words, they access the exact same machinery within the cell. The COMT enzyme degrades estrogen metabolites and stress hormones via the same methylation pathway, which is why high stress levels slow down estrogen degradation and vice versa. Furthermore, estrogen triggers the release of histamine from mast cells, whereas progesterone stabilizes mast cells—explaining why some women suddenly develop histamine sensitivity in midlife.

For me, the main takeaway is the obligation to pinpoint precisely where the first domino falls in the network. Anyone who understands this can target interventions at that exact spot without having to treat every symptom individually. That is precisely why, for a woman experiencing fatigue, I always test the thyroid, sex hormones, iron status, and inflammatory markers together, and I never rely on TSH alone. Only this complete picture shows where support needs to begin.

“Hormones work in a feedback loop in which every factor influences the others [...]. So, a single declining value pulls metabolism, the nervous system, and the immune defense along with it.”

Autoimmunity and the Female System

2. Dr. Koch, as an expert and bestselling author on Hashimoto's thyroiditis, you know the statistics: women are many times more likely to be affected by autoimmune processes than men. Which biological characteristics in the female system, also in interplay with hormones, favor this dynamic, and which developments are you currently observing most closely in this field of research?

Dr. Koch: In Hashimoto's, the ratio of women to men ranges between seven and ten to one depending on the study, and this figure has occupied my mind for years. A large part of the answer lies on the X chromosome. Women have two of them, and one is silenced in every cell to ensure proper gene dosage. However, this silencing is incomplete. Between fifteen and twenty-three percent of genes escape inactivation, and several key immune genes happen to be among them—such as TLR7, CD40L, and FoxP3. As a result, women produce these immune switches in double dosage, making the immune response more sensitive and reactive.

Estrogen further amplifies this effect because it upregulates TLR7-mediated interferon production. Hormonal transition phases such as puberty, postpartum, and perimenopause are therefore typical windows during which an autoimmune disease first appears or flares up. In Hashimoto's, I see this repeatedly around pregnancies and during menopause.

Right now, I am following research on the so-called Xist ribonucleoprotein with particular attention. A 2024 study in the journal Cell showed that the very molecular complex controlling X-inactivation acts as an autoantigen itself, directly driving female susceptibility to autoimmunity. When male mice were experimentally given this complex, they developed autoantibodies. This is so exciting because, for the first time, it decouples female prevalence from hormones and attributes it to a distinct genetic mechanism. This holds great promise for precision medicine: the more precisely we understand which X-chromosomal switches are active in an individual patient, the more targeted our future interventions can be.

Uncovering the Phenomenon of 'Brain Fog'

3. Many women report "brain fog" symptoms during certain phases of life—meaning reduced mental clarity, concentration problems, or the feeling of no longer being as high-performing as before. In your experience, which factors are frequently underestimated in this context?

Dr. Koch: The term "brain fog" is often hastily dismissed as psychological or stress-related, even though a measurable physical cause is almost always behind it. The most underestimated factor is the interaction of multiple systems slipping out of balance simultaneously.

First and foremost is the thyroid. Low free T3 alongside a completely normal TSH is regularly overlooked because routine check-ups usually only measure TSH. Yet it is precisely this active thyroid hormone that supplies the brain, and a deficiency manifests as a constant "cotton wool" feeling in the head.

For women in midlife, the hormonal layer comes into play. Estrogen acts directly on receptors in memory regions of the brain. Its decline makes itself felt as fluctuating, cycle-dependent clarity. Progesterone drops years earlier, and when sleep deteriorates as a result, concentration suffers immediately the next day. The crucial point is that these causes can be distinguished. A constant cotton wool feeling points more toward the thyroid, whereas clarity that fluctuates throughout the day and across the cycle points more toward hormones. Anyone who recognizes these patterns and measures the right markers will almost always find a concrete starting point without having to settle for the label of "menopause."

Another very important point is the massive, increasing dysregulation of mast cells. Through various mechanisms, this can restrict the breakdown of histamine in the brain and thus lead to "brain fog." This is particularly pronounced in perimenopause due to the tight interplay between hormonal balance and the immune system.

“The term brain fog is often hastily dismissed as psychological or stress-related, even though a measurable physical cause is almost always behind it. [...] Anyone who recognizes these patterns and measures the right markers will almost always find a concrete starting point [...].”

Magnesium in the Context of Women's Health

4. When it comes to individual female well-being, aspects of mental health must not be overlooked. What role does magnesium play in normal psychological function and the nervous system? 

Dr. Koch: In the nervous system, magnesium functions as a brake, so to speak. It ensures that nerve cells do not fire immediately at every minor stimulus. When there is insufficient magnesium, they react more strongly than necessary. Many women experience this as finding it harder to unwind. When people say magnesium contributes to normal nervous system function, this calming, braking effect is precisely what is meant.

On top of that, there is stress. People under high stress lose more magnesium through the kidneys because stress hormones boost its excretion. At the same time, a body low in magnesium reacts more sensitively to stress. For women, there is an added specificity: freely available magnesium in the blood reaches its lowest level in the second half of the menstrual cycle, when progesterone peaks. On the exact days when many women feel more thin-skinned, the nervous system has the least magnesium available. Therefore, the fact that magnesium contributes to normal psychological function carries special weight for women.

The third point is energy. Every cell generates its energy from a molecule called ATP, which can only function in combination with magnesium. The brain consumes more ATP than any other organ. Consequently, when magnesium runs low, it is felt first in the head as fatigue. This relates to the claim that magnesium contributes to the reduction of tiredness and fatigue. Anyone wishing to assess their status should request whole-blood magnesium testing, as standard serum levels remain normal for a long time even when tissue stores are depleted.

Thyroid, Metabolism, and Individual Needs

5. As the pacemaker of metabolism, the thyroid influences numerous bodily functions. What role does an individually tailored consideration of lifestyle, nutrition, and targeted micronutrient supply play when women want to actively support their thyroid health and vitality long-term?

Dr. Koch: The thyroid indeed sets the pace for the entire metabolism, which is why a cookie-cutter approach backfires particularly fast. The first issue is evaluation itself. The conventional TSH reference range often differs from what I consider optimal.

With micronutrients, it comes down to synergy. The thyroid requires iodine as a building block for hormones; it contributes to normal thyroid hormone production and normal thyroid function. It also requires selenium for converting the storage hormone T4 into active T3, meaning selenium likewise contributes to normal thyroid function. These and other nutrients interact closely, and a deficiency in a single one slows down the whole chain.

Because the immune system and the thyroid are closely intertwined, a balanced immune system plays a central role. What matters most is that every woman has distinct needs. My recommendation is to test relevant markers in whole blood, evaluate them in the context of individual well-being, and then supplement in a targeted, demand-oriented manner. It is precisely this individualization that determines how sustainably a woman can support her overall well-being in daily life.

The Future of Precision Medicine for Women

6. Looking ten years ahead: which developments could change women's health the most, and why will the individualization of medical decisions play an increasingly large role?

Dr. Koch: Looking ten years into the future, I see the single biggest shift in moving away from statistical averages toward the individual woman. Conventional medicine established reference ranges across broad population groups, while long underrepresenting women because many studies were conducted primarily on men. That is changing right now.

The strongest leverage point for me is genetics—and I deliberately emphasize that I view it as an opportunity. Knowing a woman's COMT status tells me how quickly she metabolizes estrogen and stress hormones, allowing me to tailor hormone therapy dosing from the outset instead of spending months guessing the right dose. Variants like MTHFR or CYP enzymes reveal individual metabolic vulnerabilities. This is already daily practice in my work today, not distant science fiction, and it will become more widely available and affordable in the coming years.

Added to this is new research into female biology itself, such as the X chromosome and its role in autoimmune conditions. The better we understand which genetic switches are active in an individual woman, the more precisely we can detect and address autoimmune processes early. I also expect continuous real-time daily data—such as cycle tracking, blood glucose, and sleep metrics—to inform decisions and complement periodic laboratory testing.

The reason individualization is becoming so vital is simple: the female body changes constantly across cycles and life stages. Medicine aimed at capturing this dynamic cannot operate with a single target value for everyone. It must determine the individual optimal range for each woman. That is where the true promise of precision medicine lies.

“Looking ten years into the future, I see the single biggest shift in moving away from statistical averages toward the individual woman. [...] Medicine aimed at capturing this dynamic cannot operate with a single target value for everyone.”

Note: This interview is for general informational purposes only. The assessments and opinions presented reflect the personal scientific views and clinical experience of the interviewed expert and are based, among other things, on their own research.

The shared information reflects the expert's personal, professional experience and does not constitute official statements or claims by VitaminExpress.

The content does not constitute authorized health claims under EU Regulation (EC) No 1924/2006 and should not be understood as claims for the prevention, treatment, or cure of any disease. This interview is not a substitute for individual medical advice. For health-related questions, please consult a qualified medical professional.