- Does cinnamon help control blood sugar or blood pressure? Cinnamon may modestly help control blood sugar levels. The evidence is less clear regarding blood pressure (See What It Does).
- What is the correct dose of cinnamon? A dose of 1 gram (1,000 mg or about 1/2 teaspoon) of cinnamon bark powder per day may be sufficient to lower blood sugar levels in people with type 2 diabetes or prediabetes. With some extracts, smaller doses (as little as 120 mg) may be sufficient (See ConsumerTips™).
- Which cinnamon supplement provided the most PACs? In the supplements tested, PACs ranged from less than 5 mg to over 40 mg per daily serving. Interestingly, the most expensive products provided the least PACs, and there was a 15-fold difference in the cost to obtain PACs across the products (for amounts of PACs, see the Supplements Results Table).
- Is cinnamon safe? What did ConsumerLab find? A concern with cinnamon is that it may contain significant amounts of coumarin — a naturally occurring compound that may cause liver toxicity and is a potential carcinogen. Coumarin can be high in cassia cinnamon (the most common type of cinnamon), but should be low in Ceylon cinnamon — also called "true" cinnamon or Cinnamonum verum — which is, typically, more expensive. However, ConsumerLab found that a "Ceylon" cinnamon product contained 4 mg of coumarin per serving — more than any other cinnamon supplement, suggesting that it is mislabeled. None of the products, however, exceeded the tolerable daily intake limit of 7 mg for an average-sized adult, but two exceeded the limit for children (see coumarin amounts in the Results Tables for Supplements and for Spices.
- One of the cinnamon spices had a particularly high concentration of lead — right at ConsumerLab's limit. Another cinnamon spice had higher concentration of coumarin. We would not recommend either for frequent use. No spice exceeded limits for filth and none (including bark powder supplements) was contaminated with Salmonella.
- Which cinnamon supplement is best? One supplement stood out among the others for providing a high amount of PACs, a safe amount of coumarin, passing all contamination testing, and being relatively inexpensive. It was chosen as our Top Pick among cinnamon supplements.
- Which cinnamon spice is best? We chose three products as our Top Picks for spices. Two were chosen because they had no detectable lead and relatively low amounts of coumarin. The third was chosen because it had no detectable coumarin.