Bayer Roundup is a widely used brand of systemic, non-selective, post-emergent herbicides designed to kill weeds and grasses, primarily using the active ingredient glyphosate. Acquired by Bayer in 2018 from Monsanto, it is used in agriculture,1 residential lawns, and gardens to manage broad-leaf weeds and grasses by inhibiting necessary enzyme production.
Key details about Bayer Roundup include:
- Usage: It acts as a systemic herbicide, meaning it moves through the plant to kill roots, usually within 1 to 4 weeks.
- Formulations: Products range from professional-grade agricultural concentrates to ready-to-use consumer sprays, some of which do not contain glyphosate.
- Controversy & Legal Issues: While regulators often deem it safe when used as directed, the International Agency for Research on Cancer (IARC) classified glyphosate as "probably carcinogenic". Bayer has faced over 114,000 lawsuits regarding non-Hodgkin lymphoma, with billions in settlements, according to this YouTube video.
- Types: Popular versions include Roundup WeatherMAX, Roundup Transorb HC, and Roundup Dual Action.
Bayer's Roundup, containing the active ingredient glyphosate, is heavily scrutinized for potential links to cancer, specifically non-Hodgkin lymphoma (NHL). While many studies and the WHO's International Agency for Research on Cancer (IARC) classify it as a "probable human carcinogen," the EPA maintains it is safe, leading to intense legal battles, including a proposed $7.25B settlement.
Key Details on the Link to Cancer:
- Scientific Evidence: Some studies, including a 2019 meta-analysis, found that high exposure to glyphosate-based herbicides (like Roundup) is associated with a 41% increased risk of developing non-Hodgkin lymphoma.
- Contradictory Findings: Research is divided. The U.S. Environmental Protection Agency (EPA) and Health Canada have concluded that glyphosate is not likely to be carcinogenic to humans. However, the IARC classified it as "probably carcinogenic to humans".
- Targeted Cancer: The primary cancer linked to Roundup in lawsuits and studies is non-Hodgkin lymphoma, a type of cancer that begins in the lymphatic system.
- Lawsuits and Settlements: Thousands of lawsuits allege that Bayer/Monsanto failed to warn users of the cancer risks. In 2026, Bayer agreed to a $7.25B proposed settlement to resolve many of these claims.
- Company Stance: Bayer continues to insist that Roundup is safe, citing over 800 studies that show no link to cancer.
Potential Risks:
- Exposure: The risks are generally linked to long-term, high-level exposure, such as for farmers, agricultural workers, or landscapers.
- Mechanisms: Studies suggest glyphosate may cause DNA damage and inflammation, which are key factors in cancer development.
For more information, you can read about the World Health Organization's findings on glyphosate and the U.S. Agency for Toxic Substances and Disease Registry's toxicological profile.
