What’s the Bottom Line?

What is currently known about dietary supplements for hepatitis C?

• No dietary supplement has been proven to effectively treat hepatitis C.

• Research on silymarin (milk thistle), the most commonly used supplement for this condition, has not demonstrated meaningful benefits in people with hepatitis C.

What is known about safety?

• Colloidal silver, sometimes promoted for hepatitis C, is unsafe and may cause permanent and serious side effects.

• In clinical studies of silymarin (milk thistle), side effects were infrequent and generally mild.

• For most other supplements, safety information is limited. Some may cause side effects or interact negatively with prescription medications.

About Hepatitis C

Hepatitis C is a viral infection that affects the liver. In most cases, it becomes chronic, meaning it persists over time. Many people experience no symptoms for years, often until significant liver damage has occurred, which may take a decade or longer. If left untreated, chronic hepatitis C can lead to serious complications such as liver failure or liver cancer. Standard treatment typically involves a combination of antiviral medications.

The hepatitis C virus spreads primarily through contact with infected blood and, less commonly, through sexual contact with an infected individual. Once infected, most people develop a long-term infection.

In the United States, an estimated 2.7 to 3.9 million people are living with chronic hepatitis C.

About Dietary Supplements for Hepatitis C

A variety of dietary supplements have been investigated for possible use in hepatitis C, and many individuals with the condition report trying them. Silymarin, an extract derived from milk thistle, is the supplement most frequently used.

What the Science Says About Dietary Supplements for Hepatitis C

Silymarin (Milk Thistle)

• Milk thistle (Silybum marianum) is a plant in the aster family. Silymarin is a compound extracted from its seeds. A 2014 review analyzing five clinical trials involving 389 participants with hepatitis C found no meaningful benefit from silymarin. It did not improve liver function tests or reduce levels of the hepatitis C virus.

• In one large study of 154 participants who had not responded to standard drug therapy, high doses of silymarin taken for 24 weeks were no more effective than a placebo in improving liver function. There were also no significant differences in viral levels or quality of life between the treatment and placebo groups.

• Across studies, side effects linked to silymarin were uncommon. When reported, they were usually mild digestive complaints such as bloating, nausea, diarrhea, or indigestion.

Probiotics

• Probiotics are live microorganisms intended to provide health benefits. Current research does not offer clear evidence that probiotics improve outcomes in people with hepatitis C. In generally healthy individuals, probiotics tend to cause few, if any, side effects. However, in people with serious underlying conditions, including weakened immune systems, rare but serious infections have been reported.

Zinc

• Early studies, many conducted outside the United States, have explored zinc supplementation in hepatitis C. Zinc may help correct deficiencies associated with the disease and could potentially ease certain symptoms or enhance response to antiviral therapy. However, evidence supporting these effects remains limited. While zinc is usually safe when taken as directed, excessive intake can lead to toxicity.

Licorice Root and Glycyrrhizin

• Glycyrrhizin, a compound found in licorice root, has been examined in a small number of studies involving hepatitis C patients. At present, there is insufficient evidence to determine whether it provides benefit. Products containing glycyrrhizin can pose risks, especially for individuals with high blood pressure, heart disease, kidney problems, or diabetes.

Colloidal Silver

• Colloidal silver has been promoted as a remedy for hepatitis C, but no scientific evidence supports its use for this or any other medical condition. It can cause serious adverse effects, including argyria, a permanent bluish-gray discoloration of the skin.

Other Dietary Supplements

• Preliminary investigations have evaluated additional products for chronic hepatitis C, including TJ-108 (a traditional Japanese herbal formula), oxymatrine, chlorella, black cumin (Nigella sativa), S-adenosyl-L-methionine (SAMe), and thymus extract. Current evidence does not convincingly demonstrate that these products are effective.

• Some early research has explored combining supplements such as lactoferrin, SAMe, or zinc with standard antiviral therapy. The available data are insufficient to determine whether these combinations improve treatment outcomes or are safe.

• Researchers have also studied whether supplements like carotenoids or vitamin K might reduce the risk of liver cancer in people with hepatitis C. So far, evidence is too limited to draw firm conclusions.

NCCIH-Funded Research

Research supported by NCCIH has included projects examining:

• Potential antiviral compounds derived from rare or endangered plants

• How silymarin interacts with liver cells and affects liver biology

More To Consider

• Do not use complementary health products as a substitute for conventional medical treatment for hepatitis C or delay seeking professional care.

• Keep in mind that dietary supplements may cause side effects or interact with prescription medications.

• If you are pregnant, breastfeeding, or considering giving a supplement to a child, consult a health care provider. Many supplements have not been adequately tested in these groups.

• Inform all your health care providers about any supplements or alternative approaches you use so they can help ensure safe and coordinated care.

Key References

• Dhiman RK, Chawla YK. Herbal medicines for liver diseases. Digestive Diseases and Sciences. 2005;50(10):1807-1812.

• Fried MW, Navarro VJ, Afdhal N, et al. Effect of silymarin (milk thistle) on liver disease in chronic hepatitis C: a randomized controlled trial. JAMA. 2012;308(3):274-282.

• Grüngreiff K, Reinhold D. Zinc as a complementary factor in chronic hepatitis C treatment. Molecular Medicine Reports. 2010;3(3):371-375.

• Yang Z, Zhuang L, Lu Y, et al. Effects and tolerance of silymarin in chronic hepatitis C: a meta-analysis. BioMed Research International. 2014;2014:941085.

Acknowledgments

This publication was prepared with contributions from experts in complementary and integrative health research.

The material is provided for informational purposes only and is not a substitute for professional medical advice. Always consult your health care provider regarding treatment decisions. Mention of specific products or therapies does not constitute endorsement.