male testosterone shots ?

betta • 33👧 ▪️Canadian Girl 🇨🇦 Happily Married💍 ▪️GirlMom💜 ▪️Dog mom💚🐾
Hi, my husband has recently gone to the doctor to see help in our fertility struggle. We are on almost two years of trying. He has gotten a semen sample done and also blood tests. We were told everything came back great for his semen sample which is good  but his blood work showed very low testosterone.
 His doctor has given him a prescription for Injections.  I am just wondering if anybody else has any experience with this and if so did it work? 
Pros and cons? We are shocked cause we didn't think anything would Come back but this might be the missing piece to our puzzle!!!! HELP