NAC side effects

Hey guys! I'm new here and just wanted to know if those of you who use/have used NAC as an alternative to metformin or for other reasons have experienced any side effects. I seem to have developed a cold/runny nose and an irritated eye over the past few days, and interestingly enough the start of the symptoms pretty much coincide with when I started the NAC. I connected the two as I know NAC is used as a 'mucolytic agent' in people suffering from mucus buildups like COPD sufferers.
Has anyone experienced this or any other side effects?
Also, did NAC work for you, and if so, what changes did you see?

Thanks :)

NAC side effects