Is it safe to use dianabol in low amounts for gaining muscle?

No : Too many bad side effects, some of which may never go away. Just not worth it. There is no "safe" dose.

Dianabol: Dianabol is an anabolic steroid and can cause a host of side effects such as acne, impotence, weight gain, and male baldness.

Probably Not: No one really knows the long term effects of low dose steroids including dianabol. I would not listen to your local gym rats who say it "good for you" either. In the short term it can cause aggression issues, skin problems and I have even seen a couple of cases of gynecomastia. At 19, you don't need steroids to build muscle, just dedication. Lift 5-6 days a week and increase your protein.