What’s Causing Your Oily Hair (And How to Fix It)

Oily hair is primarily caused by the overproduction of a natural oil called sebum from the sebaceous glands in your scalp.

While sebum is vital for healthy, moisturized hair, excess amounts can lead to a greasy appearance, weigh down your strands, and even contribute to scalp issues.

This common concern isn’t just about aesthetics, it’s a biological process influenced by genetics, hormones and your daily habits.

Did you know you’re not alone in this battle? Recent studies reveal that an oily scalp affects a significant portion of the population, with a prevalence of 31% among American women and up to 46.7% in other parts of the world, according to a 2025 report in the Journal of the American Academy of Dermatology.

This guide will delve into the science behind oily hair, explore the surprising root causes and provide a comprehensive, expert-backed action plan to help you manage grease and restore balance to your scalp.

Keep reading to reclaim your good hair days.

What Exactly Is Oily Hair and Sebum?

Before we can effectively treat oily hair, it’s crucial to understand what it is and the biological mechanisms behind it.

The term “oily hair” is a bit of a misnomer, the hair shafts themselves don’t produce oil. The real source is the scalp.

Defining Sebum: Your Body’s Natural Moisturizer

Your skin, including your scalp, is covered in microscopic glands called sebaceous glands.

The primary function of these glands is to produce and secrete a complex, oily substance known as sebum.

According to research published by the National Center for Biotechnology Information (NCBI), sebum is a mixture of lipids, including triglycerides, fatty acids, wax esters, squalene and cholesterol.

This natural oil isn’t the enemy. Sebum plays several vital roles:

• Moisturization: It forms a protective, waterproof barrier on the skin and hair, preventing moisture loss.
• Protection: It has antimicrobial properties that help protect the skin from pathogens.
• Conditioning: It travels down the hair shaft, naturally conditioning the hair and giving it a healthy shine.

When Does Sebum Become a Problem?

The issue arises when the sebaceous glands go into overdrive, a condition known as seborrhea.

This excess sebum coats the scalp and hair, transitioning from a healthy sheen to a greasy, heavy feeling.

This can make hair appear limp, dirty and difficult to style.

Furthermore, an excessively oily environment can disrupt the delicate balance of microorganisms on your scalp, leading to other problems.

As noted in a 2025 study in Frontiers in Microbiology, this imbalance, or dysbiosis, is linked to conditions like dandruff and seborrheic dermatitis, characterized by itching, flaking and inflammation.

Why Is My Hair So Oily? Uncovering the Root Causes

If you’re constantly asking “why is my hair so oily?”, the answer is likely a combination of factors.

From your genetic code to your stress levels, several internal and external triggers can ramp up sebum production.

Genetic Predisposition: Is It in Your DNA?

The most significant factor determining your skin and hair type is genetics.

Your genes dictate the size and activity of your sebaceous glands. If your parents had oily skin and hair, there’s a strong likelihood you will too.

As dermatologist Dr. Carlos Portinha of Insparya explains, this genetic tendency is the primary driver behind your hair’s natural capacity to produce oil.

Hormonal Fluctuations: Puberty, Menstrual Cycles and Stress

Hormones, particularly androgens like testosterone, are powerful regulators of sebum production.

When androgen levels rise, they signal the sebaceous glands to produce more oil. This is why oily hair is common during:

• Puberty: A surge in hormones during adolescence is a classic trigger for oily skin and hair.
• Menstrual Cycle: Many women notice their hair becomes oilier in the days leading up to their period, when progesterone levels spike, increasing sebum production.
• Pregnancy and Menopause: These major life stages involve significant hormonal shifts that can temporarily or permanently alter your scalp’s oiliness.
• Stress: When you’re stressed, your body releases cortisol. This stress hormone can increase oil production, creating a vicious cycle where you stress about your oily hair, which in turn can make it oilier.

The Scalp Microbiome: An Unbalanced Ecosystem

Your scalp is home to a complex community of microorganisms, including bacteria and fungi, known as the scalp microbiome. In a healthy state, these microbes live in harmony.

However, an excess of sebum can disrupt this balance.

The yeast-like fungus Malassezia, a normal inhabitant of the scalp, feeds on the fatty acids in sebum.

An overabundance of sebum allows Malassezia to proliferate, which can lead to scalp irritation, inflammation and the rapid shedding of skin cells we know as dandruff.

Studies have also linked an increase in Staphylococcus bacteria to oily, dandruff-prone scalps.

Hair Care Habits: The Overwashing vs. Underwashing Debate

Your hair care routine plays a massive role. Both washing too much and too little can exacerbate the problem.

• Overwashing: Using harsh shampoos daily can strip the scalp of its natural oils. In response, the scalp may enter a state of overcompensation, producing even more oil to rehydrate itself.
• Underwashing: Not washing enough allows sebum, dead skin cells, sweat and product residue to build up, leading to a greasy, itchy and potentially smelly scalp.

Finding the right balance is key, and we’ll explore how to do that in the next section.

Diet and Lifestyle Factors

While the direct link is still being researched, some evidence suggests that diet can influence sebum production.

Diets high in refined carbohydrates, sugar, and saturated fats may contribute to inflammation and hormonal shifts that increase oiliness.

Conversely, a balanced diet rich in fruits, vegetables and healthy fats supports overall skin and scalp health.

How Often Should You Wash Oily Hair?

This is one of the most debated questions in hair care, and the answer is: it depends.

The optimal frequency is a personal balance that depends on your hair type, activity level and how your scalp responds.

The goal is to remove excess oil without stripping the scalp.

“There are few questions in personal care that elicit more debate than ‘How frequently should I use a shampoo?’ The opinions can vary from one end of the spectrum (as infrequently as possible) to the other (daily)”. – James Schwartz, The Procter & Gamble Company, in a study on wash frequency.

A landmark study published in the journal Skin Appendage Disorders  investigated this very question.

Researchers found that for the Asian populations studied, washing 5-6 times per week resulted in the highest overall satisfaction with hair and scalp condition, with no detrimental effects observed from frequent washing.

Here’s a practical approach to finding your ideal frequency:

1. If you wash daily and are still greasy: Your scalp might be in overproduction mode. Try skipping a day. Use a quality dry shampoo on your off-day to absorb oil at the roots. Do this for a week or two and see if your scalp starts to regulate.
2. If you wash every few days and have buildup: You may need to increase your frequency. According to the American Academy of Dermatology (AAD), people with very oily hair may need to shampoo as often as once a day.
3. Consider your lifestyle: If you work out and sweat daily, you’ll likely need to wash more often to remove sweat and prevent buildup.

How to Get Rid of Oily Hair: A Step-by-Step Guide

Managing oily hair involves a multi-pronged approach that combines proper washing techniques, the right products and smart styling habits.

Step 1: Master Your Washing Technique

It’s not just about frequency, but also *how* you wash.

• Focus on the Scalp: Apply a small amount of shampoo and gently massage it into your scalp with your fingertips (not your nails). Aggressive scrubbing can irritate the scalp and trigger more oil production.
• Don’t Shampoo the Ends: The ends of your hair are the oldest and driest. Let the shampoo simply run down the strands as you rinse. This is enough to cleanse them without stripping moisture.
• Condition Carefully: Conditioner is for your hair, not your scalp. Apply it only from the mid-lengths to the ends to avoid weighing down your roots and adding unnecessary oils.
• Rinse Thoroughly: Spend an extra minute or two rinsing your hair. Product residue is a major culprit behind hair that feels dirty and greasy right after washing. Use lukewarm or cool water, as hot water can stimulate sebaceous glands.

Step 2: Choose the Right Products

The products you use are your primary weapons in the fight against grease. Look for products specifically formulated for oily hair. These are designed to effectively cleanse without being overly harsh.

A key strategy is to avoid certain ingredients that can cause buildup. Silicones, often ending in “-cone” (like dimethicone or cyclomethicone), are used to add shine and smoothness.

However, they can build up on the hair, making it look heavy and greasy. Opting for silicone-free formulas can make a noticeable difference.

Step 3: Incorporate a Clarifying Shampoo

Once a week, or as needed, use a clarifying shampoo. These are like a “deep clean” for your scalp, designed to remove stubborn product buildup, hard water minerals, and excess oil that your regular shampoo might miss.

This resets your scalp, allowing your regular products to work more effectively.

Step 4: Use Dry Shampoo Strategically

Dry shampoo is an essential tool for anyone with oily hair. It works by absorbing excess oil and sebum from your roots, instantly refreshing your hair and adding volume.

It’s perfect for extending the time between washes or for a quick touch-up after a workout.

Pro Tip: Apply dry shampoo *before* your hair looks greasy, such as at night before bed. This allows it to absorb oils as they are produced, preventing the greasy look from ever taking hold.

What Are the Best Shampoo Ingredients for Oily Hair?

Navigating the ingredient list on a shampoo bottle can be daunting. Here’s a breakdown of what to look for and what to avoid to effectively manage oily hair.tr>

Ingredients to Look For (The Heroes)	Why They Work	Ingredients to Avoid (The Villains)	Why They’re Problematic
Salicylic Acid	A beta-hydroxy acid (BHA) that exfoliates the scalp, removing dead skin cells and excess oil to keep follicles clear.	Heavy Silicones (e.g., Dimethicone)	Cause non-water-soluble buildup, weighing hair down and creating a greasy film.
Tea Tree Oil	Has natural antifungal and antibacterial properties that help control the scalp microbiome and reduce inflammation.	Heavy Oils & Butters (e.g., Mineral Oil, Petrolatum)	Can be too occlusive for an already oily scalp, clogging pores and adding to the grease.
Zinc PCA / Pyrithione Zinc	Helps regulate sebum production and has antifungal properties, making it effective against dandruff associated with oiliness.	Harsh Sulfates (e.g., Sodium Lauryl Sulfate)	Can be overly stripping, leading to a cycle of dryness and compensatory oil overproduction. Look for milder sulfates or sulfate-free options.
Niacinamide	A form of Vitamin B3 known to help regulate oil production and improve the skin barrier function of the scalp.	Parabens	Preservatives that some people prefer to avoid, though their direct link to oiliness is less clear than their potential for irritation.
Clays (e.g., Bentonite, Kaolin)	Excellent at absorbing excess oil and impurities from the scalp without being overly drying.	Certain Alcohols (e.g., Alcohol Denat.)	Can be very drying and irritating to the scalp, potentially triggering more oil production.

Lifestyle Changes That Make a Big Difference

Beyond your shower routine, several daily habits can have a surprising impact on your hair’s oiliness.

Hands Off!

This is one of the simplest yet most difficult habits to break.

Constantly touching your hair, scratching your scalp, or running your fingers through your strands transfers oils from your hands to your hair.

It also stimulates the sebaceous glands on your scalp. Try to be mindful and keep your hands off.

Clean Your Brushes and Pillowcases

• Hairbrushes: Your brush accumulates hair, dead skin cells, product residue and oil. If you use a dirty brush on clean hair, you’re just redepositing that grime. Clean your brushes at least once a week with a gentle soap or shampoo.
• Pillowcases: Your pillowcase absorbs oils, sweat, and skincare products from your face and hair every night. Change your pillowcase every few days to give your hair a clean surface to rest on.

Rethink Your Hairstyle

Constantly wearing tight ponytails or buns can trap oil and sweat against the scalp and spread it down the hair shaft.

Letting your hair down allows your scalp to breathe.

Alternate between updos and wearing your hair down to give your scalp a break.

When to See a Dermatologist: Professional Treatments

If you’ve tried everything and are still struggling with extreme oiliness, persistent itching, or severe flaking, it may be time to consult a board-certified dermatologist or a certified trichologist (a specialist in hair and scalp health).

An underlying medical condition could be the cause, such as:

• Seborrheic Dermatitis: A common inflammatory skin condition that causes flaky, yellowish scales on oily areas such as the scalp.
• Scalp Psoriasis: An autoimmune condition that causes raised, reddish, scaly patches.
• Hormonal Imbalances: Conditions like Polycystic Ovary Syndrome (PCOS) can cause excess androgen production, leading to severe oily skin and hair.

A dermatologist can provide an accurate diagnosis and recommend prescription-strength treatments, which may include:

• Prescription Shampoos: Formulations with higher concentrations of active ingredients like ketoconazole or ciclopirox.
• Topical Corticosteroids: To reduce inflammation and itching associated with conditions like seborrheic dermatitis.
• Oral Medications: In severe cases, medications that regulate hormones (like birth control pills) or reduce sebum production (like isotretinoin) may be considered.

Myths vs. Facts About Oily Hair

There’s a lot of misinformation out there. Let’s clear up some common myths.

Myth: Oily hair causes hair loss.
Fact: Oily hair itself doesn’t directly cause hair loss. However, the underlying conditions that cause extreme oiliness, like severe seborrheic dermatitis or hormonal imbalances, can contribute to hair thinning. An excessively oily scalp can also lead to inflammation that may impact follicle health. A 2025 article in the New York Post highlighted that an oily scalp can sometimes be an early indicator of androgenetic alopecia.

Myth: You can “train” your hair to be less oily by not washing it.
Fact: This is an oversimplification. While reducing overwashing can help an irritated scalp calm down, you cannot fundamentally change your genetic predisposition for oil production simply by avoiding shampoo. The “training” period often just involves enduring a greasy scalp until it reaches its natural baseline, which may still be oilier than you’d like.

Myth: You shouldn’t use conditioner on oily hair.
Fact: This is incorrect. The ends of your hair, even if your roots are oily, still need moisture to prevent dryness, split ends and breakage. The key is to apply a lightweight conditioner only to the mid-lengths and ends, avoiding the scalp entirely.

Frequently Asked Questions

1. Why does my hair get oily so fast, even after washing?

This is often a sign of an over-stripped scalp compensating by producing more oil. It can also be due to hormonal fluctuations, using the wrong products, or not rinsing shampoo and conditioner out thoroughly.

2. Does dry shampoo actually clean oily hair?

No, dry shampoo doesn’t clean hair. It works by absorbing excess oil and sebum, which makes the hair appear less greasy. It’s a temporary fix and should be washed out properly to prevent scalp buildup and irritation.

3. Can stress make my hair more oily?

Yes. Stress increases the body’s production of the hormone cortisol, which can signal your sebaceous glands to produce more sebum, leading to oilier skin and hair. Managing stress can have a positive impact on your scalp health.

4. Will cutting out certain foods help my oily hair?

While research is ongoing, some experts believe diets high in sugar and refined carbohydrates can influence hormones and inflammation, potentially worsening oiliness. A balanced diet supports overall scalp health, but diet alone is rarely a complete cure.

5. Is it bad to wash oily hair every day?

Not necessarily. According to the American Academy of Dermatology, daily washing may be necessary for those with very oily scalps. If your hair feels and looks better with daily washing using a gentle shampoo, it is perfectly fine.

6. Does hair type (straight, curly) affect oiliness?

Yes. It’s easier for sebum to travel down the shaft of straight, fine hair, making it appear greasy faster. In curly or coily hair, the oil has a harder time navigating the twists and turns, so roots may be oily while ends remain dry.

7. Can oily hair cause dandruff?

Excess oil can contribute to dandruff. The scalp fungus Malassezia globosa feeds on sebum. An overgrowth of this fungus can irritate the scalp and accelerate cell turnover, leading to the flakes characteristic of dandruff.

8. Why is only my scalp oily but my ends are dry?

This is very common and is known as “combination hair”. The oil is produced at the scalp, but due to hair length, texture (like curls), or damage, it doesn’t travel down to moisturize the ends, which then become dry and brittle.

The Takeaway

Dealing with oily hair can be a frustrating, ongoing battle, but it’s one you can win with the right knowledge and tools.

The key is to understand that the goal isn’t to eliminate oil completely, but to manage its production and keep your scalp in a healthy, balanced state.

By adopting proper washing techniques, choosing products with effective ingredients, and making small but impactful lifestyle adjustments, you can significantly reduce greasiness.

Remember to be patient and consistent with your new routine, as it can take a few weeks for your scalp to adjust.

If your oily hair persists or is accompanied by severe itching, inflammation, or hair loss, don’t hesitate to seek professional advice.

A dermatologist can help you identify any underlying conditions and create a targeted treatment plan.

What are your go-to tips for managing oily hair? Share your experiences in the comments below to help others in the community!

Medical Disclaimer

The information in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.