DIM is a molecule derived from cruciferous vegetables like broccoli, cauliflower,
brussels sprouts, cabbage, kale, etc., that moderates the effects of estrogen in
both females and males. (Yes, estrogen plays important roles in male health too!)In general, DIM helps you get more of the effects you want from estrogen, such as maintenance of skin, energy, mood, and memory, and less of those you don't, like increased fat storage....or for females PMS, menopausal symptoms, and hot flashes. It does this by increasing the amount of favourable estrogen metabolites you produce, and simultaneously decreasing production of estrogen's less favourable metabolites.   
Related article: What Is The Connection Between Female Hormones And Belly Fat?
What does this mean? A metabolite is produced when your body acts on and modifies a molecule or substance. For example, estrogen in the body can be modified by the addition of a molecule of one oxygen and one hydrogen, -OH, called a hydroxyl group. Where this group is tacked-on to the estrogen makes an immense difference in how it acts in the body. The specific spot the -OH is added to estrogen can mean the difference between the estrogen being reactive, proliferative, unhappy, and inflammatory...or being calm, anti-proliferative, friendly, and anti-inflammatory. 
One of the challenges in understanding why the metabolites are important is because of what we assume about estrogen. We have always been taught that what's important is the outright levels of estrogen that our bodies produce, rather than the personalities our estrogens take on after they are metabolized. In reality our estrogen metabolism can be just as, or even more important than our overall estrogen levels in determining whether we have too much estrogenic influence relative to our other sex-hormones...a condition known as "estrogen dominance".
Prevent estrogen dominance with DIM.
DIM can definitely help prevent or reverse estrogen dominance, and support hormone balance by encouraging production of "friendly" estrogen metabolites with a much gentler, less pronounced estrogenic effect, (termed 2-OH-estrogens). At the same time, DIM reduces production of the much more potent, proliferative, and inflammatory estrogens, i.e. 16-OH estrogens, and 4-OH estrogens. The reactive 16-OH estrogen metabolites, (i.e. the "undesirable" ones), can exert up to 10x the level of estrogenic influence as the "friendly" 2-OH metabolites.  And the 4-OH variety of metabolite can be really nasty. It can cause what are called DNA adducts that bind to your genes, raise inflammation, and can cause offramp, uncontrolled mutations and divisions in cells.
Now what would you rather have? A gentle, balanced, "smiling" estrogen which is protective against excessive cell replication, (for example cancer, or endometriosis, or fibroids), or a reactive, jumpy, crabby estrogen, which can turn downright malicious? Not much of a choice is it?
DIM is produced when a substance called I3C or indole-3-carbinol from cruciferous vegetables hits your stomach acid and "dimerizes"...meaning two molecules of I3C react to form one molecule of DIM. So you might ask, "Well then, shouldn't I just take the I3C supplement?" And the answer is No! Because when you take isolated I3C there are additional side reactions that occur which result in increased levels of the undesirable estrogen metabolites, whereas DIM both increases the "good" ones, and decreases the "bad".   
Any female going through the inflammatory events involved in painful menstrual cramps will tell you that any anti-inflammatory help is welcome. This is why the "go to" in these situations is NSAIDs like Naproxen, which reduce inflammation by blocking production of a substance called prostaglandin E2, or PgE2. Hot flashes are another event that are made worse by higher levels of inflammation, and in both of these situations unfriendly estrogen metabolites can dramatically worsen the situation. Since one of DIM's charcteristics is that it is anti-inflammatory, and it also helps produce less inflammatory estrogen metabolites, it can be helpful in preventing, or reversing these problems, as the huge number of women who have had relief from dysmennorhea and menopausal symptoms like hot flashes with DIM will attest to. (Though, like anything it is not 100%, in our experience at Optimum Health the proportion of women who get these kinds of relief is very high.)
DIM also provides anti-inflammatory properties by activating an enzyme called AMPK which plays a huge roll in energy regulation. AMPK increases insulin sensitivity, thereby reducing the amount of the inflammatory storage hormone insulin that is produced by the body, and hence decreasing the tendency to store energy as fat. If you have heard claims about DIM decreasing tummy fat this is why!
Also, consider that in the past 50 years our bodies are have been exposed to chemicals that they have never seen before, and many of these are similar enough to estrogen that they bind the estrogen receptors, and add to our overall estrogen loads, wreaking havoc on our hormonal balance, and adding to the inflammatory metabolites that are produced. Collectively these chemicals are called "xenoestrogens", (i.e. foreign estrogens,). Chemicals emitted from plastics such as pthalates and phenols like Bisphenol A, or such as those from herbicides and pesticides for example, have a xenoestrogenic effect in the body, and can be carcinogenic. The anti-inflammatory estrogen metabolites produced by DIM help counteract these effects.
For reducing excess estrogenic influence DIM combines particularly well with herbs like Vitex and Maca. Adding Dong Quai for those who are still menstruating, or Black Cohosh for those going through menopause can also be most helpful. These are the herbs found in Opti Female Balance and Opti Meno Balance respectively.
But DIM's benefits are definitely not limited to women. As men age, the levels of the basic "upstream" sex-hormone precursor DHEA declines, and with it testosterone production drops. At the same time, the activity of the enzyme that converts testosterone into estrogen, called "aromatase", also increases. The effect of both situations is to increase estrogen influence. And if a man is producing a lot of potent, reactive 16-OH metabolites, its going to make matters worse. DIM can help lessen these effects.
Excessive alcohol consumption can also increase estrogens, and this can be particularly consequential in a male. Once again, if this is an issue DIM may be helpful at ameliorating the side-effects.
So think about it. Estrogen is a mitogenic hormone, i.e. it is proliferative, and makes cells divide. The 16-OH metabolites are far more estrogenic, proliferative, and inflammatory in nature than the 2-OH metabolites. This may be good in a tissue like bone to maintain bone-mass, but not so great in reproductive tissues like ovaries or cervix, or breast, or prostate. Would this give you an inkling that DIM could be helpful in preventing the proliferation of prostate cells in BPH, or preventing and arresting cancer, particularly in such reproductive tissues as those just mentioned? Yes, and this is what the large preponderance of research on DIM, and its precursor I-3-C, shows.  In fact there is so much research on DIM and cancer (prevention, apoptosis, and cell cycle arrest), that I am not sure what surprises me more....that we haven't heard more about it, or that the Government hasn't restricted it?!
You may wonder why DIM is often combined with Calcium D-Glucarate?
Well, adding to our estrogen load are old estrogens that we do not eliminate effectively, and get recycled in our body. This process starts in the liver in Phase I detoxification, where DIM helps get the old estrogens ready to be packaged up and shipped out in phase II. And it is glucarate that is the preferred molecule (i.e. conjugate) to join estrogen to for shipping it out. So adding D-glucarate to DIM also helps relieve our estrogen burden, and indeed also has good evidence that this can help reduce cancer incidence, particularly breast cancers. (Recycling of old estrogens is also much more likely in a dysbiotic gut, so for hormonal balance, don' forget the importance of probiotics.)
Women suffering from endometriosis may also be interested to know that both DIM and D-glucarate are supplements suggested by The University of Maryland Medical Center as being something which may help.
It is also important to mentiom that in order for estrogens to be completely metabolized, after the -OH group is added they must go through a process of methylation. So if you are not getting the results you are looking for from DIM, this is another avenue to explore. (For this purpose definitely my favourite product is Methyl Protect by Xymogen.)
Lastly, remember that even though some detoxification and metabolizing of hormones and toxins goes on around the body, the vast majority of the responsibility for processing and metabolizing both toxins and hormones still falls on the liver. If your liver function is poor, hormonal imbalances and the associated symptoms are one of the outcomes. Many have had improvements in their hormonal health just from cleaning up their liver with supplements like Opti-Liv or Opti-Liv Extra.
If you would like to purchase our brand of DIM, you can online here, or by calling us toll-free in North America at 1-844-259-8590.
Till next time,
Sources and References
1. Brignall, MS: Prevention and Treatment of Cancer with Indole-3-Carbinol; Alternative Medicine Review; Vol 6 No. 6; 2001; page 583.
2. Applied Biochemistry and Nutrition of Endocrinology: The Eighth International Symposium on Functional Medicine; Pre-Conference Course; The Institute For Functional Medicine , Inc., 2001.
3. Functional Medicine Approaches to Endocrine Disturbances of Aging: The Eighth International Symposium on Functional Medicine, Vancouver, B.C., 2001
4. Lukaczer, D : Estrogen's Two-Way Street; Nutrition Science News, vol 6, no 11, Nov 2001, pp 398, 399, 402. see: Frank. M. Painter, D.C.
5. H. Leon Bradlow: Indole-3-carbinol as a Chemoprotective Agent in Breat and Prostate Cancer. In Vivo; July-August 2008; vol 22 no 4; p.441-445. see
6. Ahmad A, Biersack B, LI Y, Kong D, Bao B, Schobert R, Padhye SB, Sarkar FH: Targeteted Regulation of PI3K/Akt/mTOR/NF-kB Signaling by Indole Compoundsand their Derivatives: Mechanistic Details and Biological Implications for Cancer Therapy; Anticancer Agents Med Chem. 2013 Sep; 13(7): 1002-1013.
Disclaimer: The above information is provided for informational purposes only and is not intended to replace the advice of your physician.