Hormone-disrupting chemicals found in South African sanitary pads and pantyliners, study finds

Menstrual products used by millions of South Africans contain hormone-disrupting chemicals, even when marketed as “free from harmful chemicals”, new research from the University of the Free State (UFS), has revealed.

The study, published in Science of the Total Environment, found that every sanitary pad and pantyliner tested contained at least two endocrine-disrupting chemicals (EDCs), raising serious questions about consumer safety, chemical disclosure and long-term health risks.

Researchers analysed 16 brands of sanitary pads and eight types of pantyliners sold at popular South African retailers, spanning a range of prices and including products marketed as “organic”, “plant-based” or “free from harmful chemicals”. The findings showed widespread contamination across all the tested products. 

The authors screened for three major classes of EDCs — phthalates, bisphenols (including bisphenol A, or BPA) and parabens. Every pad and liner contained at least two of the target chemicals. 

“EDCs, such as phthalates, bisphenols and parabens, are widely used in consumer products and have been associated with reproductive toxicity, hormonal imbalance and cancer,” the study noted.

“Menstrual products represent a potential but under-recognised source of exposure. In South Africa, several brands advertise as being free from harmful chemicals, yet limited research has verified these as potential EDC sources.”

The study highlighted a concerning reality regarding the safety of menstrual products, head of the university’s department of chemistry Deon Visser said. “Many sanitary pads and liners contain hormone-disrupting chemicals, even when they are marketed as being ‘free from harmful chemicals’.”

Bisphenols were detected in 100% of sanitary pads and 75% of pantyliners, while parabens were found in more than 81% of pads and 75% of liners. Phthalates, commonly used as plasticisers, were present in all pantyliners tested and in half of sanitary pads.

The researchers emphasised that the chemicals were not necessarily added intentionally. Instead, they could migrate into products during manufacturing from plastics, adhesives, packaging materials and even contaminated water used in production.

“The heat-pressing process can cause these chemicals to move into the top layer that touches your skin,” Visser said.

While the amounts detected in individual products might appear small, the study warns that the real concern lies in cumulative exposure over time.

Menstrual products are worn directly against highly permeable genital and mucosal tissue, which absorbs chemicals more readily than the skin on other parts of the body. Most users rely on pads and liners for several days every month over decades.

The results reveal that menstrual products such as sanitary pads and liners in South Africa are a “significant but overlooked source of toxic exposure”. Although daily doses might seem low, the long-term, repeated contact with sensitive tissues poses cumulative health risks, including reproductive toxicity and cancer.

EDCs, such as phthalates, bisphenols and parabens, are known female endocrine disruptors because they can mimic or interfere with natural hormones in the body. BPA, in particular, has a chemical structure similar to oestrogen, allowing it to bind to oestrogen receptors. Because oestrogen drives the growth of some breast cancers, this raises concern about long-term risk.

Heightened phthalate exposures have also been linked to fertility issues among men and women, premature puberty onset, endometriosis and ovulation disorders. Cases of contact dermatitis, thyroid hormone disruption, elevated sex steroid hormone levels and the induction of reactive oxygen species in the body have been reported too. 

“These issues, its transplacental transfer ability, its bio-cumulative nature and the serious damage chronic poisoning can cause to the reproductive system and the liver have raised concerns about its safety, especially in PCPs … There is increasing evidence that dermal contact is a relevant route of exposure,” the study said.

Using standard exposure calculations, the researchers found that daily exposure to BPA from pads and liners exceeded the European Food Safety Authority’s tolerable daily intake by dozens of times. When higher absorption rates — more realistic for vulvar skin — were considered, exposure levels increased dramatically.

“Although individual daily doses may look low, the group and cumulative exposure becomes significant,” the authors note, particularly given that menstrual products are only one of many daily sources of EDC exposure, alongside food, cosmetics, dust and water.

The findings highlight gaps in the country’s regulatory framework. While the South African Bureau of Standards sets requirements for aspects such as absorbency, size and microbiological safety, there are no standards governing chemical content in menstrual products.

“Manufacturers are not required to disclose the full chemical composition of menstrual products,” Visser said. “We believe they should disclose all chemicals, even if levels fall below daily limits.”

Globally, only a handful of regulators provide guidance on chemicals permitted in sanitary products, including the Food and Drug Administration in the US and Japan’s Pharmaceuticals and Medical Devices Agency. In South Africa, the only BPA-specific regulation applies to baby feeding bottles, not menstrual products.

The researchers warn that environmental contamination and weak regulation might continue to shape the chemical profiles of pads and liners sold locally. The study cautions that insufficient regulation and safety oversight of menstrual products compounds period poverty and increases the risk of harmful exposure among marginalised groups.

Disposable pads and liners are also mass-produced and widely discarded, where they can leach chemicals into soil and water systems, creating additional exposure pathways through food, drinking water and dust.

Unlike food or cosmetics, the chemical composition of menstrual products is rarely communicated to users, leaving little opportunity for informed choice.

While calling for stronger regulation, clearer labelling and routine monitoring of menstrual products, the researchers also offer practical advice. Visser recommends choosing products certified under the OEKO-TEX Standard 100, which restricts hazardous substances, or considering reusable menstrual products.

The research forms part of a broader UFS initiative on menstrual health and access. The interdisciplinary team is developing a reusable sanitary pad with antimicrobial properties.

“This study serves as a wake-up call,” Visser said. “Current regulations and ‘clean’ labels in South Africa may not be providing the protection consumers expect.”

The authors said further research was urgently needed to better understand long-term, low-dose exposure through menstrual products and to inform evidence-based policies that protected consumer health.