Hair oils are popular over-the-counter products that many people use to boost hair health, especially in Indian and African cultures. However, dermatologists often could only provide advice based on the absence of harmful side effects rather than proven benefits, highlighting the need for better understanding of hair care in skin of color.
Researchers at the University of California, Irvine (Phong et al.) reviewed 22 studies published from 1964 to 2020, examining the effects of coconut, castor, and argan oils, which are most commonly used hair oils, on hair health. The review included over 1,000 patients, with about 700 identifying as skin of color (Black, Hispanic, Asian, Bengali, Marquesan). The goal was to evaluate the scientific evidence behind claims that these oils promote hair growth, protect the hair shaft, and treat head lice.
Coconut oil had the strongest evidence supporting its benefits. Seventeen studies involving 370 patients evaluated the benefits of coconut oil. Although evidence for hair growth was limited, coconut oil showed a clear ability to reduce hair breakage by 41.8%, improve scalp hydration, and minimize protein loss and water absorption. Moreover, coconut oil demonstrated anti-infestation properties, with eight studies highlighting its effectiveness in treating head lice.
Castor oil had more limited evidence supporting its benefits. Three studies involving 109 patients showed a modest improvement in hair luster and some efficacy in treating head lice. However, its overall benefits were less well-established compared to coconut oil.
Argan oil, often marketed as Moroccan oil, had the least scientific backing. Only one study suggested its potential to improve hair quality, but it was no more effective than silicone-based controls. There was no evidence supporting its claims to promote hair growth or treat head lice.
In conclusion, while the evidence supporting the benefits of coconut, castor, and argan oils is limited, they may help improve hair texture. Coconut oil shows the strongest evidence, especially for patients with skin of color. However, it can occasionally cause allergic reactions. It's also important to note that some oils may worsen seborrheic dermatitis (a severe form of dandruff) by promoting yeast growth on the scalp. Hair oils may be be used cautiously, with attention to any worsening of hair or scalp conditions.
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Article Summary By Andrea Quartey, MD Candidate at Lewis Katz School of Medicine at Temple University, 2024
References:
Phong C, Lee V, Yale K, Sung C, Mesinkovska N. Coconut, Castor, and Argan Oil for Hair in Skin of Color Patients: A Systematic Review. J Drugs Dermatol. 2022 Jul 1;21(7):751-757. doi: 10.36849/JDD.6972. PMID: 35816075.
Mayo T, Dinkins J, Elewski B. Hair Oils May Worsen Seborrheic Dermatitis in Black Patients. Skin Appendage Disord. 2023 Mar;9(2):151-152. doi: 10.1159/000527778. Epub 2023 Jan 18. PMID: 36937158; PMCID: PMC10015641.