I've been using it for about 6 weeks because my eyebrows were thinning ( with age, not plucking) and am really chuffed at the difference. The new hair is thicker and a different colour to my former eyebrows ( it's darker and may be dark grey :( (not sure...) but it is certainly there so much so that I am not using the product for a while or I'll have to start plucking. I used to be complimented on my shapely brows ( nothing else!) that I never plucked so am really pleased to have some fullness back.