Hair gets oily in a day when the scalp makes lots of oil. Fine hair, hormones, and some products can make it worse.
Common causes
- Overactive sebaceous glands.
- Fine hair, which shows oil faster.
- Hormones, stress and puberty.
- Heavy conditioners and products.
- Over-washing, which can trigger more oil.
- Seborrheic dermatitis.
Fix
- Use a clarifying shampoo weekly.
- Condition only the ends.
- Avoid touching your hair.
Normal
Washing every 2 to 3 days is fine for most.
See a dermatologist
If flaking or itching.
The role of sebum
Sebaceous glands release sebum, which coats hair. The scalp has about 100 to 400 glands per square centimeter. Hormones (androgens) control output, so oiliness rises at puberty and varies with hormonal cycles. Fine hair is oily-looking faster because oil travels along each strand more easily and it has less surface area per gram.
- Over-washing can prompt the scalp to produce more oil, though evidence is mixed.
- Heavy conditioners applied at the roots add weight and shine.
- Seborrheic dermatitis causes greasy yellow flakes and affects about 3 to 5 percent of people.
- Humid weather, sweating and touching the hair add to oil.
Fixes
Shampoo the scalp thoroughly and condition mostly mid-lengths to ends. Clarifying shampoo once a week removes buildup. Ingredients such as zinc pyrithione, ketoconazole or selenium sulfide help seborrheic dermatitis. Dry shampoo helps between washes but should not replace cleansing. See a dermatologist if hair is oily with itching, redness or hair loss.
Oil production
Sebaceous glands produce sebum, which keeps hair healthy. Fine hair gets oily faster because oil travels along strands more easily. Hormones, humidity, heavy conditioner and overbrushing increase oiliness.
Fixes
Wash with a clarifying shampoo weekly, rinse thoroughly, apply conditioner only to ends and avoid touching hair. Seborrheic dermatitis may also make scalp oily and flaky, treated with ketoconazole shampoo.
Scalp biology
The scalp has 100 to 150 sebaceous glands per square centimeter, among the densest on the body. Sebum production is driven by androgens and increases at puberty. Washing every day does not cause more oil; the gland adapts slowly over weeks. Oily scalp is common in teenagers and people with seborrheic dermatitis.
Choosing products
Use a gentle clarifying shampoo once a week, a lightweight conditioner on lengths only, and avoid heavy oils. Dry shampoo can extend a wash but builds up. If oiliness comes with flaking and redness, ketoconazole 1 percent shampoo twice a week is effective. Hormonal changes, PCOS or some medications can raise oil production.
Based on data from the American Academy of Dermatology
