Unwanted - Does your mino 15% contain other ingredients? I am only using Regaine shampoo to keep my scalp clean for the mino dose.
normally min 15% will contain an acid. this is because in order to dissolve such huge amount of minoxidil in a solution the PH of the solution need to be slightly acidic. commonly, the acid will be 5% azelaic acid. reason is because the seller will try to market azelaic acid as a type of "anti-androgen". sadly, that appear to be only marketing hype as azelaic acid only show to have that effect in-vitro while in-vivo similar effect is absent. another common acid use for more honest or better inform seller is phosphoric acid.
the vehical of min 15% commonly use is glycerin, alcohol and water. as mention before, propylene glycol the commonly use vehical for standard min 5% is a much more better vehical then glycerin as it penetrate the skin much better then glycerin. so it to say although it contain 15% of minoxidil, it is not accurate to say it is min 15% VS min 5% if comparing the 2 strength due to different vehical usage.
oh, to add on. just use some standard and cheaper shampoo will do. there really nothing special about the Progaine shampoo.