PFAS: why the forever chemicals are also a hormone topic

You are standing in the kitchen turning the pan into the light. A fine scratch, right across the base. Yesterday the radio said something about forever chemicals, today it is in your news feed, and someone in the comments has written that they wreck your hormones.

You put the pan back. Then your eye falls on the rain jacket in the hallway. On the baking paper in the drawer. On the water bottle.

Many women know this pattern. It starts with a headline and ends with half the kitchen looking suspicious. And usually the actual question never gets asked: what of this concerns me, and on what scale.

So I am not starting with the pan. I am starting with a number that sorts everything else: with the time these substances stay inside you.

One note up front, because it stands above the whole text. Every single statement here carries a label saying which kind of study it comes from. Cell culture, animal model, observation in humans, or intervention in humans. In environmental medicine this distinction is exactly what separates a serious text from one that frightens you.

What PFAS are, and why forever chemicals is not a marketing word

The word sounds like an exaggeration. Like a term invented by a campaign because it shares well.

It is not. It is a chemical description.

PFAS stands for per- and polyfluoroalkyl substances. Picture a short chain of carbon atoms, like a string of beads. Normally there is hydrogen attached to every bead. In PFAS this hydrogen has been replaced by fluorine, partly or completely.

That one change makes the whole difference. Fluorine is the most electronegative element there is. It holds on to its binding partners like hardly any other atom. The carbon-fluorine bond is one of the strongest single bonds in organic chemistry.

In practical terms: sunlight does not get through it. Soil bacteria do not either. And the enzymes of your liver, which otherwise take apart almost anything foreign, find no point of attack here.

The result is a material that repels water, repels grease and repels dirt. That is exactly why it is everywhere: in coatings, in impregnations, in packaging, in firefighting foam, in thousands of industrial applications.

How large the group of substances is depends on where the definition is drawn. The European Food Safety Authority speaks of a very large group in its 2020 assessment. Figures circulating publicly range from several thousand to more than ten thousand compounds, depending on the boundary. I give the range because I cannot document the one fixed number.

What an endocrine disruptor actually is and how these substances dock onto receptors I have described in detail in the overview of xenoestrogens in everyday life. Here I take that as read and look only at what sets PFAS apart from all the others.

A second difference belongs right here, because it is regularly misrepresented in consumer texts. PFAS are not broken down through the classic detoxification pathways of the liver. There is no phase 1 step that cracks them open and no phase 2 step that makes them water soluble. They bind to proteins in the blood, are filtered in the kidney and to a large extent brought back there, and they run the same loop several times through the circuit between liver and gut. How these phases normally work is described in the article on phase 1 and phase 2 of detoxification. With PFAS this model simply does not apply.

And now you know why with these substances the clock is the more important measure than the scales.

How long PFAS stay in the body, and what that means for you

Picture a bathtub. Water runs in at the top, and there is a drain at the bottom.

With most environmental substances the drain is wide open. You turn off the tap and the tub is empty the next day. With PFAS the drain is a bottleneck. You turn off the tap and the tub needs years.

That number is not known from the laboratory but from a tragic natural experiment.

The second large study on this comes from the USA and delivers the same order of magnitude by a completely different route.

A third, very small study supports the same order of magnitude. In the Tama region west of Tokyo the drinking water source had been changed in 2019. In 17 participants aged between 53 and 83 years the estimated half-lives, after subtracting Japanese background values, were 2.7 years for PFOS, 5.6 years for PFHxS and 5.1 years for PFOA. With only 17 people that is not proof but an indication. Still, the order of magnitude of years turns up again in another country. Lyu Z, Harada KH, Sugii Y et al. Environ Health Prev Med. 2026;31:3. PMID: 41548900 · DOI: 10.1265/ehpm.25-00330 [Cohort, small, human]

Not all PFAS behave the same. The German Environment Agency sums it up like this: short-chain compounds leave the body within a few days to about a month, long-chain ones take several years. The industry switch to short-chain replacements is therefore, seen from the residence time in humans, a step forward. For the environment that does not hold, because there they are practically not degraded either.

And now you know why with PFAS I do not talk about single contacts but about years.

Where PFAS really come from, in the honest order

If someone asks you about PFAS, you think of the pan. Almost everyone does.

But the pan is not the quantity. It is the symbol.

In 2020 the European Food Safety Authority assessed what people in Europe actually take up PFAS through. The result: food and drinking water contribute the most. As the main contributing food groups across all population groups the authority names fish meat, fruit and fruit products, and eggs and egg products.

That is uncomfortable, because it shifts the room for action to where you have the least influence. That is exactly why it stands here first and not at the end.

Drinking water and food

Drinking water is the route through which exposure varies most strongly by location. We owe both large cohorts in this field to contaminated drinking water, Ronneby and the mid Ohio valley. With food the distribution is more diffuse. For the combined exposure to PFOA, PFNA, PFHxS and PFOS, EFSA names three contributing groups: fish meat, fruit and fruit products, and eggs and egg products. That fruit is among them surprises many, and that is exactly why I name it. The simple formula that animal foods carry the load and plant foods are clean does not hold for this group of substances.

Packaging, paper and coatings

The limitation that belongs with it: those were US samples from 2014 and 2015. I am not aware of a comparable German market survey. The European legal framework for food contact materials is a different one.

With non-stick coatings the situation is more nuanced than the headlines suggest. The coating is a polymer, that is a very large molecule, considered largely unreactive while intact. The figures circulating about millions of particles per scratch come from work on microplastics and not on PFAS uptake in humans. I did not find a robust human study on this. That is a gap, not an all clear.

Textiles, furniture, cosmetics, firefighting foam

Impregnated outdoor clothing, water repellent furniture covers, individual cosmetic products and above all firefighting foam belong here too. Firefighting foam is historically the most important cause of local drinking water contamination, because it went into the ground directly and in large quantities. That is why people living near airfields and fire service sites turn up in almost all exposure cohorts.

How high is exposure in Germany

And now you know why the honest order starts with the water glass and not with the pan.

The EFSA assessment of 2020, and why of all things the vaccine response counts

When an authority sets a limit value, it has to decide on an endpoint. On the one effect that becomes measurable at the lowest exposure.

With PFAS you might have expected cancer. Or the liver. Or hormones.

It turned out to be something else: the antibody response of children after vaccinations.

In the American health survey NHANES the same pattern showed up in 12 to 19 year olds: in seropositive children a doubling of PFOS went along with a 13.3 percent lower rubella antibody concentration (-19.9 to -6.2). For current allergic conditions including asthma, by contrast, no unfavourable association was found. The finding is therefore directed at the vaccine response and not at allergies. Stein CR, McGovern KJ, Pajak AM et al. Pediatr Res. 2016;79(2):348-357. PMID: 26492286 · DOI: 10.1038/pr.2015.213 [Cohort, cross-sectional]

A literature review of 42 human studies since 2010 sorts the gradation within the same organ system: strong indication of a reduced vaccine antibody response, some indication of increased infection risks, and only limited indications for allergy, atopic dermatitis and asthma.

And now you know why I do not treat PFAS as a marginal topic even though the hormonal data are thinner than the immunological ones.

The hormonal endpoints, cleanly sorted by strength of evidence

This is where serious and unserious texts on this topic part ways.

Online the endpoints usually stand side by side as if they were equally well documented. Vaccine response, cholesterol, thyroid, fertility, endometriosis, PCOS, all in one list. That is convenient and wrong. The data are very unequal. So I build them as a ladder: at the top what is documented, at the bottom what is hypothesis.

Cholesterol: the association that pleases nobody

That higher PFAS values go along with higher cholesterol values is one of the most stable findings in this whole field. It turns up again and again in large exposure cohorts. And nobody can properly explain it.

The most obvious alternative explanation was for a long time: perhaps someone who takes up a lot of fat through the gut also takes up more PFAS at the same time, and then both values rise together without one causing the other. This assumption was tested on purpose.

In the C8 Health Project 44,126 adults from six exposed water districts were examined, 1,075 of them were taking ezetimibe, a medicine that inhibits cholesterol absorption in the gut. After adjustment for age, sex, BMI, kidney function, smoking, education and income, the PFAS levels did not differ significantly between the two groups. So this is one of the few papers that specifically looked for an obvious alternative explanation and did not find it. That makes the association more credible, but it does not explain it. Ma G, Ducatman A. Toxics. 2022;10(12):799. PMID: 36548632 · DOI: 10.3390/toxics10120799 [Cohort, cross-sectional]

Why this stands in a hormone article: cholesterol is the starting molecule for all steroid hormones. A substance that measurably shifts this metabolism therefore touches an area connected with hormone production. That a relevant hormonal change follows from this is explicitly not shown. The wider context is under cholesterol: firefighter rather than fire.

Thyroid: TSH moves, the free hormones do not

The older, much cited finding on this comes from NHANES: women with PFOA in the top quartile, that is 5.7 ng/mL or more, more often reported a currently treated thyroid disease than women with 4.0 ng/mL or less, with an odds ratio of 2.24 (1.38 to 3.65). In men a similar, just not significant trend appeared for PFOA, while for PFOS there was an association in men and not in women. The authors themselves write that confounders and pharmacokinetic explanations still have to be ruled out. It is exactly this self limitation that is missing in almost every retelling.

More does not belong here. What TSH, fT3 and fT4 really mean is under thyroid values: which ones really count, and the connection to the female cycle under thyroid and female hormones. Important with this: anyone already taking a thyroid preparation does not change anything about it independently because of an environmental finding. Every adjustment belongs under medical supervision.

Birth weight and fertility

A methodological note that is almost always missing in consumer texts: in pregnancy the plasma volume rises markedly. Women whose plasma volume increases less have higher concentrations in the blood and at the same time statistically smaller babies, without one having to have caused the other. This dilution effect tends to pull the measured associations in one direction. It does not invalidate the finding, but it probably explains part of it.

In men there is an old, small finding that is often cited large. Of 105 Danish men with a median age of 19 years, those with high combined PFOS and PFOA levels had a median of 6.2 million normally formed sperm in the ejaculate compared with 15.5 million in those with low values. For concentration, total count and the pituitary-gonadal hormones the trends remained without statistical support, and the authors themselves call for confirmation. The PFOS medians of 24.5 ng/mL at the time lie far above today's German values. Usable as an indication, not as proof. More on this under improving sperm quality.

Endometriosis: the section in which this article does not claim something

I would have liked to write something clever here about PFAS and endometriosis. It does not work, because the data do not support it.

That is a good example of the fact that environmental toxin is not one single thing. In the same review organochlorine compounds stand out and PFAS do not. Anyone who throws everything into one pot loses exactly the information that would change something clinically.

If you have endometriosis: the diagnosis and the treatment decision belong in gynaecological hands, including the question of whether and when a laparoscopy makes sense. Nothing in this article speaks in favour of postponing an indicated operation or replacing a work-up. What an integrative view can contribute alongside is under endometriosis viewed integratively.

PCOS and ovary function: here it is hypothesis

On PCOS there is a review from 2025 describing possible effects of PFAS on the hypothalamic-pituitary-ovarian axis, on AMH, follicle maturation and gonadotropin receptor signalling. It is narrative, that is without a systematic search and without its own data. The authors describe associations between PFAS exposure and reduced fertility as well as an emerging link to PCOS, and at the same time state that the underlying molecular pathways are insufficiently understood. I cite that as a hypothesis, not as a finding.

Cell study and mouse oocytes A second paper exposed mouse granulosa cells and oocytes to a mixture of PFOA, PFOS, DDE, PCB 153 and hexachlorobenzene, at exactly the concentration previously measured in human follicular fluid. The mixture disturbed steroidogenesis, less oestradiol and progesterone were released, the viability of the granulosa cells fell and in the oocytes the concentration of reactive oxygen species rose. The mechanism is comprehensible. It nonetheless remains cell culture and mouse, and it was a mixture, not PFAS alone. Krawczyk K, Marynowicz W, Pich K et al. Reprod Fertil Dev. 2023;35(3):294-305. PMID: 36403477 · DOI: 10.1071/RD21326 [In vitro, cell culture and mouse]

PCOS is a medical diagnosis with defined criteria and its own work-up. It is not made on the basis of an environmental finding and not treated on your own. The overview on this is under PCO syndrome: causes and symptoms. Anyone already taking metformin, an antiandrogen or a hormonal preparation does not change anything about that on their own because of this article.

A comparison that makes the placement easier: zearalenone, a mould toxin, is a documented mycoestrogen. It docks directly onto the oestrogen receptor, and that is well studied. PFAS do not belong in the same category, their points of attack lie elsewhere, among others at nuclear receptors of fat metabolism. If mould is on the table for you, the article on zearalenone as a mycoestrogen is the more fitting one.

And now you know why with environmental topics I always ask first which kind of study a statement comes from.

Menopause, menstrual cycle and the reasoning error that stands almost everywhere

If you search for PFAS and menopause, within seconds you will find a headline saying, in effect: forever chemicals push women into menopause earlier.

That headline goes back to a real study. It just draws the wrong conclusion from it.

Do you remember the paragraph further up? Menstruation is an elimination route.

Then think the finding through the other way round.

This is not hair splitting. It has been calculated through.

What still stands nonetheless: not everything on PFAS and reproduction is affected by this distortion. The preconception cohort from Singapore measured before pregnancy and observed afterwards. That is a longitudinal design, and there the reversal does not apply to the same degree. Birth cohorts that measure early in pregnancy and then follow the child are also more robust than a cross-section.

For you in practical terms: if your menstrual cycle is changing right now, the first question is not the environment. It is sleep, stress, thyroid, blood sugar, weight change and life phase. What actually happens in perimenopause is under perimenopause: when it begins. And if you want to know which hormone values on which cycle day carry any meaning at all, you will find that under testing hormones: which test, which timing.

And now you know why with this topic I ask about the type of study first and only then about the result.

Measuring PFAS in blood: when that makes sense and when it does not

At some point in this article almost everyone has the same thought: can I have that measured?

Yes, technically that is possible. The question is a different one. What do you do with the result.

What the German assessment values mean

The German Human Biomonitoring Commission has set assessment values for PFAS. HBM-I is the value below which, according to current knowledge, no health impairment is expected: 2 µg/L for PFOA and 5 µg/L for PFOS in blood plasma. HBM-II lies higher and is graded by group, for women of childbearing age at 5 µg/L for PFOA and 10 µg/L for PFOS, for the rest of the population at 10 µg/L for PFOA and 20 µg/L for PFOS.

The honest limit of a measurement

I say this here as plainly as I say it in the consultation.

In Germany a PFAS blood measurement is not covered by statutory insurance. There is no guideline from a medical society recommending such a measurement for hormonal complaints in the general population. And there is no approved treatment that specifically lowers an elevated value.

That is what the reticence of routine care hangs on, and it is understandable. Almost everyone has measurable values, so a positive finding distinguishes you from nobody. And a value without an option for action can trigger worry, which is itself a health factor.

Important: I deliberately name no laboratories, no test providers and no prices here. That is not reticence out of caution but out of conviction. An environmental test belongs in a conversation, not in a shopping basket.

And now you know why with this topic I advise against a measurement more often than you would have expected from an integrative practice.

What you can do, and where avoidance reaches its limit

Now the part you have probably been waiting for. I am doing it honestly, even if that makes it less satisfying than the usual ten point lists.

Drinking water

Since 12 January 2026 the German drinking water ordinance has applied a combined limit of 0.1 µg/L for twenty PFAS compounds. From 12 January 2028 a markedly stricter combined limit of 0.02 µg/L for four particularly relevant compounds will be added.

The practical step is unspectacular: ask your water supplier for the current values. Most publish them or release them on request. With your own well a water analysis makes more sense than any blood measurement.

Filters, honestly considered

That is why I name no models and no brands. A filter is only as good as its maintenance interval, and that depends on your consumption and your starting exposure.

Pans, air fryers and coatings

The label PFOA free means that one single, long restricted compound is no longer used. It does not mean PFAS free. That is not a deception but a correct statement about a single substance which in everyday life is read as something else.

Anyone who wants to sidestep the question cooks in stainless steel or cast iron. I would replace heavily scratched coatings, not because of a body of studies but because a broken coating has lost its purpose anyway. With the air fryer it is the same material question in a different appliance.

Baking paper and packaging

The rule of thumb that follows from the packaging analysis is simple: do not leave greasy and warm food sitting in coated paper for long. That applies to the pizza in the box just as much as to the sandwich in greaseproof paper. In the oven you can use unbleached, uncoated baking paper or a silicone baking mat. Transfer leftovers into glass or stainless steel rather than storing them in coated board.

Textiles and furniture

Impregnations on outdoor clothing, rucksacks, tents and furniture covers are a further route. In practice that does not mean clearing out the wardrobe. It means: look at the details at the next purchase and do not re-impregnate as a matter of routine.

What explicitly achieves nothing here

Juice cleanses, detox teas, alkaline powders and the usual detox weeks achieve nothing against PFAS. The reason is further up: these substances are not broken down through the liver phases but transported bound to proteins and reabsorbed. An approach aimed at phase 1 and phase 2 comes up empty here. What makes sense in detox concepts and what does not I have written down under detox done right instead of wrong.

For sauna and sweating I also found no robust data on PFAS. The idea of sweating them out is not supported. And the binders and plant based agents from the heavy metal field cannot be transferred, that is a different class of substance with a different transport route. How your body's own oestrogen is actually disposed of through the liver is under lowering oestrogen naturally through the liver.

Blood donation and bloodletting: what the study says and what it does not

The open question is currently being worked on. A study protocol from Arizona describes a randomised trial with up to 1,500 active firefighters and three arms: blood and plasma donation, moderate endurance exercise, intermittent fasting. Alongside the PFAS values, cardiovascular risk profiles and epigenetic ageing are also being examined. Data collection ended in December 2025, and results were not available at the time of this research.

The paragraph that matters most to me

And now the uncomfortable part. There is no zero solution here.

You can swap your pan, change your baking paper and install a filter, and you will still keep measurable values. Because PFAS are in drinking water, in rain, in soil, in food, in house dust. And because what you carry inside you today comes from years you cannot undo. This is not an invitation to resignation. It is an invitation to a sense of proportion.

Where the level that actually works lies

At the European Chemicals Agency a restriction procedure under REACH is running that covers the entire group of substances. As of August 2026 the Committee for Risk Assessment has completed its opinion, and the opinion of the Committee for Socio-Economic Analysis is expected by the end of 2026. Under discussion are a far reaching restriction with transition periods, sector specific derogations of five and of twelve years, each following a transition period of 18 months, and conditions for continued use. This status is in motion.

I write this without political outrage, because it is the sober description of the situation. With a substance distributed through drinking water, rain and food, it is not the shopping list that decides but regulation. That takes pressure off you. Your job is not to work on an environmental problem in your kitchen.

And now you know why I wrote this article even though the practical recommendations in it are shorter than in almost every other text on this topic.

Frequently asked questions about PFAS and hormones

Where this topic connects to the rest of your system

PFAS do not stand alone. They are one building block in a larger question: which influences from outside end up in your hormone balance, and in what order is it worth looking.