Gym and creatine can cause hair loss by increasing testosterone and androgenic activity. DHT blockers may help some, while others need androgen suppression with topical AA like RU or Pyri.
People have been using finasteride for 10 to 20+ years to maintain their hairline, with many reporting success and no significant side effects. Some users have combined finasteride with minoxidil for better results, and a few have switched to dutasteride or added hair transplants when finasteride was less effective.
Creatine use with finasteride increased DHT levels, possibly affecting hair loss. The user plans to reduce creatine to stabilize DHT and hair shedding.