I'm 42 and early last year I ran a short 4 week cycle at 2mg every other day to help with my cardio endurance. I fell in love with it. Didn't help my cardio much since I was till fat and out of shape. Even now my cardio still sucks! But I felt all around better. Improved my energy, more focus, better sleep, better weight lifting performance, less brain fog, and a myriad of other small quality of life improvements. After that I decided to do the 14 week NAD+, SS31, Mots-C protocol. Again, it was life changing for me. All the benefits of before but intensified.
I think it really just depends on where you're at with your cellular health to begin with. After 20 years of heavy drug and alcohol abuse, being obese, sedentary, and depressed, I had wrecked my health worse than was evident by my appearance and what common blood panels showed. I have since ran it 3 times with diminishing returns. Last cycle I felt almost nothing which I'm hoping means I repaired my cellular health to a major degree. I plan on running a cycle once a year for maintenance from now on.