What are the scientifically proven benefits of sweet almond oil for hair and scalp health?

Sweet almond oil is sometimes credited with the ability to stimulate hair growth or slow its loss. However, no clinical study in humans has demonstrated this effect to date. Only one study conducted in mice suggests that certain components of the oil extracted from Prunus mira, an almond variety, could have a positive impact on the hair growth cycle. In this study, 110 mice were divided into different groups, including a control group, a minoxidil group as a positive control, and three groups tested with various dilutions of almond oil. After shaving, the solutions were applied daily for 21 days. The researchers observed faster hair regrowth in the mice treated with almond oil, almost comparable to that seen with minoxidil.

From a mechanistic standpoint, almond oil appears to accelerate the transition of hair follicles into the anagen phase, corresponding to the growth phase. This stimulation is associated with an increased expression of the Wnt10b gene, as well as the β-catenin and GSK3β proteins, key players in the Wnt/β-catenin signaling pathway, known to regulate hair follicle regeneration. However, although these findings are promising, they are limited to an animal model. Further studies in humans are still needed.

Sweet almond oil is naturally rich in antioxidants, notably vitamin E and phytosterols, which could help limit the effects of oxidative stress on hair fiber and the scalp. As a reminder, oxidative stress corresponds to an imbalance between the production of free radicals and the antioxidant capacity of cells. Although free radicals are generated naturally during cellular metabolism, they can sometimes be present in excess, notably following exposure to UV radiation, pollution, or tobacco.

Research has shown that oxidative stress can be harmful to the health of hair and scalp by altering keratin, promoting the development of white hair and accelerating hair loss. Free radicals can also weaken the hair fiber by modifying its mechanical properties, causing a loss of shine, more brittle hair, and even split ends. Regular application of an antioxidant-rich oil, like sweet almond oil, may help to protect hair and scalp from free radicals.

No study has demonstrated that sweet almond oil slows the onset of gray hair or prevents hair loss. It is only known that it contains antioxidants and that the role of oxidative stress in fiber bleaching and hair shedding is well established. Therefore, the evidence remains indirect.

Sweet almond oil is often described as a vegetable oil with soothing and calming properties that can improve scalp comfort. By forming a protective surface film, it helps reduce water loss and support the integrity of the skin barrier, which can reduce sensations of tightness or irritation, particularly on dry scalps. Additionally, it contains oleic acid and linoleic acid, two fatty acids known for their anti-inflammatory effects. Oleic acid can upregulate the anti-inflammatory cytokine IL-10 while downregulating the pro-inflammatory cytokines TNF-α and IL-1β. Linoleic acid, meanwhile, may inhibit cyclooxygenase 1 and 2 (COX-1 and COX-2) activity, enzymes responsible for synthesizing pro-inflammatory prostaglandins.

A clinical study evaluated the effect of topically applied sweet almond oil on pruritus-related quality of life in 42 patients suffering from uremic pruritus due to chronic kidney disease and experiencing intense itching. Participants were divided into two groups: a control group and an intervention group that applied 7 to 10 mL of sweet almond oil to the pruritic areas once daily for two weeks. Pruritus-related quality of life (itchyQoL) was assessed before the intervention, then at one and two weeks. The results showed a significant reduction in pruritus scores in the intervention group (from 50.3 ± 16.7 to 31.7 ± 8.9 over two weeks), while no improvement was observed in the control group.

These results suggest that sweet almond oil may contribute to the alleviation of itching, possibly at the scalp level, and, by extension, help reduce irritation more generally.