Calcium D-glucarate is the calcium salt of D-glucaric acid, a sugar acid that the human body makes in small amounts and that also occurs in fruits and vegetables. It is sold as a dietary supplement. In bodybuilding circles it is often described as a way to “clear estrogen,” and it is sometimes taken alongside anabolic steroids for that reason.
The single most important fact is that the evidence is almost entirely from animals. In rats, calcium D-glucarate lowers the activity of an enzyme called beta-glucuronidase and slows chemically induced tumors. We could not find a single published controlled trial of calcium D-glucarate on its own in people. No study has shown that it lowers estradiol in men or women.
This page summarizes what the animal studies, the few human data and regulators report. It is for education only and is not medical advice.
| Property | Detail |
|---|---|
| Type | Dietary supplement; calcium salt of D-glucaric acid |
| Other name | Calcium saccharate (saccharic acid is a synonym for glucaric acid) |
| Formula | C₆H₈CaO₈, 248.2 g/mol (anhydrous; PubChem) |
| Route | Oral |
| Proposed mechanism | Forms D-glucaro-1,4-lactone, an inhibitor of the enzyme beta-glucuronidase |
| Human dose studied | No trial of calcium D-glucarate alone; one 28-day trial used 150 mg/day inside a six-ingredient mixture |
| Half-life | Not established in humans; animal data only |
| Effect on estrogen in people | Not demonstrated |
| US status | Sold as a dietary supplement; not an FDA-approved drug |
| WADA status | Not named on the 2026 Prohibited List |
What it is
D-glucaric acid is a six-carbon sugar acid with a carboxylic acid group at each end (PubChem). Calcium D-glucarate is its calcium salt. PubChem files it under the name calcium saccharate (PubChem).
In mammals, D-glucaric acid and D-glucaro-1,4-lactone are end products of the glucuronic acid pathway (Zółtaszek et al., Postepy Hig Med Dosw 2008). Glucaric acid exists in equilibrium with ring-shaped forms (lactones). One of them, D-glucaro-1,4-lactone, is a potent natural inhibitor of beta-glucuronidase (Dwivedi et al., Biochem Med Metab Biol 1990).
Small amounts of glucaric acid are present in ordinary food. In one analysis, content ranged from 1.12–1.73 mg per 100 g in broccoli and potatoes to 4.53 mg per 100 g in oranges (Dwivedi et al., 1990).
Most of the research on calcium D-glucarate as a supplement came from one group of investigators (Walaszek, Hanausek, Webb and colleagues) at Ohio State University and the University of Texas M.D. Anderson Cancer Center in the 1980s and 1990s. They studied it as a possible cancer-prevention agent, not as an estrogen blocker for athletes (Walaszek, Cancer Lett 1990).
How it is supposed to work
The liver attaches glucuronic acid to many fat-soluble substances so they can be excreted in bile. This step is called glucuronidation. Steroid hormones, chemical carcinogens and other fat-soluble compounds are handled this way (Altern Med Rev 2002).
Beta-glucuronidase, found in blood and most tissues and also made by gut bacteria, can cut that glucuronic acid off again (Zółtaszek et al., 2008). The freed substance can then be reabsorbed from the gut, a loop called enterohepatic circulation. Gut bacteria that make beta-glucuronidase help regulate circulating estrogen by reactivating conjugated estrogens this way (Baker et al., Maturitas 2017).
The theory behind calcium D-glucarate is simple:
- it releases D-glucaric acid and D-glucaro-1,4-lactone in the gut;
- the lactone inhibits beta-glucuronidase;
- more of the conjugated estrogens and toxins stay conjugated and leave the body in stool.
The theory is plausible, but each step has been shown mainly in rodents.
It is not an aromatase inhibitor. Calcium D-glucarate does not block the conversion of testosterone to estradiol, and it does not block the estrogen receptor. Drugs that do this, such as anastrozole and exemestane, have been measured in human trials. Calcium D-glucarate has not.
How it behaves in the body
There are no published pharmacokinetic studies of calcium D-glucarate in humans. What is known comes from rats.
A 2002 supplement monograph summarized the proposed sequence (Altern Med Rev 2002):
- stomach acid converts the salt to D-glucaric acid;
- in the gut it forms an equilibrium of roughly 40% D-glucaric acid, 30% D-glucaro-1,4-lactone and 30% D-glucaro-6,3-lactone;
- these are absorbed, carried to organs and excreted in urine and, to a lesser extent, bile.
A radiolabeled study in rats confirmed that the lactone forms in the stomach, is absorbed and is excreted mainly in urine. Male and female rats handled it the same way (Walaszek et al., Cancer Detect Prev 1997).
| Finding in rats | Result | Source |
|---|---|---|
| Blood glucarate after one oral dose | Peak within 1 h at 0.4 µmol/mL (endogenous level ≈ 0.04 µmol/mL), fell to 0.1 at 3 h, then rose again to 0.75 µmol/mL at 24 h | Webb et al., 1994 |
| Tissue concentration | 3–4 times higher in liver and intestinal lining than in serum | Webb et al., 1994 |
| Beta-glucuronidase after one large dose (4.5 mmol/kg) | Inhibited 57% in serum, 44% liver, 37% lung, 39% intestine | Dwivedi et al., 1990 |
| Gut bacterial beta-glucuronidase on a 4% diet | Inhibited 70% (small intestine) and 54% (colon) | Dwivedi et al., 1990 |
| Duration of enzyme inhibition | About 5 h with calcium D-glucarate vs about 1 h with the pure lactone | Altern Med Rev 2002 |
The rat doses were large. A single 4.5 mmol/kg dose and diets containing 4% calcium D-glucarate are far beyond what a capsule supplies, so these results cannot be scaled directly to a person.
Glucaric acid made by the body
Humans make and excrete D-glucaric acid every day. In 573 healthy adults, urinary D-glucaric acid averaged 3.05 mmol per mol of creatinine in men and 3.35 in women, and smoking raised it (Colombi et al., Clin Chim Acta 1983). Urinary D-glucaric acid has long been used as a marker of liver enzyme induction by drugs such as anticonvulsants and rifampicin (Perry and Stamp, Clin Pharmacol Ther 1984). These studies describe the body’s own glucaric acid, not supplement use.
Regulatory status
- United States. Calcium D-glucarate is sold as a dietary supplement, alone and in multi-ingredient products (NIH Dietary Supplement Label Database). It is not approved by the FDA to treat or prevent any disease.
- As a drug ingredient. The same salt, calcium saccharate, is used as an inactive stabilizer in FDA-labeled calcium gluconate injection, at 4.5 mg per mL (Fresenius Kabi label, DailyMed). This is not an approved use of calcium D-glucarate as an active drug.
- Controlled substances. It is not a controlled substance; it is not named in the US anabolic steroid schedule (21 CFR 1308.13).
- Sport. It is not named on the WADA 2026 Prohibited List. The list’s hormone and metabolic modulator class (S4) includes aromatase inhibitors such as anastrozole and anti-estrogens such as tamoxifen. Calcium D-glucarate belongs to neither group.
What the research shows
Cancer prevention in animals
This is where nearly all the data are. In rodent models, the carcinogen is given first, and calcium D-glucarate is added to the diet before or after.
| Model | Result | Source |
|---|---|---|
| Rat mammary tumors (DMBA) | Diet given after the carcinogen inhibited tumor development by over 70%; lower estradiol was offered as part of the explanation | Walaszek et al., Carcinogenesis 1986 |
| Rat mammary tumors, by phase | Tumor incidence cut 18% (initiation), 42% (promotion) and 50% (both); multiplicity cut 28%, 42% and 63% | Abou-Issa et al., Anticancer Res 1995 |
| Rat mammary gland | 2–4 weeks of diet lowered gland beta-glucuronidase and cell proliferation | Walaszek et al., Cancer Lett 1990 |
| Rat colon tumors (azoxymethane) | Potassium hydrogen D-glucarate, a related salt, cut tumor incidence and multiplicity by about 60% | Yoshimi et al., Int J Oncol 2000 |
| Mouse lung tumors (benzo[a]pyrene) | Reduced carcinogen DNA binding and lung adenoma formation in a susceptible strain | Walaszek et al., Cancer Lett 1986 |
These are consistent results across several models, but they come largely from the same research network and from very high dietary doses. None of them shows that calcium D-glucarate prevents cancer in people.
Estrogen in humans
No published study has given calcium D-glucarate alone to people and measured estradiol or other estrogens.
In 1995, researchers from the Breast Service at Memorial Sloan Kettering described the rationale for testing calcium glucarate in breast cancer prevention and said they hoped clinical trials would clarify its role (Heerdt et al., Isr J Med Sci 1995). The 2002 monograph reported a National Cancer Institute phase I trial in high-risk women and said results were “pending” (Altern Med Rev 2002). We found no peer-reviewed publication of those results.
The only randomized trial we found that included calcium D-glucarate tested a mixture (Laidlaw et al., Breast Cancer (Auckl) 2010):
| Detail | Value |
|---|---|
| Design | Randomized, placebo-controlled, 28 days |
| Participants | 96 women (47 premenopausal, 49 postmenopausal) |
| Daily product | 400 mg indole-3-carbinol and 20 mg lignan, plus milk thistle, schisandra, nettle root, vitamin D and 150 mg calcium D-glucarate |
| Main result | Urinary 2-hydroxyestrone rose; in premenopausal women the 2:16α-hydroxyestrone ratio also rose |
The authors credited the effect to indole-3-carbinol and the lignan, and called calcium D-glucarate a minor constituent. The trial cannot show any effect of calcium D-glucarate itself. Indole-3-carbinol is the precursor of DIM, which has its own page.
Men and steroid users
We found no study of calcium D-glucarate in men using testosterone or other anabolic steroids. The claim that it controls on-cycle estrogen is an extrapolation from rat data and from the mechanism, not a measured result.
Cholesterol
A 1996 study in rats reported cholesterol-lowering effects of dietary D-glucarate (Walaszek et al., Nutr Res 1996). The 2002 monograph cites “preliminary results in humans” showing lower cholesterol and triglycerides, but its only reference for this is a 1991 conference abstract (Altern Med Rev 2002). We found no peer-reviewed human lipid trial, so we do not repeat those figures here.
Where the “1,500–3,000 mg a day” figure comes from. Supplement sites often quote this range. It traces back to the 2002 monograph, which appeared in Alternative Medicine Review, a journal copyrighted by the supplement maker Thorne Research. The same paragraph says the optimal dose “remains elusive” until human trials are completed. No trial has established a dose.
Side effects and risks
What is known about safety
There are no published human safety data from controlled trials of calcium D-glucarate alone. The monograph reports that rats and mice fed diets containing 70, 140 or 350 mmol/kg showed no adverse effects (Altern Med Rev 2002). The Laidlaw mixture trial did not attribute any problems to the calcium D-glucarate component, but it gave only 150 mg/day for 28 days (Laidlaw et al., 2010).
“No reported harms” in a small evidence base is not the same as being shown safe. Long-term effects of daily supplement use in people have not been studied.
Possible drug interactions
The monograph lists no known interactions. It notes a theoretical concern: many drugs and hormones are cleared by glucuronidation. If calcium D-glucarate increases their elimination, it could reduce their effect (Altern Med Rev 2002). This has not been tested in people.
Relying on it instead of proven treatment
The main practical risk for steroid users is false reassurance. Calcium D-glucarate has no measured effect on estradiol in humans. It cannot be assumed to prevent estrogen-related side effects such as gynecomastia, and it is not a substitute for drugs whose effects on estradiol have been shown in trials.
Key takeaways
- A sugar-acid salt the body already makes. Calcium D-glucarate supplies D-glucaric acid, which forms D-glucaro-1,4-lactone, a natural inhibitor of the enzyme beta-glucuronidase.
- The mechanism is plausible but mostly shown in rodents. In rats it lowers beta-glucuronidase, mammary cell proliferation and chemically induced tumors, at very high dietary doses.
- No human trial of it alone. The only randomized trial we found used 150 mg/day inside a six-ingredient mixture, and its effect was credited to indole-3-carbinol.
- No proof it lowers estrogen in people. It is not an aromatase inhibitor, and no study has measured its effect on estradiol in men or in steroid users.
- Dose and safety are unestablished. The common 1,500–3,000 mg/day figure is not based on a trial. Animal studies showed no toxicity, but human safety data are lacking.
- Legal and not banned in sport. It is sold as a US dietary supplement and is not named on the WADA 2026 Prohibited List.
Sources
- National Center for Biotechnology Information. PubChem Compound Summary: Calcium Saccharate (CID 154911). PubChem.
- National Center for Biotechnology Information. PubChem Compound Summary: Glucaric Acid (CID 33037). PubChem.
- Zółtaszek R, Hanausek M, Kiliańska ZM, Walaszek Z. The biological role of D-glucaric acid and its derivatives: potential use in medicine [in Polish]. Postepy Hig Med Dosw (Online). 2008;62:451–462. PubMed.
- Dwivedi C, Heck WJ, Downie AA, Larroya S, Webb TE. Effect of calcium glucarate on beta-glucuronidase activity and glucarate content of certain vegetables and fruits. Biochem Med Metab Biol. 1990;43(2):83–92. PubMed.
- Walaszek Z. Potential use of D-glucaric acid derivatives in cancer prevention. Cancer Lett. 1990;54(1-2):1–8. PubMed.
- Baker JM, Al-Nakkash L, Herbst-Kralovetz MM. Estrogen-gut microbiome axis: Physiological and clinical implications. Maturitas. 2017;103:45–53. PubMed.
- Calcium-D-glucarate (monograph). Altern Med Rev. 2002;7(4):336–339. PubMed.
- Walaszek Z, Szemraj J, Narog M, et al. Metabolism, uptake, and excretion of a D-glucaric acid salt and its potential use in cancer prevention. Cancer Detect Prev. 1997;21(2):178–190. PubMed.
- Webb TE, Pham-Nguyen MH, Darby M, Hamme AT 2nd. Pharmacokinetics relevant to the anti-carcinogenic and anti-tumor activities of glucarate and the synergistic combination of glucarate:retinoid in the rat. Biochem Pharmacol. 1994;47(9):1655–1660. PubMed.
- Colombi A, Maroni M, Antonini C, et al. Influence of sex, age, and smoking habits on the urinary excretion of D-glucaric acid. Clin Chim Acta. 1983;128(2-3):349–358. PubMed.
- Perry W, Stamp TC. Urinary D-glucaric acid excretion during rifampicin/isoniazid and anticonvulsant enzyme induction. Clin Pharmacol Ther. 1984;35(5):710–715. PubMed.
- National Institutes of Health, Office of Dietary Supplements. Dietary Supplement Label Database: search for calcium D-glucarate. DSLD.
- Fresenius Kabi USA. Calcium Gluconate Injection, USP prescribing information. DailyMed.
- Code of Federal Regulations. 21 CFR 1308.13, Schedule III. eCFR.
- World Anti-Doping Agency. World Anti-Doping Code International Standard: Prohibited List 2026. WADA 2026 Prohibited List.
- Walaszek Z, Hanausek-Walaszek M, Minton JP, Webb TE. Dietary glucarate as anti-promoter of 7,12-dimethylbenz[a]anthracene-induced mammary tumorigenesis. Carcinogenesis. 1986;7(9):1463–1466. PubMed.
- Abou-Issa H, Moeschberger M, el-Masry W, et al. Relative efficacy of glucarate on the initiation and promotion phases of rat mammary carcinogenesis. Anticancer Res. 1995;15(3):805–810. PubMed.
- Walaszek Z, Hanausek M, Sherman U, Adams AK. Antiproliferative effect of dietary glucarate on the Sprague-Dawley rat mammary gland. Cancer Lett. 1990;49(1):51–57. PubMed.
- Yoshimi N, Walaszek Z, Mori H, et al. Inhibition of azoxymethane-induced rat colon carcinogenesis by potassium hydrogen D-glucarate. Int J Oncol. 2000;16(1):43–48. PubMed.
- Walaszek Z, Hanausek-Walaszek M, Webb TE. Dietary glucarate-mediated reduction of sensitivity of murine strains to chemical carcinogenesis. Cancer Lett. 1986;33(1):25–32. PubMed.
- Heerdt AS, Young CW, Borgen PI. Calcium glucarate as a chemopreventive agent in breast cancer. Isr J Med Sci. 1995;31(2-3):101–105. PubMed.
- Laidlaw M, Cockerline CA, Sepkovic DW. Effects of a breast-health herbal formula supplement on estrogen metabolism in pre- and post-menopausal women not taking hormonal contraceptives or supplements: a randomized controlled trial. Breast Cancer (Auckl). 2010;4:85–95. PubMed; PMC.
- Walaszek Z, Szemraj J, Hanausek M, Adams AK, Sherman U. D-Glucaric acid content of various fruits and vegetables and cholesterol-lowering effects of dietary D-glucarate in the rat. Nutr Res. 1996;16(4):673–681. DOI.