Editor’s Note (Updated 03 February 2026):
First published on May 31, 2025, this article has been substantially revised to reflect emerging research on chemical contaminants in menstrual products, including recent peer-reviewed studies. We’ve expanded the scientific context, clarified regulatory considerations, and refined our analysis to ensure the discussion remains evidence-led and transparent.
When we talk about glyphosate exposure, the focus is usually on food, water, or agricultural workers.
Rarely do we ask whether residues could be present in products used internally and repeatedly — including menstrual products made from conventionally grown cotton.
We’ve previously explored how glyphosate’s reach extends far beyond agriculture in our article why glyphosate isn’t just a weed killer.
That question moved from theoretical to practical after a 2025 UK investigation reported detectable glyphosate residues in tampons. The levels were described as significantly higher than the legal limit set for drinking water in the UK and EU.
The number itself sparked headlines, but the more substantive issue is whether menstrual products are routinely tested for pesticide residues — and whether current regulations were ever designed to account for this type of exposure pathway.
How Does Glyphosate Get Into Tampons?
The answer, if present, would likely begin in the cotton field.
Cotton is one of the most chemically treated crops in global agriculture. Glyphosate is widely used in cotton production, particularly in genetically modified glyphosate-tolerant varieties. It may be used for weed control during growth and sometimes as a pre-harvest desiccant.
If residues remain in harvested cotton fibre, the question becomes whether processing removes them completely — and whether finished products are routinely tested for such residues. We’ve seen similar residue pathways in food systems, including how glyphosate can appear in honey without directly harming bees, as discussed in how glyphosate ends up in honey.
Unlike food, menstrual products are not regulated under pesticide maximum residue limits (MRLs). Questions about testing transparency are not new. In New Zealand, food residue monitoring debates have already highlighted gaps in publicly available data — an issue we explored in MPI’s Missing Data: Why We Can’t Trust the Glyphosate Reassurance.
That doesn’t mean residues are common or unsafe — it means the regulatory framework was not built around this exposure pathway, a distinction that matters when evaluating emerging concerns.
What Research Says About Chemicals in Tampons
While glyphosate research in tampons is limited, menstrual products themselves have recently come under scientific scrutiny.
A 2024 study published in Environment International analysed 30 tampons from 14 brands and detected measurable levels of 16 metals, including lead and arsenic. The researchers noted that vaginal tissue can absorb substances differently than external skin, and that more research is needed to determine how much of these detected substances may enter the bloodstream.
Importantly, the study did not conclude that tampons are causing harm — but it did establish that menstrual products are a potential exposure route that has historically received little scientific attention.
Earlier reviews, including a 2022 systematic review of environmental contaminants in menstrual products, reached a similar conclusion: chemical exposures are plausible, but human exposure data remains limited.
In other words, the science is emerging — not settled.
Glyphosate Exposure Through Tampons: What Do We Know?
Glyphosate has been classified by the International Agency for Research on Cancer (IARC) as “probably carcinogenic to humans,” while other regulatory agencies, including the European Food Safety Authority (EFSA) and U.S. EPA, have concluded it is unlikely to pose a cancer risk at regulated exposure levels.
Concerns about endocrine and reproductive effects have also been explored in laboratory and animal studies, which we examine in more detail in our article on glyphosate and hormone disruption.
Most of the risk assessments underpinning those conclusions focus on dietary exposure or occupational contact. Those assessments are often based on Acceptable Daily Intake thresholds, which we unpack in our article on how ADI limits are set.
Internal exposure through menstrual products is not typically part of standard regulatory modelling.
That gap does not automatically mean there is danger — but it does mean this exposure pathway has not been deeply studied.
And when a pathway hasn’t been studied, reassurance tends to rest on assumption rather than measurement.
Are Glyphosate Levels in Tampons a Safety Concern?
The UK report that sparked concern compared detected glyphosate levels in tampons to drinking water limits.
It’s an understandable comparison — drinking water standards are familiar benchmarks. But they are not directly equivalent exposure models.
Drinking water limits assume daily ingestion over a lifetime. Tampon exposure would involve intermittent, internal contact over several days per month.
The more relevant scientific question is not whether the number exceeds a water limit, but whether glyphosate can migrate from cotton fibre into vaginal tissue — and if so, at what level.
At present, we don’t have definitive human absorption studies answering that question.
That uncertainty cuts both ways. It prevents us from declaring the risk severe — and it prevents us from declaring it negligible.
Are Tampons Tested for Glyphosate or Pesticide Residues?
Menstrual products often fall into regulatory grey zones.
They are not classified as food.
They are not pharmaceuticals.
They are medical devices in some jurisdictions — but pesticide residue testing is not routinely mandated the way it is for food crops.
If cotton is treated with herbicides, and if residues remain in fibre, and if those fibres are used internally, then logically the exposure pathway deserves examination.
Whether it proves to be significant or minimal should be determined through testing — not assumption.
What Should Happen Next? Testing, Transparency, and Regulation
A measured response would include:
- Independent residue testing across multiple brands
- Migration studies examining absorption through vaginal tissue
- Transparent reporting of findings
- Clear regulatory guidance if thresholds are deemed necessary
None of these steps require alarm.
They require curiosity and evidence.
That’s the consistent thread across environmental health history: we often discover exposure routes decades after products become normalised.
Why Glyphosate in Tampons Deserves Further Investigation
The presence of glyphosate in tampons — if confirmed through repeated independent testing — would not automatically equate to harm.
But it would raise legitimate questions about how we evaluate chemical exposure in products used internally and repeatedly.
Menstrual products are intimate by nature. That intimacy deserves a higher standard of transparency.
This isn’t about panic.
It’s about measurement.
And as we’ve seen across food, water, and agricultural debates, meaningful public confidence begins with one simple step:
Test first. Reassure later.
Resources and References
It’s one thing to raise questions—it’s another to back them with evidence. While research specific to glyphosate in tampons is still emerging, several related studies shed light on the broader issue of chemical exposure through menstrual products. From herbicide residues in cotton to toxic metals in tampons, these findings reveal a troubling pattern of under-regulation and underestimation.
Blood, Sweat & Pesticides Report (2025)
A collaborative study by PAN UK, Women’s Environmental Network, and the Pesticide Collaboration found glyphosate in tampons at levels 40 times higher than the UK and EU legal limit for drinking water. The report highlights the lack of regulation for chemical residues in period products and calls for urgent reforms.
Read the report
Toxic pesticide levels found in tampons 40 times higher than legal limit for water
Reported that glyphosate was found in tampons at levels 40 times higher than the legal limit for drinking water, emphasizing the potential health risks due to direct absorption through vaginal tissue.
As reported in The Guardian
Menstrual Products as a Source of Environmental Chemical Exposure (2022)
This comprehensive review examines nearly two dozen studies measuring environmental contaminants in menstrual products, including glyphosate, dioxins, and phthalates. It emphasizes the need for further research into the health risks associated with these exposures.
Access the study
Glyphosate Herbicide: Reproductive Outcomes and Multigenerational Effects (2021)
This review discusses the potential estrogenic effects of glyphosate and its formulations, highlighting concerns about endocrine disruption, fertility issues, and multigenerational health impacts.
View the publication
Tampons as a Source of Exposure to Metal(loid)s (2024)
A study published in Environment International detected 16 metals, including lead and arsenic, in tampons. The findings raise concerns about the potential health risks of metal exposure through menstrual products.
Read the study
Toxic Metals Found in Tampons (2024)
Research by the University of California, Berkeley, revealed the presence of toxic metals in tampons, including lead, arsenic, cadmium, chromium, and zinc. The study underscores the need for transparency and regulation in menstrual product manufacturing.
Learn more
Even when glyphosate isn’t the primary focus, the pattern is clear: harmful substances are showing up in the very products we use most intimately. It’s time we stopped treating that as normal.
Further Reading on NoMoreGlyphosate.nz
Glyphosate and Hormone Disruption: What We Know So Far
This article explores the potential endocrine-disrupting effects of glyphosate, the active ingredient in many herbicides. It discusses studies suggesting that glyphosate exposure may interfere with hormonal balance, potentially impacting reproductive health. The piece emphasizes the need for further research to fully understand the implications of glyphosate on the endocrine system.
Read all about Glyphosate and Hormone Disruption
MPI’s Missing Data: Why We Can’t Trust the Glyphosate Reassurance
This piece critiques the New Zealand Ministry for Primary Industries (MPI) for its lack of comprehensive data on glyphosate residues in food and the environment. It argues that without transparent and thorough testing, assurances about glyphosate’s safety remain questionable. The article calls for more rigorous monitoring and public disclosure to ensure informed decision-making.
Discover MPI’s Missing Data
Why Glyphosate Isn’t Just a Weed Killer — It’s a Public Health Issue
This article delves into the broader implications of glyphosate use beyond its herbicidal function. It examines concerns about glyphosate’s potential links to cancer, environmental degradation, and its presence in various consumer products. The piece advocates for a reevaluation of glyphosate’s widespread application in light of emerging health and ecological concerns.
Learn Why Glyphosate Isn’t Just a Weed Killer
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