"I drink socially most nights of the week, but I know it's not good for me. I'd like to lose some weight and avoid my occasional hangovers, so I should probably cut back. I like the relaxing effect of drinking and how sociable I feel, so I'm hoping marijuana could be an alternative?"
This is a rather complex question. The first thing to determine is how much you are drinking. The current U.S. recommendation for men is to not exceed 14 drinks in a week nor 4 drinks in a day. The current recommendation for women is to not exceed 7 drinks in a week nor 2 drinks in a day. If you drink on a daily basis, it is important that you slowly decrease the amount you are consuming by no more than two drinks a day to prevent withdrawal which can be serious or life-threatening.
The next step is to understand why you drink. You might want to keep a drinking journal to better understand your behavior. There may be other ways to deal with your problem, such as cognitive behavioral therapy, or seeking treatment by a psychiatrist or addiction medicine specialist.
Marijuana may help, or it may worsen your problem. If you drink for leisure and relaxation, it is possible that sedating forms of marijuana could provide a substitute to drink. Some patients, though, find that marijuana increases their energy and decreases their inhibitions, promoting drinking. Also, xerostomia ("dry mouth" or "cotton mouth") is a common side effect of marijuana and may make you more prone to drinking.