Age:Libido: Viagra

In my 70s and struggling getting it up, even with 50mg of Viagra. Is this an age related libido issue? Am I safe to try 100mg of Viagra without exploding? Any other suggestions?

My father in law is 71. He had his prostate removed at 60. The only thing that works for him is trimex. It’s a shot. I asked him at the family 4th of July party and he said it works like a charm