Libido often has less to do with test levels ESPECIALLY if talking about still in normal ranges (going from 400-700 as example) and more with other factors. I actually did a lot of IF waaaay back in the day about 5-6 years back. I did get more energy at times, spikes in libido.....but no increase in testosterone. It also did not favorably affect my body comp....it didn't ruin my physique but it certainly didn't make it better. Ending conclusion: I am not a fan. Now having a protein/fat breakfast in the morning small in quantity then saving larger meals for later in the day.....this I can vouch for! I stay more energetic and my physique chugs along with no issue.