You’ve done everything right: You’ve washed your hair, avoided all gunky styling products, and haven’t worked up a sweat. And yet less than 12 hours later, your scalp is somehow stillcoated in oil and your head is a greasy mess. What gives? Well, according to stylists, certain lifestyle factors could be to blame.

“The glands in your scalp produce a lot of grease,” says Millie Morales, Garnier Celebrity Hairstylist, adding that there are a lot of internal factors that dictate exactly how much. Stress, genetics, and hormonal changes can all play a role in how much oil your pores are pumping out, and admittedly there isn’t a whole lot any of us can do to help that. What we can help, though, is changing up certain things we do throughout the day that might be making things worse.

Here, stylists reveal the common habits that are unexpectedly greasing up your scalp, and preventing you from making every precious wash last as long as humanly possible.

7 causes for greasy hair

1. Overwashing

You might think that you’re doing your scalp a favor by scrubbing it regularly, but overwashing  your hair can actually make it even greasier. “The scalp produces natural oils rich in vitamins and nutrients that help hair to grow healthy and strong, but when you wash too frequently, the hair is stripped of its natural vitamins and nutrients,” says FEKKAI celebrity stylist partner Chad Wood. When this happens, it starts to overproduce those natural oils, which leads to grease. To combat the issue, he suggests limiting washing your hair—even down to once or twice a week.

2. Washing the wrong way

Even if you’re limiting your washes to a few times a week, unless you’re doing it right you still may wind up feeling extra oily. “The way you wash your hair has a lot to do with how your scalp behaves,” says Morales. “When applying shampoo, you have to massage your scalp with your fingers to remove dirt. And when using conditioner, you have to wash it out really well, so that the pH of your hair doesn’t change and it doesn’t become greasy.”

3. Dirty air

There’s a startling statistic that the air indoors is actually more polluted than the air outside, which can be bad news for keeping your scalp clean. “If you live in a dustier area or home, that dust can collect on your scalp which can cause glands to become blocked and sweat more, producing more grease,” says Wood. Investing in an air filter, like the Levoit Air Purifier ($90), can help.

4. Your diet

You know how certain foods can cause your skin to become oily? Well, the same thing can happen on your head. “Think of your scalp as you do you face: when you eat junk food, you can see it on your face, and the same goes for your scalp,” says Wood. Your best bet for keeping it clear is through a healthy diet packed with fruits, veggies, calcium, and protein.

5. Touching your hair

Running your hands through your hair is a surefire way to wind up with a greasy scalp. “The oils and dirt that collect on your fingers and palms of your hand will deposit into wherever you’re touching your hair, and usually that’s along the front hairline around your face,” says SACHAJUAN artistic director Trey Gillen. So unless you’re styling, keep your fingers far, far away from your strands.

6. The temperature

If you’ve got the heat on full blast in your home (or are hanging out in hot, humid weather), you could start to see the effects on your scalp. “If the temperature becomes too hot and you are prone to sweating, that will definitely contribute to a greasier scalp,” says Wood. Plus, says Gillen, “when your AC isn’t removing all the moisture out of the air it could make your hair look more greasy,” so try to keep things cool as much as possible.

7. Accessorizing

Popping on a hat or a headband is an easy way to cover up dirty hair, but it could actually be contributing to the problem. The fabrics they’re made of “absorb the oil, then every time you put them on you’re redepositing it back onto your scalp,” says Gillen. So skip the accessories, and opt for a wash (or at least some dry shampoo) instead.

What to do to combat an oily scalp:

Now that you know the oily scalp causes responsible for the grease on your head, we can help you clear them up. In addition to steering clear of these behaviors, a solid product lineup can work wonders on the de-greasing process. “I suggest finding a clean shampoo and conditioner with no parabens and sulfates,” says Wood. He’s a fan of FEKKAI Super Strength Shampoo ($20) and FEKKAI Super Strength Conditioner ($20), while we love SACHAJUAN Scalp Shampoo ($29). “Remember the cleaner your products the more your hair can do what it’s naturally supposed to do. Your scalp will be able to regulate and create natural oils at a normal rate without added chemicals,” he says. Morales suggests only using conditioner on your ends, rather than applying it to your entire head, and extending the life of your wash with a dry shampoo, like Garnier Fructis Invisible Dry Shampoo ($5).

And one more thing to keep in mind as your ridding yourself of these everyday oily scalp causes? “It won’t happen overnight,” says Gillen. “If you have active sebaceous glands it will take three to four weeks of using the proper shampoo to turn it around.” So time to start on those good hair health habits now.

These nighttime hair routines will have you waking up with your healthiest hair ever. Plus, how to deal with overgrown hair (and the split ends that come along with it) when heading to the salon for a cut simply isn’t an option.