The short answer
Not known in people. In a placebo-controlled trial of 98 women with type 2 diabetes, three months of a tribulus extract lowered blood sugar more than placebo. The published summary does not say whether the women were on metformin, or whether anyone had low sugar. Memorial Sloan Kettering's herb database warns that tribulus may add to the effect of sugar-lowering medicines.
We found no study of gokshura (gokhru) taken with metformin. If you take metformin, especially alongside insulin or a sulfonylurea such as glimepiride, tell your prescribing doctor before you start gokshura and ask whether to check your sugar more often. Rare reports of kidney injury after tribulus also matter, because metformin use depends on kidney function.
Metformin is sold in India as Glycomet and Glycomet SR. Glycomet-GP also contains glimepiride.
At a glance
| What was seen | How it may work | Direction | Evidence |
|---|---|---|---|
| Lower blood sugar with tribulus extract in women with diabetes; their other medicines are not reported[1] | Not established | Could add to metformin's effect on sugar | RCT |
| Possible extra fall in blood sugar[4][5] | Two sugar-lowering effects adding up | Sugar may fall further, more so with insulin or sulfonylureas | Theoretical by mechanism |
| Liver and kidney injury after tribulus, not linked to metformin[2][3] | Not established | Harm to the kidneys, which matter for metformin use | Case report |
No listing is not a clearance. A missing interaction here never means a combination is safe.
The evidence, study by study
Trial in women with type 2 diabetes, 2016 RCT
Ninety-eight women with type 2 diabetes took 1,000 mg a day of a water-and-alcohol extract of tribulus, or a placebo, for three months. Blood sugar fell significantly more with the extract. The abstract gives no size of effect, no count of low-sugar episodes and no separate result for women on metformin, and the authors call the results preliminary.[1]
Case report, 2015 Case report
A young, healthy man developed severe jaundice (hyperbilirubinaemia) and then kidney failure after taking tribulus. Memorial Sloan Kettering describes him as a 30-year-old bodybuilder who had taken tablets daily for months. The summary does not say whether he took metformin, and other causes could not be ruled out.[4]
Case report, Iran, 2010 Case report
A 28-year-old man drank tribulus herbal water for two days to prevent kidney stones. He then had seizures, with liver enzymes more than 40 times the upper limit and a raised creatinine, a marker of kidney function. He improved after he stopped.[4]
What your doctor may watch for
- Blood sugar. The metformin label notes a higher risk of low sugar when metformin is combined with insulin.[5]
- Kidney function. Kidney injury would matter for metformin on its own, whatever caused it.[5]
What to tell your prescribing doctor
You can read this out, or show them this page:
“I am taking, or planning to take, gokshura or a tribulus product (name of product, dose) along with metformin. Tribulus lowered blood sugar in one trial, and there are reports of kidney injury. Should I check my sugar more often, and do I need a kidney test?”
Withheld until review
Questions people ask
Related
Gokshura (gokhru) and blood pressure medicines
Gokshura lowered blood pressure on its own in one trial, so it could add to BP medicines. We found no study of the two taken together.
ConditionType 2 diabetes (sugar): what Ayurveda offers
Some herbs, such as methi and karela, lowered HbA1c a little in trials. Taken with diabetes medicines, they can add to the risk of low sugar.
InteractionNeem and diabetes medicines (metformin, insulin)
In a 12-week trial, a neem leaf and twig extract lowered blood sugar further in people already on metformin. Insulin was not studied.
InteractionKarela (bitter gourd) and diabetes medicines
Added to metformin and dapagliflozin, a karela extract lowered HbA1c further in a 2026 study. With insulin or sulfonylureas, low sugar is the worry.
Sources
- Samani NB, Jokar A, Soveid M, Heydari M, Mosavat SH. Efficacy of the hydroalcoholic extract of Tribulus terrestris on the serum glucose and lipid profile of women with diabetes mellitus: a double-blind randomized placebo-controlled clinical trial. J Evid Based Complementary Altern Med. 2016;21(4):NP91-7. PMID 27255456.
- Ryan M, Lazar I, Nadasdy GM, Nadasdy T, Satoskar AA. Acute kidney injury and hyperbilirubinemia in a young male after ingestion of Tribulus terrestris. Clin Nephrol. 2015;83(3):177-183. PMID 25295577.
- Talasaz AH, Abbasi MR, Abkhiz S, Dashti-Khavidaki S. Tribulus terrestris-induced severe nephrotoxicity in a young healthy male. Nephrol Dial Transplant. 2010;25(11):3792-3793. PMID 20667992.
- Memorial Sloan Kettering Cancer Center. About Herbs: Tribulus terrestris.
- Metformin hydrochloride tablets, US prescribing information (DailyMed). Renal impairment and hypoglycaemia sections.
Updated 4 November 2026
Taking gokshura with other medicines? A vaidya can check your full list.
Medicine Check · ₹299