Greetings. There are subsets of normal individuals who do not develop adequate hair for their age. You can wait for another year or so and see if it comes. The other option is to meet a Dermatologist and share your concerns. Laboratory evaluation may be needed to rule in or rule out any hormonal cause of such issue. Many a times, it is constitutional i.e you do not have any problem but your hairs have limited capacity. No wonder medications will help. The market is full of fake brands and waiting for customers like you. Apply your knowledge and reasoning and decide