Life Extension Magazine®

Milk thistle flowers shown to support health liver function

Milk Thistle Reduces Elevated Glucose

Milk thistle, often taken for liver support, has been shown to reduce fasting blood glucose by 11% and insulin by 14%.

Scientifically reviewed by: Dr. Kathy Wilson, Ph.D., NHD, in August 2023. Written by: Cindy Rawson.

Sometimes, no matter how healthy we try to be, we lose our ability to control blood sugar.

This is reflected in the fact that estimates of diabetes prevalence in people over age 64 in the U.S. are:

50% higher than for those aged 45-64, and 6.3 times higher than those aged 18-44.1

Millions supplement with milk thistle today to support healthy liver function.

Recent studies show it also helps support healthy glucose balance and insulin sensitivity.

In one human study, milk thistle reduced fasting blood glucose by 11% and reduced insulin levels by 14%.2 (Excess insulin creates metabolic health issues.)

For years, Life Extension® has stressed the importance of keeping fasting blood glucose between 70-85 mg/dL to protect against the many complications of normal aging.

Milk thistle provides another tool to help manage high glucose levels.

Milk Thistle Lowers Blood Sugar

Botanical scientist working with milk thistle

A randomized controlled trial tested milk thistle on people with type II diabetes.

The study involved 40 diabetic adults, aged 25-50, who were on anti-diabetic medications. They were given either a pill containing 140 mg of silymarin (an extract of milk thistle), or a placebo, three times daily for 45 days.2

Compared with the placebo, milk thistle extract:2

  • Reduced fasting blood sugar by 11%,
  • Reduced blood insulin levels by 14%,
  • Reduced insulin resistance, when cells ignore insulin’s signal to remove sugar from the blood, by 26%,
  • Reduced triglyceride levels by 24%,
  • Raised HDL (“good”) cholesterol by 7%,
  • Reduced the triglyceride-to-HDL ratio by 28%, and
  • Increased insulin sensitivity, how well cells respond to insulin, by over 5.5%.

Two other randomized, placebo-controlled clinical trials have shown similar results, indicating that milk thistle extracts–including as part of a multi-herb combination–successfully lowered both fasting blood sugar and hemoglobin A1c, a test that measures average blood sugar levels over the previous three months.3,4

Increasing Milk Thistle Absorption

Spiky milk thistle flower

Silybin, the star component of milk thistle, does not dissolve well in water.5,6 That makes it difficult for it to reach tissues and cells in the body.7-10

Scientists have developed a simple but effective technology to overcome silybin’s poor bioavailability. The solution is to mix the silybin with a nutrient called phosphatidylcholine.

Phosphatidylcholine is a major component of cell membranes; it can facilitate transport across the cells lining the intestines, making it an ideal “carrier molecule” for silybin.7,11

The silybin-phosphatidylcholine complex is absorbed nearly five times better than silymarin alone, and its ultimate concentration in the liver, its target organ, is 10-fold greater than silymarin alone.8-10

In a study of rats exposed to various liver toxins (including dry-cleaning fluid, acetaminophen, and alcohol), silybin plus phosphatidylcholine protected against the telltale rise in plasma levels of liver enzymes (a marker of liver damage), while the same doses of either nutrient alone had no detectable effect.12

A series of human trials has found that this complex also has better results than silymarin or silybin alone, lowering serum levels of liver enzymes and producing clinical improvement in studies of liver cirrhosis and hepatitis caused by alcohol, drugs, and viruses.5


Home nurse taking glucose level from patient

For decades, readers of this magazine have been warned about the dangers of elevated glucose levels.

Diet, exercise, supplements, and medical intervention are all important means to achieve this.

Now scientists have revealed that an herb usually thought of for liver complaints is a valuable tool against diabetes and metabolic problems.

Studies in diabetics have shown that milk thistle drives glucose levels down, corrects lipid disturbances, and reduces hemoglobin A1C levels, a marker of blood sugar exposure over the medium term.

If you have any questions on the scientific content of this article, please call a Life Extension® Wellness Specialist at 1-866-864-3027.

What you need to know

Support Healthy Glucose with Milk Thistle

  • Age is a major risk factor for diabetes, even when we take steps to control our diet and get ample exercise.
  • Science reveals that milk thistle, an herb usually used for liver complaints, offers support in metabolic problems.
  • Studies on diabetics show improved blood glucose and insulin levels with daily milk thistle use.
  • Preclinical and clinical evidence showed that a silybin-phosphatidylcholine complex resulted in almost five-fold greater concentrations of silybin in the bloodstream than silymarin alone.
  • Along with diet, exercise, supplements, and medications, milk thistle is another tool to keep blood sugar and insulin resistance under control.


  1. Available at: Accessed January 21, 2020.
  2. Ebrahimpour-Koujan S, Gargari BP, Mobasseri M, et al. Lower glycemic indices and lipid profile among type 2 diabetes mellitus patients who received novel dose of Silybum marianum (L.) Gaertn. (silymarin) extract supplement: A Triple-blinded randomized controlled clinical trial. Phytomedicine. 2018 May 15;44: 39-44.
  3. Huseini HF, Larijani B, Heshmat R, et al. 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.
  4. Khalili N, Fereydoonzadeh R, Mohtashami R, et al. Silymarin, Olibanum, and Nettle, A Mixed Herbal Formulation in the Treatment of Type II Diabetes: A Randomized, Double-Blind, Placebo-Controlled, Clinical Trial. J Evid Based Complementary Altern Med. 2017 Oct;22(4):603-8.
  5. Kidd P, Head K. A review of the bioavailability and clinical efficacy of milk thistle phytosome: a silybin-phosphatidylcholine complex (Siliphos). Altern Med Rev. 2005 Sep;10(3):193-203.
  6. Dixit N, Baboota S, Kohli K, et al. Silymarin: A review of pharmacological aspects and bioavailability enhancement approaches. Indian J Pharmacol. 2007;39(4):172-79.
  7. Kidd PM. Bioavailability and activity of phytosome complexes from botanical polyphenols: the silymarin, curcumin, green tea, and grape seed extracts. Altern Med Rev. 2009 Sep;14(3):226-46.
  8. Barzaghi N, Crema F, Gatti G, et al. Pharmacokinetic studies on IdB 1016, a silybin- phosphatidylcholine complex, in healthy human subjects. Eur J Drug Metab Pharmacokinet. 1990 Oct-Dec;15(4):333-8.
  9. Morazzoni P, Montalbetti A, Malandrino S, et al. Comparative pharmacokinetics of silipide and silymarin in rats. Eur J Drug Metab Pharmacokinet. 1993 Jul-Sep;18(3):289-97.
  10. Morazzoni P, Magistretti MJ, Giachetti C, et al. Comparative bioavailability of Silipide, a new flavanolignan complex, in rats. Eur J Drug Metab Pharmacokinet. 1992 Jan-Mar;17(1):39-44.
  11. Available at: Accessed January 20, 2020.
  12. Conti M, Malandrino S, Magistretti MJ. Protective activity of silipide on liver damage in rodents. Jpn J Pharmacol. 1992 Dec;60(4):315-21.