I am currently taking d-aspartic acid as part of my pct after a cycle of t-bol. Its really cheap and after about 10 days, I can feel my test levels increase...libido-wise and it seems to be helping me keep my strength. I just take 1.5 grams in the morning and 1.5 grams before my workout. Tasteless so easy to mix it with anything. This DAA is from Omega Sports, which is a company I buy other supplements from too.