When WG first presented itself 20 years ago I was on CTX for just a short period as I could not tolerate it. I lost pretty much all my hair due to CTX. Since then I've been on Azathioprine for most of my life without any hair loss issues. That was until earlier this year. I asked my Dr if it was due to my meds, but he thought it was just a result of my body being unwell (WG relapse).
The strange thing is I've only just started Folic acid earlier this year, just about the same time as my hair has started to thin significantly. I'm not suggesting that this is proof that Folic acid doesn't help hair loss as, maybe, my hair loss would be even worse if I wasn't already on folic acid.