Best Teas for Blood Sugar: 5 Research-Backed Options to Support A1c Naturally

25/11/2025

By: Laura Collins

Flat-lay image of Oolong tea, chamomile flowers, Ceylon cinnamon sticks, yerba maté, and mulberry leaves arranged on a clean background, representing teas that may help support healthy blood sugar levels.

Managing blood sugar levels is essential for individuals with prediabetes, type 2 diabetes, or insulin resistance. Many people look for natural options, which is why interest in the best teas for blood sugar has grown. Alongside diet, physical activity, and medical care, certain teas have been studied for their potential metabolic benefits. While tea alone cannot treat or cure diabetes, some varieties contain bioactive compounds that may support healthier glucose regulation.

Below are five teas with research exploring their effects on fasting glucose, post-meal glucose, insulin response, and A1c.

1. Oolong Tea

Oolong tea contains partially fermented polyphenols that may influence glucose metabolism.
A small study in adults with type 2 diabetes found that drinking 1.5 liters of oolong tea daily for 30 days significantly reduced fasting blood glucose compared to a control group (Diabetes Care, 2003)¹. Participants also showed improvements in hemoglobin A1c.

How it may help:

  • May inhibit intestinal glucose absorption
  • May support improved glucose uptake in cells
  • Contains antioxidants that may reduce oxidative stress

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2. Chamomile Tea

Chamomile has high levels of flavonoids such as apigenin, which exhibit antioxidant and anti-inflammatory effects.
A randomized controlled trial found that drinking chamomile tea three times daily after meals for 8 weeks led to modest reductions in A1c, improvements in insulin resistance, and better antioxidant status (Nutrition, 2015)².

How it may help:

  • May reduce post-meal glucose spikes
  • May improve insulin sensitivity
  • May lower oxidative stress markers

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3. Cinnamon Tea

While cinnamon tea itself is less studied, cinnamon extracts and powdered cinnamon have been researched extensively.
A meta-analysis found that cinnamon supplementation was associated with an average A1c reduction of 0.24% and reduced fasting glucose (Annals of Family Medicine, 2013)³.
Another review reported an average fasting glucose decrease of 19 mg/dL across multiple trials.

How it may help:

  • Polyphenols may act on insulin receptors
  • May enhance glucose transport into cells
  • May slow carbohydrate digestion

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4. Yerba Maté

Yerba maté contains polyphenols, xanthines, and saponins with metabolic effects.
A clinical trial found that adults with type 2 diabetes who consumed maté tea three times daily for 60 days experienced reductions in fasting glucose, A1c (−0.85%), and LDL cholesterol (Journal of the American College of Nutrition, 2011)⁴.

How it may help:

  • May reduce fasting glucose
  • May provide antioxidant support
  • Contains caffeine, which some individuals may be sensitive to

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5. Mulberry Leaf Tea

Mulberry leaves contain DNJ (1-deoxynojirimycin), a compound that inhibits carbohydrate-digesting enzymes.
A human study found that drinking mulberry tea after breakfast reduced both fasting glucose and post-meal glucose spikes compared to control beverages (Saudi Journal of Biological Sciences, 2014)⁵.

How it may help:

  • May slow carbohydrate absorption
  • May reduce post-meal glucose rise
  • May support antioxidant defenses

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Who May Benefit From These Teas?

These teas may be supportive for individuals who want to:
✔ Reduce post-meal glucose spikes
✔ Support healthy fasting glucose
✔ Improve antioxidant status
✔ Complement a diabetes-friendly diet

They should not replace prescribed medication or medical guidance.

Potential Side Effects & Safety Notes

  • Cinnamon: Use Ceylon cinnamon to minimize coumarin exposure.
  • Yerba maté: Contains caffeine; avoid if sensitive.
  • Chamomile: Avoid if allergic to ragweed.
  • Oolong: Contains caffeine; may not be suitable for all.
  • Mulberry: May lower glucose significantly; monitor if on medication.

Always consult a healthcare professional before adding herbal teas if you take medications or have chronic conditions.

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References