Ceylon Cinnamon is what I have used for many years. I like its smell and flavor. There is also the blood sugar control for Type II Diabetics. Clinical trials that have been completed that seem to confirm the effects that Ceylon Cinnamon (Cinnamomum verum. and Cinnamonum cassia) These trials are rather thin, especially for verum. There is a large clinical trial in progress right now that should answer some of these questions. I have personally used it and it seems to help. I tell people if it doesn't work for you it still makes damn good Cinnamon rolls. I consulted with Grok looking for a good source. The information I learned was really eye opening. The problem with Cinnamon is coumarin this is a natural plant compound that your body metabolizes into a compound that can damage your liver. Cinnamomum cassia has coumarin about 1% by weight in bark. Cinnamonum verum has almost none. But there is another problem, lead. The Cinnamons lead content depends on the soil in is grown in. The best way to medicinally use Cinnamonum verum is to lightly crunch up the quills in mortar & pestle add these crunched up quills to your French Press coffee maker or floating tea infuser. The steeping time gives plenty of time for the cinnamaldehyde, and other compounds to infuse into the hot water, the lead mostly stays in the bark. I have always liked a cinnamon latte, or chia so this works out great. There are a number of direct sources for Cinnamonum verum quills I have not figured out which on them the best.