A recent US Berkely Study from July 2024 has found that toxic metals like arsenic and lead show in all the 30 different tested tampons, organic and non-organic, across 14 different US and EU tampon brands. 

These toxins disrupt our hormones and have been clinically linked to reproductive problems, dementia, diabetes, and even cancers. They can damage the liver, kidneys, and brain, as well as the cardiovascular, nervous, and endocrine systems. In addition, metals can harm maternal health and fetal development.

While this is the first study on tampons, previous studies on pads and liners have found similar issues. They’ve found dioxins and furans which are chemical contaminants from the bleaching process and can cause cancer, endocrine disruption, and reproductive toxicity. Fragrance is often used to mask odours, but it contains undisclosed chemicals of unknown toxicity, likely to contain allergens, and can cause allergic rash, endocrine disruption, and cancer. Further, pesticide residues are often found in tampons made from conventionally grown (non-organic) cotton, and these chemical residues can cause cancer, endocrine disruption, and acute toxicity.

Some period underwear has also been found to contain PFAS, forever chemicals linked to cancer and heart disorders. 

While it might be obvious that pads, liners and tampons contain a lot of plastic, the amount of plastic may be surprising. Some pads contain up to 90% – the equivalent of four plastic bags! One menstruator is estimated to use up to 16,000 disposable sanitary products in their lifetime, and disposable period products are the fifth most found plastic waste in our oceans and take up to 800 years to decompose.

So what about reusable period underwear? You probably want to check what the underwear is made from.

Most reusable pads and period underwear use up to 100% polyester in their gusset fabrics (hey, it’s cheap and absorbent!), and many brands also use polyester in the main underwear fabric. Let’s get one thing straight: polyester is plastic, derived from fossil fuels. It is a synthetic fibre that sheds microplastics every time it is washed (yes, recycled polyester too) and it is non-biodegradable. 

Yet, the reason for steering clear of polyester (to the extent possible) is not only environmental.

Polyester is not breathable, causing sweat, and the fibre repels water and thereby also attracts oils from the skin, which is why you might have experienced odour and skin irritation from polyester clothes, pads and pantyliners. Research has shown that certain bacteria is present on the skin after contact with polyester, causing unpleasant smells. And it builds up over time, as polyester isn't easily releasing those smelling compounds when washed.

To combat this, many fabric manufacturers and brands – including period underwear brands – choose to use nanosilver coated polyester, as the silver kills the bacteria, and then they can label their fabrics or products as “anti-bacterial” and “odour-free”...

But - and this is a huge but - research has shown that these metals do not stay on the fabric over time, and the use of silver coating has been criticised for having harmful impacts on the environment. As for the wearer, there are concerns for health impacts, but still only very little research done.

In addition to all this, vulvar and vaginal tissue are structurally different from the skin of the rest of the body. They are more hydrated and up to 10 times more permeable than other skin, which means this area of the body is potentially more vulnerable to exposure to toxic chemicals and irritants.

Some studies find that the toxin concentrations are relatively low, and hence that it isn’t an issue. However, considering that the exposure is for hours at a time, several days each month for around 30-40 years of menstruation on highly permeable tissues, more research on this issue is needed.