I was wondering what supplements are safe to use to gain weight? this is my first month hitting the gym. thanks in advance.

As long as you are: Healthy, the majority of the supplements on the market are "safe". That being said, i would recommend more pure protein supplements as you want to gain muscle mass more than just add calories. Consider a 3:1 to 4:1 carb:protein ratio as just post workout, Insulin boosts have been shown to have some benefit. However, the rest of the time, try to stick to protein supplements to avoid fat increase.