Mike thistle is a herbal supplement that is alleged to support liver function. Although there have been several studies that demonstrate its effectiveness in the laboratory and on animals, there has not been much research done with humans. As a result, there are no official guidelines for a recommended daily dosage of milk thistle.
About Milk Thistle
Milk thistle is a dietary supplement made from the seeds of the milk thistle plant 1. Its active ingredient is silymarin, which is said to have antioxidant and anti-inflammatory properties. Milk thistle is generally available to the public in capsule form, although some herbalists make milk thistle tea. Silymarin is not water soluble, so teas aren't an effective way to benefit from milk thistle. There have been studies in Europe that have shown silymarin to be an effective antidote for death cap mushroom poisoning. Silymarin is administered intravenously in these cases.
Understand the Silymarin Content
Because the FDA doesn't regulate herbal supplements like milk thistle, capsules can contain varying amounts of silymarin. Look for products made by reputable manufacturers of vitamins and supplements, who list the standardized silymarin extract on the package. This way you can understand the dosage you're taking. A 250 mg capsule of milk thistle that is standardized to contain 40% silymarin will deliver half the dosage of silymarin than one that is standardized to contain 80%, for example.
Milk Thistle Dosage
Because there are no official guidelines on milk thistle dosage, each supplement manufacturer is free to place its own recommendations on package labels. Suggested dosages range between 70 mg twice a day to 420 mg of silymarin three times a day. The PDR for Herbal Medicines recommends taking a milk thistle supplement of 200 to 400 mg three times a day. This would provide 140 to 360 mg of silymarin in each dose, if the supplement was standardized to 70% to 80%. Most tests of silymarin have been done using a dosage of 140 mg three times per day.
Milk Thistle Cautions
Certain individuals should not take milk thistle 1. Milk thistle should be avoided by women who are pregnant, have hormone sensitive cancers or suffer from conditions such as uterine fibroids or endometriosis. Milk thistle can also intensify the effect of drugs that lower blood sugar, so consult your doctor about what dosage of milk thistle to take if you are being treated with hypoglycemic medications.
Milk thistle can occasionally have a laxative effect, or produce other gastrointestinal symptoms such as stomach upset. If you experience these symptoms, reduce the amount of milk thistle that you are taking.