Sweet almond oil: what are its hair-care benefits?

Benefit No. 1: Sweet almond oil may nourish and protect hair.

Rich in mono- and polyunsaturated fatty acids, primarily oleic and linoleic acids, sweet almond oil is of particular interest for nourishing its hair by reinforcing the hydrolipidic film naturally present on their surface and partially filling the irregularities of the cuticle, the protective outer layer of the fibres. The lipidic nature of sweet almond oil indeed suggests that it may exhibit a good affinity with the hair, allowing it to smooth the cuticle scales and reduce the coefficient of friction between the fibres, two parameters closely linked to the appearance of split ends and frizz and to decreased shine.

Sweet almond oil could therefore have a conditioning effect.

However, caution is warranted: to date, no clinical study has investigated the effects of sweet almond oil on hair—whether on its mechanical strength, shine or hydration. The proposed hypotheses are based on its biochemical composition, extrapolations from general mechanisms known for vegetable oils rich in fatty acids and empirical observations. Indeed, when used as an oil bath before shampooing or incorporated into a hair mask, sweet almond oil can improve hair appearance and softness. These effects remain temporary and depend on hair porosity, hair type (fine, coily, wavy, curly or straight) and formulation (pure sweet almond oil or combined with other film-forming agents).

Note: If you wish to apply sweet almond oil pure to your hair, use it sparingly. Although relatively light, it is still an oil with a greasy texture: a few drops are more than enough.

L'huile végétale d'amande douce. — Sweet almond vegetable oil.
Source: SONAWANE S.G. et al. Formulation and evaluation of herbal hair oil. Journal of Pharmaceutical Research (2024).

Benefit No. 2: Does sweet almond oil accelerate hair growth?

Sweet almond oil is sometimes credited with the ability to stimulate hair growth or to slow hair loss. However, no clinical study in humans has demonstrated this effect to date. Only a study conducted in mice suggests that certain constituents of the oil extracted fromPrunus mira, an almond variety, may have a positive impact on the hair growth cycle. In this study, 110 mice were allocated into different groups, including a control group, a minoxidil group as a positive control, and three groups treated 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 use.

Effets de l'huile d'amande sur la pousse des poils de souris. — Effects of almond oil on hair growth in mice.
Source: WANG Z. et al. Study of the chemical constituents of Prunus mira Koehne nut oil and its mechanism for promoting hair growth. Journal of Ethnopharmacology (2020).

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 increase in the expression of the Wnt10b gene, as well as the β-catenin and GSK3β proteins, key players in the Wnt/β-catenin signalling pathway, known to regulate hair follicle regeneration. Nevertheless, although these results are promising, they remain confined to an animal model. Further studies in humans are still required.

Benefit No. 3: Sweet almond oil could protect hair against oxidative stress.

Sweet almond oil is naturally rich in antioxidants, notably in vitamin E and phytosterols, which may help mitigate the effects of oxidative stress on hair fibre and the scalp. As a reminder, oxidative stress refers 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, especially following exposure to UV, pollution or tobacco.

Research has shown that oxidative stress can be detrimental to the health of hair and scalp, by altering keratin and promoting the appearance of white hair and accelerating the hair loss. Free radicals can also weaken the fibre by altering its mechanical properties, leading to a loss of shine, more brittle hair and even split ends. Regular application of an antioxidant-rich oil, such as sweet almond oil, could help to protect the hair and scalp from free radicals.

No study has demonstrated that sweet almond oil slows the appearance of white hair or hair loss. It is simply known to contain antioxidants, and the role of oxidative stress in the greying and shedding of hair fibres is well established. The evidence therefore remains indirect.

Benefit No. 4: Sweet almond oil could soothe the scalp.

Sweet almond oil is often described as a vegetable oil with soothing and calming properties, capable of enhancing scalp comfort. Thanks to its ability to form a protective surface film, it helps limit water loss and support the integrity of the skin barrier, which can reduce sensations of tightness or irritation, especially on dry scalps. Moreover, it contains oleic and linoleic acids, two fatty acids recognised for their anti-inflammatory action. Oleic acid can stimulate the production of the anti-inflammatory cytokine IL-10 while reducing that of the pro-inflammatory cytokines TNF-α and IL-1β. Linoleic acid, for its part, can inhibit the activity of cyclooxygenases 1 and 2 (COX-1 and COX-2), the enzymes involved in the synthesis of pro-inflammatory prostaglandins.

A clinical study evaluated the effect of topical sweet almond oil application on itch-related quality of life in 42 patients suffering from uraemic pruritus, due to chronic renal failure and presenting with intense itching. Participants were allocated into two groups: a control group and an intervention group applying 7 to 10 mL of sweet almond oil to pruritic areas once daily for two weeks. The evaluation of itch-related quality of life (itchyQoL) was conducted before the intervention, and again after one and two weeks. The results demonstrated a significant reduction in pruritus scores in the intervention group (from 50.3 ± 16.7 to 31.7 ± 8.9 over two weeks), whereas no improvement was observed in the control group.

These findings suggest that sweet almond oil may help soothe itching, possibly on the scalp, and, by extension, contribute to reducing irritation more generally.