What Causes Oily Hair?

We've all woken up to a dreaded bad hair day. For some people, that may mean tangled, unmanageable curls. For others, it could be a matter of split ends and a haircut long overdue for a trim. But often, bad hair days are caused by hair that looks oily, dirty, and lifeless. When greasy locks strike, you may hide them under a beanie or reach desperately for your favorite dry shampoo to mattify oily hair.

Even experts swear by dry shampoo as an easy, waterless beauty hack. "Add it to your root area to absorb excess oils, sweat, and impurities. It can also create volume and texture in yesterday's hairdo," Dominic Roach, Creative Director of Colour at Butchers Salon, tells Glamour. But dry shampoo isn't just costly — it can be tough to find reliable products amid massive dry shampoo recalls. So instead of burning through bottle after bottle of mattifying powder or aerosol, wouldn't it be nice if your hair was less oily in the first place?

Of course, to perfect your hair care routine and help your locks live their least greasy life, it's important to understand why they even get so oily. As it turns out, there are a number of factors that play into the condition of your hair.

The oil in your hair, known officially as sebum, is the same oil that appears on your face and other stretches of skin. It is released by sebaceous glands under your scalp, providing hydration and a protective barrier for your skin and hair (via Head & Shoulders). But left unchecked, it can also run wild and leave your hair looking greasy and limp.

Pretty much anyone can end up with oily hair if you go long enough between washes. But how long is too long? That can vary widely depending on your genetics, hormone levels, and the condition of your scalp. "Our scalps are loaded with oil glands, just as our faces are. Oil production is controlled by our genes, and that's not something we can voluntarily control," Joshua Zeichner, M.D., tells Self. So while some people might be genetically predisposed to hair that looks great for a week, less fortunate souls may see their locks go slick and flat in a mere 24 hours (per Insider).

If you naturally happen to have an oily complexion, the oil in your hair may build up faster. Even humid weather and air pollution can play a role. But there are also certain habits that could be worsening the issue. Healthline attributes greasy hair to factors like excessive use of hair products, intensive exercise, and overwashing. Overwashing essentially strips your hair and scalp of so much oil that the glands think you're drying out, and respond by producing even more oil than before. So while you may be tempted to declare total war on your oily hair, make sure you're allowing your scalp time to breathe between washes.

With everything from your hormones to your environment making your oily hair worse, it can seem like you're fighting an uphill battle for fresh, bouncy tresses. But there are some tips and tricks to help keep your oily hair under control. For instance, Medical News Today suggests choosing a clarifying shampoo and a light conditioner while avoiding any heavy, buildup-inducing styling products with a lot of oil or wax. The site also recommends regularly cleaning anything that touches your hair, such as brushes, combs, hats, or pillowcases.

How you apply your products can also make or break the oiliness of your hair. To reduce greasiness and scalp buildup, try limiting your application of conditioner to the ends of your hair while avoiding areas near the roots (per Goldie Locks). And always be sure to rinse out any shampoo and conditioner thoroughly to keep excess residue out of your lustrous mane.

If these tricks don't help, you may need to take steps to balance your oil-triggering hormones, such as rethinking your diet. "A diet rich in sugars, dairy products, and red meats can make the scalp produce more oil," stylist Michael Bowman tells Byrdie. Setting healthier habits can have a domino effect on many different aspects of your well-being, so don't be afraid to use your oily hair as an inspiration to make bigger lifestyle changes like cleaner eating. At the very least, your scalp might appreciate it!