Chances are, you hated broccoli as a kid, but your mother implored you to eat it anyway. “Eat your broccoli!” is a common trope – it’s in memes, advertisements, and cartoons. It has even become slang for going through a hard time or “paying your dues.” However, as research repeatedly shows, eating broccoli is a good thing, which is why mom wanted you to do it. 

Broccoli is a good source of many vitamins and minerals, antioxidants, fiber, and even protein. A single serving (1 cup) of cooked, chopped broccoli provides one-fifth of your fiber needs for the day. One-half cup of cooked broccoli provides more vitamin C than half an orange. There is a wide variety of antioxidants in broccoli, including flavonoids (kaempferol) studied for inflammatory response, carotenoids (lutein and zeaxanthin) studied for eye health, and glucosinolates (metabolized to sulforaphane, diindolylmethane/DIM, and indole-3-carbinol/I3C) studied for liver detoxification and body-wide free radical neutralizing effects.*

This article will focus on the science and health benefits of those last two, indole 3 carbinol vs. DIM. 

First a little biochemistry

The glucosinolates found in broccoli and other cruciferous vegetables, like Brussels sprouts and cabbage, go through a series of reactions in your stomach when eaten. There is an enzyme called myrosinase that is stored in plant cells away from the glucosinolates. But once veggies are chopped or chewed, the myrosinase is released so it can react with the glucosinolates, and that’s when the magic happens. 

One type of glucosinolate, glucoraphanin (also referred to as sulforaphane glucosinolate, or SGS, for short), is converted to sulforaphane, an indirect antioxidant that stays active in the body for up to 72 hours and is contained in Thorne’s Broccoli Seed Extract and MediClear-SGS.* 

Another type, glucobrassicin, is changed by myrosinase into I3C. When I3C reaches your stomach, the acidic environment there causes many of the I3C molecules to combine in pairs, becoming 3,3’-diindolylmethane (DIM).


Indole-3-carbinol (I3C)1


3,3’-diindolylmethane (DIM)2


What are glucosinolates?

Fruits and vegetables are filled with many different types of compounds that are collectively labeled antioxidants. Some of these, such as carotenoids (yellow, orange, and red pigments) add to the color of plants. 

Others might play a role in the smell – think sulfur-containing molecules. These chemical compounds help protect cells against oxidative stress and play important roles in different detoxification processes managed by your liver. Cruciferous vegetables from the Brassica family contain an important category of these compounds, known as glucosinolates, which have long-lasting antioxidant properties. Two frequently talked about compounds metabolized from glucosinolates are I3C and DIM.

Let’s take a closer look at indole-3-carbinol vs. DIM.

What is I3C?

I3C is a compound that is created when glucobrassicin, a glucosinolate, is broken down. When you chop or chew raw broccoli (or other cruciferous veggies), the glucobrassicin is exposed to the enzyme myrosinase. Myrosinase triggers a reaction called hydrolysis, and through several spontaneous steps of conversion, I3C is formed. Cooking deactivates myrosinase; however, certain bacteria that make up the microbiome in your colon have myrosinase activity and are able to convert glucobrassicin from cooked veggies. 

What is DIM?

When you eat raw cruciferous vegetables, the I3C that was created by chewing/chopping reaches the stomach and interacts with your stomach acid. The I3C molecules start to join up in pairs, creating a new molecule – DIM – which is absorbed from the GI tract and used in the liver to support estrogen metabolism.

I3C vs DIM: Are they basically the same?

Now you might be wondering about DIM vs. indole-3-carbinol: Are they really just the same thing? They do come from the same source, and the majority of I3C is converted to DIM – so much so that DIM can be detectable in your blood shortly after taking I3C.3 

However, DIM and I3C are different molecules with different (albeit similar) chemical structures. And research even discovered that after four weeks of daily supplementation of I3C, only DIM – not I3C – was found in the blood of the study volunteers.3

One of the main differences between I3C and DIM lies in the stability of the molecules. I3C is relatively unstable – meaning it quickly converts to DIM and other substances after it’s in your stomach. DIM, on the other hand, is quite stable. Whether converted from I3C or taken as a supplement, DIM progresses beyond your stomach as the active molecule in your body.

Why choose DIM over I3C?

In terms of a dietary supplement, the benefits for I3C and DIM are similar, most likely because of the high rate at which I3C converts to DIM. 

You might also be wondering, can you take DIM and I3C together. These days DIM tends to be the preferred supplemental form because of the relative instability of I3C and its conversion to other molecules whose biological actions are not well studied.4 When you supplement with DIM, you are going straight to the active molecule without waiting for your body to first complete all of the conversion steps. And because of the increased efficiency of supplementing with DIM, it is unnecessary to take both DIM and I3C.

What are the benefits of DIM?

There are several reasons to supplement with DIM. After it moves through your stomach, DIM is absorbed in the digestive tract and carried to the liver where it is used in certain phase 1 liver detoxification processes. Through phase 1 detoxification, DIM supports hormone metabolism processes, including improving the ratio of healthy-to-less-healthy estrogens.* 

Because of its estrogen-balancing properties, DIM supports breast, cervical, and uterine health. It also balances hormone levels related to breast tenderness, mood changes, and other symptoms that occur before menses.*

In addition, DIM benefits include promoting the clearance of estrogen-mimicking toxins encountered in daily life – like those toxins found in pesticides, herbicides, and plastics. DIM also supports healthy testosterone levels by improving the estrogen-to-testosterone ratio.* 

Because of these hormone-balancing effects, both men and women can benefit from DIM supplementation. You can find all of the benefits of DIM, along with the antioxidant effects of SGS and pomegranate, in Thorne’s Hormone Advantage.

When should I take DIM – morning or night?

When it comes to the question of when to take DIM, morning or night, there are no specific guidelines for the best time of day to take DIM. It is best practice to consult your health-care practitioner about individualized supplement use.

Thorne’s Hormone Advantage provides 150 mg of DIM per serving. The recommended use of Hormone Advantage is to take one capsule one to two times daily, or as recommended by your health-care practitioner.

References

  1. PubChem. Indole-3-carbinol. https://pubchem.ncbi.nlm.nih.gov/compound/3712 [Accessed August 28, 2025.]
  2. PubChem. 3,3’-Diindolylmethane. https://pubchem.ncbi.nlm.nih.gov/compound/3071 [Accessed August 28, 2025].
  3. Reed G, Arneson D, Putnam W, et al. Single-dose and multiple-dose administration of indole-3-carbinol to women: pharmacokinetics based on 3,3’-diindolylmethane. Cancer Epidemiol Biomarkers Prev 2006;15(12):2477-2481. 
  4. Diindolylmethane (DIM) Information Resource Center - UC Berkeley - Formation. https://www.diindolylmethane-dim.com/formation.htm#.X39kbJpKhPZ [Accessed August 28, 2025]