Glyphosate is water soluble. Glyphosate does not accumulate in fat or adipose tissue (unlike fat-soluble toxins). There's some speculation that glyphosate may affect or be retained by gut microbes, especially in a dysbiotic environment, potentially leading to a slower clearance. ("Alterations in the gut microbiome caused by glyphosate and Roundup", DOI: 10.1016/j.toxrep.2017.05.008)
Summary of Absorption and Excretion:
- Absorption: After ingestion (typically through contaminated food or water), glyphosate is partially absorbed in the GI tract—roughly 20–30% depending on the individual and the form ingested.
- Excretion: Most glyphosate is excreted unchanged in the urine. This is why urine testing is the primary method for assessing glyphosate exposure.
- Half-life: Glyphosate’s half-life in the human body is generally short—estimated to be less than 7 days in most studies. So if exposure stops, levels should decline fairly quickly.
Even patients avoiding known glyphosate sources may test positive due to:
- Contaminated water (well or municipal).
- Spray drift or runoff in agricultural regions.
- Pre-harvest desiccation residues on grains and legumes (including some organic).
- Occupational or household exposure to glyphosate-containing products (e.g., Roundup).
Persistent exposure could be environmental exposures to water:
- Glyphosate has been found in municipal water, rain, and air, especially in agricultural regions.
- Even organic consumers may show urinary glyphosate due to drift or water contamination.
Key References
- EFSA (2015): EFSA Journal 2015;13(11):4302
- FAO/WHO JMPR (2004): Pesticide Residues Report
- Zhang et al. (2020): J Expo Sci Environ Epidemiol
- Mesnage et al. (2017): Toxicol Rep
- Samsel & Seneff (2013): Entropy (theoretical, not consensus)