Your greasy hair might be trying to tell you something — and it’s not necessarily that you’re overdue for a shower.

“An oily scalp can be a symptom of androgenetic alopecia,” AKA the dreaded pattern baldness, Sophia Emmanuela trichologist and cosmetologist, told The Post.

This follicle foe is no joke, affecting some 50 million men and 30 million women in the US alone.

The condition is caused by a genetic sensitivity to dihydrotestosterone (DHT), a hormone that plays a role in hair production.

“Dihydrotestosterone causes hair follicles to shrink, leading to thinner hair, shorter growth cycles and increased shedding,” Emmanuel explained.

She broke down how to tell if your greasy scalp is a red flag for hair loss — and shared four simple tips that everyone can use to keep their oily roots in check.

What causes some people to have oilier hair than others?

Sebaceous glands on your scalp produce sebum — a natural, waxy substance that keeps your strands moisturized and protected.

But when sebum production goes into overdrive, it can turn your mane into a greasy mess, clog hair follicles and irritate the scalp. Over time, this may weaken the hair roots or trigger chronic inflammation, disrupting the normal growth cycle and potentially leading to thinning and hair loss.

“Hormone fluctuations, genetics, diet and stress can influence excess sebum,” Emmanuel said.

When grease is a sign of future hair loss

Excess sebum is common, but in some cases, it could be a sign of something more serious: androgenetic alopecia.

The condition is linked to increased activity of hormones like DHT, which can ramp up oil production. This creates an oily scalp environment that puts already sensitive hair follicles at greater risk, potentially speeding up thinning and shedding.

You’ll need a professional evaluation to be sure, but if you’re diagnosed, Emmanuel recommends treatments like Rogaine or low-level laser therapy, which may help slow or reverse the process. At home, hair-thickening products can also support fuller-looking strands.

“V&Co. Beauty’s Thickening Shampoo and Conditioner can be used to promote fullness, with ingredients like biotin and peptides to add strength and thickness,” she said, speaking on behalf of the brand.

Can hair training make your scalp less oily?

If you’re battling oily hair, the simplest first step is often the most effective: Wash more often.

That said, some people swear by a method called “hair training,” which involves washing less frequently in hopes of encouraging the scalp to produce less oil over time. But according to Emmanuel, the results can vary widely.

“Whether hair training is practical depends on several factors, including the individual’s hair products, hair texture, and the underlying cause of their oily hair,” she explained. “How often you shampoo your hair is just one factor that can influence sebum production.”

How can you make hair less oily?

To reduce greasiness, Emmanuel recommended avoiding putting oils directly on the scalp, as they can cause buildup, clog pores and lead to excess oil and dandruff.

Diet also plays a role.

“Reduce your intake of processed, sugary and fried foods,” Emmanuel said. “These foods influence hormonal responses that increase sebum production.”

For cleansing, she advised people with oily scalps to opt for clarifying or volumizing shampoos, which can help remove sebum, dirt and impurities.

“Many people with oily hair struggle with limp hair,” Emmanuel said. “V&Co. Beauty’s Volumizing Shampoo features a proprietary blend of collagen, amino acids, protein and vitamins, protecting the hair from damage and giving it body.”

Finally, try pre-shampoo treatments with ingredients like bentonite clay, zinc and salicylic acid, which help absorb excess oil and impurities before washing.