HRT USERS: Some men on HRT may find that they only need to control estradiol with a supplement or medication for six to twelve months, because often the body's testosterone and estrogen levels are stabilizing. You may be able to get away with lowering estradiol for six months while your a) estradiol levels stabilize or b) you lose weight.
2. Zinc. Although the studies have been somewhat mixed, many experts feel that zinc supplementation will likely raise testosterone in zinc deficient men. And zinc deficiency is probably not too unusual. As you can see in My Page on Sleep Aids, a combination of zinc, magnesium and melatonin greatly improves insomnia and some users on the forum have reported that just simple ZMA greatly helps with sleep. (Anything that helps with sleep will likely give a little boost to testosterone.)
Zinc is also known for its ability to limit the activity of aromatase. I don't think anyone has any doubt that it works to a certain extent and probably most powerfully if you are zinc deficient. However, I don't know of any studies that actually show zinc being used to clinically lower male estrogen/estradiol levels. (If you know of one, please post it on The Forum!) Furthermore, I do not read of the steroid guys reporting zinc as a silver bullet in this area.
I suspect the reason is that, to get a significant E2-lowering effect, one would have to consume a lot of zinc and this is probably risky based on the opinion of many experts. I cover this issue in my link on Zinc and ZMA, where I discuss how taking megadoses of zinc is a) likely hard on neurons and b) could lead to copper depletion.
So the bottom line is that taking a reasonable dosage (1-3 RDA's) of supplemental zinc, especially vegetarians and plant-based eaters, is not a bad idea. You may get a little bump downward in estradiol levels and many other benefits from taking zinc. However, but don't expect it to solve elevated estradiol levels.
3. Chrysin. This is an old and well-known aromatase inhibitor. It has a spotty reputation for a number of reasons, including poor absorbtion. However, a few years ago, Life Extension release a turbo-charged version that basically included piperine. Piperine increases the absorption rates of many herbals and supplements and it seems to work well with chrysin. For example, two of the anti-aging physicians, Drs. Smith and Whitcomb, that have answered the Peak Testosterone Questionnaires have mentioned (unprompted) chrysin as a regularly-used estrogen controller. And the fact that Life Extension, which is a well-respected supplement company, backs it is also a sign of its efficacy.
Are there concerns with chrysin? One side effect that has been reported is the slowing down of thyroid function. Obviously, you don't want to solve your estradiol problems just to create a new thyroid issue. See my link on Controlling Estrogen for a study that shows this as well.
4. Grape Seed Extract. Many studies have shown Grape Seed Extact to be an aromatase inhibitor [3]. It also, in vitro at least, gives Vitamin C a longer shelf life. However, Grape Seed Extract has a couple of cautions that need to go along with it: 1) in combination with Vitamin C it apparently raises blood pressure [2] and 2) it may slightly decrease free testosterone because it can raise SHBG, the protein that binds to testosterone. It also is known for improving venous insufficiency. That said, Grape Seed Extract has many properties that will very likely help with erectile dysfunction and perhaps serve as a cheap subsitute for Pynogenol. For more information, read about it on my page covering Grape Seed Extract and Erectile Dysfunction.
However, there is one problem in using Grape Seed Extract as an aromatase inhibitor: you would simply have to take too much. For this reason, I have read of very few men actually using it for this purpose.