The only time I've heard of adverse side effects of cinnamon are from people who happen to be allergic. Obviously, everything in moderation. I'm sure long-term use or ingestion of large amounts are probably not "good" for you.
On the pro side, cinnamon has loads of health benefits, mainly because it tops the ORAC list for antioxidant content. That's why I like to use a daily raw honey and organic cinnamon mask (which happens to be quite tasty). Sometimes I'll throw some lemon juice, witch hazel, and turmeric powder in there too.
I use a tiny amount of cinammon leaf oil in lotion -- just one drop per 200 ml.
In the US cinammon oil is used in lip plumpers that claim to make women's lips fuller and redder. Apparently it's a very hot (oxidative) oil.
I don't like the peppery taste of cinammon, just the aroma.
Daal cheeni (cinnamon) ? It has a beautiful aroma. I had a cup of cinnamon tea at a cafe here in Dehradun. I fell in love with cinnamon right there and then! Though i don't know about it's effects on acne and our body in general but anything in moderation is good for us.Chewing cinnamon sticks? lol . Have hot cinnamon green tea.You gonna love every bit of it.Take my word 
just for those who doesnt know, cinnamon acts as insulin inside and thus helps with insulin spikes.
so, u could have a pinch(say 1 gram or so) after each meal.
lips plummer?
okay.=)
i have had cinnamon tea and i liked it.
but i have stopped buying those bags now and i make my tea with leaves at home.
i add ginger instead.
plus i have cinnamon after lunch and dinner or when i am having something "indulging"
u're right about moderation.
in fact,one should never exceed 4 grams per day.it might lower ur sugar level in a bad way.
considering it acts as insulin!
but i was still curious if it does anything with the body heat??
elaichi(cardamon) does.its said to increase the body heat.
so i was wandering this too is anyway related(considering that cinammon and cardamom are all part of garam masala)
just curious!
i would like to thank everyone who replied.
I've used cinnamon in an attempt to control my acne. It didn't work.
However, it did drop my blood sugar quite a bit. I have a very high metabolism normally. I felt cold and tired while taking cinnamon.
But sadly, no effect on acne. I think I took 2g 2x a day, or maybe 1g. Idk. Came in capsules.
i take the powdered cinnamon that we use in the kitchen.after lunch and dinner mainly for i have rice.
frankly i dnt think i have insulin spikes that could be bothering for my acne.no!
so i was skeptical about whether or not i should continue?
i am scared it might make my sugar level fall below normal.
(i have no/less chances of sugar test actually).
its difficult for me to weight.
i just have a small pinch.not even a full big pinch.