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Can our genetic profile also influence the effect of medications?
July 29, 2025
Dr. Andrea Gartenbach
Dr. Andrea Gartenbach is a specialist in internal and functional medicine, an expert in longevity, and a former competitive athlete. In her current column for Premium Medical Circle, she discusses the opportunities of genetics and why everyone should know their genetic architecture.
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I accompanied a patient last year: an entrepreneur in her early forties. She exercised enough, did strength training, practiced yoga, ate healthily, and meditated regularly. One could say she did a lot right. And yet there was this constant tension – a diffuse inner restlessness. Not sick, but also not fully functional and balanced.
"I function," she said. "But just barely." Her blood values were inconspicuous. The turning point came when we conducted a comprehensive gene and hormone status.
She carried a COMT variant with reduced enzyme activity. COMT stands for catechol-O-methyltransferase, an enzyme that plays a key role in the breakdown of catecholamines like dopamine, norepinephrine, and adrenaline. This means her body broke down stress hormones and estrogens more slowly.
In combination with the onset of estrogen dominance in perimenopause, this had particular relevance: A slowed estrogen breakdown can lead to the increased formation of reactive, potentially toxic metabolites. This increases the risk for hormone-related complaints and, in the long term, for diseases such as hormone-dependent breast cancer. In addition, for years she had been taking the antioxidant quercetin with the best intentions – a substance that additionally inhibits COMT and exacerbates the problem.
We adjusted her routines: magnesium supplements for the nervous system, a different supplement profile, focus on phase-II detox, and mindful cycle monitoring. After three months, she felt significantly better. The fears and inner restlessness had disappeared. Her hormone profile was also significantly more balanced. This experience is exemplary of what modern genetics can achieve.
Many people think of genetics in terms of fixed risk genes like BRCA1/2 – mutations that are associated with a significantly increased risk of breast cancer and often lead to serious medical decisions. Other variants such as ApoE4, which are associated with a higher risk for neurodegenerative diseases like Alzheimer's, seem similarly dramatic at first glance – but are significantly more modifiable.
ApoE4 in particular shows how much lifestyle factors such as inflammation reduction, sleep quality, blood sugar regulation, exercise, and cognitive stimulation can influence gene expression. By knowing about this variant, we can specifically counteract it.
Dr. Andrea Gartenbach: "Genes don't provide certainties – but clear indications. And the chance to act purposefully."
But what if we not only know the genetic potential - but also what is actually active?
The real revolution in precision medicine lies in the field of so-called SNPs - short for Single Nucleotide Polymorphisms - small genetic variations that are often overlooked. They show how individually our metabolism works and which risks we can identify early. The amount of data is manageable, the evaluation uncomplicated - and significantly cheaper than a full genome sequencing.
Some SNPs affect so-called lifestyle processes:
Pharmacogenetics is also exciting - the question of how our genetic profile influences the effect of drugs. Certain enzymes like CYP2D6 or CYP2C19 ensure that drugs are broken down faster or slower. Two people can take the same drug in the same dosage and experience completely different effects or side effects. This is not a theoretical problem, but everyday life in the clinic. And one of the main reasons why "trial-and-error" therapies are increasingly being replaced by personalized strategies.
Modern precision medicine goes even further today. Instead of just looking at the genome, so-called multiomics approaches also include other biological levels:
This data shows which genes are currently read and which are inactive. Particularly exciting are epigenetic tests like the Horvath Clock or organ-specific aging clocks (for heart, brain, or skin). They make biological changes measurable – often before symptoms even appear. Thus, they function like a precise feedback system for our lifestyle.
The future lies in medicine that does not react but anticipates.
Those who know their genetic architecture – and understand how diet, exercise, sleep, and targeted supplementation affect it – make better decisions. Every day.
And what everyone should be aware of: One of the largest analyses to date on human longevity has shown that only about 7% is genetically predetermined - the rest is Fullgevity. So we have over 90% control over our health, performance, and vitality into old age. Longevity does not begin in the gene - but in the daily decision.
