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Ranking the best DIM supplements of 2021

Written by John Davis

Last updated: December 8, 2020

Diindolylmethane, or DIM for short, is a natural compound that’s found in copious quantities in cruciferous vegetables like broccoli, kale, Brussel sprouts, and bok choy.

It’s found heavily in superfood green drinks, too.

It’s widely reputed as a strong anti-cancer agent that can also be used to reduce inflammation and detox your body thanks to the biological activity of DIM.

If these benefits are what you are looking for, our research team has ranked the ten best DIM supplements on the market according to purity and efficacy. Rad on for our rankings.


1. Nutricost DIM

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Nutricost delivers a DIM supplement with a dosage of 300 mg per capsule. It’s also got 5 mg of BioPerine, a proprietary black pepper extract that’s included in many higher-quality supplements for its reputed ability to boost absorption and bioavailability.

The capsules are vegetarian-friendly, and though there are a couple of extra binders included, it’s still a solid pick for a DIM supplement.

2. Zhou DIM Active

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Zhou attempts to rectify one of the recurrent limitations with compounds isolated from healthy foods—when you take just one chemical out of a healthy food, you lose some of the synergy between the other compounds found in the food.

Zhou’s solution is to provide DIM (at a strong dose of 250 mg) alongside broccoli seed extract, vitamin C, and vitamin E.

The hope here is that the combined action of these ingredients will result in better outcomes than just consuming DIM by itself. This is sound reasoning, but clinical studies do tend to look at DIM in isolation, so whether you want to go with this supplement depends on your supplementation philosophy.

If you want DIM alongside the other nutrients in cruciferous vegetables, this supplement is definitely the way to go.

3. Smoky Mountains Nutrition DIM

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Smoky Mountains has a good dose of DIM with 200 mg of DIM plus 2.5 mg of BioPerine per capsule. BioPerine has been shown to increase the bioavailability of DIM for better absorption.

The capsules themselves are vegetable cellulose derived, which allows some pretty simple supplement design (the only other ingredient is organic rice concentrate), which make this supplement a go ahead for vegetarians.

4. aSquared Nutrition DIM

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aSquared Nutrition is a solid source of DIM if you are looking for a supplement that has a low dose and no additional ingredients.

It has 100 mg of DIM per capsule, and no unnecessary ingredients—just gelatin for the capsule and rice flour to fill out the rest of the space inside the capsule.

5. Source Naturals DIM

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Source Naturals DIM is a formulation specifically made to support breast health. Its DIM dosage is low, at 100 mg per capsule, but it also provides lecithin from soybeans to support estrogen function and BioPerine for superior bioavailability and vitamin E for added antioxidant power.

It’s a good choice for women looking to optimize breast health, but for all-around DIM versatility, it’s not the best.

6. DrFormulas DIM

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DrFormulas is a very popular DIM supplement that includes BioPerine for superior absorption and delivers 100 mg of DIM per capsule.

This dosage is lower than the most effective doses found in clinical trials, so you’ll likely be taking at least two capsules twice per day.

In addition, the supplement design isn’t very clean; there’s a lot of extra binders and excipients included that hurt the product’s purity.

7. Purest Vantage DIM

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Purest Vantage DIM is a supplement geared specifically for hormonal applications: while it includes BioPerine like many of its competitors, it also uses 600 IU of vitamin D (which is technically a hormone) and dong quai, a Chinese herbal extract with hormone-modulating properties.

This makes it possibly more useful for hormonal conditions, but less versatile than some of its competitors without these additional ingredients. At 250 mg per capsule, the DIM content is still solid.

8. Bulksupplements DIM

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While Bulksupplements is always a good choice for highly pure supplements, in the case of DIM, it’s only a good call for a very small subset of people.

Because DIM’s optimal dosage is so small, you’ll need a milligram-accurate scale to measure out the right dosage.

So, unless you are planning on making a special blend of DIM and other supplements, or you need to mix DIM into smoothies or shakes, you should probably opt for a capsule based DIM supplement. If you don’t fit into these categories, though, Bulksupplements is the way to go.

9. Nature’s Way DIM-plus Estrogen Metabolism

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Nature’s Way has a DIM formulation that is specially designed for processing estrogen. This makes it well-suited for women who use DIM for treating premenstrual syndrome, and possibly for other estrogen-related issues.

However, it does hamper its use for the wide range of other uses that DIM is known for. The actual DIM dosage is fairly low, though it is paired with a small amount of vegetable isolates from spinach, broccoli, and cabbage.

This pins Nature’s Way DIM-plus Estrogen Metabolism into a fairly niche use category, making it difficult to recommend for most people.

10. Nutrissence DIM

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Nutrissence DIM provides a modest dose of DIM (100 mg per capsule), which is nice if you know you want a lower dose. However, beyond the dose, it doesn’t really distinguish itself from the other competitors on the market, which means it ends up lower in the rankings. 

Category winners

Best DIM overall: Nutricost DIM

Nutricost DIM is high-potency and pure. It boasts an industry-leading 300 mg of DIM per capsule and 5 mg of BioPerine for maximum absorption. If you need a powerful, all-purpose DIM supplement, Nutricost is the way to go. 

Best DIM for men: Nutricost DIM

Maintaining high levels of DIM can help support your body’s free testosterone levels. Nutricost, with 300 mg of DIM per capsule, is perfectly suited for the task. 

Best DIM for women: Zhou Nutrition DIM Active

Zhou Nutrition DIM Active includes broccoli extract alongside a high dose of DIM to support estrogen metabolism and turnover, making it perfect for women. 

Best DIM for acne: Smoky Mountains Nutrition

Harnessing DIM’s anti-inflammatory and testosterone-modulating potential to reduce acne is an underutilized strategy for skin health. We recommend Smoky Mountains Nutrition DIM for this purpose, thanks to its moderate dosage and high purity. 

Best DIM for oxidative damage and inflammation: Zhou DIM Active

Zhou DIM Active pairs 250 mg of DIM with three synergistic antioxidants and anti-inflammatories: vitamin C, vitamin E, and broccoli seed extract. It’s your best option if you want to amplify DIM’s oxidation and inflammation-fighting capabilities.

Best DIM for bodybuilding: Nutricost DIM

Nutricost DIM’s high dose and superb purity makes it an easy add-on to any bodybuilding supplement stack. With a minimum of additional ingredients, you don’t have to worry about interactions with other supplements that you may be taking. 

Who should buy DIM?

DIM is a supplement that is has a small number of highly specific and targeted applications. First among these is as an experimental method for slowing the growth of potentially cancerous cells, or as a way to reduce the risk of cancer.

While the evidence thus far is limited to small pilot studies, or animal model and cellular studies, DIM has nevertheless shown promise as a way to target malignant cells and slow or stop their growth.

DIM may interact with estrogen, and since certain types of cancer have receptors for this hormone, DIM’s action on these might explain its efficacy.

Beyond potential anticancer effects, DIM has been investigated for activity against the HPV virus, with mixed success. It also exerts more general anti-inflammatory effects that might be useful for health conditions characterized by a lot of systemic inflammation, including digestive tract problems like irritable bowel syndrome, or IBS.

How we ranked

To formulate our DIM rankings, our primary two criteria were dosage and efficacy. DIM’s action inside the body is fairly well-understood, at least in terms of its short-term effects and bioavailability, so we had a very narrow range of DIM doses in mind.

Doses below 100 mg are not particularly effective, and doses above 300 mg are poorly researched and are more likely to cause side effects, so we restricted the DIM products under consideration only to those that provided at least 100 but no more than 300 mg of pure DIM.

On the efficacy front, we eliminated any products whose primary focus wasn’t DIM. We allowed products with additional potentially useful ingredients, such as vitamin D or aids to bioavailability such as BioPerine (a proprietary black pepper extract).

While supplements that had ingredients to boost bioavailability can be useful, we noted that some research indicates that these agents can work too well at high doses, triggering side effects when the dose of DIM is 300 mg or more. To that end, we dropped products that had a high dose of DIM alongside aids for absorption.

Thereafter, we looked at the supplement design and the presence of any potential ingredients to boost efficacy. We found hormone modulators, like vitamin D, to be helpful, while bunders or stabilizing agents meant that a particular DIM supplement scored lower in the final rankings.

With our rankings, which combine purity, efficacy, and clean supplement design, you can be sure you’re getting a high-quality product.


DIM has been intensely studied for its beneficial biochemical effects inside your body. Diindolylmethane is a metabolite of Indole-3-carbinol, a compound found in cruciferous vegetables including broccoli, red cabbage, cauliflower, collard greens, kale and kohlrabi.

In addition to having anticancer effects, it has been shown to have anti-inflammatory effects and the ability to increase bone mass in animal studies.

Researchers believe that DIM can induce cancer cell death by modulating the expression of Bax/Bcl-2 (regulator proteins that regulate cell death) 1.

Diindolylmethane exhibits anti-tumor activity in prostate cancer models. A 2011 study set out to examine whether DIM inhibits the development of prostate cancer using an adenocarcinoma mouse prostate model.

The conclusion of the study revealed positive findings. Feeding the rats DIM inhibited prostate carcinogenesis and induced a substantial reduction in the numbers of viable cells and induced apoptosis in prostate cancer cells.

Researchers concluded that DIM inhibits prostate carcinogenesis via induction of apoptosis and inhibition of cell cycle progression, and induces the death of prostate cancer cells via the mitochondria- and death receptor-mediated pathways (2).

Diindolylmethane could play a role in the prevention and treatment of breast cancer. A 2016 review published in Nutrition Reviews journal described current evidence related to the metabolism and mechanisms of this compound’s involvement in the prevention of breast cancer.

The following are some highlights.

DIM can be considered an anti-initiating breast tumor agent through its ability to stimulate cellular detoxification pathways. It is reported to modulate aryl hydrocarbon receptor (a cytosolic ligand-activated transcription factor that is involved in various signaling pathways critical to many aspects of physiology, such as cell proliferation and differentiation, gene regulation, cell motility and migration and inflammation) as evidenced in multiple breast cancer cell lines (3).

Evidence from mammary cell lines has demonstrated the role of DIM in reducing oxidative stress and demonstrating a role in reducing cyclooxygenase-2–induced inflammation in mammary cell lines.

In advanced stages of tumor development, DIM has been shown to inhibit the expression of genes involved in angiogenesis (the growth of new blood vessels that tumors need to grow) and energy metabolism.

DIM may reduce the invasive and metastatic potential of breast tumors. In combination with Taxotere, a concentration of 40μM DIM resulted in a 78 percent inhibition of growth and a decreased invasive capacity of the aggressive breast cancer cell line MDA-MB-231 (4).

Despite these extremely promising results, researchers stress that the number of intervention studies with DIM supplementation remains limited. Several trials evaluating the role of DIM in breast cancer prevention are currently under way.

Diindolylmethane is shown to inhibit the growth of endometrial cancer cells. Endometrial cancer is the most common form of cancer affecting the female reproductive organs (5). In a study published in Carcinogenesis, the effect of DIM on cell proliferation was examined using a human endometrial adenocarcinoma cell line.

Cells were treated with either a range of concentrations of DIM for 24 hours or with 10 μM DIM for up to 6 days.

Results indicated that after 24 hours of treatment, DIM suppressed growth cell growth by 20 and 40 percent with 10 and 30 μM concentrations, respectively. Researchers also noted that 10 μM DIM inhibited proliferation by 55 percent after four days and by 60 percent after six days of treatment.

In addition, treatments with DIM at concentrations of 50 μM or greater induced apoptosis (6).

Diindolylmethane is capable of increasing bone mass. A 2015 study evaluated the effect of DIM on bone mass in mice. Treating female mice with injections of DIM twice a week for four weeks resulted in a significant increase in bone mass.

Furthermore, administration of DIM in ovariectomized mice (ovariectomy induced bone loss in rats and postmenopausal bone loss in women share many similar characteristics) effectively prevented bone loss resulting from increased bone resorption (7,8).

Diindolylmethane has anti-inflammatory properties. Due to a correlation between chronic inflammation and the development of a variety of human cancers, researchers have been studying DIM’s anti-inflammatory effects.

In a 2008 issue of The Journal of Nutrition, researchers reported that DIM inhibits the inflammatory responses of murine macrophages. Macrophages are the main pro-inflammatory cells that respond to invading pathogens by releasing many pro-inflammatory molecules, including nitric oxide and prostaglandins.

In addition, downregulation of NF-κB and AP-1 signaling (mediators of inflammatory responses) contributes to the anti-inflammatory actions of DIM (10).

In another study, researchers concluded that DIM can inhibit inflammation of the periodontal tissue in mice after one week of treatment, which promoted alveolar bone recovery in the experimental periodontitis mouse model (9).

Periodontitis is a gum infection that damages the soft tissue and destroys the bone that supports teeth.

These results suggest that DIM may be a future adjuvant therapy for periodontal diseases.

DIM might be part of why cruciferous vegetables reduce the risk of cancer. The cruciferous vegetable family, which includes broccoli, cauliflower, kale, bok choy, cabbage, has been associated with a reduced risk of cancer in numerous epidemiological studies (11).

People whose diets are high in these vegetables appear to have lower rates of certain cancers, which has led researchers to search for biochemical reasons why these vegetables might help prevent regrowth of cancerous cells. DIM is one promising candidate, as it is contained in cruciferous vegetables at high levels, and further, researchers have identified potential biochemical pathways that DIM might manipulate to help slow or stop the growth of cancerous cells.

DIM interacts with estrogen, and many types of tumors are activated by this same hormone, so research papers have proposed a connection between DIM, estrogen, and cancer risk.

However, specific types of cancer that are known to be linked to estrogen, like breast cancer or ovarian cancer, have not been definitely linked to cruciferous vegetable intake or DIM intake, so more research needs to be done to confirm this link.

DIM may act against the HPV virus. The estrogen-related mechanism behind DIM’s potential benefit for fighting cancers has led to additional research that may support a use for DIM in treating the human papillomavirus, or HPV, a viral infection that can cause genital warts and cervical cancer (hence the DIM/estrogen connection).

A patent for this application was registered in 2008, and cites potential biological mechanisms by which DIM could assist with treating the HPV virus (12).

However, a clinical trial published in 2011 did not find a significant effect of a 150 mg supplement of DIM on HPV-related symptoms, and with the advent of an vaccine for HPV, it remains unclear whether DIM will be an important agent for treating HPV-related symptoms in the future (13).

Side effects

Some reported side effects include darkening of urine, increase in bowel frequency, headache and excess gas (14).

In one study, a healthy female patient who took an excessive daily intake of DIM for two months experienced central serous chorioretinopathy, a disease resulting in visual impairment. Symptoms resolved after discontinuing use.

Rash has also been reported and DIM may cause hormonal disturbances (15).

It is believed DIM interacts with cytochrome P450 substrates (enzymes essential for the metabolism of medications); DIM may affect the serum concentration of drugs metabolized by this enzyme.

DIM has also been shown to induce Multidrug Resistance Protein and can affect the transport of drugs mediated by this protein (16).

Other research into the safety of DIM has reported that headaches and vomiting can occur with DIM, but this study only noted them at high doses (300 mg taken all at once) (17).

Notably, these side effects only occured at the highest dose and also only occurred in a variant of DIM that had been specifically engineered for rapid absorption and bioavailability. Headache and nausea were not seen in the regular, garden-variety DIM.

Since this was a single-dose study, it’s unclear whether taking DIM on a daily basis would have improved tolerance to DIM, or would have exacerbated symptoms.

Recommended dosage

Several clinical trials have been conducted using DIM, and the aggregation of these trials gives some insights into the best way to take DIM for maximum efficacy.

The typical clinical trial uses between 150 and 300 mg of DIM, taken all at once. Other work by researchers at the University of Kansas Medical Center on the absorption bioavailability of DIM gives further insights into the range of doses that’s likely to be tolerable (18).

The minimum dose of DIM that’s likely to have any biological effect seems to be at least 100 mg, because at a dose of 50 mg, most people do not show any traces of DIM in their blood. As we saw above, if you are taking a formulation of DIM that’s engineered for maximum absorption, you want to be careful with doses above 200 mg, since 300 mg doses have been associated with side effects like headache and vomiting.

This same study also determined that it takes upwards of two hours for DIM to be fully absorbed into your body, and that a dose will remain at a high concentration in your blood for four to eight hours. These findings suggest either taking a 150 mg dosage once per day, or a 100 mg dosage in the morning and the evening, for maximum efficacy.

Closely spaced and small doses taken throughout the day, as you’d typically do with something like beta alanine, are not necessary with DIM.


Q: What is DIM?

A: DIM stands for diindolylmethane, which is a molecular compound found in vegetables from the cruciferous vegetable family.

It’s been heavily researched as a possible anticancer compound, and appears to exert estrogen blocking effects in some studies as well. DIM is sometimes used alongside hormonal supplements like vitamin D for potentially synergistic effects.

Q: What is DIM used for?

A: DIM is popular as a supplement that may target and slow or prevent the growth of certain cancerous cells, at least in preliminary research.

DIM has found some occasional use in the bodybuilding and athletic communities as well due to the belief that it acts as an estrogen blocker. Indeed, DIM has been found to block estrogen receptors in certain studies, which may reduce the effects of estrogen on your system, even though it may not lower your blood levels of estrogen per se.

Q: How long does DIM stay in your system?

A: DIM is excreted from your body fairly quickly. After you take DIM, it reaches a peak concentration in your blood within two hours or so; every four hours after that, your levels of DIM are cut in half.

That means that by 24 hours, your body’s level of DIM is effectively back to zero. This means that it’s important to either take DIM at the same time every day (e.g. right away in the morning) or split your dosage up into two doses, taken in the morning and in the evening.

Q: How long does it take for DIM to work?

A: DIM’s efficacy appears to be pretty rapid. Once you take a dose of it, your body has fully absorbed the compound within two hours or so.

Furthermore, some studies (albeit small pilot studies) have found that biological effects attributable to DIM start appearing within two weeks of starting to take DIM. However, other studies have been a month or more, so count on it taking at least a few weeks for DIM to start working.

Q: What foods are naturally high in DIM?

A: By far the best natural source for DIM is found in cruciferous vegetables. This family of greens includes Brussels sprouts, kale, broccoli, watercress, and collard greens, to name a few.

Unlike more common nutrients in fruits and vegetables, such as vitamin C, DIM is not really found in significant amounts in any other types of foods, excluding cruciferous vegetables, so make sure you fill up on these if you want more DIM in your diet.

Q: Is DIM an estrogen blocker?

A: Interestingly, DIM’s ability to act against estrogen is one of the potential avenues that it may use to fight cancerous cells. DIM may be useful as an estrogen blocker, but it has only been studied in small experiments, typically in cancer patients.

Nevertheless, biological evidence indicates that it may act on estrogen receptors, which could hypothetically limit the effects of estrogen on your body. While many people would like to see more studies

Q: Is DIM bad for your thyroid?

A: In the context of thyroid function, DIM has only been researched as a potential way to slow the growth of thyroid tumors.

DIM’s mechanism of action has been linked to hormonal functions in the thyroid, but its action in people who have mild hypothyroid, or hyperthyroid, is unknown. So, because of limited research, we can’t say if DIM is necessarily good or bad for your thyroid.

Q: Is a DIM supplement good for men?

A: The utility of DIM as a supplement for men revolves around its potential ability to act as an estrogen blocker. While DIM does not appear to directly reduce the level of estrogen in your body, it does appear to act on receptors for estrogen.

While the findings that support this come only from very small studies, mostly on cancer patients, the implication is that DIM could lower the effective level of estrogen experienced by your body (as the action of some amount of the actual estrogen in your body would be “blocked” by DIM).

It should be emphasized that this effect is largely theoretical, though this has not stopped it from being adopted widely by men looking to boost their testosterone levels.

Q: When should you take a DIM supplement?

A: Based on data on the rate at which DIM is absorbed and excreted from your body, the current scientific data bets support taking DIM once or twice per day.

The timing of exactly when you take DIM is less important than the consistency with which you take it. You should take the same dose of DIM at the same time every day for best results.

That way, you’ll maintain a decent level of DIM in your body at all times, even taking into account the delayed absorption and and relatively fast excretion of DIM from your body.

Studies have not yet compared whether it’s better to take one individual dose of DIM per day or split it into two, but we do know that taking less than 100 mg of DIM at a time is not recommended, as doses lower than this do not generate detectable levels of DIM in the bloodstream.

Related articles


DIM is a dietary compound found in several cruciferous vegetables that holds promise in preventing and treating certain cancers. This compound also plays a role in preventing bone loss and has anti-inflammatory properties.

Medical professionals have long stressed the link between eating a diet high in vegetables and the prevention of many types of cancers. Mounting evidence from clinical studies shows DIM’s strong positive impact on breast cancer, endometrial cancer, prostate cancer and other cancers.

Along another thread of potential applications, DIM looks like it may be a useful estrogen blocker. It does not directly lower the levels of estrogen in your body, but it might be able to block estrogen receptors in your body, which would reduce the effective level of estrogen that you are exposed to.

For BodyNutrition‘s #1 DIM recommendation, click here.


John Davis