Zion Ko Lamm, M.D. (고시온) on Instagram: "Should you be double shampooing? Maybe… depends on your scalp, hair type, how often you wash… Double shampooing just means using shampoo twice in the same wash. The first cleanse helps lift oil, dirt, and product buildup, and the second cleanse actually lets the shampoo do its job on the scalp and hair. It’s like “vacuuming the floors THEN mopping.” If you wash infrequently (say every 3–5 days), use a lot of styling products, or have an oily scalp - do