I3C or DIM?
What's the right choice for increasing testosterone levels?

Increasing testosterone levels with certain kinds of vegetables works well, but not everyone wants to eat plate after plate of broccoli. So what if you want these anti-estrogenic benefits and you just want to take a little pill? There is good news. You can supplement your way to an effect here. But first you need to get clear on which supplement to take, indole-3-carbinol (I3C) or di-indolylmethane (DIM). This article outlines arguements for taking each, and explains why I ultimately recommend taking I3C.

As we covered in this article on increasing testosterone levels, crucifers work by indirectly increasing testosterone levels by training your liver to blunt the impacts of estrogen. The two major players involved are I3C, and it's direct metabolite, DIM. The breakdown between the two is simple: I3C is better studied and known to be safe, and DIM is thought to be more potent.

DIM: good for increasing testosterone levels, or unsafe?
First, let's talk about DIM. While DIM has been proven to be more potent than I3C in cell culture, the human data is considerably more sparse. The single published clinical trial showed behavior similar to I3C, that is a significant shift in the ratio of estrogen metabolites was observed (1).

What is interesting about the DIM clinical study is that only 108 mg/day was supplemented, as opposed to 500 mg/day in most I3C studies. On the downside, approximately 4 of 19 subjects showed side effects like rashes or hot flashes, and the study was only conducted for 30 days.

The other option: I3C
On the other hand, I3C has been studied in 13 published clinical trials (2). These trials have consistently shown that I3C favorably shifts the 2-OH-E/16-OH-E ratio. Additionally, one trial went on for over 6 years, adequately demonstrating that I3C supplementation is safe.

At the end of the analysis we are always left wondering about dose. Japanese diets are rich in crucifers and typically offer about 110 mg/day I3C, while Western diets are far lower. Compare that figure to supplementation trials which use 400-500 mg/day to see a substantial effect. The key question is always almost impossible to ask: how much broccoli do I need to eat to receive anti-estrogenic benefits? A satisfactory study of that question, unfortunately, has not been done.

Here's what I recommend.
First, eat more crucifers. Bok choy sauteed with a little olive oil and oyster sauce is fantastic. And broccoli can taste quite good with the right sauces, too. Second, if you are motivated to purge estrogen out of your system, especially if you are overweight, a period of supplementation with I3C can be very positive for increasing testosterone levels. However, I personally shy away from anything more than short term supplementation with high doses of dietary compounds. Like resveratrol it's just not possible to know what this will do over the long haul.

For a different approach, check out this supplement

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1. Dalessandri, KM, Firestone, GL, Fitch, MD, et al. "Pilot study: Effect of 3,3'-diindolylmethane supplements on urinary hormone metaboloites in post menopausal women with a history of early-stage breast cancer." Nutr Cancer 2004 50(2) 161-7.
2. Minich, DM, Bland, JS. "A review of the clinical efficacy and safety of cruciferous vegetable phytochemicals." Nutr Reviews 2007 65(6) 259-67.