Almond oil usually refers to the sweet kind which can be used in cooking as well as hair and cosmetics. Sweet almond oil has a lot more applications than the bitter form and can be applied directly on the skin and scalp.
Bitter almond oil is an essential oil. Like Tea Tree Oil, bitter almond oil is better suited for medical applications because of its antimicrobial properties. It is also beneficial for hair and cosmetics but only when it is diluted first.
Sun exposure can damage our hair. So how does it help prevent sun damage? Almond oil has been found to reduce structural damage to the hair strands themselves caused by ultraviolet radiation in a study on animals by Yasmin et al. Another study found that almond oil has an SPF level of almost 5. SPF 5 doesn't sound like a lot, but it blocks over 75% of UVB-type radiation. It's vitamin E in almond oil that carries this anti-UV protection.
Almond oil can be used as a conditioner. It's great for adding shine to the hair, strengthening hair (especially when processed) and softening the hair.
Almond oil fills in the gaps between the cuticles, flattening the cuticles, adding to the shine of the hair. When the cuticles of our hair are flat, it reflects more light, hence, providing the shiny quality associated with many oils.
Almond oil may increase the strength of the hair because of a fatty acid molecule called linoleic acid. Almond oil is composed of 13-29% linoleic acid which notably increases hair tensile strength as reported by Si Hyun Lee and Cheunsoon Ahn on processed hair. Almond oil is a good option for hair conditioners when trying to limit the damage due to styling processes.
Almond oil locks in moisture with its "emollient property, and hence can be used to soften and moisturize dry hair" as summarised by Venkataram Mysore and Arpita Arghya on 'Hair Oils: Indigenous Knowledge Revisited'.
Almond oil is light enough that it's easily absorbed into the skin, including chapped lips. As for hair care, almond oil is light enough to penetrate the hair fiber, which is good for improving strength against breakage, but it doesn't help with damage caused by combing, whereas a heavier oil like coconut oil would be better suited.
The almond oil industry is almost a staggering 2 trillion US dollar market, one-quarter the size of the global and very popular olive oil market. Aside from aromatherapy, people use it for cooking to flavour food as it has a nutty taste, but when refined, it's also very suitable for frying. As for hair care, it can even be found in popular shampoos and hair conditioners.
Unfortunately, almond oil farming is unsustainable as it has a high carbon footprint in comparison to other foods and harms bees. Nonetheless work on improving its sustainability has begun after criticism of growing almond trees over other nut trees.