As for how much moisture a scalp needs, that depends on the individual. Hill says that each of our scalps has a unique ideal balance of sebum—the scalp's natural moisture. And actually, the sebaceous gland connected to the hair follicle is regulated by hormones. "We cannot address scalp moisture without connecting our internal health and wellness," she says. "When this becomes imbalanced, it creates a breeding ground for overproduction of unwanted bacteria, inflammation, flakiness, tight scalp, compromising the health of the hair follicle."
You might think that your scalp's moisture levels are determined by your hair type—I did—but it's based on a number of factors: lifestyle, genetics, diet, stressors, medications, etc. "Hair type plays a role in moisture level but rather the type of products and our styling habits based on our hair type and texture," Hill explains. "For example, if you have curly hair and you blow-dry your hair regularly, the blow-drying is affecting the moisture levels, not the curly hair. And vice versa if you have fine straight hair and you shampoo multiple times a day. It is the impact of the frequent shampooing, not the fine straight hair, that would cause unwanted dryness."
And board-certified dermatologist and founder of Ziering Medical Craig Ziering, DO, says you do have to keep in mind how you care for your specific hair type and its effect on the scalp. "Hair length and hair texture play a role in managing sebum production," he says. "Those with curly hair require more time between washes than those with straight hair, as the oil needs to travel along corkscrew-shaped strands to moisturize all the way to the ends."
So what are some signs that your scalp isn't moisturized enough? Well, you'll probably notice some flakes. "Dry scalps can present in many ways but are often slightly pink, flaky, and itchy," Ellis says. "The flakes that come from a dry scalp tend to be white and powder-like, whereas flakes from oily scalps tend to be larger, thicker, and sometimes slightly yellow in color." You might also notice dry brittle hair fibers, tightness on the scalp, and dry-looking hair.