When selecting a hair growth shampoo to combat hair thinning and promote stronger hair, look for premium ingredients that are known to nourish and fortify hair, such as biotin, keratin, saw palmetto, caffeine, aloe vera, and niacin. Additionally, keep an eye out for nutrient-rich ingredients like vitamins A, C, and E, as well as natural extracts like rosemary, tea tree oil, and argan oil. These ingredients work together to stimulate hair follicles and create a healthy environment for hair growth while strengthening the hair shaft and reducing breakage.