PFAS in dietary supplements and peptides: what has been measured and how a lab tests for them

PFAS in dietary supplements: what has been measured

PFAS are a large family of synthetic fluorinated chemicals. The FDA’s December 2025 report on cosmetics uses the OECD’s 2021 definition: fluorinated substances with at least one fully fluorinated methyl or methylene carbon atom. With a few exceptions, any chemical with a –CF3 or –CF2– group counts. The same report notes that there is no consensus definition internationally and no federal one in the US. A “PFAS-free” claim therefore means little without its definition and its list of compounds.

Few published studies have measured PFAS in supplements. One is a 2026 study in the Journal of AOAC International. It measured four PFAS (PFOA, PFODA, PFOS and PFBS) in 13 DHA products, 11 algal oils and 2 fish oils, and found trace amounts in 3. The authors write that no standardised method exists for PFAS in DHA products.

Validated methods for similar materials exist. AOAC Official Method 2025.07, a First Action method published in 2026, measures 30 PFAS by LC-MS/MS in foods that include protein powders and fish oil. Its limits of quantification run from 0.0055 to 0.55 µg/kg, depending on compound and food.

In the EU, Regulation (EU) 2023/915 sets maximum levels for PFOS, PFOA, PFNA and PFHxS, alone and summed, in eggs, fish, fishery products, bivalve molluscs, crustaceans, meat, game and offal. Supplements are not on the list. A research peptide has no official PFAS limit.

Where PFAS can enter a supplement

The FDA tests food grown or produced in areas with known environmental contamination, and it lists PFAS uses in food processing equipment. The EPA lists packaging. All three routes apply to supplements:

• Raw materials. The FDA has tested foods from its Total Diet Study for PFAS since 2019. Most detectable levels were in seafood, so it tested 81 seafood samples in a targeted survey in 2022. Fish oil starts from that raw material.
• Processing equipment. The FDA’s authorised food contact uses of PFAS include nonstick coatings, sealing gaskets and O-rings in food processing equipment, and manufacturing aids.
• Packaging. The EPA lists grease-resistant paper and food wrappers. The FDA announced in February 2024 that PFAS grease-proofing agents for paper and paperboard are no longer sold into the US market. For plastic particles, see microplastics in supplements and how labs test for microplastics.

Which products have PFAS

Product group	Where PFAS are used	Listed by
Food packaging	Grease-resistant paper, fast food wrappers, microwave popcorn bags, pizza boxes	EPA
Household products	Stain and water repellents for fabrics, nonstick cookware, cleaning products, paints, sealants	EPA
Personal care	Some shampoos, dental floss, cosmetics	EPA, FDA
Food processing	Sealing gaskets and O-rings	FDA
Injectable packaging	ETFE fluoropolymer film on some vial stoppers and syringe plungers, as a barrier between drug and rubber	Stopper maker
Synthetic peptides	TFA as the counter-ion	Erckes 2025, FDA

PFAS in peptides: the TFA counter-ion

Synthetic peptides usually end up as trifluoroacetic acid (TFA) salts, as our guide to TFA in peptides explains. TFA carries a –CF3 group. The FDA report names it among ultrashort-chain PFAS. A 2024 perspective in Environmental Science & Technology reports environmental TFA levels orders of magnitude above those of other PFAS.

The FDA report counts cosmetic ingredients with this group as PFAS, a peptide among them: trifluoroacetyl tripeptide-2, in 164 listed US products.

In a peptide vial the amounts are large. Erckes and colleagues calculated that trifluoroacetate is 21.9 to 35.2% of the weight of seven peptide TFA salts. Fluorine is about half the mass of trifluoroacetate, so such a powder is roughly 11 to 18% fluorine by weight. This has two effects on testing:

• Targeted panels do not report it. The shortest perfluorocarboxylic acid in EPA Method 533 and FDA Method C-010.03 is PFBA, with four carbons; TFA has two. A 2024 leaching study measured C2 to C4 acids by ion chromatography–mass spectrometry and C4 to C9 acids by LC-MS/MS. In a 2023 study, fluorine NMR found TFA in a wastewater sample at more than five times the total PFAS that LC-MS quantified.
• A total fluorine screen sees mostly TFA. On a TFA salt, the counter-ion supplies most of the fluorine, so the number says little about other PFAS.

The vial and the lab

Some vial stoppers carry an ETFE film that keeps the drug away from the rubber. ETFE is a fluoropolymer, and the FDA report counts fluoropolymers among polymer PFAS. Materials can add PFAS of their own: in the 2024 leaching study, all six tubing materials tested, including the three without fluorine, released TFA into water above the blank.

The lab is a source too. EPA Method 533 names PTFE products, LC solvent lines, methanol and aluminium foil as places its analytes can come from. It requires polypropylene autosampler vials and caps because PTFE-coated septa can contaminate samples, and it keeps water samples out of glass because PFAS can adsorb to glass. A peptide arrives in glass under a rubber stopper, so a method for it has to handle both. Our guide to extractables and leachables covers what packaging can add to a product.

How to identify PFAS in products

1. Read the ingredient list. Names with “fluoro” or “PTFE” are clues. The most frequent PFAS in US cosmetics were PTFE, perfluorononyl dimethicone and trifluoroacetyl tripeptide-2. Fluoride salts contain no carbon, so they fall outside the OECD definition.
2. Accept that labels miss some. In a 2021 study of North American cosmetics, only 1 of the 29 products analysed in detail listed a fluorinated ingredient, its authors’ lab reports.
3. Screen for total fluorine. PIGE (particle-induced gamma-ray emission) and combustion ion chromatography count fluorine without naming the compound.
4. Measure named PFAS. Targeted LC-MS/MS gives a number for each compound on the list. Fluorine NMR and high-resolution MS can look for compounds outside it.

PFAS testing methods for consumer products

Method	PFAS measured	Validated for	Detail
EPA 537.1	18	Drinking water	SPE and LC-MS/MS
EPA 533 (2019)	25	Drinking water	Isotope dilution; shortest acid is PFBA
EPA 1633	40	Wastewater, surface and groundwater, soil, biosolids, sediment, landfill leachate, fish tissue	LC-MS/MS
FDA C-010.03 (2024)	30	Lettuce, chocolate milk, salmon, bread, eggs, clams, blueberries, two animal feeds	5 g of food, or 1 g of feed or very dry food such as protein powder; PFBA and PFPeA hits confirmed by high-resolution MS
AOAC 2025.07	30	Foods including protein powders and fish oil	LOQ 0.0055–0.55 µg/kg
EPA 1621 (2024)	Total adsorbable organic fluorine	Wastewater	Combustion ion chromatography; names no compound
Fluorine NMR (2023 study)	Total –CF3 signal, TFA included	Research method, tested on wastewater	Detection limit 50 µg/L

None of these was validated on a lyophilised peptide, so a lab adapts one and should show its own validation for that product. Our guide to PFAS testing covers each method.

PFAS testing in cosmetics

The FDA counted 51 PFAS intentionally added to 1,744 cosmetic formulations sold in the US, as of 30 August 2024. That is 0.41% of products registered with the FDA. PTFE appeared in 490. Eye shadows, leave-on face and neck products, eyeliners, face powders and foundations made up about 56% of PFAS-containing products.

Whitehead and colleagues found that foundations, mascaras and lip products had the highest share of high-fluorine results. Fluorotelomer compounds were the PFAS detected most often in their targeted analysis. They screened for total fluorine first, then ran the targeted analysis.

How to read a PFAS result

On the report	What to check
Analyte list	How many compounds, which ones, and whether TFA is among them. “Not detected” covers only the list
Limit of quantification	One per compound, in ng/g, µg/kg or ng per vial. “Below LOQ” is not zero
Sample mass	In the FDA method, 1 ng/mL in a 10 mL extract of 5 g is 2 ng/g. From 10 mg in the same volume, the same reading would mean 1,000 ng/g
Blanks	The FDA method says PFAS are prevalent in all lab environments and calls for method blanks every day
Standards	Isotope-labelled standards, and which one each compound is calculated against
Confirmation	PFBA and PFPeA have one MS/MS transition, so the FDA confirms them by high-resolution MS
Limit	Who chose it. Research peptides have no official PFAS limit

What drives the cost of PFAS testing

• The list and the product. More compounds mean more standards; an oil, a powder and a capsule each need their own extraction and validation.
• The LOQ. A lower limit needs more sample and cleaner blanks. A vial holds milligrams; see how many vials to send.
• Ultrashort acids. TFA and its neighbours need a separate method.
• Controls. Blanks, spikes, duplicates and confirmation runs add instrument time.

Ask every lab to quote the analyte list and the LOQ per compound, so two quotes describe the same test.

What HK Analytical does

We do not test for PFAS today. HK Analytical is adding microplastic, PFAS and BPA testing. Write to contact@hkanalytical.com to hear when it starts. You can also use the contact form.

For peptides, our counter-ion test reports TFA and acetate as a share of the powder. TFA is the only PFAS it measures, so it is not a PFAS panel. It can join identity (LC-MS), purity (HPLC) and our other tests in one order, per sample. Every number comes with its raw data, in a signed record you can check on our verify page; see the example report. To price a panel, request a quote.