I’m kinda laughing to myself as I write this post, because to most people who have never had hormonal issues or period problems, the acronyms I3C, DIM and SGS may as well be computer language or something!

But they’re not – they’re actually powerful compounds that can help support you on your quest for rockin’ hormones and amazing periods.

And, who doesn’t want that right?

In fact, if you have heavy or long periods, short menstrual cycles,  pesky physical and emotional PMS symptoms like mood swings, and irritability, OR symptoms of high androgens (male sex hormones – testosterone being the most well known), like acne and redness or splotchy skin, and even weight gain then you should definitely keep reading.

So, what exactly are DIM, SGS and I3C?

Indole 3 Carbinol or I3C for short, is a compound found in cruciferous vegetables like broccoli, broccoli sprouts, cabbage, brussels sprouts, kale and cauliflower. It breaks down into the metabolites Diindolylmethane (DIM) and Sulforaphane Glucosinolate (SGS).

I am alwayssss telling women to eat more cruciferous veggies, in particular broccoli sprouts? These compounds are a big part of the reason why 🙂

Which one should I use?

DIM is the most studied metabolite of I3C, and as such, its use has become very popular among women. SGS is less popular, but no less useful (I explain below).

There are a couple of issues I’ve found with I3C but I honestly think there needs to be some more research:

  1. Adequate stomach acid is required for proper breakdown of I3C into DIM, so if you have low stomach acid or are/have been on a stomach acid blocker medication, or you have Hashimoto’s, then you should supplement with DIM while you work to address your stomach acid issues. Please check out Dr. Izabella Wentz’s excellent article on low thyroid function and low stomach acid.
  2. While I3C has been shown to be an amazing chemo-protective agent, there is some evidence that it could also be a tumor promoter in some cases. I am cautious about it and still think further research is needed. (See studies in references below).
  3. There have also been reports of nausea, stomach upset, and dizziness in doses over 300mg daily, and taking it for longer than 3 months could be problematic.

So, you definitely want to do your research on IC3, talk to your functional or naturopathic doctor and decide what is best for you. 

On the flip side, there have been no serious side effects reported with DIM and SGS supplementation in mammals (but long-term studies are still needed).

In comparison to I3C, DIM actually reduces the activity of an enzyme called CYP1B1, which plays a role in estrogen metabolism – increasing the production of 4-hydroxyestrone – the “bad” estrogen metabolite I mentioned above. The CYP1B1 enzyme comes from the CYP1B1 gene (not confusing at all!), so depending on your genetic variations (or mutations haha), you’ll either be a good estrogen metabolizer or a not so good estrogen metabolizer. I know, I know, we can’t have it all!

How do these compounds impact women’s hormones?


  1. There are two phases of liver detoxification. DIM is useful for supporting phase 1 of the liver detoxification process, whereas SGS supports phase 2 of liver detoxification. In other words, DIM supports and thus improves the process of estrogen breakdown by the liver, and increases conversion of estrogen to more favorable metabolites. You just learned about the 4-hydroxyestrone, but estrogen also breaks down into other metabolites, some “good”, some “not good”. Like I said before, DIM will encourage estrogen to break down into the good metabolites rather than the bad ones.(1)
  2. DIM is an aromatase inhibitor, which means it prevents the conversion of testosterone into estrogen. So taking DIM has a two-fold effect on estrogen – it will reduce the overall effect of estrogen on a woman’s body by supporting estrogen detoxification AND reduce the conversion of testosterone to estrogen.
  3. Finally, DIM also blocks androgen receptors, which means it blocks the effects of testosterone or dihydrotestosterone (a more potent form of testosterone). Essentially, DIM helps improve and even eliminate acne by preventing potentially harmful androgens from getting into their receptors.

There is also evidence that DIM has a positive effect on breast and prostate cancers as well as cervical dysplasia. (2,3,4)


SGS is one of the most potent antioxidants and detoxifiers on the block. Broccoli sprouts in particular have been found to be robust phase II supporters, which is why SGS works so well in effectively supporting phase 2 of liver detoxification.

This phase tends to get backlogged when the levels of toxins that are being processed in phase 1 are too high for the second phase to keep up. This typically happens when a person is overexposed to alcohol, heavy metals, radiation, caffeine and pesticides.

This leads to a backlog where the byproducts of phase 1 remain in the system awaiting their turn for phase 2 detoxification. These byproducts are in a state that can cause significant harm to the body, so it’s crucial that phase 2 is working properly. That way, those harmful toxins can move seamlessly into phase 2 detoxification and they can be neutralized.

Why would I take DIM or SGS?

DIM and SGS are especially helpful for cases of estrogen dominance, which means estrogen has become dominant over its sister hormone progesterone.

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I recommend DIM and SGS for women who are showing symptoms of estrogen dominance, which often include heavy or long periods (longer than 7 days), short menstrual cycles (shorter than 25 days), and emotional PMS symptoms (e.g. major mood swings, irritability, severe fatigue, uncontrollable anger, and feelings of depression).

If you suspect you’re in an estrogen dominant state, then I suggest the Progesterone Test Kit and the Female Hormone Test Kit.

In addition, I also recommend DIM for symptoms of high androgens (male sex hormones – testosterone being the most well known), the most common being acne, redness or splotchy skin.

Brands and Dosage

I recommend starting with SGS (because most people have slower phase 2 liver detoxification than phase 1), and then moving onto DIM if you don’t have the desired results after 30 days of SGS supplementation.

Typical recommended dosage for SGS is 100 mg every other day for 30 days.

The brand I recommend for SGS is Thorne Research Crucera SGS.

Typical recommended dosage for DIM is 75-150 mg a day for 30 days. I always like to err on the side of caution and suggest starting with the lowest recommended dose.

DIM is not readily absorbed by the body in its pure state, which is why you have to look for supplements that contain a microencapsulated form of DIM in them, which is the more absorbable form of DIM. The brands below are the ones I recommend.

BioResponse DIM 75 or Designs for Health DIM-Evail

I also highly recommend a B complex supplement in conjunction, because the B vitamins are really critical for supporting the detoxification of estrogen, in addition to other very important functions in the body. Check out Designs for Health B Supreme.

I should also point out the obvious – you should be eating at least 2-3 servings of cruciferous veggies a week. And, you can also add broccoli sprouts to your meals as well.

Potential results of DIM or SGS use

With my clients, I have seen significant improvement in ALL of the symptoms I described above. Some women report seeing improvement after only a few doses, whereas others need to take it for 3-4 weeks before seeing noticeable change.

Side effects of DIM and SGS, or drug interactions

DIM and SGS are considered to be generally safe, with no serious side effects reported with use. Most of the studies show negative effects only in very high doses. Also, there is no real evidence on the long-term effects of these supplements which is why I only recommend it be taken for 30 days. Consult your healthcare practitioner before taking either of them for longer than 30 days.

I would say about 10% of my clients who have used DIM see a change in their menstrual cycle – some of them have developed shorter menstrual cycles, others developed longer periods, and a few got their period twice in one month. Not ideal, so I suggest stopping DIM if something like this happens.

I noticed that SGS gave me loose bowels. A few other clients reported this along with minor GI discomfort to me after about two weeks of use. I suggest taking the dosage every two days instead of every other day to see if this improves the GI issues that come up.

Thyroid health concerns

A lot of women ask if these supplements are safe to take if you have thyroid problems, because certain compounds in cruciferous veggies known as goitrogens can have a negative effect on thyroid function. DIM and SGS are other compounds found in cruciferous veggies. The supplements only contain DIM and SGS, and won’t contain any other compound found in these foods.

If you’re unsure about the health of your thyroid, this Thyroid Test will provide a complete picture of how your thyroid is performing.  Use code Hormones20 to get 20% off the test.

One should absolutely consult with their trusted healthcare provider about taking I3C, DIM and SGS if they are on any medications or other supplements, because there is always the risk of an interaction, especially with medications that are broken down by the liver. 


  1. DIM supplementation alters estrogen urinary metabolite profiles in women in favor of the healthier metabolites – https://www.ncbi.nlm.nih.gov/pubmed/15623462
  2. http://www.ncbi.nlm.nih.gov/pubmed/19062173
  3. https://www.ncbi.nlm.nih.gov/pubmed/26693258
  4. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC23369/

Studies on potential issues with I3C:

  1. https://www.ncbi.nlm.nih.gov/pubmed/2040485
  2. https://www.ncbi.nlm.nih.gov/pubmed/12419834
  3. https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/3-indolemethanol
  4. https://www.sciencedirect.com/science/article/pii/S0009279797001154?via%3Dihub
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5989150/
  6. https://www.ncbi.nlm.nih.gov/pubmed/15240508
  7. https://www.ncbi.nlm.nih.gov/pubmed/16211236