Shelf life of liquid Fin, Min, Trent

I’ve been buying topical Minoxidil 5% + Finasteride 0.1% + Tretinoin 0.025% from Jacks.health online. They have been supplying it in a 90ml bottle (3 month supply). I recently decided to try going through my GP/local pharmacy and the pharmacy informed me they can only supply a months worth at a time because it goes bad after about 1 month. Does this mean I’ve been using garbage product from jacks.health for 2 or every 3 months?