Some popular period pants contain unnecessarily high levels of silver, Which? warns
A new Which? investigation has found some popular period pant brands contain unnecessarily high levels of silver, which could have unknown health implications for wearers and damage the environment.
Period pants have become a popular alternative to disposable sanitary products. However, a growing body of scientists have raised concerns about the potential health impacts of using silver in these products.
Which? worked with Italian consumer organisation AltroConsumo to independently test a range of popular brands and check if they contained any chemicals of concern. They were concerned to find that some products contained significant levels of silver, which was not always made clear on the packaging.
Intima by Bodyform and Marks & Spencer in particular 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.
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.
However, Which? believes this is an unnecessary addition as not all period pants contain silver, and testing has shown it may not be effective anyway. Previous testing by AltroConsumo has shown that textile items treated with silver often do not actually have the promised antimicrobial properties.
Consumers might find several different types of silver in period pants, including nano-silver (microscopic particles of silver), silver copper zeolite, silver zinc zeolite, silver chloride, or Agion (a branded product made using silver zeolite). Which? and AltroConsumo’s tests were not able to determine which type of silver was present, but the consumer champion has concerns regardless of the type.
Limited research is available into the health impact of silver treatments in textiles, but some experts have raised concerns about particles potentially migrating into the body, and disrupting the skin microbiome by killing beneficial bacteria.
The US Food and Drug Administration found that nano-silver can kill lactobacillus, the healthy bacteria in your vagina which help fight off infection. Ironically, this can put period pant users more at risk of harmful bacteria, potentially leading to increased risk of bacterial infections and pregnancy complications.
Products containing silver treatments could also harm the environment. The European Chemicals Agency says that silver treatments, such as nanosilver and silver zeolite, are very toxic to aquatic life with long-lasting effects. Repeated washing of period pants will lead to small particles of fabric being released into the environment via wastewater, which could contain silver.
There are currently no legal limits in the UK about how much silver can be added to period pants. Manufacturers also do not have to declare the presence of silver on their packaging or website.
Which? saw an assortment of ways manufacturers handled this. Some noted the presence of silver, or a marketing name for silver, on the packaging. Others only mentioned silver on their websites. Some made no mention of silver on their packaging or websites. Some simply mention anti-odour or anti-microbial technology.
This makes it difficult for consumers to make informed decisions about the products they are buying. Consumers should not be expected to conduct extensive research to find out about the ingredients in the clothes they are buying.
Which? is advising shoppers to be cautious about buying period pants containing silver at the moment, as it is not necessary and there is insufficient research to show that it is safe or effective. Brands should also make it clear if their products contain silver at the point of sale so consumers can make an informed decision about their purchase and potentially choose a brand that does not contain silver.
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.
“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.”
-ENDS-
Notes to editors
Research
Our chemical analysis of period pantsWe bought the nearest equivalent to medium flow, medium sized black pants, in the most popular or standard style (bikini / classic) from each brand.Our independent lab conducted chemical analysis to check for a list of common ‘chemicals of concern’, including:
- Silver
- Forever chemicals (PFCAs, PFOs and PFOAs)
- Chromium VI
- Cadmium
- Lead
- Arsenic
None of the pants that we tested contained any PFAs (per- and poly- fluoroalkyl substances - also known as forever chemicals) banned by REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals). We can't categorically say, however, that no PFAs are present in these pants, as PFAs are a very large class of chemicals and not all of them are regulated. More research is needed to establish what other PFAs exist.
We didn't detect any Chromium VI, Cadmium or Arsenic.
The pants we tested from Lovable and Sloggi contained very low levels of lead, but below legal limits and not in amounts to cause concern.
Nanosilvers in period pants
Which? spoke to Thiago Verano-Braga, Associate Professor at the Universidade Federal de Minas Gerais in Brazil, who has studied silver nanoparticles for a number of years. He told us that "manufacturers absolutely shouldn't be using silver nanoparticles in pants before a critical assessment of potential risks" and that, "while the anti-microbial properties of silver nanoparticles have led to them becoming one of the most widely used nanomaterials in consumer products, there is a high chance of these nanoparticles being absorbed into the human body.
“Furthermore, it is important to test whether silver ions are being generated since they are extremely toxic and may be released from silver nanoparticles in acidic conditions. Typical vaginal pH is more acidic than neutral".
Right of replies
Essity (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.”
Essity said in their own testing, they found less silver in the Bodyform period pants.
Marks & Spencer declined to comment.
A Primark spokesperson said: “The antimicrobial finish used on our period pants is Micro-Fresh® which kills the bacteria that causes odours and is tested to be effective for 50 washes. Micro-Fresh® contains natural active ingredients including silver chloride which is approved for use on garments under the Biocidal Products Regulation in the EU and UK and the EPA in the US. “The nature of period pants means there is a potential for odour to develop duringwear (in the same way that bacteria can cause socks and shoes to develop odoursduring wear) and our antimicrobial finish minimises such odours, giving customersthe confidence to wear the product for the intended duration.”
Sloggi had not replied to Which?’s requests for comment at the time of publication.
Superdrug said: “Superdrug Luna period pants uses Micro-Fresh technology, a commercially proven anti-microbial fabric treatment that ensures the product has anti-odour benefits, which we believe is a customer benefit with intimate apparel. We have not seen any evidence to suggest that silver is unsafe to use in these product areas and it has been used for many years. Superdrug’s 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.”
Thinx said: “The odour controlling layers in Thinx products are treated with Agion®, an EU regulated treatment containing silver zeolite and silver copper zeolite. Agion® is widely used for odor resistance in textiles and deemed safe for consumers by the EU. In 2024, we will be debuting underwear with a different treatment that helps minimizeand control odor (which doesn’t contain Agion). Our underwear is certified based on the rigorous chemical safety requirements of the STANDARD 100 by OEKO-TEX® [20.HUS.04850 | HOHENSTEIN HTTI] and complies with the even more stringent OEKO-TEX® 100 Class II, Annexure IV. As part of this accreditation, we must pass a series of tests, showing no detection of PFAS or harmful chemicals. We require suppliers of our raw materials to sign a Supplier Code of Conduct and Chemical Supplier Agreement confirming compliance with the AFIRM RSL. We also test our finished products through an accredited, globally recognized third-party laboratory to help ensure they are compliant with U.S. and international regulations.”
Uniqlo said: "We adhere to the strictest safety standards in all of our markets of operation, including Japan, Europe and the U.S. The company has incorporated these standards into the UNIQLO Global Quality and Safety Standards. In addition, materials that UNIQLO uses are subject to multiple safety inspections by third-party monitoring organizations.You can find details of our product quality and safety control system here. Silver is used in UNIQLO Period Pant products to prevent the growth of odour causing microorganisms, and is used in accordance with UK and EU regulations. We clearly state the purpose for using silver on the packaging of each product."
XUETAO, the brand which makes Cool Period pants, appears to be based in China and does not provide contact details for customers or journalists on online marketplaces where the product is sold.
About Which?
Which? is the UK’s consumer champion, here to make life simpler, fairer and safer for everyone. Our research gets to the heart of consumer issues, our advice is impartial, and our rigorous product tests lead to expert recommendations. We’re the independent consumer voice that influences politicians and lawmakers, investigates, holds businesses to account and makes change happen. As an organisation we’re not for profit and all for making consumers more powerful.The information in this press release is for editorial use by journalists and media outlets only. Any business seeking to reproduce information in this release should contact the Which? Endorsement Scheme team at endorsementscheme@which.co.uk.