Fluorine in Your Medicine Cabinet: What the PFAS-Drug Study Does and Does Not Show
Dr. Thomas Lee Abshier, ND |
A recent piece circulated by Dr. Joseph Mercola tells readers to check the generic names in their medicine cabinets. If a drug’s name begins with “flu” or contains “fluor,” it carries fluorine, and a new analysis suggests the fluorine may be there for the manufacturer’s benefit rather than the patient’s. The study behind that claim is real and important. The advice built on it needs some correction before it is useful.
I prefer fluorine-free medicines when a doctor judges them equally effective, especially when starting a new prescription. The reasons are good ones. But the strongest reason is not the one most readers will assume, and the “flu” rule of thumb will mislead many people.
The study
A team at the University of Freiburg, led by Prof. Michael Müller, conducted the research, commissioned by Germany’s Federal Environment Agency (UBA), and published it this summer in Sustainable Chemistry and Pharmacy (Greinke et al., 2026). The team identified 111 active ingredients in human medicines and 28 in veterinary medicines that qualify as PFAS under the OECD definition.
Their main findings:
- For 87 percent of the human medicines and 65 percent of the veterinary medicines, an active ingredient without PFAS structures already exists for the same use. For nearly all the rest, PFAS-free alternatives are in development.
- In every drug examined with a known mechanism of action, the fluorinated portion of the molecule does not produce the intended medical effect.
- More than 80 percent of the PFAS drug ingredients can break down into trifluoroacetic acid (TFA), a persistent substance now accumulating in water worldwide.
Prof. Müller’s conclusion was that, pharmacologically, adding these fluorinated groups is not strictly necessary.
Why fluorine is in drugs
The claim that fluorine is there “for the manufacturer’s benefit rather than yours” is half right. Chemists add fluorine because the carbon–fluorine bond is the strongest in organic chemistry. A fluorinated group shields a drug from liver breakdown, so more of it reaches the bloodstream and lasts longer between doses. It can also help a drug cross membranes. These are real pharmacological advantages, and some benefit the patient through once-daily dosing or lower doses.
But that same resistance to breakdown makes these molecules a problem once they leave the body. And the convenience of a fluorinated design does benefit the manufacturer: it is a reliable way to make a molecule more drug-like, and a new fluorinated variant of an existing drug can be patented as a new molecule. Where an equally good non-fluorinated drug already exists, the case for the fluorinated one rests more on habit and commerce than on necessity.
What the study does not show
The study’s concern is primarily environmental, not a finding that these drugs harm the patient who takes them. The Freiburg team and the German Environment Agency stated plainly that there is no immediate risk to patients, because these medicines undergo safety testing before approval. Most fluorinated drugs are not the long-chain industrial PFAS (such as PFOS or PFOA) that are notorious for lingering in human blood for years. The body clears a drug like fluoxetine in days to weeks, not years.
The real concern is what happens after excretion. Drug residues pass through wastewater plants largely untouched, and many degrade into TFA. TFA does not break down in nature, moves freely with water, and is rising in rain, rivers, drinking water, and human blood. This month, the European Chemicals Agency’s risk-assessment committee recommended classifying TFA as toxic to reproduction, based on animal studies showing developmental harm, though the European Commission has not yet acted. Pharmaceuticals are one source among several; refrigerant gases and pesticides contribute more.
So the honest message is not “this pill is poisoning you.” It is “this pill adds, in a small way, to a permanent chemical load that all of us, and our grandchildren, will carry.”
The “flu” rule of thumb is unreliable
Checking for “flu” or “fluor” in a drug’s name will produce both false alarms and misses.
The OECD definition of PFAS, used in the study, requires at least one carbon fully bonded to fluorine, typically a –CF₃ (trifluoromethyl) or –CF₂– group. A single fluorine atom on a ring does not qualify. So:
- False alarms: Many “fluoro” drugs carry only single fluorine atoms on a ring and are not PFAS under this definition. Fluconazole and ciprofloxacin (a fluoroquinolone) are examples.
- Misses: Many PFAS drugs have no hint of fluorine in their names. Celecoxib (Celebrex), sitagliptin (Januvia), and several others carry a –CF₃ group.
- Correct hits: Some names do flag it, such as fluoxetine (Prozac), which carries a –CF₃ group.
Fluoroquinolone antibiotics deserve their own caution for a different reason: the FDA carries boxed warnings for tendon rupture and nerve damage. That is a patient-safety issue unrelated to the PFAS question, and it shows why each drug must be judged on its own record.
The reliable way to know is to ask your pharmacist, who can look up the structure in seconds. Germany is building a public “Environmental Medicines Index” with a traffic-light rating for this purpose; nothing comparable yet exists in the United States.
Why the concern remains plausible
Some will say the patient-safety data are reassuring and drugs’ environmental contribution is small. Both statements are partly true. But there are good reasons not to dismiss the concern.
First, persistence is cumulative and irreversible. A substance that never degrades does not need to be very toxic to become a problem; it only needs to keep being added. TFA concentrations have climbed steadily for decades and, on present practice, will keep climbing. We are running an experiment whose results our descendants will inherit.
Second, the safety testing that reassures us measures the patient over months or years. It does not measure the lifelong, multigenerational exposure to breakdown products in drinking water. Those are different questions, and approval answers only the first.
Third, the history of PFAS is not encouraging. The industrial PFAS were declared safe for decades before their persistence and health effects were acknowledged, and the companies that profited from them knew more than they disclosed. Medicines have so far been exempted from Europe’s proposed PFAS restrictions on the grounds that they are essential. The Freiburg study shows that, for most of them, the fluorinated version is not essential at all.
Fourth, something feels intuitively wrong with designing molecules for stability inside the body without asking what that stability means outside it. Nature recycles what it makes. A medicine that cannot return to the earth is a burden we choose to hand forward.
What a patient can do
- Do not stop a medication on your own. A fluorinated drug that works well for you is not dangerous to take. Changing medications carries its own risks.
- At your next appointment, ask: “Does this medicine contain PFAS, and is there an equally effective alternative without it?” This matters most when starting a new prescription.
- Ask your pharmacist rather than relying on the drug’s name.
- Never flush unused medicines. Use pharmacy or law-enforcement take-back programs.
- Consider whether you need the drug at all. The least-polluting prescription is the one made unnecessary by better diet, sleep, movement, and treatment of root causes. That is the naturopathic principle, and it applies here.
What I would ask of policy and industry
- Require that each drug’s PFAS status be listed in prescribing information, so doctors and pharmacists can see it.
- Create a U.S. equivalent of Germany’s environmental drug index.
- Make environmental persistence a factor in new-drug development and approval, not an afterthought.
- Fund research into how well wastewater treatment can capture fluorinated drug residues and TFA.
Conclusion
Dr. Mercola is right that most fluorinated drugs can be replaced and that patients should ask about it. Where his summary implies the drug is accumulating in the patient, it goes further than the study. The truth is more sobering: these molecules are designed to be hard to destroy, and they keep their promise long after they leave us. A wise physician prescribes with the patient and the patient’s grandchildren in mind.
This article is for general information and is not medical advice. Discuss any change in medication with your prescribing physician.
Resources
- Mercola, “PFAS-Containing Medicines and Their Alternatives” (September 21, 2026): https://articles.mercola.com/sites/articles/archive/2026/09/21/pfas-containing-medicines-alternatives.aspx
- University of Freiburg, “PFAS in medicines can often be replaced with alternatives” (June 29, 2026): https://uni-freiburg.de/en/pfas-in-medicines-can-often-be-replaced-with-alternatives/
- German Environment Agency (UBA), “There are often substitutes for PFAS in medicine”: https://www.umweltbundesamt.de/en/press/pressinformation/there-are-often-substitutes-for-pfas-in-medicine
- Greinke J., Mußler P., Maack G., Hug M.J., Müller M., Speichert G., “Per- and polyfluorinated active pharmaceutical ingredients: Overview and alternatives,” Sustainable Chemistry and Pharmacy (2026), DOI: 10.1016/j.scp.2026.102416
- Arp H.P.H. et al., “The Global Threat from the Irreversible Accumulation of Trifluoroacetic Acid (TFA),” Environmental Science & Technology 58 (2024): 19925–19935