There are TWO types of creams, one you can ONLY apply to the scrotum, the other you apply anywhere EXCEPT the scrotum. The type that you do NOT apply to the scrotum has a type of chemical in there that will make the absorption of test more effective through all the various layers of the skin. I forget which chemical, but it works very similar to DMSO and drives the test into the blood stream quicker and more effectively. Since the scrotum has only a few thin layers of skin, and is very sensitive, you do not use this type there. It would be an irritant AND be too effective in driving in test into the bloodstream, making your blood plasma levels too high. Therefore, the type that you apply to the scrotum does NOT have this chemical agent.
Unless otherwise prescribed, rubbing Testosterone cream into your scrotum can increase the amount of Testosterone into the blood stream than what the cream was made for and could impact E2 levels in a negative way. Also, the scrotum has a great deal of 5-AR so you could get very high levels of DHT as well…that’s not a good thing for some men.