Menstrual products used by millions of South Africans may contain hormone-disrupting chemicals – even when marketed as ‘free from harmful chemicals’ – according to new research from the University of the Free State (UFS).

Published in Science of the Total Environment, the study found that every sanitary pad and pantyliner tested contained at least two endocrine-disrupting chemicals (EDCs), raising concerns about consumer safety, transparency, and long-term exposure.

The research was conducted by a UFS team, including Janine Blignaut (PhD candidate), Dr Gabre Kemp from the Department of Microbiology and Biochemistry, Prof Elizabeth Erasmus, Prof Deon Visser, and Prof Marietjie Schutte-Smith from the Department of Chemistry.

“Our study highlights a concerning reality regarding the safety of menstrual products,” said Prof Visser, Head of the Department of Chemistry at the UFS. “Many sanitary pads and liners contain hormone-disrupting chemicals, even when they are marketed as being ‘free from harmful chemicals’.”

Chemicals found across all products tested

The UFS research team analysed 16 brands of sanitary pads and eight types of pantyliners popular in South African retail stores. The study focused on three groups of endocrine-disrupting chemicals (EDCs):

• Phthalates
• Bisphenols (including BPA)
• ParabensThe findings showed widespread contamination across all products tested. Every single pad and liner contained at least two of the target chemicals.

The findings showed widespread contamination across all products tested. Every single pad and liner contained at least two of the target 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 were present in all pantyliners tested and in 50% of sanitary pads.

The researchers note that these substances are not always added intentionally, but may migrate into products from plastics, adhesives, and manufacturing processes.

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

Why long-term exposure matters

Although the levels detected in a single product may appear small, the researchers emphasise that the concern lies in repeated exposure over time.

Menstrual products come into contact with mucosal tissue, which absorbs chemicals more quickly and directly than normal skin. Most individuals use these products for several days each month over several decades. This repeated contact may contribute to cumulative exposure, which has been linked to hormonal imbalances, fertility problems, endometriosis, and even certain types of cancer.

Limited regulation and lack of disclosure

The study also highlights gaps in chemical regulation in South Africa. “SABS does have the SANS 1043 test, but it only tests for microbiology, absorbency, etc. According to our knowledge, there are no standards regarding the chemicals we observed,” Prof Visser said.

Manufacturers are also generally not required to disclose the full chemical composition of menstrual products. “We do believe that manufacturers should disclose all chemicals in their products, even if they fall below daily limits,” he added.

Practical steps and future solutions

Prof Visser advises consumers to look for products certified under the OEKO-TEX Standard 100, or to consider reusable alternatives.

“Look for the OEKO-TEX Standard 100 verification – an international standard – or use a reusable sanitary towel,” he said.

This research forms part of a broader UFS initiative addressing menstrual health and access.

“Our research started off several years ago when we discussed a radio programme that mentioned that many young girls do not have access to feminine products. We decided to get involved,” Prof Visser said.

The interdisciplinary team is now working on new innovations. “Our team is in the process of developing a reusable sanitary pad with superpowers – antimicrobial properties,” he added.

A call for transparency

The researchers say the findings underscore the need for clearer labelling, stronger chemical standards, and continued monitoring of everyday menstrual products.

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

Read the full article here.