The short answer
The evidence points in different directions, and neither study looked at low blood sugar. In a 12-week trial in 200 women with PCOS, those given both metformin and nanocurcumin, a specially processed curcumin, improved most on metabolic measures. In a three-month trial in 60 people with type 2 diabetes on glimepiride, adding curcumin capsules made no significant difference to blood sugar or HbA1c.
The two trials tested different people, products and outcomes, so they are not two tests of the same question. Both used capsules, not haldi in food, which is a different exposure and has not been studied. If you take metformin or a sulfonylurea such as glimepiride, tell your prescribing doctor before you start curcumin capsules, and ask whether to check your sugar more often.
Metformin is sold in India as Glycomet, glimepiride as Amaryl and gliclazide as Diamicron. Glycomet-GP combines metformin with glimepiride.
At a glance
| What was seen | How it may work | Direction | Evidence |
|---|---|---|---|
| Greatest metabolic improvement with metformin plus nanocurcumin, in women with PCOS[1] | Possible added effect on blood sugar; not established | Combined effect on metabolism; low sugar not reported | RCT |
| No significant change in sugar or HbA1c when curcumin was added to glimepiride[2] | Not established | No measurable added effect over three months; low sugar not reported | RCT |
No listing is not a clearance. A missing interaction here never means a combination is safe.
The evidence, study by study
Factorial trial in PCOS, 2024 RCT
Two hundred women with PCOS took metformin (500 mg every eight hours), nanocurcumin (80 mg every eight hours), both, or two placebos for 12 weeks. The abstract reports the greatest metabolic improvement with both together, but gives no effect sizes and no count of low-sugar episodes. The women did not have diabetes.[1]
Add-on trial in type 2 diabetes, 2025 RCT
Sixty adults with poorly controlled type 2 diabetes and high blood fats, all on glimepiride 4 mg a day, added curcumin (1,100 mg a day), fenofibrate or placebo for three months. Fasting sugar, two-hour sugar and HbA1c did not differ significantly between the groups. The abstract does not report episodes of low sugar.[2]
What your doctor may watch for
- Your blood sugar, including any readings that run low. Neither trial reported how often low sugars happened.
- The metformin label asks patients to tell their doctor about any herbal supplements they take.[3]
What to tell your prescribing doctor
You can read this out, or show them this page:
“I am taking, or planning to take, turmeric or curcumin (name of product, how much) along with my diabetes medicine. Trials of curcumin with metformin and glimepiride gave mixed results, and none measured low sugars. Should I check my sugar more often?”
Withheld until review
Questions people ask
Is turmeric tea or haldi doodh a problem with metformin?
We found no study of turmeric tea, haldi doodh or cooking amounts of haldi with diabetes medicines. If you take them daily, include them when you tell your doctor what you take.[1][2]
Can curcumin replace my diabetes medicine?
No study here tested that. In the trial in type 2 diabetes, curcumin added to glimepiride did not improve blood sugar more than placebo.[2]
Related
Type 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.
ConditionPCOS and PCOD: what Ayurveda offers
Curcumin improved blood sugar markers, and periods a little, in small trials. Most Ayurveda studies of PCOS are single case reports.
InteractionTulsi and metformin
Holy basil leaves lowered blood sugar in a 1996 trial in type 2 diabetes. With metformin, sugar could fall further. The pair has not been 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
- Feghhi F, Ghaznavi H, Sheervalilou R, Razavi M, Sepidarkish M. Effects of metformin and curcumin in women with polycystic ovary syndrome: a factorial clinical trial. Phytomedicine. 2024;135:156160. PMID 39461199.
- Nada EM, El-Gharbawy NM, Abbas H, Werida RH. Effect of adding fenofibrate versus curcumin to glimepiride in patients with type 2 diabetes: a randomized controlled trial. BMC Pharmacol Toxicol. 2025;26(1):119. PMID 40481568.
- Metformin hydrochloride tablets, US prescribing information (DailyMed).
Awaiting review by The Good Vaidya Medical Board. Prepared from the sources below and checked against each one.
Published 4 November 2026 · Last updated 4 November 2026
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