Sounds like you've been talking about Human
Chorionic Gonadotropin (HCG). I've been taking
it for years. HCG stimulates a hormone that
"tells" the testicles to produce more
testosterone.

If your body does not produce enough testosterone,
it may be due to a chemical imbalance. This
imbalance can cause testicles to atrophy. HCG
has been prescribed to stave off further shrinking
of testicles. (If your testosterone level is
not amiss, use of HCG may just "turn off" the
hormone sent from your brain to the testicles..
until you reach normal levels.

Some doctors may be hesitant to make use of HCG
in these instances, since this use is purely
cosmetic use.

Hope the info helps.