DIM: good aromatase inhibitor or male toxin?

DIM is more likely to castrate you than help with estrogen.

DIM is meant to help lower excess estrogen, but it has a dark side.

Let’s dive in.

Hans here! I increased my testosterone to 1254ng/dl and have been maintaining high T naturally. I’ve turned myself into an Alpha Energy Male.

An Alpha Energy Male with high energy, fast recovery, high sex drive, and confidence.

This is why I research obsessively, experiment and write, and have been doing so for the past decade.

Hope you enjoy and join me on this journey.

Why do we want to be an alpha energy male?

Being an alpha energy male is synonymous with possessing both high testosterone levels and abundant energy. Consequently, the question arises: what exactly is the significance of having elevated testosterone and energy levels?

Because high T and energy make us feel incredible and powerups our motivation, drive, confidence, and sexual function.

A life without high T and energy isn’t a life worth living.

Quick background on DIM

Cruciferous vegetables contain glucobracissin, which is converted to I3C and ultimately acid-catalyzed to an I3C dimer (better known as DIM).

On average, 100 g of cruciferous vegetables contains up to 30 mg of glucobrassicin, which is estimated to convert to approximately 2 mg of DIM. However, the variation in DIM content between different cruciferous vegetables is considerable, with differences ranging from 5- to 8-fold (R).

Eating 500g of cruciferous vegetables a day is enough to have a hormonal effect.

Aromatase inhibitor

DIM is mostly used to modulate estrogen levels in the body as an aromatase inhibitor and estrogen detoxification agent.

The aromatase inhibitory effects of DIM have only been confirmed by in vitro study (R).

The only other humans study I could find was in women with breast cancer. At 300mg daily for 12 months it actually increased estradiol (from 97 to 111pg/ml) (R).

There aren’t any studies in men investigating DIM on estradiol levels, but a few reviews on Reddit said that it didn’t lower their estrogen.

Estrogen metabolism

So far 16 metabolites of estrogen have been discovered, all of which have different affinities to estrogen receptors.

The two I’m going to focus on are 2-hydroxyestrone (2-OHE1) and 16α-hydroxyestrone (16-OHE1).

2-OHE1 has weak estrogenic effects (some even say it’s an estrogen antagonist) whereas 16-OHE1 has potent estrogenic effects. The 2-OHE1 to 16-OHE ratio drops with cancer. Meaning 2-OHE drops and 16-OHE increases, which puts someone in a stronger estrogen environment, potentially making them estrogen dominant.

This ratio is similar to the 5 alpha and 5 beta reductase ratio

A similar example would be 5 alpha and 5 beta reductase. 5 beta-reductase creates very weak to neutral androgen metabolites, whereas 5 alpha reductase creates our strongest androgen; DHT.

A 1:1 ratio of 5 alpha to 5 beta will create a mildly androgenic environment, but a 2 to 1 or 10 to 1 ratio will put you in a much great androgenic environment.

Similarly, a high 16/2-OHE ratio will be a lot more estrogenic.

2/16-OHE1 ratio in women

The average 2/16-OHE1 ratio is ∼2.27 for normal women and ratios <2.0 are observed to have an increased risk of developing estrogen-sensitive cancers.

DIM has been shown to significantly alter this ratio in women.

For example, 300mg DIM for 12 months increased the ratio from 1.6 to 5 (R).

Other examples include:

  • 150 mg of DIM increased the ratio by 76% (R)
  • 100mg DIM for 30 days increased the ratio by 16-229% (R)
  • 108 mg nonsignificant increased the ratio by 47% (from 1.46 to 2.14) (R)

2/16-OHE1 ratio in men

There are two studies that I could find on this.

In men with prostate cancer, 400mg DIM didn’t affect testosterone, but did increase the 2/16-OHE1 ratio from 1.28 to 1.69 in 15 days (R). Not really wow. It would seem that the effect is more potent in women.

Furthermore, 500g of daily broccoli intake for 12 days increased the ratio by 29.5% on average in two females and 14 males (R). Not too bad.

DIM on androgen and estrogen receptors

DIM can act on the estrogen and androgen receptors (as an agonist or antagonist) as well as modulate their expression.

DIM on estrogen receptors

One study found that DIM strongly inhibits estrogen receptor-α (ERα) expression and estrogen signaling (R). Whereas another found that DIM activated it. The effect is likely dose-dependent and it’s difficult to say what that dose would be in humans due to individual absorption and tissue accumulation differences.

DIM does not bind to ERβ but selectively recruits ERβ and coactivators to target genes (R).

Androgen receptors

In this in vitro study, DIM is a strong androgen receptor antagonist in the prostate. It’s classified as the first example of a pure androgen receptor antagonist from plants (R).

In this rat study, DIM decreased androgen receptors in the prostate but increased it in the testes (R).

DIM on testosterone

DIM in male rats had all kinds of effects on testosterone and estradiol (R).

None of the groups saw an increase in testosterone, but the 10mg/kg group did see a decrease in estrogen, but the testosterone to estrogen ratio remained more or less the same (R).

The 50mg/kg and 100mg/kg groups saw massive increases in estrogen and awful testosterone to estrogen ratio.

In terms of dose conversion to humans:

  • 10mg/kg was equivalent to 1.62mg/kg for the human dose.
  • 50mg/kg -> 8.11mg/kg
  • 100mg/kg -> 16.22mg/kg

In humans, in the short term (15 days), it didn’t affect testosterone and it barely affected the 2/16-OHE ratio.

Therefore I don’t think this is a very useful supplement for men at all, but might be useful for women.


Some people say the ideal dose is 100mg, but that’s just useless. It’s definitely not going to act like an aromatase inhibitor at that dose and might barely affect your 2/16-OHE ratio. At best it might slightly help with estrogenic symptoms without altering total estradiol levels, and at worse, will have anti-androgenic effects.

As you can see, I’m not a fan of this ingredient as it’s close to useless for men.


Instead, you can alter/improve the ratio with:

  • Thyroid optimization (R)
  • Fruit intake (R)
  • Exercise (R)
  • Aryl hydrocarbon receptor agonists (it upregulates CYP1A1, which produces 2-hydroxyestrone) namely quercetin and β-napthoflavone (R).
  • Broccoli intake

Some broccoli humor for the day

😂😂😂 Anyway, back to business.

On the flip side, the ratio might not be as important as the total amount of estrogen you have in your body. This study found that calcium from dietary sources is associated with a shift in estrogen metabolism toward the active 16 alpha-hydroxyl metabolic pathway (R). Women with a family history of osteoporosis had significantly higher ratios of 2-hydroxyestrone/16α-hydroxyestrone (R).

And one of the best ways to lower excess estrogen is to eat enough zinc (meat, organ meat and oysters).

👉The complete guide on how to inhibit aromatase

Additional articles that’ll help you become an Andro-naut

>1000ng/dl Testosterone: My Step-by-Step Guide on How I Do It Naturally!

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