Roundup Science 2026: How New Evidence May Shape Lawsuits

Last updated: October 2026

New scientific evidence could shape the next phase of Roundup litigation in two ways. It can affect whether courts accept that glyphosate can cause non-Hodgkin lymphoma (NHL), and, after the Supreme Court’s June 2026 ruling, it may matter more than ever what the EPA decides about glyphosate. It also explains how to read different types of Roundup science, what two often-cited human studies found and how the research connects to an individual claim.

Here is a plain-language look at the Roundup science that is changing, what it does and does not show, and why it matters for people with pending or future claims.

Why Roundup science sits at the center of the litigation

Every Roundup case turns on causation. A person must show that glyphosate-based herbicides can cause NHL in general, and that exposure likely contributed to their own cancer.

For years, the two sides have pointed to different scientific bodies. In 2015, the International Agency for Research on Cancer (IARC) classified glyphosate as “probably carcinogenic to humans,” citing limited evidence in humans for NHL. The EPA, by contrast, concluded in 2017 that glyphosate is “not likely to be carcinogenic to humans.”

Courts decide which scientific testimony juries may hear. So new studies, retractions and agency reviews can all shift how cases are argued.

The Supreme Court made EPA’s review more important

On June 25, 2026, the Supreme Court decided Monsanto Co. v. Durnell by a 7–2 vote. It held that federal pesticide law preempts a state-law failure-to-warn claim that would require a cancer warning on Roundup’s EPA-approved label.

That ruling ties label-based claims closely to what the EPA requires. The Court did not decide other theories, such as design defect claims.

This is one reason the EPA’s ongoing glyphosate review matters. What the agency concludes about cancer risk could influence both the label and the arguments made in future cases.

EPA’s glyphosate review is still open

The EPA’s 2020 interim decision on glyphosate was withdrawn in 2022 after a federal appeals court vacated its human health portion. The agency has been redoing that work since.

In August 2026, EPA released a large review of published studies for public comment, with comments due September 24, 2026. Then, on September 22, 2026, HHS and EPA signed an agreement to expand research on glyphosate’s possible health effects.

Under that agreement:

• A joint working group will look for gaps in the research
• Groups such as the National Toxicology Program, the National Cancer Institute and NIOSH will take part
• EPA expects to finish its updated human health and cancer evaluation in early 2027

No one knows yet what EPA will conclude. But its findings will be closely watched by both sides.

A key safety review was retracted

In late 2025, the journal Regulatory Toxicology and Pharmacology retracted a widely cited 2000 review of glyphosate safety by Williams, Kroes and Munro. The editors cited concerns including undisclosed writing contributions by Monsanto employees.

Bayer responded that Monsanto’s involvement was noted in the article’s acknowledgments. It also repeated that regulators around the world have found glyphosate can be used safely as directed.

In June 2026, Retraction Watch reported that another publisher was investigating two more glyphosate safety papers over similar ghostwriting concerns. As of that report, no decision had been made on those papers.

Why a retraction matters

A retraction does not prove glyphosate causes cancer. But it can affect how much weight courts and agencies give to studies that relied on that review. It may also come up when lawyers question witnesses about the science.

New animal research, and its limits

In 2025, researchers linked to Italy’s Ramazzini Institute published a long-term rat study in the journal Environmental Health. They reported that low doses of glyphosate and glyphosate-based products were linked to tumors in several organs, including leukemia and lymphoma.

Germany’s risk agency, BfR, reviewed the study and raised methodological concerns. It noted that the rats received glyphosate in drinking water rather than food, and it questioned how historical control data were handled. BfR said the study does not justify changing its current assessment and called for a detailed EU-level analysis.

This is typical of how new science works in litigation. One side will say a study supports causation, and the other will point to its limits.

How courts screen scientific testimony

New studies only matter in court if a judge lets the jury hear about them. Judges act as gatekeepers for scientific and medical testimony, and they can exclude opinions they find unreliable.

In federal court, that gatekeeping is governed by Federal Rule of Evidence 702. A 2023 amendment made clear that the side offering the testimony must show it is more likely than not that the testimony meets the rule’s reliability requirements. State courts use their own rules, which can differ.

For Roundup cases, this means each side’s scientific witnesses must explain how they reached their conclusions. A retracted review, a new animal study or a new EPA finding can each become part of that debate.

What new evidence could mean for claimants

New science does not change the facts of your own exposure or diagnosis. But it may affect the legal landscape around your claim.

• Causation arguments. Stronger or weaker evidence can change which scientific testimony courts allow.
• Label-based claims. After Durnell, these depend heavily on what EPA requires on the label.
• Settlement dynamics. Scientific uncertainty is one reason both sides may prefer to settle rather than try cases.

Separately, Monsanto has proposed a class settlement of up to $7.25 billion for people exposed before February 17, 2026 who have NHL or are diagnosed within 16 years after final approval. A final approval hearing was held on September 14, 2026.

As of the latest reports we could find in late September 2026, Judge Boyer had not announced a ruling on final approval. Check the court record or ask a participating law firm for the current status.

How to Read Roundup Science Without Getting Lost

Roundup science can feel like a flood of studies that seem to point in different directions. Part of the confusion comes from the fact that scientists use very different kinds of studies, and each kind answers a different question. Knowing the basic types makes the headlines easier to follow.

Human studies that follow people over time

A cohort study follows a large group of people for years and compares who gets sick. Cohort studies can track exposure before anyone is diagnosed, which helps reduce memory errors. Their weakness is that a rare cancer like NHL may produce only a small number of cases, even in a big group.

Human studies that look back

A case-control study starts with people who already have a disease and compares them with similar people who do not. Researchers ask both groups about past exposures. These studies are useful for rare cancers, but they depend on people remembering their past use accurately.

Studies that combine other studies

A meta-analysis pools the results of several earlier studies to get a larger overall picture. Its results depend heavily on which studies are included and how they are weighed. Two meta-analyses on the same topic can reach different conclusions. Readers should check which studies were included, and whether the authors chose the highest exposure groups or all exposed people.

Animal and lab studies

Animal studies, like the 2025 rat study described above, test what happens at controlled doses. Lab studies look at how a chemical acts on cells. These can suggest how harm might happen, but people and lab animals differ, and doses may not match real-world use.

Dose and duration

Many studies try to measure not just whether someone was exposed, but how much and for how long. If risk rises as exposure rises, scientists call that a dose-response pattern. A pattern like this can make a link more convincing. Its absence is often raised by the other side. Questions about dose come up in nearly every discussion of Roundup science.

Time between exposure and diagnosis

Cancers usually take years to develop after an exposure. Scientists call this gap latency. Studies that follow people for only a short time may miss cancers that appear later, which is one reason follow-up length matters when comparing Roundup science studies.

Courts and agencies usually look at all of these kinds of Roundup science together, rather than relying on any single study.

Two Human Studies Often Cited in Roundup Science

Two large human studies come up again and again in Roundup science debates. They reached different results, which helps explain why the question is still argued.

The Agricultural Health Study

The Agricultural Health Study is a long-running U.S. study of pesticide applicators. According to the University of Iowa College of Public Health, a glyphosate analysis published in the Journal of the National Cancer Institute looked at 54,251 applicators, of whom 44,932, or 82.9%, used glyphosate. It found no association between glyphosate and solid tumors or lymphoid cancers overall, including NHL and its subtypes. The researchers did note some evidence of a higher risk of acute myeloid leukemia among the most heavily exposed group, but that result was not statistically significant.

The 2019 meta-analysis

A 2019 meta-analysis published in Mutation Research, Reviews in Mutation Research, took a different approach. It focused on the people with the highest exposure in each study it included. According to the published abstract, it reported that the overall risk of NHL in people exposed to glyphosate-based herbicides was increased by 41%, and the authors described “a compelling link.”

Why the results differ

The two studies asked slightly different questions. One looked at a single large group of applicators. The other combined several studies and focused on the highest exposures. Each side in the litigation tends to emphasize the study that fits its view. Neither study, on its own, settles the question.

These are only two examples, and both have been debated by scientists on each side. The EPA’s ongoing review, IARC’s 2015 classification and many smaller studies are all part of the wider body of Roundup science.

Questions to Ask When You See a New Roundup Science Headline

New Roundup science stories appear often, and many headlines overstate what a study found. A few simple questions can help you judge what a new report really means.

• Was it a human study, an animal study or a lab study? Human studies usually carry more weight for questions about people.
• How many people or animals were studied? Larger studies tend to give more stable results.
• How was exposure measured? Records, interviews and lab tests all have strengths and weaknesses.
• Did the study look at NHL specifically, or at cancer in general?
• Were the results statistically significant, or could they be due to chance?
• Has the study been peer reviewed and published in a journal?
• Who paid for it, and did the authors disclose any conflicts of interest?
• Does it agree with earlier studies, or is it the first to find this result?
• Has a government agency or other scientists responded to it?

Where to find the original study

News stories usually name the journal and the lead author. With that information, you can often find a free summary, called an abstract, on the journal’s website or in public research databases. Reading the abstract can tell you what the researchers actually claimed, which is not always what the headline says about Roundup science.

Relative risk and real-world risk

Headlines often report relative risk, such as “41% higher risk.” That compares two groups. It does not tell you how many people actually got sick. NHL is fairly uncommon, so even a higher relative risk can mean a small change in the number of cases. Both numbers matter when weighing Roundup science.

Be patient with new findings

A single study rarely changes the scientific picture overnight. Other researchers need time to test the methods, repeat the work and respond. Agencies like the EPA usually review many studies before changing a conclusion. Courts also tend to give more weight to findings that have been repeated by different research teams using different methods.

How Roundup Science Connects to Your Own Claim

Roundup science is about glyphosate in general. A claim is about one person. The legal system bridges the two with two separate questions. Keeping them apart can make court news much easier to understand.

General causation

Can glyphosate-based herbicides cause NHL at all? This is where most of the Roundup science discussed in this article comes in. Courts decide which scientific testimony on this question juries may hear.

Specific causation

Did Roundup likely contribute to this person’s cancer? This looks at your own history: how long and how often you used the product, how you were exposed, your NHL subtype and your other health factors. Strong general science does not prove specific causation for everyone, and weaker science does not rule it out for everyone either.

Records that connect the science to you

Because specific causation depends on your own facts, records matter. Helpful items often include:

• A written timeline of your Roundup use, with years, frequency and how you sprayed
• Proof of purchase, old containers or photos of products and equipment
• Work records if you sprayed on the job, such as for a farm, landscaper or city
• Your pathology report naming the NHL subtype
• Your full medical history, including other conditions and medicines
• Names of people who saw you spray and can describe how you used the product

Share your full history

Doctors know that NHL has several known risk factors, such as older age and certain immune system conditions. The other side will usually look closely at these. Telling your law firm everything from the start helps it understand how Roundup science may apply to your situation.

Talk with your doctor

Your doctor can explain your NHL subtype, your treatment and any other health factors in plain words. Bring your questions, and ask for copies of your pathology and treatment records for your own files. Medical decisions should be based on your health, not on a legal claim.

Don’t wait for the science to settle

Roundup science may keep changing for years. Filing deadlines vary by state and claim type, and they usually do not pause while new studies come out. If you used Roundup and were diagnosed with NHL, a participating law firm may review your situation now.

Frequently asked questions

How Direct2Attorney can help

If you were exposed to Roundup and diagnosed with non-Hodgkin lymphoma, Direct2Attorney can connect you with a participating law firm for a free case review. Visit our Roundup lawsuit page to learn more, or see our paraquat lawsuit page for another herbicide litigation.

Roundup science is still evolving. A firm may review your exposure history and records and help you understand what the latest developments mean for you.

Direct2Attorney is a legal marketing and referral service, not a law firm. This article is general information, not legal advice. Submitting information does not create an attorney-client relationship.