T Nation

Clen Safety Question

I wonder if somebody could help me out please. I’m considering starting a 10 week Clen cycle soon (2 weeks on, 2 weeks off breaks during). I’ve never taken Clen before, although I HAVE run a couple of cycles of Testoviron several years back. Having read and watched some Youtube videos, a lot of people are claiming that Clen is extremely dangerous and not worth taking whatsoever. They claim that Clen can enlarge the cells in your heart, and even kill them off, causing strokes and heart attacks, etc. I was of course aware that Clen would have some side effects, as no Stimulant is completely safe, although I didn’t realise there were so many articles, posts, and videos online advising people to stay well clear of Clen.

Do you know how true this is, and how at risk of heart problems I’d be by taking a 10 week cycle of Clen? Has it all been exacerbated by the ‘STEROIDS ARE BAD’ crowd? Provided I very slowly taper up my dosage (starting at 20mcg and increasing by 20mcg per day, up to 120mcg max), how worried should I be about the supposed dangers to my heart? I’m absolutely fine with things like agitation, tremors, etc as that’s to be expected, but having read now that it can cause irreversible damage to your heart, it’s got my feeling a little bit worried, and I’m now unfortunately 50/50 about whether or not to start a cycle of Clen.

How common are these side effects, especially with somebody who doesn’t mess around and stupidly take a massive dosage all of a sudden without first tapering up?

Would appreciate a reply, thank you.


Side effects are proportional to the dose and the length of use. 120mcg sounds like an aggressive dose. Yes, I know people do that. People also use heroin, shove lightbulbs up their asses, and listen to Nickelback. Just because people do it doesn’t mean it’s a good idea.

If you can’t get serious benefit from 40-80mcg/d then your diet and training are too terrible to even consider starting any kind of drugs. Unless you make your living off of your body you don’t need to use heavy doses of semi-dangerous compounds.


Out of all three examples listed… I think this might be the one most detrimental to overall health and longevity


I’ve ran clen several times. You are correct to start at 20mcg a day and ramp up from there. If its real and properly dosed you will get the shakes from even that low dose. If you have any preexisting heart conditions its not for you. I don’t believe it actually causes any heart conditions but you need to read up on that yourself. Most common side effects are shakiness and excess sweating.