Hair oils and hair growth: coconut oil and others

Oiling the hair is a long tradition across Malaysia and much of Asia. Many of us grew up with coconut oil, olive oil or herbal hair oils being massaged into our scalp. Today, hair oils are sold as treatments for everything from frizz to hair loss. So what can oils really do? The answer depends on whether you are talking about the hair strand or hair growth.

Oils and the hair strand

The best-known research on hair oils looks at protecting the hair fibre itself.

A lab study compared coconut oil, sunflower oil and mineral oil on hair samples ¹:

• Coconut oil was the only one of the three that clearly reduced protein loss from both undamaged and damaged hair, when used either before or after washing.
• Sunflower oil and mineral oil did not help reduce protein loss.
• The researchers explained that coconut oil is mainly made of lauric acid, which is small and straight enough to get inside the hair shaft. Mineral oil and sunflower oil do not penetrate the fibre in the same way.

Protein loss is part of how hair becomes damaged and weak. So this suggests coconut oil may help protect hair from some everyday damage.

The limits

• This was a lab study on hair samples, not a trial in people.
• It measured protein loss, not hair fall or hair growth.
• The researchers worked for a company that makes hair oil products.

Oils and hair growth

This is where the evidence is much weaker. A 2025 review of herbal remedies for hair loss covered several oils and plant products, including coconut oil, olive oil, rosemary, pumpkin seed oil and onion juice ².

• The review found that some studies suggested possible benefits.
• But many of the studies had small sample sizes, short treatment periods and no long-term follow-up.
• The authors concluded that larger, well-designed trials are needed to confirm whether these remedies work ².

In plain terms: a few oils have some early research, but none has been shown to reliably treat hair loss. We look at the individual oils in more detail in rosemary oil, pumpkin seed oil and onion juice.

What oils can and cannot do

Oils may help:

• Reduce frizz and make hair feel softer
• Protect hair during washing and combing, especially coconut oil ¹
• Ease dryness in thick, curly or textured hair. The AAD notes that some flaking can come from not using the right conditioner, oil or scalp moisturiser for your hair type ³.

Oils have not been shown to:

• Treat pattern hair loss
• Stop shedding caused by stress, illness, hormones or medicines
• Repair hair that is already broken

Hot oil treatments

Hot oil treatments are popular in salons. But for people whose hair is already thinning, the AAD advises skipping hot-oil treatments, because the heat can further damage fragile hair ⁴. If you like oiling, use oil at room temperature or only slightly warm.

Oils and an oily or flaky scalp

Malaysia's heat and humidity already make many scalps oily. Seborrhoeic dermatitis, a common cause of flaking, is associated with oily skin ⁵. We could not find good studies on whether adding oil makes flaking worse, but it makes sense to be careful:

• If your scalp is oily or flaky, apply oil mainly to the lengths and ends, not the scalp.
• Wash it out within a few hours rather than leaving it on for days.
• Stop if flaking, itching or spots get worse. See dry scalp vs dandruff.

How to use hair oil sensibly

• Use a small amount. A few drops spread through the ends is usually enough for frizz.
• Try it before washing. In the lab study, coconut oil used before washing reduced protein loss ¹.
• Patch test new oils, especially essential oils, on a small area of skin first. Stop if you get redness or itching.
• Dilute essential oils in a carrier oil. Do not apply strong essential oils directly to the scalp.
• Massage gently if you like, using your fingertips. See scalp massage.
• Keep washing your scalp regularly. See how often to wash hair.

Watch out for big claims

Some hair oils are sold with promises of thicker, fuller hair in weeks. Be wary of products that claim to treat hair loss quickly or work for everyone. The research does not support those promises ².

When to see a doctor

If your hair is thinning, falling out in patches, or shedding heavily, oils alone are unlikely to solve the problem. See a doctor to find the cause. Many causes of hair loss can be treated. See sudden severe hair fall and genetic hair loss.

The bottom line

Hair oils, especially coconut oil, may help protect the hair strand and make hair feel softer. But the evidence that any oil helps hair grow is weak, with small and short studies. Use oils for hair care if you enjoy them, keep them off an oily or flaky scalp, and see a doctor for ongoing hair loss.

Frequently asked questions

Does coconut oil help hair grow?

There is no good evidence. A lab study found coconut oil reduced protein loss from hair, which may help protect the strand, but it did not test hair growth ¹.

Which hair oil is best?

In one lab comparison, coconut oil reduced protein loss while sunflower and mineral oil did not ¹. No oil has been proven to treat hair loss ².

Are hot oil treatments good for thinning hair?

The AAD advises skipping hot-oil treatments if your hair is thinning, because heat can damage fragile hair ⁴.

Should I oil my scalp if I have dandruff?

Be careful. Seborrhoeic dermatitis is associated with oily skin ⁵. Keep oil to the lengths and wash it out.

Educational content. Not medical advice.