Seborrhea occurs when the sebaceous glands create excess oil, or sebum, making the skin and scalp oily. Most people with seborrhea do not have any underlying health problems. However, some people may have an underlying condition, such as a hormone imbalance.
Sebum production is controlled by our hormones, so a sudden surge in scalp oil production could be down to hormonal changes. If you've recently gone through a major life event that's known to have an impact on your hormone levels, this may be having a knock-on effect on the amount of sebum your scalp is producing.
Hair and puberty
These are both likely caused by the sex hormone testosterone, which is a major player in both female and male reproductive development. Testosterone is thought to increase the production of sebum which is the substance that can make both skin and hair feel oily.
Women going through menopause experience a change in their hormone levels. One hormone, androgen, surges, increasing the production of sebum in the scalp. Sebum is vital to our hair, protecting it from environmental damage and keeping it supple, but too much can lead to a greasy look.
"As the estrogen levels fall after ovulation, there is a relative excess of androgen hormones causing increased oil production, clogged pores and growth of bacteria," Weiser told SELF.
Shampooing too little or even too often can contribute to greasy hair. Typically, if you have greasy hair, you should shampoo daily. Washing more than once a day can cause your glands to overreact and produce more oil to make up for the extra shampooing. You'll also want to choose a shampoo that's made for oily hair.
Confusingly, hyperthyroid states can also lead to effluvium, together with thinned hair shaft diameter and brittle, greasy hair (1, 9–11), despite an apparently increased hair matrix proliferation (3).
Those with fine or thin hair, however, may find their hair looks greasy after just one day. It's all to do with the amount of oil your scalp produces, as well as how well your hair can carry that oil.
Sebum production influenced by hormones like testosterone and estrogen can mean greasy skin and hair.
Androgens are the hormones mostly responsible for oil production, and sometimes they can fluctuate, stimulating an increase in sebum production. This often happens during puberty, just before menstruation, during pregnancy and during menopause.
Every time you wash your hair with shampoo, it sends the scalp the signal to produce more sebum. If you're washing your hair too often, your scalp gets the message that it needs to be in oil production overdrive. This can result in oily buildup on your scalp.
Modern lifestyles have led to an increase in anxiety and stress levels, making them one of the most common causes of oily hair. “Stress causes your cortisol levels to rise. Cortisol stresses out the oil glands to produce more sebum, naturally leading to oily hair,” explains Sethi.
Oily hair isn't healthy or unhealthy by default. People with an oily scalp can have healthy hair or dry, brittle hair. Your hair needs oil to be healthy, but too much oil can lead to buildup on the hair and scalp. Oily skin may also contribute to a condition called seborrheic dermatitis.
Lifestyle and diet changes to fix oily hair
Your diet should consist of foods rich in vitamin B, especially B2 and B6. It is believed that these components in your diet can help keep your sebum production in control. So, consider adding foods like leafy vegetables, pulses, and seaweed.
Science supports the use of apple cider vinegar as a hair rinse. It could help strengthen hair and improve luster by lowering hair and scalp pH. It may also keep pesky scalp infections and itchiness at bay.
People with oily hair or who use hair care products daily should consider washing their hair once every 1–2 days. People with dry hair can wash their hair less frequently. Those with textured or coily hair should only wash it once every 1–2 weeks.
Thyroid hormones also influence the quality of your skin in a variety of ways. With hyperthyroidism, you may notice itchy and dry patches of skin. Your face may feel softer and swollen. You may even notice swelling around your fingertips.
Oily scalp and dandruff are also commonly seen in PCOS due to elevated androgens and increased oil production.
The hair cycle and hair follicle structure are highly affected by various hormones. Androgens—such as testosterone (T); dihydrotestosterone (DHT); and their prohormones, dehydroepiandrosterone sulfate (DHEAS) and androstendione (A)—are the key factors in terminal hair growth.