its becasue its a sustained release pill. i had the same issue, i could not breathe, red hot, neck, face, head. felt like i was in the sun too long. I stop taking it and got the Flush Free, and all side affects have stopped. The flush free i have are in powder form (pill) and of course the time release pill was compressed and coated. Hope this helps, i got both FF and Time release for about 9 bucks from GNC.