Does Cinnamon Help Lower Blood Sugars?

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Cinnamon for Diabetes

The use of cinnamon to help treat diabetes remains controversial. We know that cinnamon is so good at controlling one’s blood sugar that you can cheat on a diabetes test by consuming two teaspoons of cinnamon the night before your glucose tolerance test. That’s where they make you drink some sugar water to see how well your body can keep your blood sugar levels under control, and if you eat those two teaspoons right when the test starts or 12 hours before you can significantly blunt the spike. Even a teaspoon a day appears to make a significant difference. A review of the best studies done to date found that the intake of cinnamon by type 2 diabetics or prediabetics does lower their blood glucose significantly. So what’s the controversy?

Well, as I described in my video The Safer Cinnamon, cassia cinnamon, also known as Chinese cinnamon (probably what you’re getting at the store if it just says “cinnamon”) contains a compound called coumarin which may be toxic to the liver at high doses. Originally the concern was mainly for kids during Christmas-time where they might get an above average exposure, but more recently some researchers suggest that kids just sprinkling some cassia cinnamon on their oatmeal a few times a week might exceed the recommended safety limit.

As you can see in my 5-min video Update on Cinnamon for Blood Sugar Control just a quarter teaspoon of cinnamon a few times a week may be too much for little kids, and if they’re eating that cinnamon-sprinkled oatmeal more like every day they can bump up against the limit for adults. So a teaspoon a day of cassia cinnamon might be too much for anyone, but can’t we just switch from cassia cinnamon to Ceylon cinnamon and get the benefits without the potential risks? Without the risks, yes, but we’re no longer so sure about the benefits.

Nearly all of the studies showing blood sugar benefits of cinnamon have been done on cassia. We’ve just assumed that the same would apply for the safer cinnamon, Ceylon, but only recently was it put to the test. That nice blunting of blood sugars we saw in response to cassia cinnamon disappeared when the researchers tried Ceylon cinnamon instead.  In fact, it may actually be the potentially toxic coumarin that was the active ingredient in the cassia cinnamon all along. Thus, sidestepping the toxin by switching may sidestep the benefit.

So should we just give up on going out of our way to add cinnamon to our diet? No, I think it’s still a good idea to shoot for a teaspoon a day of Ceylon cinnamon since there are a bunch of other benefits linked to cinnamon besides blood sugar control, not the least of which is it’s potent antioxidant content (as I show in my one of my favorite videos Antioxidants in a Pinch). In my Superfood Bargains video, where I rank foods in terms of antioxidants per unit cost, cinnamon comes out as one of the cheapest food sources of antioxidants, beating out cloves and coming in just under purple cabbage. What about the Oxalates in Cinnamon? Not a problem, but the oxalates in too much turmeric may be a concern. As you’re making a Healthy Pumpkin Pie with all that cinnamon, don’t accidentally add too much nutmeg, though, the subject of my follow-up video Don’t Eat Too Much Nutmeg.

Ultimately cinnamon can no longer be considered a safe and effective treatment for diabetes. Either you’re using cassia cinnamon, and it’s effective, but may not be safe, or you’re using Ceylon cinnamon, which is safe, but does not appear effective. Note that even the cassia cinnamon only brought down blood sugars modestly (in other words, only as good as the leading diabetes drug in the world, metformin, sold as Glucophage). So yes, it may work as good as the leading drug, but that’s not saying much. The best way to treat diabetes is to attempt to cure it completely, reversing diabetes with a healthy diet.  Books I would recommend (in order of publication) are Defeating DiabetesDr. Neal Barnard’s Program for Reversing Diabetes, and The End of Diabetes.

I talk more about the potential potency of plants in general in Power Plants and more about spices in particular in videos such as:

Amla Versus Diabetes explores the use of Indian gooseberries as a way to help control blood sugar, though, again, the best way to deal with diabetes is to prevent and treat it with a healthy diet.

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my videos for free by clicking here and watch my full 2012 – 2015 presentations Uprooting the Leading Causes of Death, More than an Apple a Day, From Table to Able, and Food as Medicine.


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

17 responses to “Cinnamon for Diabetes

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  1. Dear Doctor G. Love you dude, don’t ever stop. One suggestion, please label your postings, like this one, as re-post (unchanged), revised (updated), or new. This way I will know that I’m not having a seizure (deja vu), but rather just reading something important, again.

    1. It seems like he may be intentionally trying to have each “blog” as a video and as an article. I think it’s nice to reiterate some older points.

  2. Thank you for this life-transforming and energizing site, Dr. Gregger! Our friends and we use Cost Co’s Saigon Cinnamon and cannot find any called Ceylon. Any new tests to see if Saigon is OK? Any tips for online or Marin County CA sources?

    1. Hey Gayle,

      If you would like to purchase locally, Whole Foods carries Organic Ceylon Cinnamon in their bulk section for around $22.99-$24.99/lb. As far as purchasing online, is a good place to purchase herbs, spices, or tea. They even offer bulk discounts without having to purchase the same items, so you can mix and match. Ceylon “True” Cinnamon is listed as Sweet Cinnamon on their website and priced at $13.50/lb+S&H. However, I believe it’s currently out of stock.

    2. Hey Gayle,

      If you would like to purchase locally, Whole Foods sells Organic Ceylon (a.k.a. “True” or Sweet) Cinnamon for $22.99-24.99/lb in the bulk section where all the herbs and spices are located. If you would like to purchase online, Vitacost, MountainRoseHerbs, and Amazon may be a few options to check out.

  3. Hi Dr Greger, Do you have a way to donate directly through Paypal without logging into Google? The donation setup makes me a little nervous.

    1. Hey Phil,

      Click “Donate” at the top of the homepage. Then, click where it says “click here” under the Donations & Tax Receipts on the right side. From this webpage, you have the choice of either logging into your PayPal account or using a credit card to donate (at the bottom left where it says “Don’t have a PayPal account?”). Hope this helps!

  4. Please note that coumarin, the toxic component in cassia cinnamon, is oil soluable. Simply preparing cassia cinnamon as a tea (hot water infusion) will leave the bad stuff behind, and preserve the benefits. Just use a mini-coffe maker, with a non-bleached paper filter, put a teaspoon of cassia right in the filter section, and enjoy. Sometimes simple solutions (pun!) can be best.

  5. Good article. I like the angle of the discussion focusing on the two kinds of cinnamon which is seldom discussed in other posts

  6. Dr. Greger when you said “I think it’s still a good idea to shoot for a teaspoon a day of Ceylon cinnamon since there are a bunch of other benefits linked to cinnamon …” did you mean to say “linked to Ceylon cinnamon?

    Again how do we know the benefits of Ceylon are the same as Cassia?

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