Hepatitis C is a viral disease of the liver that afflicts an estimated four million Americans. Chronic hepatitis C is typically associated with fatigue, depression, joint pain and liver impairment, including cirrhosis and liver cancer.
Scientists theorize that the endocannabinoid system may moderate aspects of chronic liver disease[1-2] Population data shows that adults with a history of cannabis use are less likely to suffer from specific liver problems, such as non-alcoholic fatty liver disease (NAFLD), than non-users. Specifically, a 2017 University of Massachusetts study reported that frequent consumers of cannabis were 52 percent less likely to be diagnosed with NAFLD as compared to non-users, while occasional consumers were 15 percent less likely to suffer from the disease. A Stanford University study similarly reported that cannabis use independently predicted a lower risk of suspected NAFLD in a dose-dependent manner. "Active marijuana use provided a protective effect against NAFLD independent of known metabolic risk factors," authors concluded.
Patients diagnosed with hepatitis C frequently report using cannabis to treat both symptoms of the disease as well as the nausea associated with antiviral therapy.[5-6] An observational study by investigators at the University of California at San Francisco (UCSF) reports that hepatitis C patients who used cannabis were significantly more likely to adhere to their treatment regimen than patients who didn't use it.
While some older observational studies cautioned that heavy cannabis use among hepatitis C patients may adversely impact the liver,[8-10] more recent studies report that cannabis inhalation is not associated with the promotion of liver disease in hepatitis C subjects, and, in some cases, may even act as a protective agent against steatosis. Separate longitudinal data finds that patients co-infected with hepatitis C and HIV who consume cannabis are also less likely to suffer from insulin resistance as compared to non-users.
Experts in the field offer divergent opinions regarding the therapeutic use of cannabinoids for hepatitis C treatment. While some experts opine that cannabis' "potential benefits of a higher likelihood of treatment success [for hepatitis C patients] appear to outweigh [its] risks" others discourage the use of cannabis in patients with chronic hepatitis until further studies are performed.[15-19]
 Zamora-Valdes et al. 2005. The endocannabinoid system in chronic liver disease (PDF). Annals of Hepatology 4: 248-254.
 Adejumo et al. 2017. Cannabis use is associated with reduced prevalence of non-alcoholic fatty liver disease: A cross-sectional study. PLoS One [open access journal].
 Kim et al. 2017. Inverse association of marijuana use with nonalcoholic fatty liver disease among adults in the United States. PLoS One [open access journal].
 Schnelle et al. 1999. Results of a standardized survey on the medical use of cannabis products in the German-speaking area. Forschende Komplementarmedizin (Germany) 3: 28-36.
 MedScape Today. 2004. “Hepatitis C – Current state of the art and future directions.” MedScape Today.
 Sylvestre et al. 2006. Cannabis use improves retention and virological outcomes in patients treated for hepatitis C. European Journal of Gastroenterology & Hepatology. 18: 1057-1063.
 Hezode et al. 2005. Daily cannabis smoking as a risk factor for progression of fibrosis in chronic hepatitis C. Hepatology 42: 63-71.
 Ishida et al. 2008. Influence of cannabis use on severity of hepatitis C disease. Clinical Gastroenterology and Hepatology 6: 69-75.
 Brunet et al. 2013. Marijuana smoking does not accelerate progression of liver disease in HIV-hepatitis C coinfection: a longitudinal cohort analysis. Clinical Infectious Diseases 57: 663-670.
 Nordmann et al. 2017. Daily cannabis and reduced risk of steatosis in human immunodeficiency virus and hepatitis C virus co-infected patients. Journal of Viral Hepatitis [online ahead of print]
 Patrizia-Carrie et al 2015. Cannabis use and reduced risk of insulin resistance in HIV-HCV infected patients: A longitudinal analysis. Clinical Infectious Diseases 61: 40-48.
 Fischer et al. 2006. Treatment for hepatitis C virus and cannabis use in illicit drug user patients: implications and questions. European Journal of Gastroenterology & Hepatology. 18: 1039-1042.
 Schwabe and Siegmund. 2005. op. cit.
 Hezode et al. 2005. op. cit.
 David Berstein. 2004. op. cit.
 Hezode et al. 2008. Daily cannabis use: a novel risk factor of steatosis severity in patients with chronic hepatitis C. Gastroenterology 134: 432-439.
 Purohit et al. 2010. Role of cannabinoids in the development of fatty liver (steatosis). The AAPS Journal 12: 233-237.