Colesevelam to help remove PFAS and other environmental toxins from firefighters
Official title: Assessing the Impact of a Bile Acid Sequestrant on Serum PFAS Levels in Highly Exposed Individuals
Run by University of California, San Francisco · NCT07226440 · Data updated 2026-11-12
This trial will test whether the oral medicine colesevelam can lower blood PFAS and urine toxin levels in male firefighters with high occupational exposure.
Quick facts
| Phase | Phase1; Phase2 |
|---|---|
| Study type | Interventional |
| Ages | 18 Years and up |
| Sex | Men only |
| Enrollment | 50 (estimated) |
| Sponsor | University of California, San Francisco Academic / other |
| Locations | 1 site (San Francisco, California) |
| Status | Recruiting |
| Started | March 1, 2026 |
| Main results expected | December 2028 |
| Study ends | December 2028 |
| Registry record updated | April 24, 2026 |
| Trial ID | NCT07226440 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Male active or retired firefighters in California with elevated PFAS exposure who can attend three in-person visits in the San Francisco Bay Area and follow study procedures are ideal candidates.
✕Probably not a fit
Individuals with severe gastrointestinal motility disorders, bowel obstruction, major prior GI surgery, difficulty swallowing, very high triglycerides, or inability to attend Bay Area visits are unlikely to benefit or be eligible.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
UCSF is running a randomized, placebo-controlled crossover trial of colesevelam versus placebo in male firefighters with elevated PFAS exposure. Participants will take colesevelam or placebo twice daily during study periods and cross over to the other arm, with total participation spanning about 6.5 months. The trial will measure serum PFAS concentrations and urine environmental toxicants and mold mycotoxins while also tracking feasibility, adherence, and acceptability using in-person visits, weekly text reminders, and mail-based finger-prick blood tests. Recruitment is limited to English-speaking adult California residents who can attend three in-person visits in the San Francisco Bay Area.
Why it matters
Potential benefit: If successful, colesevelam could provide a simple, low-risk way to reduce body PFAS levels and related toxin burdens in exposed firefighters.
How similar studies have gone: Observational studies and one small randomized trial have suggested bile acid sequestrants can lower PFAS levels, but evidence is still limited.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * Male firefighter, active or retired * California resident * Age 18 or older * English-speaking * Access to a reliable internet connection * Willing to attend 3 in-person study visits in the San Francisco Bay Area over about 6.5 months * Willing to receive weekly text message reminders to complete online surveys * Willing to complete a mail-based, at-home finger-prick blood test * Willing to take 3 tablets (each tablet about the size of a multivitamin) orally twice daily for a total of 6 months * Evaluated by study team to have an elevated risk of PFAS exposure (e.g., duration of firefighting service, prior NASEM-7 result greater than or equal to 10 ng/mL) Exclusion Criteria: * Gastroparesis or other severe gastrointestinal motility disorders * Bowel obstruction * History of major gastrointestinal tract surgery * Dysphagia or difficulty swallowing (due to tablet size) * History of hypertriglyceridemia (triglycerides exceeding 500 mg/dL) * History of hypertriglyceridemia-induced pancreatitis * Type 1 or 2 diabetes * History of fat-soluble vitamin deficiencies, i.e., vitamins A, D, E, or K * Phenylketonuria * History of known bleeding/clotting disorders * Medications or treatments that may impact the excretion of PFAS, such as activated charcoal, other bile acid sequestrants, chelation therapies, etc. * Unalterable plans to donate blood or plasma during the study participation period
Where it's running
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UCSF Osher Center for Integrative Health
San Francisco, California, United States Recruiting
Study contacts
- Principal investigator: Ashley E Mason, PhD — University of California San Francisco, Osher Center for Integrative Health
- Study coordinator: Ashley Mason, PhD
- Email: enginestudy@ucsf.edu
- Phone: 415-514-6820
How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.