What's in tampons, pads, and period underwear, and what is safest?

Tampons: metals

In 30 tampons from 14 brands, all 16 metals tested were detected in at least one, including lead (geometric mean 120 nanograms per gram), cadmium and arsenic. Non-organic tampons had more lead and organic ones more arsenic, so neither group was consistently cleaner⁵. The key question is how much leaves the tampon. In a lab test, 22 tampons soaked for 8 hours in simulated vaginal or menstrual fluid released measurable amounts of up to 14 metals, but release in a test tube is not absorption by the body⁷. FDA scientists tested 11 tampons under exaggerated conditions and found margins of safety for every metal, "negligible toxicological concern"⁸. FDA also says FDA-authorized tampons use a bleaching process free of elemental chlorine, which prevents dangerous dioxin levels¹. For medicines, vaginal absorption varies with the formulation, the patient's age and the point in the menstrual cycle⁹, so absorption of tampon contaminants can be neither assumed nor ruled out.

Pads

Sanitary pads varied 5,900-fold between brands in volatile organic compounds and 130-fold in phthalates, with phthalates higher than in common plastics³. In 29 pads, toluene was found in 28 and polypropylene microplastic fibers in all. The four pads whose extracts did not suppress cell metabolism all had organic cotton topsheets¹⁰.

Period underwear

Textile impregnation is one of the best-known uses of PFAS⁶. We found no peer-reviewed measurement of PFAS in period underwear, and no data on how much would reach your body. In lab skin models, short-chain PFAS were absorbed, while long-chain ones stayed in the skin tissue¹¹.

Cups and toxic shock

A cup collects blood instead of absorbing it, and a systematic review judged cups a safe option². Toxic shock syndrome (TSS) was first tied to tampons and is now seen as an interplay of bacterial toxins, immunity and vaginal changes; a few cases have followed cup use^4,2.

What to do

Choose what is comfortable and change it on time; no type has been shown to be clearly safer. For PFAS more generally, see Avoiding PFAS.

Metals in tampons

A US research team measured 16 metals by mass spectrometry in 60 samples from 30 tampons (14 brands, 18 product lines). Every metal appeared in at least one tampon. Geometric means were 120 ng/g for lead, 6.74 for cadmium and 2.56 for arsenic. Concentrations differed by region (US versus EU/UK), organic status and store versus name brand⁵. They called lead a metal with no "safe" exposure level, and noted that no study had yet shown whether the metals leach and cross vaginal tissue.

Follow-up work started to answer that. In 22 products tested at pH 4.2 and 7.4 for 8 hours at body temperature, 14 metals leached into simulated vaginal fluid and 12 into menstrual fluid. Mean lead was 40.3 ng (95% CI 6.94 to 73.7) in vaginal fluid and 15.6 ng (6.91 to 24.3) in menstrual fluid. Leaching fractions, calculated against metal totals reported in a different study, were imprecise; copper's was 233% with an interval from -87% to 553%⁷. The authors stress that release in vitro does not equal absorption. FDA scientists tested 11 legally marketed tampons under exaggerated conditions (50 degrees Celsius, 24 hours, acidified water). They found 19 metals, including trace arsenic, cadmium and lead, and every metal had a margin of safety, which they read as negligible toxicological concern⁸. FDA's consumer page repeats that very small amounts of metals can be detected in conventional and organic tampons and that the amount likely released is too small to cause harm¹.

A 2022 review found nearly two dozen studies measuring contaminants in menstrual products. All found chemicals, but conclusions about exposure risk were discrepant. Only three human studies related product use to chemical levels in the body, and all saw associations¹².

Pads

One analysis found 5,900-fold differences in VOCs and 130-fold differences in phthalates between pad brands; VOC levels were similar to residential air but phthalates were higher than in common commercial plastics³. A 2025 study of 29 pads found toluene in 97% (below 0.04 to 2.79 micrograms per pad) and 6 to 115 polypropylene fibers per pad. Pad extracts cut cell viability by a median 39% in culture. Modeled toluene exposure was below the California occupational limit, and the authors called for transparency and further testing¹⁰. Only four pads, all labeled organic, left cells unaffected, a hint rather than a conclusion.

Period underwear and PFAS

The PFAS literature shows a wide range of uses, including textile impregnation⁶. In human skin equivalents, perfluoropentanoic acid had 58.9% of the dose absorbed, while longer-chain compounds remained in the skin tissue instead¹¹. That is laboratory evidence about the compounds, not about period underwear.

Cups

The systematic review included 43 studies (3,319 participants), only three of moderate-to-high quality among the 22 analyzed. In four studies comparing cups with usual products (293 participants), leakage was similar or lower. About 73% (95% CI 59 to 84) of users wanted to continue. Four studies in 507 women showed no adverse effect on vaginal flora. Reported harms included severe pain or vaginal wounds (5), allergy or rash (6), urinary complaints (9, three with hydronephrosis), TSS (5) and IUD dislodgement (13)².

Toxic shock syndrome

Menstrual TSS incidence ranges from 0.03 to 0.50 per 100,000, with mortality around 8%. Tampon use was once seen as the main risk factor; understanding has since broadened to include S. aureus toxins, host immunity and vaginal changes during menstruation⁴.

Where the evidence disagrees

The team that first measured tampon metals stressed that lead has no safe exposure level⁵, while FDA scientists found negligible toxicological concern after a risk assessment with exaggerated release conditions⁸. Both can be right: a metal being present is not the same as it being released, and release is not absorption⁷. "Organic" gave a mixed picture, too: organic tampons had less lead but more arsenic⁵, while the only pads that left cells unaffected were labeled organic¹⁰. The cup safety review is reassuring but rests mostly on low-quality studies².

Bottom line

Confidence 2 of 5. Metals, plasticizers and other chemicals are measurable in period products, and brands differ widely. FDA's own risk assessment of tampon metals sees negligible concern, while academic teams call for more work; human data are scarce, and PFAS in period underwear is unmeasured in the peer-reviewed literature.