There's obviously a ton of material available discussing what supplements can help you gain muscle. I'm largely of the opinion that most of these are really helpful if you don't have a balanced diet (so maybe helpful while cutting on a deep calorie restriction for example). Anabolic steroids are obviously an exception and creatine looks to have plenty of evidence that they it does provide a significant enhancement to muscle output during high effort anaerobic work, which mechanistically would lend itself to enhanced stimulus and more growth potential.
There are also things you can take that will inhibit muscle growth. Metformin, for example, inhibits the mTORC1 signaling pathway which limits protein synthesis and anabolism while promoting catabolism (this is also why it appears to have general anti-cancer benefits as well). NSAIDs, aspirin, NAC, and ice baths within a day or so of a workout reduce local inflammation, which is an integral part of the growth stimulus so by their action inhibit growth.
The queestion is, with all of the emphasis on what to take to grow is there a list anywhere of what supplements to avoid if you are trying to put on muscle?
