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The Lowdown on Menstrual Panties - A question of Safety or Convenience?

In recent years, the amount of choice women have to manage their menstrual hygiene needs have multiplied. The choice is no longer about pads vs tampons - the sheer array of products available on the market today mean that we as consumers need to be more aware and educated in order to make the choices that are right for us and our health.

This is what led me to start researching menstrual panties. I had been using menstrual cups for several years, but was looking for a complementary product to manage leaks during the first few days. I thought menstrual panties would be the perfect product for me, but I couldn't help wondering how companies managed to make a panty so absorbent, and hygienic while all the while calling it organic and safe. I wondered if it was just the marketing pitch or had they actually made a scientific breakthrough that made cotton super absorbent and washable without any added chemicals! I started reading about what actually makes period panties absorb the ‘equivalent of 2 tampons’ and what I found out was far from being comforting.

The science behind absorbency in menstrual panties

First things first - the basic structure of a menstrual panty. In the majority of brands, it is made up of three layers -

  • The first layer is a water repellent layer that is closest to the skin. This makes sure that any wetness is immediately absorbed and stays inside while the layer that touches the skin remains dry.

  • The second layer is the absorbent layer or the middle layer that sucks up the menstrual blood

  • The third layer is the outside waterproof layer that makes sure the absorbed menstrual blood remains in the panty and does not leak outside of it.

In addition to this structure, manufacturers also add an antimicrobial agent, in some cases silver or zinc to make sure bacteria present in the menstrual blood does not multiply in the warm humid atmosphere, especially as they are marketed as wearable for upto 12 hours. The antimicrobial agent also makes sure that smells are reduced and kept to the minimum.

Sustainable does not necessarily mean organic

Many of these brands use science and technology to invent ways and methods to make menstrual hygiene products easier and more accessible to women. Many of these products are doing a great service in addressing issues such as period poverty and shame around menstruation. However, as consumers, it is equally important to know whether the elements present in these products have harmful effects on health. The vaginal and vulval tissues are extremely absorbent and sensitive to the environment, In addition, the vaginal microbiome is a delicate balance of good bacteria that ensures a healthy acid/alkaline balance.

It is important to stay aware of the chemicals that may be present in some of these products, that may also, in some cases, be certified bio or organic.

Recently, there was a controversy around the Thinx brand, the leader in menstrual panties, containing PFAS in their period panties. This was only discovered when a service-minded blogger decided to test Thinx products for PFAS after asking the company for information about the same and receiving none. The results showed that the panties contained a high percentage of PFAS, a substance with proven links to endocrine disorders, hampers the functioning of the immune system, and could cause cancers and affect fertility. This was denied by Thinx, and their marketing material today mentions that it does not contain PFAS but does contain silver and copper iodes for odour proofing their products.

Update as of Jan 2023: The period underwear brand Thinx made public that it had reached a settlement in a 3-year-long class action lawsuit claiming its products contain harmful chemicals. The news of the settlement brought renewed focus on the chemical compounds at the center of the lawsuit — per- and polyfluoroalkyl substances, known as PFAS or “forever chemicals” — and highlighted the broader issue of toxic ingredients in period products as a whole. Read the article in NY Times here

Why add potentially harmful products to menstrual panties?

PFOAs are widely used in household appliances. Also known as ‘forever chemicals’ they never break down. Its specific function in menstrual panties is its anti-stain properties. Some experts claim that the only way PFOAs can be harmful are if they are consumed orally. At the same time, there is no research that proves that PFOAs cannot be absorbed through the vaginal tissue, which is known to be extremely absorbent and sensitive.

Going back to the Thinxx controversy, the company replied with tests whose results contradicted those of the blogger and claimed that PFOAs were absent from their products. On further investigation, it was revealed that the tests were not carried out by the same company and did not test for the same chemicals. In other words, US companies have no legal obligation to carry out testing for every single chemical product that is suspected of toxicity. What this means is that in the US, even if a company claims that its products are toxin free, it does not mean that they have rigorously tested for most major toxins. What it probably means is that they only tested for 0.25% of 80000 synthetic chemicals listed on the EPA (US Environmental Protection Agency), which is what they are legally obliged to do. Some reports mention that the PFAS present in Thinx products were not on the list of European regulated PFAS, which is why they did not test for it.

Increased sensitivity and absorbency of vaginal tissues

From a scientific perspective, it is well known that the vaginal tissues are more absorbent and sensitive than typical skin. The vagina serves as a mucous membrane, and is capable of secreting and absorbing fluids at a higher rate than skin. In fact, the increased absorbency of vaginal tissues was proven in a study that delivered estradiol (synthetic estrogen) vaginally and compared it to oral delivery. The study found that vaginal delivery of estradiol was found to have 10 times more estrogen in the blood compared to oral dosing. Despite this, research that looks at the impact of feminine care products on women's health has been very scarce. The vaginal microbiome is a delicate balance of bacteria and the antimicrobial agents such as silver present in menstrual panties will kill the good bacteria as well as the bad, which could lead to thrush infections and UTIs.

Safety or Convenience? I vote for both!

In conclusion, although some reports say that it is virtually impossible to escape PFAS since they permeate almost every aspect of our modern lives, I still remain suspicious about using products that have known carcinogenic effects near my intimate areas that are proven to be hugely more absorbent than the skin. I am personally not convinced that the ease and practicality of menstrual panties outweighs their potential harmful effects. I would love to be able to find a brand that is honest about what they use in their products, but I get the feeling that finding this information is difficult and almost always not marked on their packaging. As consumers, we need to know what we buy and what impact it could have on our health in the long term. I believe that women shouldn't have to choose between safety and convenience, we deserve to have both.

While writing this article, I tried to contact a few companies that manufacture menstrual panties to ask about the technology they use. If you are a company that makes menstrual panties that privilege women's health, or if you would like to share the benefits of your product, we would love to hear from you. Please get in touch with us at


Disclaimer: The opinions expressed in this article belong solely to the author. Miyara Women does not undertake any financial/reputational/legal/misrepresentational impact or other obligations/ liabilities that may arise from the content

About the author

Rosemary George is a researcher and advocate for women's health. A mother of two boys, she is especially interested in sensitising both men and women to gender equality especially in terms of health. She lives in Geneva, Switzerland.

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