At the end of the day, cinnamon is one of the most delicious and healthiest spices on the planet. It can lower blood sugar levels, reduce heart disease risk factors and has a plethora of other impressive health benefits. Just make sure to get Ceylon cinnamon or stick to small doses if you're using the Cassia variety.
You can safely eat up to one teaspoon (0.5 to 2 grams) of Cassia cinnamon or up to two and a half teaspoons (5 grams) of the Ceylon type per day. While eating too much cinnamon may have some drawbacks, it's a healthy spice that's safe to eat in small to moderate amounts.