HOW TO KEEP YOUR HAIR FROM EVER FEELING (OR LOOKING) GREASY

But during the summer, your skin goes into oil-production overdrive — and yes, that applies to your scalp, too.

Styling products (even dry shampoo) and overdoing it on conditioner can also contribute to greasy buildup that winds up weighing down strands and making them look dull and generally pretty sad. Here's our complete guide on how to deal.

HERE'S WHY YOUR HAIR IS GREASY

"The most common reason that someone has an oily or greasy scalp is the fact that he or she is genetically prone to such," says Dr. Jeannette Graf, the director of dermatology at Omni Aesthetics MD in New York City. "Hormonal imbalances can also play a role. Very often an oily, greasy scalp is accompanied by facial acne and vice versa." But there are also some environmental elements that can exacerbate the situation. Exercising (as you sweat more, your skin produces more sebum), warm weather (again, more sweat = more sebum) and overdoing it on styling products can all play a role, says Graf.

Another sneaky contributing factor when it comes to greasy hair? Your hands. "Stop touching your hair. Every time you do, your fingers are adding more oil," says hairstylist Nick Arrojo. "You'll have a harder time making your stands look less greasy if you keep messing with it." So, if you absolutely must touch your hair, touch it with a hair brush, which can actually be a helpful tool for quickly diffusing oil. "Brushing your hair is the oldest trick int the book for making it feel fresh," says Arrojo. "A bristle brush will break up dead skin cells at the scalp, move oil along the lengths of your strands for shine, and stimulate blood flow to your scalp." He suggests his own paddle brushand recommends brushing your hair for a full five minutes, "moving hair back and forth around your head" for the best results. 

One thing that doesn't cause oil production, though you've probably heard that it can? Shampooing. There's a misconception floating around of late that washing your hair too often will only increase oil production. Not so, says Graf. "This is a myth. Shampooing removes excess oil. It doesn't produce oil."