In high school, I weighed about 180 at 17 and 5'5", and had the fifth highest strength index in my high school. In my late 20's, and off and on from time to time, I weigh 230, but, generally I hang 205 to 220. 230 means eating almost non stop.
If you want to get bigger, you have to have more calories (this topic comes up every few days). If you fear food..you WILL fail.
Each pound of muscle burns about 20 to 25 calories per day just sitting there, so, the bigger you get the more you MUST eat.
In general, to gain mass, about 18 calories, or more, per day, per pound of weight is the current rule of thumb.
Adding muscle is the ONLY activity that gives you a more active metabolism AS YOU GROW OLDER. (Along with a long list of other good effects, but...more muscle means more work for your heart, so you have to stay hydrated, and YOU MUST DO CARDIO.)
I am a classic meso (I was 180 in HIGH SCHOOL). If your wrists are small, you have less potential to be a big man. Just how it is.
If you want size, you need an abundance of calories, and you need to train for sarcoplasmic hypertrophy.
Testosterone, is endogenous to your body, so unlike over the counter supplements, it's much LESS likely to cause any harm.
Many current OTC supplements are JUNK, unsafe, and unhealthy.
The take away: Eat.
I've put 85 pounds of muscle on someone in just 5 months, while lowering fat by 2%. It's about EATING.
I grew up on a ranch in Nebraska, and ate lots of solid food (not fried, not sugary, not fatty, not salty).
Eat. Eat more.
You have to nudge your set point up. The higher the set point, the more calories it requires to eat.
If I'm very active, I'll consume close to 6000 calories a day...every day.
It is that very simple: calories.
The more you eat, the faster your set point moves up.