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What Is the Liver Powerhouse Silymarin?

By Sayer Ji


When it comes to treating liver and gallbladder disorders, there is one name that stands out: silymarin. As a group of flavonolignans extracted from milk thistle, silymarin has been traditionally used for various protective benefits, from reinvigorating liver function to promoting breast milk production.

The milk thistle plant, scientifically known as Silybum marianum, is a prickly plant with purple flowers and milky white veins present on the leaves, thus its name. Silymarin is the group of plant compounds that act as its active ingredient.[i]

Silymarin is the main bioactive component of this medicinal plant. It is a mix of various flavonolignans, includings silybinin A and B, isosilybinin A and B, silychristin and silydianin.[ii] Milk thistle extract has a high silymarin content of approximately 65% to 80%.

Silymarin is famed for its antioxidant, antiviral and anti-inflammatory components,[iii] as well as its traditional use or treating the liver and restoring its health. In addition, milk thistle itself is generally considered safe to take. Side effects are rare, and in an oral form standardized to contain 70% to 80% silymarin, it appears to be safe for up to 41 months of use.[iv]

Silymarin’s Liver-Protective Effects

  • Fights liver inflammation and liver damage. Mounting evidence shows improvements in liver function among people with liver diseases who have taken a milk thistle supplement.[v] This suggests protection against flavanone silibinin liver inflammation and liver damage through use of the natural — silymarin’s primary active component — which was combined with phosphatidylcholine in a specific study to enhance its solubility and bioavailability.

  • Protects from toxins such as amatoxin, produced by Amanita mushroom, which can cause death if ingested. Two cases in the U.S. were treated with N-acetylcysteine, high-dose penicillin, cimetidine and silibinin.[vi]

Uncontrolled trials and case reports cited successful treatment with intravenous silibinin, a flavonolignan isolated from milk thistle extracts, in nearly 1,500 cases.[vii] Overall mortality in those treated with the formula was less than 10%, compared to more than 20%when using penicillin, or a mix of silibinin and penicillin.

  • Reduces liver fibrosis. In a randomized trial of 99 patients, the team administered silymarin in 700-milligram (mg) doses, or a placebo, given three times daily for 48 weeks.[viii] Non-alcoholic fatty liver disease (NAFLD) activity score was reduced by 32.7% in the silymarin group compared to 26% in the placebo group.

Among the secondary outcomes were reductions in inflammation and fibrosis score in the silymarin group, leading the researchers to conclude that silymarin may decrease liver fibrosis, to be confirmed in larger trials. Fibrosis is the formation of abnormally large amounts of scar tissue in the liver.

  • Helps prevent liver cancer. Studies have concluded that the long-term use of silymarin significantly increases survival time among patients with alcohol-induced liver cirrhosis, a risk factor for liver cancer. Silymarin can also significantly reduce tumor cell proliferation, angiogenesis or new blood vessel formation, as well as insulin resistance.[ix]

The chemopreventive effects “have been established in several studies using in vitro and in vivo methods,” according to the researchers, and combine well with anti-inflammatory and inhibitory effects on the metastasis or spread of cancer.

  • Contributes to liver regeneration. An animal study suggested that silymarin played a crucial role in accelerating liver regeneration after liver resection, a kind of surgery designed to remove cancerous tumors from the liver.[x] Liver regeneration is thought to evolve to protect animals from loss of liver due to toxins or tissue injury.

Silymarin for Breastfeeding, Neurological Support

Not to be ignored is silymarin’s formidable list of other health benefits, such as boosting milk production in lactating mothers. A randomized trial found that mothers taking 420 mg of silymarin for 63 days produced more breast milk than subjects who took a placebo.[xi] Silymarin combined with phosphatidylserine and galega also increased milk production in moms of preterm infants, without any significant side effects.[xii]