Hudson had signed a three-year deal with Bradford Bulls when he tested positive for the banned steroid stanozolol.
The 26-year-old former Wakefield and Castleford loose forward said: "These last two years have been a roller-coaster ride. Two years ago, when I received the ban, I thought it was the worst day of my life.
"Now I would say it was a massive turning point in my life, for the better. I've done a lot of soul-searching deep within myself.
"I made a mistake. I trusted someone and paid the consequences. I was stupid, irresponsible and totally naive.
"I believe everyone makes mistakes, but only fools make them twice. I'm certainly not going to be that fool."
Hudson now wants to work with the RFL and Sport UK on an education programme for youngsters.
"We know how good Ryan can be and we think he can become a better player than he was two years ago," said Giants coach Jon Sharp.
"He's suffered for two years. He has paid his dues and he is looking to help others. I think that's a massive indicator of his attitude."