Core Viewpoint - The article emphasizes that proper hair washing techniques and the selection of effective ingredients are crucial for hair health and growth, rather than relying solely on new shampoos [1]. Group 1: Hair Washing Techniques - The effectiveness of shampoo ingredients requires sufficient contact time with the scalp, typically 3-5 minutes for active components like caffeine and saw palmetto [2]. - Washing frequency should be tailored to individual needs; for oily scalps, washing every 1-2 days is recommended, while dry scalps can extend to 3-5 days [3]. - Proper scalp cleaning is essential, involving techniques such as using warm water to open hair cuticles and massaging the scalp to enhance blood flow by up to 20% [4]. Group 2: Active Ingredients in Shampoos - Salicylic acid, a beta-hydroxy acid, is effective in removing scalp oil and dead skin cells, suitable for oily scalps, and should be used 1-2 times a week [5]. - Caffeine has been shown to inhibit hair follicle miniaturization and promote hair growth by increasing energy signals within follicle cells [5]. - Herbal ingredients like cedar leaf and he shou wu (fo-ti) can improve scalp circulation and prolong hair growth phases, with specific usage recommendations for their extracts [7].