Ever taken a medicine that did nothing for you, or one that gave you side effects your friend never had? A major new study suggests your DNA may be part of the reason. Researchers analyzing nearly 100,000 Americans found that every single participant carried at least one genetic variant that can change how the body handles common drugs, a field called pharmacogenomics.
The study, published Nov. 11, 2026, in Science Translational Medicine (DOI: 10.1126/scitranslmed.adt8040), also identified thousands of variants that earlier research had missed. Here is what it found and what it could mean the next time you fill a prescription.
What Is Pharmacogenomics?
Pharmacogenomics is the study of how your genes affect your response to medications. Some genes control the enzymes that break drugs down in the liver. Others shape the targets drugs act on. A small change in one of these “pharmacogenes” can mean a standard dose works too strongly, too weakly or not at all.
Think of it like a factory line. If one machine runs fast, a drug gets cleared before it can work. If it runs slow, the drug builds up and side effects become more likely. Doctors usually cannot see these differences, so most prescribing still starts with a one-size-fits-most dose.
What the All of Us Pharmacogenomics Study Found
The research drew on the National Institutes of Health’s All of Us Research Program, a long-running effort to build one of the most diverse health databases in the U.S. The senior author is Philip Empey, who directs the Center for Clinical Pharmaceutical Sciences at the University of Pittsburgh, according to STAT News.
The key findings, as reported by STAT:
- The team looked at 16 pharmacogenes in data from nearly 100,000 Americans.
- Every participant carried at least one variant in those 16 genes.
- One in four participants had actually taken a medication that their variants could affect.
- The researchers found thousands of new variants that had not turned up in earlier work using other large databases such as the UK Biobank.
Which medications are affected?
The variants can influence how people respond to several widely used drug classes, including:
- SSRIs, a common class of antidepressants
- Statins, used to lower cholesterol
- Chemotherapy drugs used in cancer care
- Clopidogrel (Plavix), a blood thinner often prescribed after heart attacks and stents
Those are not rare prescriptions. Statins and SSRIs alone are taken by tens of millions of Americans, which is why a finding that touches every participant matters.
Why Diversity Made the Difference
Most early genetics research relied heavily on people of European ancestry. That leaves gaps. A variant common in one population can be nearly invisible in a database that barely includes it.
All of Us was built to fix that by recruiting participants from a wide range of backgrounds. According to STAT, the broader ancestry mix is the reason the study caught variants that previous databases missed.
Loren Saulsberry, a health policy researcher who studies equity in pharmacogenomics and was not involved in the paper, told STAT that the work “really furthers” the evidence that genetically guided care adds benefit across diverse populations. Starting with diverse data can also help limit disparities as these findings move into clinical practice.
Pharmacogenomics and Your Prescriptions: What It Does and Doesn’t Mean
It is tempting to blame every bad drug experience on genetics. Empey cautioned against that. He told STAT you cannot say a bad reaction is “absolutely because of genetics,” but genetics “is one reason” people respond differently.
Important caveats:
- Most people have never had their genome sequenced, so they do not know which variants they carry.
- Many doctors are not trained to interpret how specific variants affect the drugs they prescribe.
- Several variants can affect a single drug, making real-world predictions complicated.
- Age, weight, kidney and liver function, other medications, diet and adherence still matter a great deal.
A program under financial pressure
The study arrives at a difficult moment for All of Us. STAT reports that the program expects about $122 million once a federal budget is finalized, roughly an 80% drop from its 2023 peak. Because of the cuts, the program has scaled back recruiting and stopped returning genetic results to participants. Former CEO Joshua Denny said community enrollment efforts were “cut back dramatically.”
About 5,000 children are enrolled, but their data are not yet available to researchers. Sara Van Driest, the program’s pediatrics director, said enrolling children at scale will require “increased and stable funding in the years ahead.”
What You Can Do Now
You do not need to wait for science to catch up to be a smarter patient. Here are practical steps:
- Keep a medication history. Note which drugs did not work or caused side effects, and share that list with every new doctor and pharmacist.
- Ask about pharmacogenomic testing. If you are starting clopidogrel, certain antidepressants or chemotherapy, ask whether a genetic test could guide the choice or dose. Some health systems already offer it.
- Tell family members. If you learn you carry a variant that affects a drug, relatives may carry it too.
- Never change a dose on your own. Genetic information should guide a conversation with your clinician, not replace it.
For more on how new research is reshaping everyday health decisions, read our report on a 5,772-patient trial questioning how doctors decide on statins and our coverage of the high-dose flu shot and Alzheimer’s risk.
The Bottom Line
This study shows that genetic differences in drug response are not rare exceptions. They appear to be universal. The challenge now is turning that knowledge into routine care, and that depends on trained clinicians, affordable testing and stable research funding.
This article is for general information and is not medical advice. Talk with your doctor or pharmacist before making any changes to your medications.
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