Four months ago I started taking a supplement called CLA (Conjugated Linoleic Acid), which is a type of trans fat that has been linked to rapid fat loss in exercising humans, as well as muscle growth. At first the results were good, in the first month my leg muscles definitely got stronger without getting much bigger and that small bit of fat round my stomach definitely nearly disappeared. Month two, and things stabilised, I was training very hard and was feeling on top form. In fact I raised my MHR by 2% in 5 weeks, and was untouchable on the climbing we did on the Sunday clubruns. Month three, and I felt comfortable recommending CLA to a couple of clubmates. Then one night out I was chatting with a mate of mine, arguing (as the two of us often do) that the women out on that night were particularly attractive / boringly generic. Then we started talking about sex, recounting funny times etc when I realised all of a sudden that I hadn't had sex since splitting up with my gf 2 months previously. The fact that it was a shock was what really perturbed me, as it meant that I hadn't thought about sex or wanted it AT ALL in over 4 weeks, and to be brutally honest I had even stopped "self service" and just not noticed. I was also feeling constantly "muted" is the best way to describe it, like I almost cared enough about everything, but not quite. That is not normal for me. I went to the doctor, who had nothing to suggest other than I might be overexercising. I wasn't convinced and saw a second doctor who asked about my diet in detail and any supplements I was taking. As soon as I said "CLA" he basically told me to stop talking. He has recently seen a small number of boxers, cyclists and runners who were all attracted to CLA because of its fat loss, lean muscle effects. They had all presented similar problems. I immediately binned the CLA as soon as I got home. I met my new gf on the night I binned the CLA, totally one of those eyes meeting, heart pounding moments. It is now 5 weeks after I stopped taking it, and I'm nearly back to normal. There have been a few disappointing occasions, and a couple of near normal times recently. Luckily she is very understanding of what is happening to me. Though I am nearly back to normal, this has knocked me back hard. Imagine the damage to my confidence, and the resulting nervousness (which adds to the problem I'm sure) I am facing at the moment. I'd never underperformed in the sack before, now suddenly I've got this beautiful, intelligent, sexy woman who I am totally head over heels for, yet my body won't cooperate fully with my mind and my heart. I also feel like a total dimwit for not seeking professional advice when considering taking this. I have been very honest here, because this is a horrible thing to have happen, and I don’t want to see it happen to anyone if I can help it. I urge anyone who it considering or already taking diet supplements to check them either with a dietician or ask your doctor about them. I have certainly learned my lesson; in fact it is still being drummed home whenever I see my gf and can’t physically express myself.