Depending on your age, I would say about 50 years give or take 5 years. This is assuming that you live to be roughly 70-75 years old, though, and are already about 20-25 years of age.
Okay, seriously, you are going to get a ton of differing opinions on this one. Some will say it is renal toxic so you should take it no longer than 6 weeks. Others, like myself, will say that it is not renal toxic (or anywhere to the level that was purported about 5 years ago) and that you can run it at normal dosages for 8-15 weeks, depending.
I DO believe that it is potentially more 'harsh' than other gear in that the affect it has on your lungs on occasion is not normal. When this shit goes pulmonary on you, and it will if you take it long enough, you will see right away that it is not at all normal. I can't explain why this is as it seems enigmatic in a sense. I have never received an explanation that was all that convincing to me.
There have been allegations that it has caused scarring of the lungs but I cannot validate or legitimize these allegations. I am simply noting this as I have heard it on a few occasions.
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