3. Your period

Helen Reavey, trichologist and founder of Act+Acre, points out that “fluctuating hormones can cause an imbalance of oil on the scalp,” which then travels down the length of the hair strand.

In particular, there is a decrease in oestrogen and an increase in progesterone a week before your period. “This hormonal change can stimulate the sebaceous glands in the skin to produce more oil,” she adds. “Mixed with product buildup, sweat, and dirt, this can contribute to greasy hair.”

4. Some contraceptive pills

Depending on your hormonal makeup, some people will be more prone to stringy strands than others. “Some birth control pills contain progestin, a synthetic form of progesterone, which can increase oil levels, too,” Helen explains.

5. The weather

“Many people find their hair is greasier in the warmer months,” says Dominic Roach, Creative Director of Colour at Butchers Salon. “Higher temperatures often mean you sweat more, which mixes with the sebum on the scalp spreading more greasiness.”

You’re up against extra humidity, too. “With increased humidity, there is more moisture in the air and therefore more moisture in your hair,” he adds.

Even our summer accessories can exacerbate the problem. “Sunglasses pushed back onto the top of the head help transfer oil and grease. So do sun accessories like hats, which make the roots flatter and greasier,” says Dominic.

6. Your diet

“Just like the skin on our faces, our scalps can be prone to oiliness from the foods we eat, such as eating a fatty or sugary diet,” says Anabel. So if you want to know how to stop greasy hair, make sure you’re bearing in mind your diet.

7. The gym

Gym-goers will need to wash their hair more after a sweaty workout.

8. Styling products

Your styling routine can play into how quickly your hair gets oily, too. “Using heavy styling products can also make your roots greasy, as can using a dirty hairbrush,” says Anabel, who recommends washing your hairbrush every 2-4 weeks.

Can you train your hair to last longer between washes?

Anabel points out that you can’t “train your hair to be less greasy by washing it less. Oil is produced on the scalp (not the hair), and once your scalp is cleansed it will simply continue producing oil at the same rate.”

It’s also quite difficult to over-wash your hair. “‘More often than not’ is always a good principle to obtain the best scalp conditions for healthy hair growth,” adds Anabel.

How often should you wash your hair and scalp?

If you’re experiencing oily roots and hair, cleansing the scalp of excess buildup is crucial to avoid blockages in your hair follicles, which can lead to irritation and dandruff. Lars Skjoth, a product developer and founder of Harklinikken haircare, also stresses that regular use of a gentle shampoo balances the scalp microbiome, resulting in the ideal pH level needed for healthy hair growth.

“You take your hair and scalp to the same places you take your face, and it gets just as dirty,” Anabel explains. “Your scalp is also a living tissue; it sweats, produces oils and sheds skin cells. You wouldn’t leave more than three days between washing your face – apply the same thinking to your hair and scalp.”