I would probably go with forskolin and if you want to add something, look into Ashwaganda(or KSM-66), LJ100, or shilajit instead of DAA. My preference leaning more towards LJ100 or KSM-66.
It is my belief based on the data on concerning DAA, Na-DAA has a very specific population that you may not fall into being a healthy 38yoM. It appears that during times of gonadal hypofunction that Na-DAA works best. Studies indicate it works best in either infertile men or sedentary men who have lower then normal test levels. I would not recommend it to active, non-sedentary, non-suppressed athlete, this is supported by studies using healthy active men (it did not have the same effect).
The only time Ive seen Na-DAA work well for individuals is coming off a cycle or with severe stress induced Low T levels. 3.12g combined with some AI's worked for a nice natural short term boost before transitioning to longer term options.
Forskolin and KSM-66 is cheap and effective. Im personally enjoying LJ100 and KSM-66 at the moment.