Milk Thistle Proven Health Benefits

Milk thistle (Silybum marianum) extract is a well known hepatoprotective remedy with strong antioxidant potentials. Silymarin is a flavonolignan complex isolated from milk thistle. Silymarin is a mixture of polyphenolic molecules, including silybin, silydianin, isosilybin, and silychristin.

Mechanism of action: Silymarin acts by antioxidative, anti-lipid peroxidative, antifibrotic, anti-inflammatory, membrane stabilizing, immunomodulatory, iron chelating and liver regenerating mechanisms. Milk thistle activates RNA polymerase, an enzyme necessary for constructing RNA chains using DNA, which in turn promotes hepatocellular regeneration.

Current scientific evidence supports the use of milk thistle extracts in many forms of liver disease.

Fatty liver disease

There is good evidence that Milk thistle is beneficial for non-alcoholic fatty liver disease.
Several preliminary studies of Milk thistle demonstrated beneficial effects on liver function.

Silymarin may reduce the biochemical, inflammatory and ultrasonic indices of hepatic steatosis[1].

High-quality randomized controlled study [2] have shown that Silybin (the major active component of silymarin) combined with phosphatidylcholine and vitamin E, when taken during 12 months, improves liver enzyme levels and liver histology in patients with non-alcoholic fatty liver disease. In patients with hepatitis C virus infection there was improvement in fibrogenesis markers.

Another randomized controlled study[3] demonstrated that silymarin at dose 140 mg per day significantly decrease in average amount of AST and ALT aspartate aminotransferase (AST), alanine aminotransferase (ALT).

  • 1. Cacciapuoti F, Scognamiglio A, Palumbo R, Forte R, Cacciapuoti F. Silymarin in non alcoholic fatty liver disease. World J Hepatol. 2013 Mar 27;5(3):109-13. PubMed
  • 2. Loguercio C, Andreone P, Brisc C, et al. Silybin combined with phosphatidylcholine and vitamin E in patients with nonalcoholic fatty liver disease: a randomized controlled trial. Free Radic Biol Med. 2012 May 1;52(9):1658-65. PubMed
  • 3. Hajiaghamohammadi AA, Ziaee A, Oveisi S, Masroor H. Effects of metformin, pioglitazone, and silymarin treatment on non-alcoholic Fatty liver disease: a randomized controlled pilot study. Hepat Mon. 2012 Aug;12(8):e6099. PubMed

Acute viral hepatitis

There is limited good evidence on beneficial effect of silymarin in symptoms of acute viral hepatitis.

Silymarin accelerates resolution of symptoms (dark urine, jaundice and scleral icterus) in patients with acute clinical hepatitis (randomized, placebo-controlled trial)[4].

In a placebo-controlled trial[5] of patients with acute hepatitis A or B reduction in serum transaminase, aspartase aminotransferase, and bilirubin levels was seen in the silymarin group, but not the placebo group.

  • 4. El-Kamary SS, Shardell MD, Abdel-Hamid M, Ismail S, El-Ateek M, Metwally M, Mikhail N, Hashem M, Mousa A, Aboul-Fotouh A, El-Kassas M, Esmat G, Strickland GT. A randomized controlled trial to assess the safety and efficacy of silymarin on symptoms, signs and biomarkers of acute hepatitis. Phytomedicine. 2009 May;16(5):391-400. PubMed
  • 5. Magliulo E, Gagliardi B, Fiori GP. Results of a double blind study on the effect of silymarin in the treatment of acute viral hepatitis, carried out at two medical centres. Med Klin. 1978 Jul 14;73(28-29):1060-5. PubMed

Chronic hepatitis

The limited evidence suggests benefits for milk thistle in the treatment for chronic viral hepatitis. Silymarin shows some promise in reducing serum transaminase levels.

A complex of silybin and phosphatidylcholine, known as sillipide was studied in a randomized clinical trial of 20 patients with chronic hepatitis C or hepatitis B[6]. Significant reductions were seen in the transaminase levels in the Silipide group compared to placebo.

Recent 2012 randomized controlled study [7] showed that high doses of silymarin did not significantly reduce blood alanine aminotransferase (ALT) levels in participants with chronic hepatitis C infection who had not responded to standard antiviral treatment.

According to the prospective study[8], silymarin at doses 650 mg per day may improve blood aminotransferases (ALT, AST), hepatic fibrosis and quality of life in people with chronic hepatitis C.

  • 6. Buzzelli G, et al. A pilot study on the liver protective effect of silybin-phosphatidylcholine complex (IdB 1016) in chronic active hepatitis. Int J Clin Pharmacol Ther Toxicol 31(9): 456-460, 1993.
  • 7. Fried MW, Navarro VJ, Afdhal N, et al. Effect of silymarin (milk thistle) on liver disease in patients with chronic hepatitis C unsuccessfully treated with interferon therapy: a randomized controlled trial. JAMA. 2012 Jul 18;308(3):274-82. PubMed
  • 8. Kalantari H, Shahshahan Z, Hejazi SM, Ghafghazi T, Sebghatolahi V. Effects of silybum marianum on patients with chronic hepatitis C. J Res Med Sci. 2011 Mar;16(3):287-90. PubMed

Liver cirrhosis

There is limited evidence from several studies on milk thistle benefits for cirrhosis. In studies up to five years long, milk thistle slightly improved liver function and decreased the number of deaths in people with liver disease.

In a clinical study [9] of 170 patients with various causes of their cirrhosis there was a significant survival benefit in the silymarin patients with a 4 year survival rate of 58% in the silymarin group and 39% in the placebo group.

However, another 2-year double-blind study of 200 alcoholics with cirrhosis found no benefits of silymarin[10].

In a six month randomized trial of patients with alcoholic cirrhosis silymarin produced small decreases in lipid peroxidation and small increases in glutathione, but no significant changes in transaminase levels[11].

  • 9. Ferenci P, Dragosics B, Di ttrich H, et al. Randomized controlled trial of silymarin treatment in patients with cirrhosis of the liver. J Hepatol 1989;9(1):105 - 113. PubMed
  • 10 .Parés A, Planas R, Torres M, et al. Effects of silymarin in alcoholic patients with cirrhosis of the liver: Results of a controlled, double-blind, randomized and multicenter trial. J Hepatology 28: 615-621, 1998. PubMed
  • 11. Lucena MI, Andrade RJ, de la Cruz JP, Rodriguez-Mendizabal M, Blanco E, Sánchez de la Cuesta F. Effects of silymarin MZ-80 on oxidative stress in patients with alcoholic cirrhosis. Results of a randomized, double-blind, placebo-controlled clinical study. Int J Clin Pharmacol Ther. 2002 Jan;40(1):2-8. PubMed

Liver damage by toxins and drugs

There is promising evidence from non-controlled human studies and animal experiments of milk thistle effectiveness in the treatment and prevention of liver damage caused by drugs or toxic chemicals. Adequate studies have yet to be done on detoxification benefits.

Silymarin acts as an antioxidant by reducing free radical production and lipid peroxidation. It may work as a toxin blockade agent by inhibiting binding of toxins to the hepatocyte cell membrane receptors. According to the ongoing research, silymarin reduces liver injury caused by acetaminophen[13], carbon tetrachloride[12], radiation, iron overload[17], phenylhydrazine, alcohol[16], and deathcap mushroom (Amanita phalloides).

In the study of 252 patients with acute Amanita phalloides mushroom poisoning those given oral silymarin had a higher survival rate than expected[15].

  • 12. Kim SH, Cheon HJ, Yun N, Oh ST, Shin E, Shim KS, Lee SM. Protective effect of a mixture of Aloe vera and Silybum marianum against carbon tetrachloride-induced acute hepatotoxicity and liver fibrosis. J Pharmacol Sci. 2009 Jan;109(1):119-27. PubMed
  • 13. Das S, Roy P, Auddy RG, Mukherjee A. Silymarin nanoparticle prevents paracetamol-induced hepatotoxicity. Int J Nanomedicine. 2011;6:1291-301 PubMed
  • 14. Abenavoli L, Capasso R, Milic N, Capasso F. Milk thistle in liver diseases: past, present, future. Phytother Res. 2010 Oct;24(10):1423-32. PubMed
  • 15. Hruby K, Caomos G, Thjaler H. Silbinin in the treatment of deathcap fungus poisoning. Forum 1984;6:23 - 26.
  • 16. Das SK, Mukherjee S. Biochemical and immunological basis of silymarin effect, a milk thistle (Silybum marianum) against ethanol-induced oxidative damage. Toxicol Mech Methods. 2012 Jun;22(5):409-13. PubMed
  • 17. Moayedi B, Gharagozloo M, Esmaeil N, Maracy MR, Hoorfar H, Jalaeikar M. A randomized double-blind, placebo-controlled study of therapeutic effects of silymarin in β-thalassemia major patients receiving desferrioxamine. Eur J Haematol. 2013 Mar;90(3):202-9. PubMed

Diabetes and insulin resistance

There is limited good evidence proving the effectiveness of milk thistle in the treatment of diabetes and related conditions [18]. A randomized placebo-controlled clinical trial found that silymarin treatment improves glycemic control in type II diabetes[23]. This effect that may be related to increased insulin sensitivity in peripheral tissues.

Milk thistle has beneficial clinical effects on diabetes caused by alcoholic liver cirrhosis. It may reduce insulin resistance, significantly decreasing endogenous insulin overproduction, and reduce insulin requirement[18].

Silybinin has potential benefits in treating non-insulin-dependent diabetes[20]. Recent 2014 animal experiment[19] demonstrated that silymarin effectively ameliorates fructose induced insulin resistance syndrome.

Milk thistle has protective effect on pancreas[21]. New study has shown that silymarin may promote regeneration of insulin-producing pancreatic cells (β cells)[22].

Also, milk thistle may prevent diabetic complications such as neuropathy and retinopathy.

  • 18. Velussi M, Cernigoi AM, De Monte A, Dapas F, Caffau C, Zilli M. Long-term (12 months) treatment with an anti-oxidant drug (silymarin) is effective on hyperinsulinemia, exogenous insulin need and malondialdehyde levels in cirrhotic diabetic patients. J Hepatol. 1997 Apr;26(4):871-9. PubMed
  • 19. Prakash P, Singh V, Jain M, Rana M, Khanna V, Barthwal MK, Dikshit M. Silymarin ameliorates fructose induced insulin resistance syndrome by reducing de novo hepatic lipogenesis in the rat. Eur J Pharmacol. 2014 Mar 15;727:15-28 PubMed
  • 20. von Schönfeld J, Weisbrod B, Müller MK. Silibinin, a plant extract with antioxidant and membrane stabilizing properties, protects exocrine pancreas from cyclosporin A toxicity. Cell Mol Life Sci. 1997 Dec;53(11-12):917-20. PubMed
  • 21. Soto C, Mena R, Luna J, Cerbón M, Larrieta E, Vital P, Uría E, Sánchez M, Recoba R, Barrón H, Favari L, Lara A. Silymarin induces recovery of pancreatic function after alloxan damage in rats. Life Sci. 2004 Sep 17;75(18):2167-80. PubMed
  • 22. Soto C, Raya L, Juárez J, Pérez J, González I. Effect of Silymarin in Pdx-1 expression and the proliferation of pancreatic β-cells in a pancreatectomy model. Phytomedicine. 2014 Feb 15;21(3):233-9. PuvMed
  • 23. Huseini HF, Larijani B, Heshmat R, Fakhrzadeh H, Radjabipour B, Toliat T, Raza M. The efficacy of Silybum marianum (L.) Gaertn. (silymarin) in the treatment of type II diabetes: a randomized, double-blind, placebo-controlled, clinical trial. Phytother Res. 2006 Dec;20(12):1036-9. PubMed

Kidney protection

Nephroprotective potential of silibinin is supported by many latest experimental studies[27], [28]. Preliminary research encourages that silymarin has significant protective effects against drug-induced renal damage[24].

The mechanisms of silymarin protection against drug-induced kidney toxicities are due to inhibition of lipid peroxidation and protection against glutathione depletion. Silymarin stimulates RNA polymerase I in kidney epithelium, leading to increased protein synthesis and cellular regeneration.

Animal research endorses silymarin as a potential treatment of diabetic nephropathy[25], [26]. High quality clinical study[29] has shown that silymarin (420 mg daily) may prevent the progression of diabetic nephropathy in patients with patients with type 2 diabetes.

  • 24. Dashti-Khavidaki S, Shahbazi F, Khalili H, Lessan-Pezeshki M. Potential renoprotective effects of silymarin against nephrotoxic drugs: a review of literature. J Pharm Pharm Sci. 2012;15(1):112-23. PubMed
  • 25. Vessal G, Akmali M, Najafi P, Moein MR, Sagheb MM. Silymarin and milk thistle extract may prevent the progression of diabetic nephropathy in streptozotocin-induced diabetic rats. Ren Fail. 2010 Jul;32(6):733-9. PubMed
  • 26. Soto C, Pérez J, García V, Uría E, Vadillo M, Raya L. Effect of silymarin on kidneys of rats suffering from alloxan-induced diabetes mellitus. Phytomedicine. 2010 Dec 1;17(14):1090-4 PubMed
  • 27. Prabu SM, Muthumani M. Silibinin ameliorates arsenic induced nephrotoxicity by abrogation of oxidative stress, inflammation and apoptosis in rats. Mol Biol Rep. 2012 Dec;39(12):11201-16. Pubmed
  • 28. Sonnenbichler J, Scalera F, Sonnenbichler I, Weyhenmeyer R. Stimulatory effects of silibinin and silicristin from the milk thistle Silybum marianum on kidney cells. J Pharmacol Exp Ther. 1999 Sep;290(3):1375-83. PubMed
  • 29. Fallahzadeh MK, Dormanesh B, Sagheb MM, Roozbeh J, Vessal G, Pakfetrat M, Daneshbod Y, Kamali-Sarvestani E, Lankarani KB. Effect of addition of silymarin to renin-angiotensin system inhibitors on proteinuria in type 2 diabetic patients with overt nephropathy: a randomized, double-blind, placebo-controlled trial. Am J Kidney Dis. 2012 Dec;60(6):896-903. PubMed

Hypolipidemic effect

Non-human research suggests silymarin supplementation may produce positive changes in blood cholesterol lipoprotein profile and in lipid content in liver[33].

Milk thistle shows promise in extenuating negative effects of a high-cholesterol or high-fat diet[32]. Animal studies have demonstrated that milk thistle extracts inhibit the oxidation of low-density lipoprotein (LDL)[30], lower low-density lipoprotein (LDL) levels associated with high-fat diets, increase high-density lipoprotein (HDL) cholesterol, and decrease liver cholesterol content[31]. It is supposed silymarin may inhibit cholesterol synthesis directly in the liver.

New 2014 high-quality human study[34] demonstrated that combination of red yeast rice, silybum marianum and octasonol decreases total cholesterol, low density lipoprotein cholesterol, triglycerides; and improves endothelial and inflammatory parameters in patients with abnormal amount of lipids in the blood.

  • 30. Wallace S, Vaughn K, Stewart BW, Viswanathan T, Clausen E, Nagarajan S, Carrier DJ. Milk thistle extracts inhibit the oxidation of low-density lipoprotein (LDL) and subsequent scavenger receptor-dependent monocyte adhesion. J Agric Food Chem. 2008 Jun 11 PubMed
  • 31. Krecman V, Skottová N, Walterová D, Ulrichová J, Simánek V. Silymarin inhibits the development of diet-induced hypercholesterolemia in rats. Planta Med. 1998 Mar;64(2):138-42. PubMed
  • 32. Skottová N, Vecera R, Urbánek K, Vána P, Walterová D, Cvak L. Effects of polyphenolic fraction of silymarin on lipoprotein profile in rats fed cholesterol-rich diets. Pharmacol Res. 2003 Jan;47(1):17-26. PubMed
  • 33. Sobolová L, Skottová N, Vecera R, Urbánek K. Effect of silymarin and its polyphenolic fraction on cholesterol absorption in rats. Pharmacol Res. 2006 Feb;53(2):104-12. PubMed
  • 34. Derosa G, Bonaventura A, Bianchi L, Romano D, D'Angelo A, Fogari E, Maffioli P. A randomized, placebo-controlled study on the effects of a nutraceutical combination of red yeast rice, silybum marianum and octasonol on lipid profile, endothelial and inflammatory parameters. J Biol Regul Homeost Agents. 2014 Apr-Jun;28(2):317-24. PubMed

Ulcerative colitis

One randomized placebo-controlled clinical study has shown that silymarin may be used in patients with ulcerative colitis to maintain remission.

  • 35. Rastegarpanah M, Malekzadeh R, Vahedi H, Mohammadi M, Elahi E, Chaharmahali M, Safarnavadeh T, Abdollahi M. A randomized, double blinded, placebo-controlled clinical trial of silymarin in ulcerative colitis. Chin J Integr Med. 2012 Apr 11. PubMed

Skin protection against UV radiation

There is growing encouraging experimental data that silymarin prevents photocarcinogenesis[37] and protects skin from UV radiation damage. Silymarin prevents UVB-induced immune suppression and oxidative stress.

In a high quality human clinical study (randomized placebo-controlled trial)[36] application of topical silymarin cream resulted in tremendous improvement of melasma (pigment improvement and lesion size reduction). Also, silymarin was found to be effective in prevention of skin damage caused by U.V. sunlight.

  • 36. Altaei T. The treatment of melasma by silymarin cream. BMC Dermatol. 2012 Oct 2;12:18. PubMed
  • 37. Svobodová A, Zdarilová A, Malisková J, Mikulková H, Walterová D, Vostalová J. Attenuation of UVA-induced damage to human keratinocytes by silymarin. J Dermatol Sci. 2007 Apr;46(1):21-30. PubMed

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Created: January 04, 2015
Last updated: January 26, 2015

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