Macadamia nut oil is increasingly used in skin care due to its emollient and moisturizing properties, which are supported by a moderate level of scientific evidence. The oil is rich in monounsaturated fatty acids, notably oleic acid (omega-9) and palmitoleic acid (omega-7), both of which are known to benefit skin health by improving barrier function and hydration. Several in vitro and in vivo studies have demonstrated that macadamia oil can enhance skin permeability, assist in wound healing, and provide antioxidant effects due to the presence of tocopherols (vitamin E compounds). For example, research published in the "International Journal of Cosmetic Science" has shown that palmitoleic acid content is particularly beneficial for mature or dry skin, as this fatty acid naturally declines with age.

While macadamia oil is widely used in cosmetic formulations as a moisturizer, occlusive, and skin-conditioning agent, there is a lack of large-scale, high-quality clinical trials directly evaluating its efficacy for specific dermatological conditions. Most support comes from laboratory studies, small clinical trials, and its favorable fatty acid profile compared to other plant oils. Adverse reactions are rare, and the oil is generally well-tolerated. Thus, while there is moderate scientific validation for its use in general skin care, further research is needed to better define its specific benefits and mechanisms in human skin.