It is known that aspirin can inhibit the activation of the enzyme aromatase, which is activates by things like stress and prostaglandins. However, studies showing direct effects of aspirin on estrogenic burden / load in humans are lacking. Speaking of estrogenic burden / load, as I mentioned in a few other threads estrone (E1) and estrone sulfate (E1S) are the proper blood biomarkers for systemic estrogenic load. Blood estradiol and estriol really do not mean much unless you can also measure tissue levels. So, I was quite happy to find that aspirin lowers estrogen levels and especially the dreaded E1S. E1 and E1S are the primary prognostic biomarkers for breast and prostate cancer progression and survival. So much for prostate cancer being caused by excess androgens...
The results quotes below are from a low dose aspirin (<100mg daily) so presumably higher doses will have even bigger effects.
Analgesic use and sex steroid hormone concentrations in postmenopausal women
https://www.sciencedaily.com/releases/2010/03/100323133043.htm
"...Frequency of all analgesic use was inversely associated with estradiol, free estradiol, estrone sulfate and the ratio of estradiol to testosterone. Average estradiol levels were 10.5 percent lower among women who regularly used aspirin or non-aspirin NSAIDs. Similarly, free estradiol levels were 10.6 percent lower and estrone sulfate levels were 11.1 percent lower among regular users of aspirin or other NSAIDs. Among regular users of any analgesic (aspirin, NSAIDs or acetaminophen), levels of these hormones were 15.2 percent, 12.9 percent and 12.6 percent lower, respectively, according to Gates."
The results quotes below are from a low dose aspirin (<100mg daily) so presumably higher doses will have even bigger effects.
Analgesic use and sex steroid hormone concentrations in postmenopausal women
https://www.sciencedaily.com/releases/2010/03/100323133043.htm
"...Frequency of all analgesic use was inversely associated with estradiol, free estradiol, estrone sulfate and the ratio of estradiol to testosterone. Average estradiol levels were 10.5 percent lower among women who regularly used aspirin or non-aspirin NSAIDs. Similarly, free estradiol levels were 10.6 percent lower and estrone sulfate levels were 11.1 percent lower among regular users of aspirin or other NSAIDs. Among regular users of any analgesic (aspirin, NSAIDs or acetaminophen), levels of these hormones were 15.2 percent, 12.9 percent and 12.6 percent lower, respectively, according to Gates."