I was reading this review on Minoxidil https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6691938/ and they mention that 5% gives better results than 2%, which got me wondering, have higher concentrations than 5% ever been tried? Seems to me higher %s than 5 might give better results yet. Here's a relevant quote from the review: "A study by McCoy et al demonstrated that an increase in topical minoxidil concentration up to 15% in patients predicted to be non-responders increased the clinical response compared to that associated with 5% minoxidil without cardiac side effects.43 Therefore, the non-responders may have a clinical response with increased concentration of minoxidil." However it also mentions that side effects are more common with 5% than 2%, so maybe that's why higher concentrations haven't been tried. Still, seems to me it would be good to try.