What are testosterone boosters? Testosterone boosters are formulated to balance and even boost the body's ability to produce natural, muscle-building testosterone or free up bound testosterone. Some ingredients in test boosters also help reduce estrogen or block conversion of testosterone into DHT (Dihydrotestosterone). Why should you take them? Here's the truth - after age 30, testosterone slowly starts to decline. This leads to a decrease in lean mass, reduced strength, and an increase in fat mass as well. To keep testosterone level at a desirable level, consider using a testosterone booster to help balance and even elevate testosterone. You will find in most products longifolia Jack (Tongkat Ali), fenugreek, Tribulus terrestris, ZMA, and/or D-Aspartic Acid. These are top ingredients in the test boosters that help increase testosterone production.