How can I gain more weight?

I am thin too and just joined the gym. Lift weight regulary but make sure you take a day or two off from gym to let your muscle grow.The key is not adding the weights but repetition! Of course you gotta eat a lot, like 6x day but in more smaller amounts. Drink a weight gain supplement like whey protein.And keep yourself hydrated, drink lots of water, Hope that helps.Good Luck!

There are definitely no antibiotics for it. Antibiotics are made to kill infections in your body, which I’m assuming you DON’T have. Plus, you don’t want to be fat! Maybe have a little more muscle and substance, but not fat. That’s just unhealthy. Nothing is going to happen suddenly, so keep exercising more, weights are good. Just find a routine and stick to it! You’ll see results eventually. Just be patient.

Eat lots of protien.

well if you want to be “in-shape” then just keep working out and you will see results. if you want to literally gain weight then you have to eat more calories than you burn in one day.