Why Use Test XS?Clinically validated dosage of D-Aspartic Acid (D-AA) to ensure real results.A recent study was conducted on 23 healthy males between the ages of 27 and 37. One group of men was administered 3,120mg of D-AA while a control group was given a placebo (salt solution) over 12 days. The group of men given D-AA had an average raise in testosterone of 42% as wellasa 33% raise in LH levels compared to no increases in the placebo group. What this means? This ingredient at this dosage has been proven to effectively work!