^^^^^^ exactly. who recommends a test/deca/dbol for a first time user? that's aweful advice. obviously the norm is test only or maybe an oral only imo. but i know the OP pretty well, don't be fooled by the 6'0 160lbs ...he's been a boxer and runner his whole life so he carries no bodyfat and with that muc activity it's hard to gain weight..he's been lifting his whole life.
That's good information to have and it's great that limits is athletic and very low body fat (at 6'0" and 160lbs that's a given). But that doesn't change the fact that he needs to eat more (or run less) if he wants to gain mass.
Just because a person works out and has a healthy diet, that alone does not guarantee a lot of muscle. The physics don't change just because you're healthy; you have to take in enough calories to maintain a given body mass, whatever that desired mass may be.
Just about every poster so far is trying to tell OP that he has the potential to gain a shit-load of muscle naturally, simply by eating more.
I graduated high-school at 5'11" 145lb so I've been there myself. A steroid cycle could put about 10 lbs on me simply from increased nitrogen retention. But in about a month after the cycle was over, all the muscle was gone because my diet didn't support it.
Also, running and adding muscle definitely work against one another. That's something else I know from experience. Even if you eat enough calories to make up for those lost, running triggers changes in your body that really slow down the rate at which you can add muscle. Distance running does anyway.
So, limits should increase his calorie intake by 1,500 calories per day and make sure he is eating at least 200g of protein every day.
Switch from distance running to wind-sprints. And, lift heavy 3-4 days/week.
Then, in 90 days when he weighs 185+ lbs, he should come back for AAS advice.