PFAS Explained: What They Are and How to Reduce Exposure

What makes PFAS so useful is also what makes them a problem. Nothing sticks to them, nothing soaks through them, and they resist breakdown for decades. That is why they turn up in your non-stick pan, your rain jacket, your takeaway packaging, your everyday cosmetics and the carpet under your feet, and why they are nicknamed "forever chemicals".

What Are PFAS?

PFAS, short for per- and polyfluoroalkyl substances, are built around a carbon-fluorine bond, one of the strongest in organic chemistry (1). Almost nothing breaks that bond, which is why non-stick coatings last and why PFAS have spread as far as Arctic ice and city rainwater (2).

Your kidneys filter waste into urine, but longer-chain PFAS are reabsorbed back into the blood instead of being excreted (3). For the three most studied compounds, PFOA, PFOS and PFHxS, the body takes roughly four to eight years to clear even half of what is there (4).

Where Do PFAS Come From?

For most people, food and drinking water are the main sources, although household dust, cosmetics, treated fabrics and certain occupations contribute (1, 5). Levels run highest near industrial sites, landfills and wastewater plants, and around airports and military bases where firefighting foams were used (5, 6). PFAS are found in the blood of most people tested. In one Canadian study of 72 adults, six different PFAS showed up in every one of them (7). EFSA found in 2020 that parts of Europe's population exceed its tolerable weekly intake for four PFAS, which it calls a health concern.

Are PFAS Bad for You?

Most human PFAS research is observational, identifying associations rather than proving cause. Several patterns are still consistent enough to take seriously.

A review of cardiovascular risk linked PFAS most strongly to raised blood pressure, cholesterol and uric acid, with no link to body fat or blood sugar (8). PFAS are classed as endocrine disruptors, which can interfere with thyroid hormone (9). A systematic review of endocrine-disrupting chemicals found evidence suggesting some compounds, including PFAS, may influence breast cancer risk (10). In adults and newborns alike, PFAS have been linked to epigenetic changes, where genes are switched on or off (11). In children, early-life exposure has been linked to raised gut inflammation markers (12).

Short-chain alternatives have since been introduced, but too little research exists to know whether they are safe (13).

Are PFAS Regulated?

Since 12 January 2026, EU member states must monitor PFAS in drinking water and act where limits are exceeded. The thresholds are 100 nanograms per litre for 20 named PFAS, and 500 for all PFAS added together. Testing is annual, and suppliers must publish the results.

For example, Berliner Wasserbetriebe publishes results for each of its nine waterworks, and in 2025 the PFAS-20 sum ranged from 1.9 to 34 ng/l against that limit of 100. There is also a postcode lookup for your own address.

Rules go beyond water: maximum levels for PFAS in food have applied since 2023, food-contact packaging is covered from 12 August 2026, and France banned PFAS in cosmetics, clothing and footwear from January 2026. Some pesticide active substances are also PFAS, and carry their own residue limits.

But a legal limit is not a health threshold: the US sets its health-based goal for PFOA and PFOS at zero, with an enforceable limit of 4 ng/l only because zero is not achievable, although water systems have until 2029 to comply.

How Do You Reduce PFAS Exposure?

Start with water, if your local numbers warrant it. Testing of household systems found under-sink reverse osmosis and dual-stage units removed nearly all PFAS, while activated carbon managed 60 to 70% for long-chain compounds and 40% for short-chain (14). Saturated carbon can release short-chain compounds back, so replace cartridges on schedule (15). Look for certification naming PFAS explicitly, since certifiers like NSF only validate the contaminants named on the label.

PFAS accumulate through water into fish, shellfish, plants and animals, and EFSA advises eating varied rather than cutting foods out. What may help is soluble fibre: some PFAS are recycled between the gut and liver in bile, people who eat more fibre have lower blood PFAS (16), and a four-week trial saw long-chain PFAS fall in those taking oat beta-glucan (7). Folate follows a similar pattern (17), and in adolescents higher folate weakened the link between PFAS and blood lipids (18). None of it establishes cause.

Cosmetics you can check: on any product, look for PTFE or ingredient names containing "fluoro", though not all are declared. Waterproof, long-wear and pressed-powder formulas are the likeliest to contain them. Stain-resistant treatments on carpet and upholstery are another route, so choose untreated when you replace them.

Read more: Why B Vitamins Work Better Together, What Is an Optimal Diet for Healthy Aging?, Is It More Effective to Get Active Ingredients Through Food or Supplements? and Bioavailability of Supplements

Where This Leaves You

You cannot avoid PFAS entirely. The evidence so far links them most consistently to cardiovascular and hormone health, with other effects still under investigation. Countries are acting on it, but standards vary, so check what applies where you live. What you control is smaller but real. Check your water report, filter if needed, read cosmetic labels, choose untreated fabrics as things wear out, and eat a varied diet with plenty of soluble fibre.

References

1. Glüge J, Scheringer M, Cousins IT, DeWitt JC, Goldenman G, Herzke D, et al. An overview of the uses of per- and polyfluoroalkyl substances (PFAS). Environ Sci Process Impacts. 2020;22(12):2345-73. https://doi.org/10.1039/d0em00291g
2. Evich MG, Davis MJB, McCord JP, Acrey B, Awkerman JA, Knappe DRU, et al. Per- and polyfluoroalkyl substances in the environment. Science. 2022;375(6580):eabg9065. https://doi.org/10.1126/science.abg9065
3. Brase RA, Mullin EJ, Spink DC. Legacy and Emerging Per- and Polyfluoroalkyl Substances: Analytical Techniques, Environmental Fate, and Health Effects. Int J Mol Sci. 2021;22(3):995. https://doi.org/10.3390/ijms22030995
4. Olsen GW, Burris JM, Ehresman DJ, Froehlich JW, Seacat AM, Butenhoff JL, Zobel LR. Half-life of serum elimination of perfluorooctanesulfonate, perfluorohexanesulfonate, and perfluorooctanoate in retired fluorochemical production workers. Environ Health Perspect. 2007;115(9):1298-1305. https://pmc.ncbi.nlm.nih.gov/articles/PMC1964923/
5. Sunderland EM, Hu XC, Dassuncao C, Tokranov AK, Wagner CC, Allen JG. A review of the pathways of human exposure to poly- and perfluoroalkyl substances (PFASs) and present understanding of health effects. J Expo Sci Environ Epidemiol. 2019;29(2):131-47. https://doi.org/10.1038/s41370-018-0094-1
6. Kurwadkar S, Dane J, Kanel SR, Nadagouda MN, Cawdrey RW, Ambade B, et al. Per- and polyfluoroalkyl substances in water and wastewater: A critical review of their global occurrence and distribution. Sci Total Environ. 2022;809:151003. https://doi.org/10.1016/j.scitotenv.2021.151003
7. Schlezinger JJ, Bello A, Mangano KM, Biswas K, Patel PP, Pennoyer EH, et al. Per- and poly-fluoroalkyl substances (PFAS) in circulation in a Canadian population: their association with serum-liver enzyme biomarkers and piloting a novel method to reduce serum-PFAS. Environ Health. 2025;24:10. https://doi.org/10.1186/s12940-025-01165-8
8. Schlezinger JJ, Gokce N. Perfluoroalkyl/Polyfluoroalkyl Substances: Links to Cardiovascular Disease Risk. Circ Res. 2024;134(9):1136-59. https://doi.org/10.1161/CIRCRESAHA.124.323697
9. Pearce EN. Endocrine Disruptors and Thyroid Health. Endocr Pract. 2024;30(2):172-6. https://doi.org/10.1016/j.eprac.2023.11.002
10. Wan MLY, Co VA, El-Nezami H. Endocrine disrupting chemicals and breast cancer: a systematic review of epidemiological studies. Crit Rev Food Sci Nutr. 2022;62(24):6549-76. https://doi.org/10.1080/10408398.2021.1903382
11. Kim S, Thapar I, Brooks BW. Epigenetic changes by per- and polyfluoroalkyl substances (PFAS). Environ Pollut. 2021;279:116929. https://doi.org/10.1016/j.envpol.2021.116929
12. Midya V, Maroli AS, Picker M, et al. Per- and polyfluoroalkyl substances (PFAS) in early life is associated with childhood intestinal inflammation: analyses of three birth cohorts. Clin Gastroenterol Hepatol. 2026. https://doi.org/10.1016/j.cgh.2026.07.001
13. Fenton SE, Ducatman A, Boobis AR, DeWitt JC, Lau C, Ng CA, et al. Per- and Polyfluoroalkyl Substance Toxicity and Human Health Review: Current State of Knowledge and Strategies for Informing Future Research. Environ Toxicol Chem. 2021;40(3):606-30. https://doi.org/10.1002/etc.4890
14. Herkert NJ, Merrill J, Peters C, Bollinger D, Zhang S, Hoffman K, et al. Assessing the Effectiveness of Point-of-Use Residential Drinking Water Filters for Perfluoroalkyl Substances (PFASs). Environ Sci Technol Lett. 2020;7(3):178-84. https://doi.org/10.1021/acs.estlett.0c00004
15. McCleaf P, Englund S, Östlund A, Lindegren K, Wiberg K, Ahrens L. Removal efficiency of multiple poly- and perfluoroalkyl substances (PFASs) in drinking water using granular activated carbon (GAC) and anion exchange (AE) column tests. Water Res. 2017;120:77-87. https://doi.org/10.1016/j.watres.2017.04.057
16. Dzierlenga MW, Keast DR, Longnecker MP. The concentration of several perfluoroalkyl acids in serum appears to be reduced by dietary fiber. Environ Int. 2021;146:106292. https://doi.org/10.1016/j.envint.2020.106292
17. Zhang Y, Mustieles V, Wang YX, Sun Y, Agudelo J, Bibi Z, et al. Folate concentrations and serum perfluoroalkyl and polyfluoroalkyl substance concentrations in adolescents and adults in the USA (NHANES 2003-16): an observational study. Lancet Planet Health. 2023;7(6):e449-58. https://doi.org/10.1016/S2542-5196(23)00088-8
18. Pan Y, Du Z, Ma Y, Chen C, He S, Zhang M, et al. Suppression effect of folate on poly- and perfluoroalkyl substance-induced alterations in lipids and the atherogenic index of plasma in adolescents. Lipids Health Dis. 2025;24:187. https://doi.org/10.1186/s12944-025-02638-y