Some period pants sold by high street retailers contain unnecessarily high levels of silver and could have a health impact on consumers, an investigation has found.
Period pants are absorbent pants that have become a popular alternative to disposable sanitary products in recent years.
Silver is used as an antimicrobial agent and, in the case of period pants, is typically added to combat user concerns about smell and hygiene.
Which? worked with Italian consumer organisation AltroConsumo to test a range of popular brands and check if they contained any chemicals of concern.
They found that Intima by Bodyform and M&S contained notably more silver than other brands, at 126.7mg/kg and 57.8mg/kg respectively.
Thinx, Luna by Superdrug, and Modibodi contained 8.3mg/kg, 7.4mg/kg and 0.9mg/kg respectively, while Airism by Uniqlo and Cool Period contained smaller amounts of 0.3mg/kg and 0.2mg/kg.
The tests, which can detect any silver above 0.1mg/kg, did not detect any silver in Primark, Repeat, Wuka, Lovable and Sloggi pants. However, Sloggi’s website states it does use a silver-based antimicrobial, and Primark says it uses Micro-Fresh which contains silver chloride.
Period pants can contain several different types of silver, including nano-silver (microscopic particles of silver), silver copper zeolite, silver zinc zeolite, silver chloride, or Agion.
Which? claims that silver is unnecessary as previous testing has shown that it may not have the promised antimicrobial properties.
Health experts have previously raised concern over silver particles migrating into the body and killing beneficial bacteria.
The US Food and Drug Administration (FDA) has found that nano-silver can kill lactobacillus, healthy bacteria in the vagina which can help fight off infection. This could put users at higher risk of harmful bacteria, potentially leading to increased risk of infections and pregnancy complications.
Natalie Hitchins, Which? Head of Home Products and Services, said: “It’s worrying that, despite their eco-credentials, some popular period pant brands contain unnecessarily high levels of silver - which could have unknown health implications and damage the environment.
“Consumers should be cautious buying period pants which contain silver as experts have concerns about the health implications. Which? believes brands should also clearly state which products contain silver so shoppers can make informed decisions about what they are buying and the possible risks.”
She added: “Those concerned about the possible side effects of silver in period pants should choose brands that don’t contain silver. Eco-conscious consumers could also consider other options such as menstrual cups, reusable applicators and reusable menstrual pads.”
Essity, the owner of Bodyform and Modibodi, said: “Consumers can wear Bodyform and Modibodi period underwear with confidence because they are safe, sustainable and provide superior performance. Both sets of underwear tested contain silver copper zeolite to prevent odor when wearing the pants for up to 12-hours, which our research shows is a key concern for customers. The Bodyform and Modibodi collections also include ranges that are without an antibacterial property for those who prefer an alternative.
“All of our washable underwear is certified according to Oeko-Tex standard 100 which means that every single component has been tested for harmful substances and that the underwear has been designated as harmless for human health.”
A spokesperson for M&S said: “We do not use either nano silver or silver zeolite and, like many brands, use a small amount of silver chloride in the middle part of the gusset – away from the skin – which is perfectly safe, approved by the UK and EU, and designed to combat odour.”
Superdrug said it had “not seen any evidence to suggest that silver is unsafe to use in these product areas and it has been used for many years”, adding: “Our policy is to avoid any harmful or hazardous materials in our products and we hold certification to demonstrate non-migration of the material. Silver is a non-harmful environmental metal and will not cause damage to the environment via waterways.”