Does Cinnamon Lower Blood Sugar? What the Research Says

It's 7 am, the coffee is brewing, and you shake in a heaping spoonful of cinnamon because a viral video said it would help your A1C. So, does cinnamon lower blood sugar? A little, in some capsule trials, for fasting glucose; not reliably, and not enough for NIH or the American Diabetes Association to recommend it for blood sugar control.

The viral claim is half right. A 2013 meta-analysis of 10 trials found fasting glucose fell by about 24.59 mg/dL, while A1C, the longer-term number your doctor watches, did not change significantly. Keep the cinnamon for flavor, on a Houseland wire spice rack with a solid wood base if you like it within reach, and keep your treatment plan exactly where it is.

Does cinnamon lower blood sugar in the studies that tested it?

The trials point to a modest drop in fasting glucose, with conflicting results for A1C and low-certainty evidence overall. Four reviews of randomized trials show how the picture has shifted.

The newer reviews pool more trials, but those trials still disagree with each other heavily: in the 2025 review, with an I² of 88% for fasting glucose and 94% for A1C.

For scale, the American Diabetes Association's 2025 Standards of Care, in section 5, still say supplementing with herbs or spices such as cinnamon for glycemic benefit is not recommended.

A modest average across messy trials is not a treatment.

Why do the cinnamon studies disagree so much?

They tested different doses, different forms and different lengths of time, and most carried a real risk of bias. That is the short version of what every review above says about itself.

• Dose: Allen's trials ran from 120 mg to 6 g a day, a 50-fold spread (6,000 mg ÷ 120 mg = 50).
• Length: those trials lasted 4 to 18 weeks, and Cochrane's ran 4 to 16 weeks.
• Form: Cochrane found most trials used cassia, at a mean of 2 g daily as a single-ingredient preparation, often capsules or extract.
• Quality: Cochrane rated risk of bias high or unclear in all but 2 of its 10 trials.

Allen's team wrote that the high heterogeneity may limit applying the results to patient care, because the preferred dose and duration are unclear. That is researchers saying, in careful language, "we don't know how much or how long."

The 2025 review screened 924 records to find its 28 trials, which ran from 30 to 120 days. It found capsules did better than other forms, and that doses of 2 g a day or less were the ones linked to lower A1C. A 2025 umbrella review in Frontiers in Nutrition, pooling 21 meta-analyses, pointed the other way, suggesting doses above 1.5 g a day may do more. Same spice, opposite hints.

When the dose advice flips between papers, nobody knows the dose.

What isn't in doubt is cinnamon as a flavor, and a jar you can see from the stove is one you actually use in oatmeal and coffee; for that, we make a one-tier wall spice rack. Recommended for this use case: the cook who reaches for cinnamon, nutmeg and ginger every breakfast should pick the Medium rack, 13.8 in (35 cm) wide, which the listing sizes for around eight standard 4 oz jars in one row, so the cinnamon stays visible instead of buried in a cupboard.

From the shop

Wall Mounted Spice Rack, Steel Wire Grid Shelf with Wood Base

Best for keeping everyday spices like cinnamon in one visible row; powder-coated steel wire with a solid wood base, 11.4, 13.8 or 17.5 in wide; a light-duty single tier, only 3.9 to 4.1 in deep, so it holds one row of jars.

View the wire spice rack — 3 sizes & current price

What do NIH and the American Diabetes Association say about cinnamon?

NCCIH, part of NIH, says it's unclear whether cinnamon supplementation helps diabetes, and the ADA says not to use cinnamon for glycemic benefit. The two agree on the practical answer even though they word it differently.

• NCCIH's cinnamon page, updated November 2024, says research does not clearly support cinnamon for managing blood sugar.
• NCCIH's diabetes and supplements page, updated November 2023, lists the positive reviews, then says people taking diabetes drugs should tell their health care providers about any herbal supplements.
• The same NCCIH page warns that combining herbs such as cinnamon with conventional diabetes drugs can cause unwanted side effects, and that supplements should not replace proven treatment.
• The ADA's 2025 Standards of Care, recommendation 5.16, rates the advice against herb and spice supplements for glycemic benefit at evidence grade C.

Advice against using it is not proof that cinnamon does nothing. It means the benefit has not been shown well enough to act on.

The ADA text adds that there is insufficient evidence for cinnamon, curcumin, aloe vera or chromium to improve glycemia in type 1 or type 2 diabetes. Oddly, the same document suggests seasoning with herbs and spices, cinnamon included, in place of salt.

So cinnamon is welcome in your food. It's just not on your prescription.

How much cinnamon is in a spoonful, and how much is too much?

A level teaspoon of ground cinnamon weighs about 2.6 g, per USDA FoodData Central, which is already above the cassia amount Germany's risk agency uses as a daily coumarin limit for a 132 lb (60 kg) adult. The limit comes from coumarin, a natural compound in cassia, the type NCCIH calls common in the US and Canada.

Germany's Federal Institute for Risk Assessment (BfR) set a tolerable daily intake of 0.1 mg of coumarin per kg of body weight. It says a 132 lb (60 kg) adult reaches that with about 2 g of cassia a day, and a 33 lb (15 kg) child with about 0.5 g. The arithmetic: 2 g divided by 2.6 g per teaspoon is about 3/4 teaspoon.

Here authorities differ. NCCIH says cinnamon below 6 g a day appears safe, which is more than 2 teaspoons. BfR, looking only at coumarin in cassia, draws the line lower, but it also says slightly exceeding the TDI for one to two weeks is safe, and in 2012 it noted no cases of liver damage from eating cinnamon had been described in the literature.

NCCIH adds that cinnamon is likely safe in the amounts commonly used in foods, but larger amounts or long-term use may cause digestive problems or allergic reactions, and some components may interact with an anticancer medicine or nicotine.

A sprinkle on oatmeal is nowhere near either number. A heaping spoonful in every coffee, every day, is where it adds up. NCCIH says Ceylon cinnamon contains only trace amounts of coumarin, and adds that people with liver disease are the ones who should be most careful with high-coumarin products.

Tip: if cinnamon is a daily habit rather than a garnish, buy a jar labeled Ceylon and level the spoon.

Sprinkle it. Don't dose it.

How should you use cinnamon if you're watching your blood sugar?

Use cinnamon as a flavor, keep your treatment plan unchanged, and tell your doctor if you take it as a supplement. That's the version every source above can agree with.

• Keep medication, meal plan and monitoring as your care team set them; NCCIH says supplements should not replace proven treatment.
• If you take cinnamon capsules, mention them at your next appointment, along with the dose.
• Judge any change by the numbers your doctor tracks, A1C and fasting glucose, not by how one morning's reading looks.
• For everyday flavor, keep portions in the sprinkle range, and pick Ceylon if you use it heavily.

Tip: cinnamon gives oatmeal, yogurt and coffee a sweet smell without sugar, which is a flavor trick, not a treatment.

Where the jar lives matters for flavor only. Our guide to how long ground spices last before they go flat covers when to replace a jar, and heat is the other half, covered in whether the wall above the hob is the worst place for a spice rack.

Houseland's wall rack is a single tier of powder-coated steel wire with a solid natural-wood base, in widths of 11.4 in (29 cm), 13.8 in (35 cm) and 17.5 in (44.5 cm), and it arrives in one piece with both screw-in hooks and adhesive pads.

The limitation is plain: a rack changes where your cinnamon sits, not what it does in your body, and no storage choice turns a spice into a treatment. It's also a light-duty shelf at 3.9 to 4.1 in deep, so it takes one row of jars, not a pantry. More kitchen storage sits in the kitchen and home collection.

Flavor on the shelf, care plan with your doctor.

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