Do many of you experiance headaches while on clen?
Im on my 3rd day and have heard from others in the gym headaches are common.
Also some said to me dont take caffeien while on clen?
umm…there is no need for caffeine on clen…you will be buzzing…the halflife is around 36 hours so if you take it in the mornings you will be awake the whole day
while the mechanism of stimulation from clen and caffeine is different, the synergistic effect can run up your blood pressure and heart rate quite high…
I guess everyone responds differently to it. I am a heavy coffee drinker, and I love ECA stack. It makes me feel very good, energetic, and happy 
However, I become literally sick when I try even smallest amount of clen for just few days. Headaches, lethargy, inability to concentrate…
Chemically ephedrine and clen are very similar. But in almost all experiences, clen is more potent in all areas, and much more sideeffect prone.
Personally I had problems running on clen, my calves would cramp something horrible even with taurine.
I switched to albuterol, and although its a nearly identical drug, I suffered few sideeffects. It has a shorter half life, which means you just have to dose it twice a day instead of once. But this is actually a huge advantage, if you dont dose at night the effect will wear off and you can actually sleep (impossible on clen).
I suggest you skip clen and use albuterol or ephedrine.