I usually stay out of threads like this to avoid a ticking match and no disrespect to anyone here but I feel like there is misinformation in this thread so I wanted to chime in.
You are completely capable of gaining muscle working out 20-30 minutes 3-4 times a week as long as you are doing things correctly.
When it comes to weight training, less is more. If you are spending hours working out, that will lead to over training.
When it comes to reps, don't get caught up in the high reps is for definition and low reps is for bulk. What happens when Guy 1 is doing high reps (with low weight) while eating 6000 calories a day and Guy 2 is doing low reps (heavy weight) eating 1500 calories a day?
As far as gaining weight, its calories in vs calories out. If you consume more calories than you are burning, it will gain weight. It you burn more calories than you are cosuming, you will lose weight. You want to make sure the calories you are consume are good calories and not junk food.
A simple formula I have always preached is:
Workout + nutrition + rest + dedication/consistency = success
If you are not seeing results you need to look at the formula and see where your weakness is. It's 100% guranteed you will be able to identify what is holding you back (sometimes its more than 1).
When it comes to supplements, I feel you can benefit from them but people depend on them too much. A supplement is "an addition to" what should already be a healthy diet. Real food will and always be your first priority. Supplements that I do recommend are protein (isolate or a blend), creatine (scientifically proven) and a multivitamin/fish oil. If you have any health issues please check with your doctor first.
Last but not least is the weight training. Always remember that reps is important that the weight. What I mean by that is select the weight you use by knowing how many reps you are trying to archive for that particular set. A lot of people select random weights without knowing exactly how many reps they will get. That is a big no no. A basic guideline for reps would be
:
1 set - 12 reps
2 set - 10 reps
3 set - 8 reps
Focus on your form and go slow on all your exercises. One day at a time and consistency is key.