Test boosters, what do they do? To put it simply a test booster supplement can help increase testosterone or free up bound testosterone. For men after the age of 30 testosterone starts to decline. When testosterone starts to decline it becomes difficult to maintain lean mass and strength levels. Lower testosterone has also shown to increase fat mass too. This sucks, however there are products that will help slow down the decline of testosterone and elevate your natural test levels safely. Check out our test boosters, we only carry the best!