The toxic truth behind period underwear

Period underwear has taken the menstrual care world by storm, and for good reason. They’re reusable, mess-free, and marketed as an eco-friendly solution to our overflowing landfills.

But while the idea sounds dreamy, not all period pants are created equal. And recent independent testing has revealed a dirty little secret: many popular period underwear brands contain silver-based chemicals (and potentially more) with unclear safety for our bodies and the environment.

Here at Arei Flow, we’re all about safety and transparency, so let's dive into this. 

What’s the problem with silver in period pants?

Some of the biggest period underwear brands have been found to include significant amounts of silver in their period underwear. Why?

Because silver is an antimicrobial agent — added to “kill bacteria” and reduce odors. Sounds great, right?

Well… not quite.

It's not needed

Menstrual blood isn’t dirty, and it doesn’t require antibacterial, or any other kind of treatment. The idea that it does plays into harmful taboos about menstruation.

The facts are:

• There’s no real need for antimicrobial treatments in period underwear if you wash them properly and change them regularly. 

• Most silver-treated textiles don’t work as promised, and they may lose their silver coating after just a few washes.

• Silver can harm good bacteria (like vaginal lactobacillus), which help prevent infections.

• Nano silver and silver-based compounds can leach out into your skin and into the environment when washed.

It's dangerous

Research is still catching up, but there’s growing concern about silver-based compounds in intimate products:

• Silver chloride, nanosilver, silver zeolite — these aren't the kind of silver you'd find in your earrings. Some are linked to reproductive toxicity and may cause structural changes to vaginal tissues (based on animal studies).

• Silver ions can disrupt your vaginal microbiome, making you more vulnerable to infections like Bacterial Vaginosis and even STIs.

• Some types of silver used in textiles are already banned in food-related products in the EU... so why are they allowed in your underwear?

And then there's the environmental impact.
Silver-treated fabrics can pollute waterways and harm aquatic life - not exactly what you expect from a product sold as “eco-friendly”...

How do I know if my menstrual underwear has silver?

Here’s the catch: brands aren’t required to disclose silver content clearly.

Look out for terms like: 

• “Antimicrobial”

• “Odor-controlling”

• “Silver-based technology”

• “Micro-Fresh®” or “Agion®”

So what should I do?

If you're concerned (and frankly, we are too), here are your best options:

✅ Choose brands that clearly state they DON’T use biocides or antimicrobial treatments.
✅ Check the label and the website. If the information is incomplete or vague, assume the product not clean.
✅ Look for certifications, but don’t rely on them blindly. OEKO-TEX, for example, doesn’t check for silver.
✅ When in doubt: go with products that are as close to natural as possible. Products that are made of natural, simple fabrics with no fancy technology are your best bet.

What do we recommend at Arei Flow? 

Obviously, we'd love for you to buy our products. We are proud to be a brand that meticulously selects materials for our products that are safe for your body and not harmful to the environment. 

• Our menstrual cups are made from 100% medical-grade silicone sourced from Germany — no toxins, no nonsense.

• Our cloth pads are handmade, breathable, washable, and silver-free. The simple organic cotton&hemp fabric in our pads will keep you fresh and dry, no need for  fancy and toxic materials. 

But even if you decide to go for a different brand, make sure you check the materials used in your chosen product and only buy from businesses that prioritise safety over profit. 

Conclusion

Not all “eco” products are as safe or sustainable as they claim. And when it comes to your period (and your most intimate body parts) you deserve the safest, best products.

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