DIM, Calcium-D-Glucarate and Zinc: What 'Estrogen Blocker' Supplements Contain

Estrogen blocker supplements usually contain DIM, calcium D-glucarate and sometimes zinc, but none of these ingredients has been shown to block oestrogen in healthy men. DIM changes how oestrogen is broken down in small studies, calcium D-glucarate has not been tested in human trials, and zinc only seems to matter if you are low in it. Here is what each ingredient does, what the evidence says, and when to see your GP instead.

What estrogen blocker supplements contain at a glance

Prices are in AUD at the time of writing. "Estrogen blocker" is a shop category name, not a description of what these products have been shown to do.

Oestrogen in men: why it is not the enemy

Men naturally make some oestrogen, and it is a normal part of male hormone balance. Problems tend to come from an imbalance between oestrogen and testosterone. The best-known sign is gynaecomastia, when male breast tissue grows larger than usual.

According to healthdirect, that imbalance has many possible causes, including some medicines, some dietary supplements, obesity, drinking too much alcohol, liver disease and an overactive thyroid. In about one in four people no cause is found. That is why breast swelling, pain or a lump in a man should always be checked by a GP, not managed with a supplement.

DIM (diindolylmethane)

DIM forms in your stomach from indole-3-carbinol, a compound in cruciferous vegetables such as broccoli, cabbage and cauliflower. Supplements give a much larger amount than you would get from food. The Memorial Sloan Kettering integrative medicine summary notes:

• small studies, mainly in women, found DIM changed the mix of oestrogen breakdown products in urine
• there are no good human studies showing that DIM lowers oestrogen or raises testosterone in healthy men
• there are case reports of side effects, including a vision problem after a high daily intake and a skin reaction, and DIM may make some medicines less effective

Most DIM products we stock contain 100 to 300 mg per capsule, and some add black pepper extract to help absorption. Eating cruciferous vegetables regularly is the food-first way to get the same compounds.

Calcium D-glucarate

Calcium D-glucarate is the supplement form of glucaric acid, which is naturally found in apples, oranges, broccoli and spinach. The theory is that it slows an enzyme called beta-glucuronidase, so the body clears oestrogen faster instead of recycling it. The catch, according to Memorial Sloan Kettering, is that no clinical trials have tested whether it has these effects in people. Most of the support comes from lab and animal studies.

Zinc

Zinc is the one ingredient with a clear role in male hormones, but only when you are short of it. In a small 1996 study, older men who were marginally low in zinc had higher testosterone after six months of zinc. In a 2009 study of 14 young men who already ate enough zinc, a high-zinc supplement (ZMA) did not change their testosterone at all.

Australian nutrient reference values recommend 14 mg of zinc a day for men and 8 mg for women, with an upper limit of 40 mg a day from food and supplements combined. Meat, seafood, dairy, legumes and wholegrains supply most of it. If you take a zinc supplement, keep the dose modest and do not stack it with another zinc product such as a ZMA. Our zinc supplements guide covers forms and doses in more detail.

Safety: when to talk to your GP

• Breast changes: swelling, pain, a lump or nipple discharge in a man needs a GP check, not a supplement.
• Medicines: DIM may reduce how well some medicines work, so talk to your GP or pharmacist first if you take regular medication.
• Pregnancy: DIM is not suitable for women who are pregnant, planning a pregnancy or breastfeeding, and women on the pill should check with a health professional first.
• Zinc dose: stay under the 40 mg a day upper limit from all sources.
• Low testosterone symptoms: these overlap with many other health problems, so a GP check and blood test is the right first step.

This fits the wider research. Healthy Male reviewed testosterone-boosting supplements, including ones with DIM and zinc, and concluded they are likely to be unhelpful.

Estrogen blocker products in this guide

If you still want to try one, choose a simple product with a clear dose and follow the label. Cost per serve is worked out from the bottle size and serve size on each label.

• Primabolics DIM: 100 mg of DIM per capsule, one capsule a serve, 60 capsules, Australian made. $39.95, about $0.67 a serve.
• EVLution Nutrition DIM 200: 200 mg of DIM plus 2.5 mg of BioPerine black pepper extract per capsule, 60 serves. $34.95, about $0.58 a serve.
• Primabolics Calcium D-Glucarate: 500 mg per capsule, one capsule a serve, 60 capsules. $69.95, about $1.17 a serve.
• Switch Nutrition DIM+: combines DIM and calcium D-glucarate in one capsule, 60 capsules, $59.95. Check the label for the amount of each.
• Swanson Zinc Picolinate 22 mg: 22 mg of zinc per capsule, one a day with food, 60 capsules. $24.95, about $0.42 a day. Useful mainly if your diet is low in zinc.

If you combine products, check the zinc content of anything you add.

Our verdict

Estrogen blocker supplements have not been shown to block oestrogen. DIM has small studies showing changes in how oestrogen is broken down, calcium D-glucarate has no human trials, and zinc only seems to matter if you are low in it. If you want to try one, Primabolics DIM is a simple, low-cost single ingredient, and Swanson Zinc Picolinate 22 mg is a sensible zinc dose if your diet falls short. If you have breast changes, low libido or other signs of a hormone problem, see your GP first. For the bigger picture, read do testosterone boosters work? and our supplements guide.

How our price compares

Here is what the same products cost at other Australian supplement stores, so you can check the difference yourself.

Supps247 prices come from our website. Other prices were checked on the websites of Nutrition Warehouse, Australian Sports Nutrition (ASN), Elite Supps and Supplement Mart on 29 October 2026 (same product and size, price for one unit) and can change at any time. Not listed means we could not find that exact product on their site. Supps247 members can use our Price Match Guarantee against Nutrition Warehouse, ASN, Elite Supps and Supplement Mart: we beat their full price by 5% or match their sale price (conditions apply).

Shop the products in this guide

Primabolics DIM 60 capsules$39.95EVLution Nutrition DIM 200$34.95Primabolics Calcium D-Glucarate$69.95Switch Nutrition DIM+$59.95Swanson Zinc Picolinate 22 mg$24.95

Browse all Primabolics and EVLution Nutrition products.

FAQs

Do estrogen blocker supplements actually work?

There is no good evidence that they lower oestrogen in healthy men. DIM changed how oestrogen is broken down in small studies, mostly in women. Calcium D-glucarate has not been tested in human trials. Zinc only seems to affect testosterone in men who are low in zinc. Healthy Male, the Australian men's health organisation, concluded that testosterone-boosting supplements are likely to be unhelpful. See your GP if you suspect a hormone problem.

What does DIM do for men?

DIM is a compound made from indole-3-carbinol in broccoli, cabbage and cauliflower. It may change the way the body breaks down oestrogen, but the human studies are small and mostly in women. There are no good studies showing it lowers oestrogen or raises testosterone in healthy men. It may also make some medicines less effective, so talk to your GP or pharmacist first if you take regular medication.

Can you take DIM and calcium D-glucarate together?

Yes, they are often sold together, for example in Switch Nutrition DIM+. They work on different steps of oestrogen metabolism in theory. In practice, neither has strong human evidence for changing hormone levels in men, and calcium D-glucarate has not been tested in human trials. If you combine products, check the total dose of each ingredient and follow the labels. Talk to your GP if you take regular medication.

How much zinc should a man take?

Australian nutrient reference values recommend 14 mg of zinc a day for men from all sources, with an upper limit of 40 mg a day. Most men can get this from meat, seafood, dairy, legumes and wholegrains. A supplement is mainly useful if your diet is low in zinc. Keep supplements modest, avoid stacking zinc products such as ZMA with a separate zinc tablet, and ask your GP if you think you are low.

What causes high oestrogen in men?

According to healthdirect, an imbalance between oestrogen and testosterone can be caused by some medicines, some dietary supplements, obesity, drinking too much alcohol, liver disease, an overactive thyroid, genetic conditions and, rarely, tumours. In about one in four cases no cause is found. Signs such as breast swelling or tenderness should be checked by a GP, who may order blood tests to find the cause.

Sources: Memorial Sloan Kettering Cancer Center: Diindolylmethane (DIM); Memorial Sloan Kettering Cancer Center: Calcium glucarate; NHMRC nutrient reference values: zinc; Koehler et al. 2009, zinc supplement and testosterone, European Journal of Clinical Nutrition; Healthy Male: Do testosterone boosting supplements work?; healthdirect: Gynaecomastia; product labels and brand nutrition panels, checked October 2026.

Order online with Australia-wide delivery, free on orders of $99.99 or more, with Afterpay available at checkout. You can also use click and collect at a store that offers it, or visit a Supps247 store in Melbourne, regional Victoria or Brisbane to compare products in person. Members can use our member price match on full-priced items.

Prices and stock were checked on 29 October 2026 and can change at any time. Always read the label and follow the directions for use. If you have a medical condition, are pregnant or take regular medication, check with your doctor first.