Critique the following t test in statistics

Critique key points about the scenario using a t-test, suggest an improvement to it, and explain your reasoning.

Scenario, I want to test a male enhancement drug.  I have 20 Men of different races ranging from ages 35-65.  I have the men rate their sex drive before and after taking the drug. Does the drug do anything?  In my scenario what would need to change to result in the need for a two-sample t test would be the number of groups.  To have a two sample t test you have to compare two sample types\groups.  The two sample scenario would be categorized as independent because they are not related and do not overlap in any way.  When it comes to Independent random sampling “The observations within each group have been randomly sampled independently of each other, and all of the observations in one group are independent of all of the observations in the other group.  The dependent variable of this study would be the scores from the men, because the scores will change. The independent variable of the study would be the men.