The benefits of coconut oil for hair.

The benefit of coconut oil for dry and damaged hair lies largely in its ability to interact with the hair fiber. Several studies have shown that, unlike many vegetable oils, coconut oil is able to partially penetrate into the hair shaft. This specificity is attributed to its high lauric acid content, a medium-chain fatty acid whose linear structure and low molecular weight facilitate its diffusion between the cells of the cuticle and cortex. This affinity for hair proteins, notably keratin, would explain why coconut oil is often associated with better preservation of fiber integrity, particularly in compromised hair.

However, it should be noted that, like all oils, coconut oil does not hydrate the hair in the strict sense, as hydration involves the presence of water.

Its role is primarily lipidic: it helps nourish the hair fiber and reduce the loss of proteins and lipids, a phenomenon commonly observed in dry, treated, or damaged hair. By partially penetrating the hair shaft, coconut oil helps fill cuticle fissures, thereby enhancing its light-reflecting capacity, which can make hair look shinier. Applied along the lengths, it also forms a protective surface film, which shields the fiber from external aggressors such as friction, pollution, or UV rays. This protective coating effect can temporarily improve the hair’s appearance.

Coconut oil is sometimes credited with the ability to combat dandruff, a common scalp disorder often associated with excessive flaking, itching, and an imbalance of the skin microbiome. While this use is partly rooted in traditional practices, recent scientific evidence does indeed suggest that coconut oil may present a potential benefit in maintaining scalp balance, without strictly constituting a dandruff treatment.

A study specifically investigated the effect of topically applied coconut oil on both the bacterial and fungal microbiome of the scalp. Conducted with 140 women, including 70 with dandruff, the 16-week trial comprised a 12-week treatment phase followed by a 4-week follow-up phase without any application. The objective was to assess the impact of coconut oil on scalp microbial composition and on certain physiological parameters associated with dandruff.

At the end of the treatment phase, the researchers observed an increase in certain microbial populations, particularly Cutibacterium acnes and Malassezia globosa, whose abundance was negatively correlated with the clinical parameters of dandruff.

These results suggest that coconut oil could help to modulate the microbial ecosystem of the scalp, but the precise mechanisms remain to be elucidated. Furthermore, coconut oil cannot replace treatment in cases of dandruff persistent or severe. However, it could be considered as an adjunct in a hair care routine.

Coconut oil ranks among the traditional natural remedies commonly recommended for pediculosis, the scientific term for an infestation by lice. It is often credited with an occlusive mode of action, the idea being that the oil coating the louse and its eggs would lead to their asphyxiation.

However, the available clinical data are far more cautious about the efficacy of coconut oil when used alone against lice.

A clinical study conducted on 31 participants evaluated a shampoo containing 1% fractionated coconut oil, applied twice at one-week intervals. The product’s efficacy was assessed by systematic combing at various follow-up time points, but the results are mixed. Lice at different developmental stages, as well as nits, were found throughout the follow-up. These results indicate a low pediculicidal and ovicidal activity, suggesting that coconut oil, even when modified and incorporated into a shampoo, does not effectively eliminate head lice.

However, some studies suggest that coconut oil may be of interest against lice when it is combined with other plant extracts. One study in vitro thus focused on the ovicidal efficacy of formulations combining an extract of Illicium verum (star anise) and coconut oil. Louse eggs were immersed for short periods in various solutions, then incubated to assess their viability.

The most effective combination (60% star anise and 40% coconut oil) achieved an 86.7% nit mortality rate after two minutes of exposure.

Overall, these data indicate that coconut oil alone cannot be considered an effective treatment for head lice. While certain combinations with other natural extracts appear promising, they require precise formulations and cannot be extrapolated to home use or to applying pure coconut oil to the scalp. In practice, the management of pediculosis relies on products with demonstrated efficacy, combined with rigorous combing.

To date, there is no scientific evidence that coconut oil promotes hair growth.

Conversely, coconut oil can help to improve the condition of the hair fiber and the scalp. By minimizing breakage in fragile hair, it can help preserve the length achieved. Over time, hair may appear longer—not due to accelerated growth, but thanks to better length retention associated with reduced breakage.

Coconut oil exhibits a naturally greasy and occlusive texture, which requires some caution in its application, particularly on fine hair or oil-prone scalps. Today, numerous coconut oil shampoos are available, along with conditioners and hair masks containing this ingredient, allowing users to enjoy its benefits. Beyond these products, it is also possible to add a few drops of coconut oil to an existing hair care formulation, in order to leverage its lipid properties while minimizing the very greasy feel associated with using the pure oil.

Coconut oil can also be used in the form of an oil bath, provided that the quantities remain moderate. An occasional application, for example once a week, to the lengths—and possibly to the scalp if it is very dry—may be sufficient. A few drops are spread over the targeted areas, then left on for about fifteen minutes before shampooing the hair.

Note : Coconut oil is solid below 20/25 °C, but this has no impact on its quality. If this happens, you can simply hold the jar under warm water until it liquefies again.

• BURGESS N. A. & al. Anti-lice protector shampoo: Clinical study shows lack of efficacy of coconut oil derivatives in the elimination of head louse infestation. Turkish Journal of Parasitology (2020).

• SUTEJO I. R. & al. In vitro ovicidal activity of combination Illicium verum extract and coconut oil against Pediculus humanus capitis. International Conference on Agromedicine and Tropical Diseases (2020).

• SHARMA V. K. & al. Longitudinal study of the scalp microbiome suggests coconut oil to enrich healthy scalp commensals. Scientific Reports (2021).

• KAMATH Y. & al. Benefit of coconut-based hair oil via hair porosity quantification. International Journal of Cosmetic Science (2022).

• AHN C. & al. Determination of penetration and protection of fatty acids in bleached hair according to the fatty acid chain length and the application to understanding the protective effects of MCT oil and coconut oil. Fashion and Textiles (2023).

• GAVA MAZZOLA P. & al. Impact of hair damage on the penetration profile of coconut, avocado, and argan oils into caucasian hair fibers. Cosmetics (2024).