@truly520, you are well-advised to discuss with your husband's oncologist. All information shared by members on the Mayo Clinic Connect is for informational purposes only and is not a substitute for professional medical advice, diagnosis or treatment.

As you know, the purpose of androgen deprivation therapy (ADT), also known as hormone therapy, for prostate cancer is to lower and/or block testosterone. Most prostate cancer cells need testosterone to grow. ADT stops testosterone from being made or from reaching prostate cancer cells. This causes prostate cancer cells to die or to grow more slowly.

Whether testosterone levels return after treatment varies from person to person. This study sought to analyze the variability that determine the return of testosterone due to factors like age and length of treatment.
- Testosterone Recovery after Androgen Deprivation Therapy in Prostate Cancer: Building a Predictive Model https://pmc.ncbi.nlm.nih.gov/articles/PMC9826908/

You mention that your husband's treatment ended a year ago and that his testosterone level remains low or neglible. From a clinical point of view, that is desirable. From a symptom management point of view, hot flashes can range from annoying to debilitating and seriously affect quality of life, especially if he can't sleep.

All that to say, it worth a discussion with the oncologist about testosterone levels, possible strategies to manage the hot flashes, and the risks and benefits of each.

Here are some related discussions that you might find helpful:
- ADT and Insomnia: What's helps you sleep? https://connect.mayoclinic.org/discussion/adt-and-insomnia/
- Relief for hot flashes during the night https://connect.mayoclinic.org/discussion/relief-for-hot-flashes-during-the-night/

@truly520 Instead of testosterone injections (my testosterone level was below 100 after 2 Lupron injections and 44 radiation sessions) and I was having muscle loss and very frequent hot flashes, I was very cautious about getting the injections and wanted a better way to control how quickly and to what degree my testosterone level went up, so I did lots of research. After reading lots of medical journals I decided to use Testosterone Gel (1.62%). It's convenient, easily controlled, and very effective. My RO and Urologist agreed that it was a good solution. The usual instructions are to rub one pumping of the gel on each shoulder and upper arm each day, but I do 1 upper arm and shoulder every other day. My testosterone level is now in the 500s (where it's been for 3 years, which is great) and my PSA has consistently been below 0.01 (which means "undetectable"). If my testosterone lab test shows my level is getting too low, or too high, I simply adjust the application frequency or do both arms for a few days. There's no way your husband can have such control if he gets testosterone injections. Your husband should discuss this solution with his doctors.