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NCCIH Clinical Digest

for health professionals

Hepatitis C and Dietary Supplements: What the Science Says

June 2019

Clinical Guidelines, Scientific Literature, Info for Patients: 
Hepatitis C and Dietary Supplements

Milk thistle flower
© Thinkstock

Dietary Supplements

No dietary supplement has been shown to be effective for hepatitis C. Several studies of silymarin (milk thistle) dietary supplements in people with hepatitis C did not find beneficial effects.

Milk Thistle

Current research suggests that milk thistle is no better than placebo as a treatment for hepatitis C.

What Does the Research Show?

  • A 2014 meta-analysis of five randomized controlled trials found that the effects of silymarin on alanine aminotransferase (ALT) levels of patients with hepatitis C were similar to those of placebo; however, no beneficial effects were found for silymarin. Improvements in the quality of life of silymarin and placebo recipients were relatively identical.
  • A 2012 controlled trial showed that two higher-than-usual doses of silymarin were no better than placebo in reducing alanine aminotransferase (ALT) levels in patients with chronic hepatitis C. Decreases in serum ALT levels are correlated with improvement in hepatic necroinflammatory activity after interferon therapy for hepatitis C.
  • Findings from the 2008 HALT-C study suggest that silymarin use by hepatitis C patients was associated with fewer and milder symptoms of liver disease and somewhat better quality of life, but there was no beneficial effect found on serum ALT or hepatitis C virus RNA levels. It is important to note that the finding of improved quality of life in patients taking silymarin was not confirmed in the more rigorous 2012 study described above.
  • A 2009 Cochrane systematic review assessed the beneficial and harmful effects of milk thistle in patients with alcoholic liver disease and/or hepatitis B or C liver diseases and found that there is not enough high-quality evidence to support the use of this intervention.


  • Available evidence from clinical trials in people with liver diseases suggests that milk thistle is generally well-tolerated.
  • Side effects can include a laxative effect, nausea, diarrhea, abdominal bloating and pain, and occasional allergic reactions.


Only a few studies have examined the effects of probiotics on hepatitis C, and of those studies, there isn’t any clear evidence that probiotics are helpful in people with hepatitis C.

What Does the Research Show?

  • A 2014 randomized controlled trial involving 53 patients with chronic liver disease found that short-term probiotic administration is effective in alleviating small intestinal bacterial overgrowth and clinical symptoms, but ineffective in improving intestinal permeability and liver function.


  • Most people can use probiotics without experiencing any side effects—or with only mild gastrointestinal side effects—but there have been some case reports of serious adverse effects in people with underlying serious health conditions.


Preliminary studies, most of which were conducted outside the United States, have found that zinc supplements might help to correct zinc deficiencies associated with hepatitis C, reduce some symptoms, or improve patients’ response to treatment, but the evidence for these possible benefits is limited.

What Does the Research Show?

  • A 2015 multicenter randomized controlled trial in 53 patients with hepatitis C found that branched-chain amino acids (BCAA) and zinc-enriched supplements reduced the serum α‑fetoprot (AFP) levels in patients who had elevated serum AFP levels at baseline. The authors of the study concluded that BCAA and zinc-enriched supplementation may prolong the survival of patients with hepatitis C by improving amino acid imbalance and zinc deficiency, and by partly down regulating AFP.
  • A 2012 study evaluating the effects of vitamins E, C, and zinc on oxidative stress in patients with hepatitis C found that the antioxidant supplementation had a protective effect on participants, attenuating oxidative stress related to the disease.


  • Zinc is generally considered to be safe when used appropriately, but it can be toxic if taken in excessive amounts.


There is currently insufficient evidence to determine if glycyrrhizin is efficacious for hepatitis C.

What Does the Research Show?

  • A 2012 randomized controlled trial in 379 patients with chronic hepatitis C who failed to respond to previous interferon-based therapies found that glycyrrhizin exhibited a significantly higher ALT reduction compared to placebo after 12 weeks of therapy and an improvement of necro-inflammation and fibrosis after 52 weeks of treatment.


  • In large amounts, glycyrrhizin or licorice can be dangerous in people with a history of hypertension, renal failure, or cardiovascular diseases.

Other Dietary Supplements

  • Preliminary studies have examined the potential of the following products for treating chronic hepatitis C: TJ-108 (a mixture of herbs used in Japanese Kampo medicine), oxymatrine (an extract from the sophora root), chlorella (a type of algae), black cumin (Nigella sativa), S-adenosyl-L-methionine (SAMe), and thymus extract (from cattle). The limited research on these products hasn’t produced convincing evidence that they’re helpful for hepatitis C.
  • A few preliminary studies have looked at the effects of combining supplements such as lactoferrin, SAMe, or zinc with conventional drug therapy for hepatitis C. The evidence isn’t sufficient to draw clear conclusions about benefit or safety.
  • Preliminary research has looked at substances that might reduce the risk of liver cancer in people with hepatitis C, including dietary supplements such as carotenoids and vitamin K, but the evidence is too limited for conclusions to be reached.


NCCIH Clinical Digest is a service of the National Center for Complementary and Integrative Health, NIH, DHHS. NCCIH Clinical Digest, a monthly e-newsletter, offers evidence-based information on complementary health approaches, including scientific literature searches, summaries of NCCIH-funded research, fact sheets for patients, and more.

The National Center for Complementary and Integrative Health is dedicated to exploring complementary health products and practices in the context of rigorous science, training complementary health researchers, and disseminating authoritative information to the public and professionals. For additional information, call NCCIH’s Clearinghouse toll-free at 1-888-644-6226, or visit the NCCIH website at NCCIH is 1 of 27 institutes and centers at the National Institutes of Health, the Federal focal point for medical research in the United States.


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