How Did Estrogen Alone Lower Breast Cancer Risk?

On Huberman Lab, estrogen plus synthetic progesterone reached one breast cancer case in a thousand and just hit statistical significance at a p-value of 0.05. Estrogen alone, given versus placebo to women without a uterus, went the opposite direction: a 24 percent risk reduction of about one in a thousand, with a p-value of 0.06 or 0.07. On Huberman Lab, the pattern suggests synthetic progesterone was playing more of a role than anything else.

Two findings in the combined arm were negative: a small increase in the risk of heart disease and a small increase in the risk of breast cancer. The breast cancer increase just reached a p-value of 0.05, one in a thousand cases. In women without a uterus, estrogen alone did not reach statistical significance. The p-value was 0.06 or 0.07, and the result was a 24 percent risk reduction, about one in a thousand.

Oral estrogen, no longer used, does increase coagulability and the ability of the blood to clot a little bit. Topical estrogen and patches of estrogen do not show the clotting rise. With estradiol, the risk of heart disease goes down.