Formulation:

Soy isoflavones can be taken as pills or as powdered supplements, but they are also found naturally in soy products like tofu that can be added into the diet to increase their intake.

Range of dosages studied:

Dosages range widely in studies, from about 25 milligrams to 300 milligrams per day of isolated soy isoflavones. ^[1][2]

Effective Dosages:

High cholesterol

General: 25 milligrams per day of soy protein could lower LDL cholesterol. It remains unclear whether the isoflavones contribute to this effect.^[3][4]

Cardiovascular health

Postmenopausal women: In women with impaired endothelial function, a dosage of 50 to 100 milligrams per day could improve coronary blood flow.^[3][5][6]

Bone health

Postmenopausal women: In perimenopausal and postmenopausal women, a dosage of 50 to 100 milligrams per day may have a small clinical effect on bone density.^[2]

Other considerations:

These dosages are based on limited evidence, and more clinical trials are needed to find the ideal doses and timing and to assess whether any benefit is clinically meaningful.

It’s also worth noting that some studies quantify the intake of soy isoflavones based on the intake of soy products in the diet; for example, food diaries that mention eating 200 grams of tofu twice per week. Since these studies do not directly measure soy isoflavone intake, the dosages they mention are not always accurate.