You would be suprised. Take M-drol, its legal. Its a designer, and can add I would say up to 18lbs realistically on a frame like yours(ours, I am 159.2, was 165 2 weeks ago but getting in shape for summer Cardio is shrinking me fast). When I came to AM I was 130 solid muscle, at 5'9 5'10(not sure wtf I am anymore). Hit up the diet/bulking/training forums and you will find what you need to grow. As for anabolics....I think differantly. Someone your size could use epistane, put on 12lbs and keep it and add another LB or two in PCT and keep going. IF you know what your doing that is. Which in comparison to someone bigger may run epistane, get 10 lbs, lost 2 in PCT then stay steady or slowly slide down. 80% of what you see in an anabolics section is freaking "broscience", and outside of that NO ONE ever needs AAS with the exception of those on HRT by doctors.
P-mag is very mild though. Some one our size can easily hit 180 within a year (thats about 25 lbs for you). I was getting close at one point but lost a job, kept getting sick, etc....voila!
Just dont rush it, enjoy the game. I am still natural because I know hell was coming my way and didnt wanna be dumb and run a cycle. Then again I now have a stock pile worth being proud of

thanks to recent friends! Would I love to jump on a couple things, gain 14 lbs while losing fat, and look sick this summer? Would LOVE to! Would it be wise atm? No, so its gona wait.
Get what interests you, throw it in a dark dry drawer, cover it with some old underwear, and come back to it in a year and a half all the while studying Steroids IF you even want to use them.
And if you do want to follow that path, "Anabolic Pharmacology" is good to read, as well as a few other really good books on the subject.
They will all shut you down to various points(people will say something like halo is so light it would barely require an OCT PCT, while something like superdrol could take many months to recover from) The individual human body is so freaking unique you cant rely on someone else's results and experiences. Some people on here could eat superdrol like candy and enjoy it and grow, and be fine. Others take 2 or 3 doses and feel like death coming for them.
Study, lift, love, enjoy yourself, and if the time comes where you feel you have accomplished yourself, and running a cycle is a want(never a need), and you have the means to do it safely, and find yourself physically ready and in the upper areas of your potential. Go for it.
You will always have haters, broskies, cheerleaders, followers, idiots, guides and mentors, smack talkers, tools, etc on these sites. Be you, do what you desire with life, just be safe.
FYI, I been studying steroids AAS/PH/DS for the last almost 3 years, still haven't cycled. Never had a "good" time for it. Never rush the important things, and one of those things for people like us is solid quality muscle and strength.