Is nicotine bad for testosterone?

Could you elaborate on the potential impact of nicotine on testosterone levels? I've heard conflicting opinions on whether smoking or nicotine intake negatively affects this important hormone. Testosterone is crucial for maintaining muscle mass, bone density, and sexual function, so understanding its potential vulnerabilities is paramount. Could you clarify if nicotine is indeed harmful to testosterone, and if so, how significantly it can impact its levels? Are there any studies or evidence to support this claim? I'd appreciate a concise yet comprehensive response to this inquiry.