This is an interesting idea for a study. Unfortunately, I believe the results are useless because the small dose of testosterone used. The abstract says:
"We did a randomised, controlled, open-label trial at four paediatric centres in Finland. Boys aged at least 14 years with CDGP who wanted medical intervention and exhibited the first signs of puberty were randomly assigned in blocks of ten to receive either six intramuscular injections of low-dose testosterone (about 1 mg/kg bodyweight) every 4 weeks for 6 months or peroral letrozole 2·5 mg once daily for 6 months. All boys were followed up for 6 months after the end of treatment. The primary outcomes were changes in testicular volume and hormonal markers of puberty at 6 months after treatment initiation, which were assessed in all participants who received the assigned treatment 30 boys were randomly assigned to receive testosterone (n=15) or letrozole (n=15). One boy in the testosterone group was excluded from the primary analyses because of a protocol deviation. During treatment, boys in the letrozole group had higher serum concentrations of luteinising hormone, follicle-stimulating hormone, testosterone, and inhibin B than did boys in the testosterone group. Testicular growth from baseline to 6 months was greater in the letrozole group than in the testosterone group"
I'm guessing the average weight was about 60 kg, so the boys received 60 mg of testosterone every four weeks, a ridiculously small dose for TRT. No wonder the letrozole group did better.
"We did a randomised, controlled, open-label trial at four paediatric centres in Finland. Boys aged at least 14 years with CDGP who wanted medical intervention and exhibited the first signs of puberty were randomly assigned in blocks of ten to receive either six intramuscular injections of low-dose testosterone (about 1 mg/kg bodyweight) every 4 weeks for 6 months or peroral letrozole 2·5 mg once daily for 6 months. All boys were followed up for 6 months after the end of treatment. The primary outcomes were changes in testicular volume and hormonal markers of puberty at 6 months after treatment initiation, which were assessed in all participants who received the assigned treatment 30 boys were randomly assigned to receive testosterone (n=15) or letrozole (n=15). One boy in the testosterone group was excluded from the primary analyses because of a protocol deviation. During treatment, boys in the letrozole group had higher serum concentrations of luteinising hormone, follicle-stimulating hormone, testosterone, and inhibin B than did boys in the testosterone group. Testicular growth from baseline to 6 months was greater in the letrozole group than in the testosterone group"
I'm guessing the average weight was about 60 kg, so the boys received 60 mg of testosterone every four weeks, a ridiculously small dose for TRT. No wonder the letrozole group did better.