What is DIM?
DIM, or diindolylmethane, is a compound that forms in the body from the breakdown of plant substances, most commonly cruciferous vegetables, including broccoli, cabbage, cauliflower, and Brussels sprouts. DIM has been reported to boost testosterone, help with prostate cancer, and help acne. Let’s take a look at the research to see if DIM can actually do these things.
Does DIM Boost Testosterone?
DIM may affect hormones in both men and women. One of the reasons why many men choose to take DIM supplements is to boost testosterone production for athletic and bodybuilding purposes. Does DIM boost testosterone production? Let’s find out.
What does the evidence show?
In one study, 38 male rats were split into four different groups. The control group received corn oil, while the other three received varying amounts of DIM for a study period of 53 days. Researchers monitored spermatological parameters as well as serum testosterone and estradiol levels.
In the study DIM at 10 mg/kg (a dose of 700 mg for the average 70 kg man) slightly lowered testosterone levels from 4.77 ng/mL in control subjects to 3.81 ng/mL. It also lowered estrogen levels from 8.00 pg/mL in controls to 4.56 pg/mL. That dose did not affect sperm growth or testicular tissue. DIM at 10mg/kg also lowered the number of androgen receptors expressed in testicular and prostate tissue.
This suggests that DIM may actually have estrogen and testosterone blocking affects at lower doses.2
Does DIM Help with Bodybuilding?
Do higher testosterone levels correlate with increased muscle growth? The anecdotal evidence says so as steroids are commonly used to increase muscle growth. Going with this reasoning men take DIM with the hopes of blocking estrogen or boosting testosterone. However, DIM appears to block both testosterone and estrogen. Furthermore, it also lowers the expression of androgen receptors in testicular and prostate tissue. This means that it lowers the number of testosterone receptors.
This means that DIM may actually make it harder to gain muscle mass. In one study, 49 resistance-trained young men were randomly placed into either a high repetition or low repetition group. The high repetition group performed exercised with low resistance but a larger number of repetitions until volitional failure, while the low repetition group performed exercises with a relatively heavy resistance with fewer repetitions until volitional failure. The study lasted 12 weeks, during which each volunteer performed a whole body resistance exercise training routine four days per week and received 30 grams of whey protein per day. Researchers took blood samples and performed hormonal analyses.
While both groups showed increased muscle mass, there were no significant hormonal differences between either repetition group for any outcomes. When looking at the men who had a hard time gaining muscle (high responders) and easy gainers (low responders), researchers found no significant differences in in intramuscular testosterone or DHT, though results did show significant changes in 5-alpha reductase expression in the high responder group.
More interestingly, the differences in intramuscular androgen receptor content were significantly greater in the high responder group than the low responder group, correlating with changes in overall muscle mass. This suggests that the increase in muscle mass in response to resistance training may depend less on testosterone levels and more on the number of androgen receptors in the muscles.3
The results from these two studies mean that DIM may actually lower testosterone levels and make it harder to build muscle.
DIM for Prostate Cancer
While DIM may not be helpful for building muscle mass, studies suggest that DIM may promote prostate health and prevent prostate cancer. Studies have found that plant-derived DIM may exhibit powerful anti-androgenic and anti-proliferative properties in human prostate cancer cells.
DIM was shown to suppress the proliferation of cancerous cells while inhibiting the stimulation of DHT, a hormone commonly associated with hair loss and benign prostatic hyperplasia (an enlarged prostate). Receptor binding assays also show that DIM is a powerful competitive inhibitor of DHT binding to androgen receptors. These results suggest that DIM may be a unique bifunctional hormone disruptor and one of the first known plant-derived androgen receptor antagonists.4 This may be why DIM was found to have anti-cancer effects of androgen-sensitive prostate cancer cells.
DIM for Acne
Androgen hormones play a role in the formation of acne. Androgen hormones signal to sebaceous glands in the skin to increase sebum production. This increased sebum production often leads to clogged pores.
Anti-androgenic medications like spironolactone are sometimes prescribed by doctors for hormonal acne. Since DIM has been shown to have anti-androgenic properties, it may be helpful for the improvement or treatment of acne. This is one of the reasons why it was included in DrFormulas® Dermatrope Acne Supplement.
Although DIM supplements may not boost testosterone or be helpful for bodybuilders, it may help to regulate hormonal imbalances and may benefit prostate health and improve acne.