Apply topical spironolactone cream to whole head?

[goodhair]

I have been applying topical spironolactone cream to the hairline and the front of my head where the hair is thin. However do I need to apply it to the entire head? Since topical spironolactone is a cream it would be diffult to apply to areas where my hair is not as thin as the front. The cream would get into the hair and be wasted and not get applied to the scalp.