Women's hormones
DIM supplements, and what to check first The broccoli compound sold for hormonal acne, bloating and heavy periods
Reviewed by a qualified clinician · analysed at UKAS-accredited UK labs (ISO 15189)
Last reviewed September 20265 min read
Every Helvy guide is written by our health editors, then checked by a qualified clinician before it goes live and re-checked as the science moves. We name clinical roles, not individuals, until each reviewer has agreed to be credited publicly. This is wellness guidance to help you understand your own data, not a diagnosis.
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DIM is a compound from broccoli and cabbage, sold in capsules for “oestrogen dominance”. It shifts how your body processes oestrogen. Human evidence is thin, and it can interfere with the pill and with HRT. The symptoms people buy it for often track androgens instead, which SHBG, testosterone and the free androgen index can show.
Find the test that reads these markers →As of September 2026. Interest picked up after a July 2025 study in Menopause found that women taking DIM alongside an oestradiol patch had different oestrogen breakdown products in their urine. UK search results have not caught up with it yet.
Your jawline breaks out the week before your period. You feel puffy. Your periods are heavier than they used to be. Somewhere on Reddit, someone told you the word for it is oestrogen dominance, and the answer is DIM.
1. What is DIM, and what does it actually do?
It comes from vegetables, and it changes how oestrogen is broken down.
DIM is short for diindolylmethane. Memorial Sloan Kettering describes it as “a compound found in cruciferous vegetables including broccoli, cabbage, and cauliflower”. Your gut makes it when you digest those vegetables. Capsules deliver far more of it than a plate of broccoli ever would.
Oestrogen does not simply leave the body. Your liver takes it apart into smaller pieces first, and DIM nudges which pieces you end up with. That is the whole basis of the marketing. It is a real effect, and it is narrower than the claims made for it.
The 2025 study is the largest look at this in people. It compared 108 postmenopausal women taking DIM with an oestradiol patch against 1,350 women on the patch alone. Six of ten oestrogen breakdown products differed. The authors were careful about what that means.
“Further research is needed to assess whether these changes are clinically significant.”
Menopause, July 2025
Read that carefully. A measurable change in a lab test is not the same as a change you would feel. It was also a look back at existing records rather than a trial, so it cannot prove cause. On acne, bloating and period changes specifically, there is no good human trial of DIM at all.
2. What is worth checking before you start?
The symptoms sold as an oestrogen problem are often an androgen one.
Androgens are a group of hormones that includes testosterone. Women make them normally, in small amounts. Jawline acne, oily skin, unwanted hair and irregular cycles sit much closer to that group than to oestrogen. And unlike “dominance”, these are numbers you can actually read.
- SHBG. SHBG is the protein that carries sex hormones around and keeps them inactive. When it falls, more testosterone is free to act on your skin.
- Total testosterone. On its own it says little. Read next to SHBG, it tells you how much is available.
- Free androgen index. This is testosterone and SHBG combined into one figure. It is the number that usually moves when skin and cycles change.
- FSH and LH. The two signals your brain sends to the ovaries. They shift as the ovaries wind down.
- Ferritin. Ferritin is the protein that holds iron in reserve, so it shows how much iron you have banked. Heavy periods drain it.
That last one matters more than people expect. The NHS says of heavy periods that “you may have a series of blood tests to check if you have any underlying conditions, such as iron deficiency anaemia”. Low iron is treatable, and no capsule of broccoli extract will touch it.
Helvy's Hormone Balance panel (£99) carries FSH, LH, SHBG, total testosterone and the free androgen index. Ferritin sits on the Vitamins & Minerals panel (£159), alongside iron, B12 and vitamin D. Both are home finger-prick kits.
3. Who should not take DIM?
This is the part the supplement pages tend to skip.
Memorial Sloan Kettering's monograph lists people who should not take it: “You are pregnant, planning to get pregnant, nursing or use birth control pills: DIM may have hormone modulation effects.” It also flags two whole classes of medicine. DIM is handled by the same liver enzymes that process many drugs, so it “may make them less effective”.
The same page records case reports in people taking DIM. They include a blurred-vision condition in a woman taking high daily doses for two months, which settled eight weeks after she stopped. A stroke in a 38-year-old woman and a clot in a 65-year-old man are also logged. Case reports do not prove the supplement caused any of it. They are still worth knowing before you order.
If you take the pill, HRT, a blood thinner, or any regular prescription, the safe order is to ask a pharmacist first. That conversation is free, and it takes five minutes.
4. What can a blood test not tell you here?
Being straight about the limits saves you money.
It cannot measure “oestrogen dominance”. No lab reports that, because it is a wellness term rather than a UK diagnosis. Our oestrogen dominance guide goes through where the phrase came from.
Oestradiol is not part of any Helvy panel. Oestradiol is the main form of oestrogen. Neither it nor progesterone is included in what we sell, so if you want oestrogen tracked directly, that is a conversation with your GP.
It cannot name the cause of your acne. A blood test measures biomarkers and offers wellness insight. It does not diagnose anything. A qualified clinician reads your results next to your history.
A urine oestrogen panel is a different thing. The 2025 study measured breakdown products in urine, not hormones in blood. Those tests are sold privately and are not standard NHS practice. Do not assume a blood panel will show you the same picture. For a wider view of what routine bloods cover, our full blood count guide is the place to start.
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Frequently asked questions
What does DIM do to oestrogen?
It changes the mix of products your liver makes when it breaks oestrogen down. A 2025 study in Menopause found six of ten urinary oestrogen breakdown products differed in women taking DIM alongside a patch. The authors said more research is needed to know whether that matters clinically.
Can I take DIM with the pill or HRT?
Ask a pharmacist or your GP first. Memorial Sloan Kettering lists birth control pills under who should not take DIM, because it may have hormone modulation effects. The 2025 study looked at women using an oestradiol patch and found their oestrogen profile shifted.
Which blood tests should I get before trying DIM?
SHBG, total testosterone and the free androgen index cover the androgen side, which is where jawline acne and cycle changes usually sit. FSH and LH show where your ovaries are. Ferritin is worth adding if your periods are heavy.
Is oestrogen dominance a real diagnosis in the UK?
No. It is a popular wellness term, not a condition a UK clinician diagnoses or a lab reports. The symptoms behind it are real, and they are usually better explained by other markers.
Can I just eat more broccoli instead?
Your gut makes DIM when you digest cruciferous vegetables, so you already get some. Capsule doses are far higher than food delivers. Eating the vegetables is sensible either way, and it carries none of the interaction warnings.