Reading time: 9 min.
Common Reasons Why Your Hair Is Greasy (and How to Fix It)
Dr Mir Malkani
Medically reviewed by
Dr Mir Malkani
Updated on May 10, 2024

Waking up in the morning to find that you have suddenly greasy hair can be very frustrating, especially if you’ve just washed it. But you may be relieved to know that there are many reasons your scalp may be oily which have nothing to do with hair hygiene.

You may be experiencing seborrhea, a common skin condition that causes your glands to produce too much oil [1]. Or you may be undergoing hormonal changes which disrupt the oil production balance in your skin and hair. Your diet, medication and stress levels could also play a part in making your strands greasy, as could the hair products you use and even the air quality around you.

While all these factors seem difficult to control, there are things you can do to fix your greasy hair and prevent it from becoming oily again. Depending on your circumstances, they may include finding the best hair care routine for your hair type, balancing your hormone levels, eating a healthy, nutritious diet and lowering your stress levels.

Keep reading this article to find out more about:

  • The biological process that leads to greasy hair
  • The main reasons why your hair is greasy
  • How to fix your greasy hair problem
  • The relationship between a greasy scalp and hair loss
Table of Contents
Diagram showing how hair grease is made

What is the grease on your hair?

The natural oil you can see on your scalp, hair and skin is called sebum. Its role is to protect the surfaces it coats from friction, sunlight and excessive moisture. Furthermore, it has been shown to possess some antibacterial and anti-inflammatory properties [2]. Sebum is produced by a multitude of sebaceous glands, which cover the entire surface of your skin, except for your palms and the soles of your feet.

Your scalp contains sebaceous glands as well, which are linked to the hair exit channel. The sebum is then spread from your hair roots to the entire length of your strands when you brush it or run your hand through it. If your tresses are long, you may not always produce enough natural oils to reach their ends. This can cause dry, brittle hair unless you keep it conditioned and moisturised.

Sometimes, due to a variety of causes, your sebaceous glands may start to produce more oil than necessary. This excess oil can not only clog your pores, leading to acne or scalp folliculitis, but it can also leave your strands looking greasy, flat and clumped together. This can make your hair look dirty even 1 day after you’ve washed it.

What causes greasy hair?

Greasy hair is caused by a variety of reasons, not just infrequent washing. Here are some of the most common causes of a greasy scalp and oily hair:

greasy fine hair

1. Overactive sebaceous glands

If you are experiencing a condition known as seborrhea, your natural oil-producing glands may be larger than usual and excrete an excessive amount of sebum. Sometimes, this can be an inherited trait, but it can also be triggered by other factors, such as your age or hormones [1].

woman experiencing a menopausal hot flash

2. Hormonal activity

Our hormones impact the level of sebum our skin and scalp produces in different ways. Male hormones (androgens) make your sebum-producing glands larger, so men naturally have oilier hair and skin than women.

During puberty, the body is flooded with androgen hormones, which make sebaceous glands increase in size and produce more sebum [3]. The same thing can happen to menopausal women, who no longer produce sufficient amounts of oestrogens to balance their androgens.

Furthermore, ovulating women experience a temporary increase in progesterone, which also leads to greater natural oils produced.

hormonal birth control pills can cause oily strands

3. Medications

Since hormonal activity influences hair’s oiliness, it may not be surprising that some kinds of birth control medication can increase your sebum secretion (especially mini-pills, which only contain progesterone). However, there are also hormonal contraceptive pills specifically designed to lower sebum production, for cosmetic purposes [4][5].

Additionally, other kinds of medications can make your scalp and skin oily as well. One such example is anabolic steroids, which some athletes take to increase their muscle mass [6]. Some corticosteroids can also cause sebaceous glands to become enlarged in certain people, producing more sebum [7].

Finally, using topical medication for hair loss or common scalp problems, be it a serum such as Minoxidil, a steroid cream or any kind of ointment, can produce a greasy look if it is not applied carefully and it gets in your hair.

person applying hair oil to dry hair

4. Hair products

Using hair styling products frequently or in large quantities can lead to buildup on your scalp, especially if you don’t wash your hair very often. This product buildup combines with sweat and sebum and can give your scalp and hair an oily, unhealthy look.

However, the products which can play the largest role in making your hair greasy are certain kinds of essential oils for hair growth, especially if the hair oil is applied in large quantities and not rinsed properly.  For example, mustard oil for hair, castor oil, olive oil for hair and marula oil for hair are heavy and fatty, so they can cause greasy hair if used on an already oily scalp.

woman washing her hair

5. Hair washing practices

Not washing your hair frequently enough, adding too much conditioner to an already greasy scalp or using the wrong kind of shampoo for your hair type can lead to greasy hair. Moreover, excessive use of dry shampoo may not cause hair loss, but it can build up on your scalp, giving it an unkempt look.

For this reason, it is important to wet-wash your hair regularly if you frequently use dry shampoo, preferably with a clarifying shampoo to deeply cleanse both the hair and oil buildup on the scalp. Read more regarding how often you should wash your hair to keep it strong and healthy.

woman with healthy straight hair out in the sunshine

6. Temperature

Excessive sunlight is not good for your hair in general, but did you know hot, humid weather can also make it greasier? That is because it can naturally increase the amount of oil brought to the surface of your scalp.

Studies have shown that a 1°C increase in temperature stimulates your sebaceous glands to excrete 10% more sebum. That is not normally due to increased oil production, but to the fact that when exposed to heat, sebum becomes less viscous, making it easier to flow to the surface of your scalp and skin [8].

traffic jam causing air pollution

7. Environmental pollution

Sometimes, simply living in a polluted environment, such as a big city, with abundant traffic, can be enough to make your hair oily [9]. That is because pollution can produce inflammation and oxidative stress which can disrupt the normal functioning of your sebaceous glands, causing them to produce more oil [10].

unhealthy foods can cause greasier hair

8. Unhealthy diet

Eating a diet high in saturated fats, refined carbohydrates and processed foods may not only take a toll on your overall health but on your hair as well. That is because studies show that these dietary habits can increase sebum production, leading to oilier hair [11].

stress can impact hair health

9. Stress

High levels of stress can have significant negative consequences on your hair and scalp and you may know that stress and anxiety can cause hair loss, as they can induce telogen effluvium. But it can also make your scalp and hair greasy [12]. When you are under psychological pressure, your body releases a hormone called cortisol, which can lead to increased sebum production.

woman upset with the amount of hair in her hair brush

10. Contact with oily objects

Frequently using the same hair brushes, hair bands, or even hats without cleaning them regularly can coat them in sebum. With every use, some of that sebum is spread across your hair. Keep this in mind when borrowing or lending this type of personal objects or hair tools.  

Furthermore, your hands themselves can make your hair greasy if you run them through it when they are not completely clean. While your palms may not produce sebum, touching your hair while you are handling greasy foods, or after you put on oily hand lotion can lead to some of it getting on your strands.  

How do you fix greasy hair?

  • Wash your hair frequently – you may have heard the myth that washing your hair every day can lead to increased sebum production. However, studies show that washing your hair 5-6 times a week makes it the healthiest [13]. So don’t hesitate to wash that excess sebum off as often as you need to.
  • Use natural remedies to lower your sebum production – rosemary oil for hair [16] and green tea tonic [14] have been proven effective in sebum reduction and treating an oily scalp. Coconut oil can provide your hair with some protection against the effects of pollution, but it should be used sparingly and rinsed well to avoid making your hair greasier [9].
  • Clean your styling tools and hair accessories thoroughly – make sure that all the objects that come in contact with your hair (especially your hairbrush) are cleaned frequently, so they don’t spread oil on your strands.
  • Get your hormone levels regulated – especially if you are a perimenopausal woman, it is a good idea to see a gynaecologist or endocrinologist and have some tests to check your hormone levels. The specialist may then be able to make recommendations for balancing out your hormones.
  • Reduce your overall stress – exercise, meditation, spending quality time with loved ones or getting therapy can lower your stress levels and improve your hair health.
  • Eat a well-balanced diet  – try limiting the intake of saturated fats and refined carbohydrates and getting enough vitamins and nutrients which support hair health, such as iron, zinc, vitamin C for hairvitamin D for hair or Vitamin E for hair.
  • Reduce or quit smoking – While smoking can cause hair loss and damage your overall health, it can also increase sebum production, making your hair greasy [15].
  • Find the best care routine for your scalp and hair type – While trial and error can be effective, they can also take time and produce frustration. If you want to know the best shampoo to use, what hair treatments may benefit your oily scalp or what hair products to stay away from, the best thing you can do is see a trichologist for advice.

Can greasy hair cause hair loss?

While greasy hair is unlikely to cause hair loss on its own, it can lead to several scalp problems which, in turn, can result in hair shedding.

When your scalp routinely produces too much sebum, it can feed a fungus that causes yeast infections on the scalp, such as dandruff or seborrheic dermatitis. While dandruff only causes unsightly white flaking and some itching, seborrheic dermatitis can produce more severe scaling, itching and inflammation, which can cause hair loss.

Excess sebum can also clog your hair follicles, leading to scalp acne or scalp folliculitis. Both these conditions manifest with pimples or pustules around your hair roots and can cause pain, itching and inflammation of the scalp. The infection can make your hair fall out, while the scratching can lead to hair breakage.

Are you concerned about your greasy hair?

If you have tried everything and your hair is still greasy, there’s no need to lose hope. Book a consultation with a trichologist at your earliest convenience. They will examine your scalp and hair and provide personalised hair care advice, tailored to your particular needs to keep hair fresh and healthy. This will help regulate your sebum levels, so you will no longer have to worry about oily hair.

Moreover, if your greasy hair is accompanied by hair loss or hair thinning, you may be experiencing a type of alopecia, such as telogen effluvium, androgenetic alopecia (male or female pattern baldness), or alopecia areata. While some of the conditions resolve on their own, others require prompt intervention from the first signs of hair thinning and balding. So getting a timely diagnosis and treatment can be the first step on your journey to beautiful healthy hair.

Common Reasons Why Your Hair Is Greasy (and How to Fix It), Wimpole Clinic

Dr Mir Malkani
Medically reviewed by Dr Mir MalkaniUpdated on May 10, 2024
The Wimpole Clinic offers FUE Hair, Beard & Eyebrow Transplants & Trichology.
Talk to a specialist ☎ 020 7935 1861.

Book a consultation

Simply fill in your details in the form below and we'll get in touch with you shortly.