Hair care routines have evolved, yet overnight hair oiling remains a trusted practice, especially in South Asian cultures. This involves massaging oil into the scalp and hair before bedtime and leaving it on overnight to allow deep penetration. Advocates claim it nourishes the hair, strengthens roots, reduces frizz, and promotes shine. Oils like coconut, argan, olive, and castor are commonly used, each offering unique benefits. However, while it can improve hair texture and scalp health, overnight oiling is not without risks. Excessive use may cause clogged pores, scalp irritation, fungal growth, or difficulty washing out heavy oils, making moderation essential.







Overnight hair oiling: Common oils used and how they work

Overnight hair oiling involves applying a generous amount of oil to the scalp and hair before bedtime and leaving it in overnight. The idea is that the extended period allows the oil to deeply penetrate the hair shaft and scalp, providing nourishment and moisture.




Common oils used for this purpose include:

• Coconut oil: Rich in fatty acids, it penetrates the hair shaft and reduces protein loss.


• Argan oil: Packed with antioxidants and vitamin E, it helps to hydrate and soften hair.


• Olive oil: Contains oleic acid, which can improve hair elasticity and shine.


• Castor oil: Known for its potential to promote hair growth and thickness.

Benefits of overnight hair oiling


1. Deep nourishment and moisture retention



Leaving oil overnight allows it to penetrate the hair shaft and scalp, delivering intense hydration and nourishment. This can repair dry, damaged hair, reduce frizz, and prevent breakage. Over time, regular oiling helps maintain the hair's natural moisture, making it softer, more supple, and easier to manage. Hair becomes more resilient to environmental damage, styling tools, and heat treatments.





2. Enhanced blood circulation



Massaging the scalp with oil stimulates blood flow, which encourages healthier hair follicles and can promote hair growth. Improved circulation ensures that essential nutrients and oxygen reach the scalp more effectively. This not only strengthens the roots but also helps reduce hair thinning and promotes overall scalp vitality.





3. Improved hair texture and shine



Overnight oiling smooths the hair cuticles and seals in moisture, resulting in shinier, more manageable hair. It reduces tangling and split ends, leaving hair looking healthier. Consistent application can make hair softer to touch, less prone to frizz, and more resistant to damage caused by daily wear and tear.





4. Scalp health maintenance



Certain oils have antimicrobial and soothing properties that help maintain a healthy scalp. They can reduce dryness, flakiness, and irritation, alleviating dandruff and itchiness. A healthy scalp environment supports strong hair growth and prevents common scalp conditions.







Risks and considerations of applying oil

The review published in
QuestJournals highlights overuse of hair oils may lead to clogged pores, scalp irritation, protein buildup, and moisture imbalance, which in turn can cause itching, inflammation, hair breakage, frizz, or even hair loss. Its thick, greasy texture can also make it difficult to wash out, weighing hair down and disrupting natural balance.






1. Potential for scalp irritation



Leaving oil on the scalp for extended periods may cause irritation or allergic reactions in some individuals. Redness, itching, or inflammation may occur if the scalp is sensitive or if the oil contains allergens. Patch testing new oils is recommended to avoid adverse reactions.





2. Clogged pores and acne



Overnight oiling can clog pores, especially for those with oily or acne-prone skin. Excess oil may mix with sweat and dirt, leading to breakouts along the hairline or scalp acne. Over time, this can worsen existing acne or cause small pimples on the forehead and scalp.





3. Increased risk of fungal overgrowth



Prolonged oil exposure can create a warm, moist environment that encourages fungal growth. Conditions like seborrheic dermatitis may develop, causing greasy flakes, itching, or scalp discomfort. Maintaining proper hygiene and washing the hair thoroughly is essential to minimise this risk.





4. Difficulty in washing out oil



Heavy oils like castor or coconut oil can be challenging to remove completely, often requiring multiple washes. Residual oil can weigh the hair down, make it look greasy, and attract dust and pollution. Regular buildup may affect scalp health, requiring occasional clarifying shampoos to maintain cleanliness.







Best practices for overnight hair oiling

• Choose the right oil: Select an oil suitable for your hair type and needs. Light oils for oily hair, heavier oils for dry hair.


• Apply moderately: Avoid excessive amounts to prevent buildup and clogging.


• Massage gently: Stimulate circulation without causing scalp damage.


• Protect your bedding: Use a silk scarf or old pillowcase to prevent stains and friction.


• Wash thoroughly: Use a gentle shampoo to remove all residual oil in the morning.


• Limit frequency: Oiling once or twice a week is usually sufficient for most hair types.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before making any changes to your health routine or treatment.