How to soothe sunburn with aloe vera?

Extracted from the plant of the same name, the aloe vera gel is a colourless, viscous substance containing at least one hundred active molecules (polysaccharides, vitamins, trace elements, enzymes, amino acids). In skincare, it is recognised for its hydrating, soothing and reparative properties that help soothe sunburn. Also called actinic erythema, this term refers to a skin burn caused by erythematous UV rays, mainly composed of UVB. Sunburns are characterised by redness, intense pain and itching. In severe instances, blisters may form. Biologically, sunburn triggers an inflammatory reaction. UV rays damage microRNAs which, once released into the extracellular environment, stimulate production of pro-inflammatory cytokines.

Prevention is better than cure : avoid direct exposure to the sun in summer during the hottest hours of the day, between 11:00 and 16:00, and apply regularly and in sufficient quantity a sunscreen.

If despite these precautions your skin develops sunburn, aloe vera gel can help soothe it. Used for centuries to calm skin irritation, it is recommended in numerous accounts to attenuate actinic erythema. Beyond these observations, an experimental study in rats showed aloe vera’s potential to protect skin against UVB-induced lesions. Researchers sought to assess whether topical application of aloe vera gel could reduce the formation of “sunburn cells” and the expression of caspase-3, a key enzyme in apoptosis or cell death. “Sunburn cells” are keratinocytes undergoing apoptosis after they received a physiological dose of UVB that caused irreversible and severe damage to their DNA.

For this purpose, two groups of animals were exposed to minimal erythemal doses. A 75 per cent aloe vera extract was then immediately applied to the backs of the mice in the first group. After six, 12, 24 and 48 hours, the researchers measured caspase-3 expression by immunohistochemistry and counted the number of "sunburn" cells under the microscope. The results showed a significant decrease in caspase-3 expression and a marked reduction in the number of "sunburn" cells in the group treated with aloe vera compared with the control group. This suggests that aloe vera gel exerts a protective effect by limiting apoptosis and UVB-induced cellular damage, thanks to its antioxidant and anti-inflammatory compounds.

The aloe vera appears capable of soothing sunburn, although additional clinical studies in humans are necessary to confirm this.

If we examine the mechanism of action of the aloe vera gel, we see that this botanical extract can act on several levels:

• Aloe vera cools the skin, soothes burning sensation, and hydrates the epidermis.

  When applied to sun-reddened skin, aloe vera gel provides a cooling effect and restores the natural hydration of the epidermis. This ingredient contains hygroscopic polysaccharides that bind water molecules, retaining them in the stratum corneum. Researchers have demonstrated that, when aloe vera gel is applied to the skin, its long-chain mucopolysaccharides polymerise and form a thin semi-permeable film that provides an immediate hydrating effect. Another study with 20 women showed that adding 0.5% aloe vera to a moisturiser increased skin hydration by approximately 20% compared with the formulation without aloe vera.

  Why is hydrating the skin beneficial for sunburn?

  After sunburn, the skin barrier is altered. The organisation of intercellular lipids is disrupted and the natural hydration factors as well as the hydrolipid film are reduced. Transepidermal water loss increases and the epidermis becomes drier. Hydrating the skin after sunburn restores its water balance and supports its barrier function. Hydration aids skin healing. Moisture helps epithelial cells migrate across wound surfaces and induce closure.

• Aloe vera gel soothes inflammation and supports skin healing.

  Other beneficial effects of aloe vera for sunburn: its anti-inflammatory and wound-healing properties. A recent study shows that aloe vera acemannan promotes wound closure and stimulates cell proliferation by activating the AKT/mTOR signalling pathway, involved in angiogenesis, the formation of new blood vessels. This process increases the supply of nutrients and oxygen, accelerating tissue repair. Due to its flavonoid content, aloe vera gel modulates the production of pro-inflammatory cytokines such as TNF-α and IL-6. This action reduces local inflammation, relieves pain and limits tissue damage from sunburn.

  Why are these effects of aloe vera relevant for sunburn treatment?

  After a sunburn, tissue repair is essential because the skin has sustained significant cellular damage and is inflamed. Healing restores the skin’s structure and protective function. It re-establishes an environment that supports keratinocyte proliferation and migration, collagen synthesis, and regeneration of damaged fibres. Aloe vera’s anti-inflammatory properties help reduce the redness and stinging that follow sunburn.

This combination of hydrating, soothing, healing and anti-inflammatory actions makes aloe vera useful for soothing irritation, including those due to sunburn.

To soothe a mild to moderate sunburn, aloe vera gel can be applied as soon as the heat and tightness are felt, a few hours after UV exposure. It is best to wait until the skin has cooled (for example by gently rinsing with lukewarm or cool water) before applying the gel. The aloe vera gel should be used on clean, dry skin in a thin layer without rubbing to avoid worsening irritation. You can reapply two to three times per day as needed until redness and sensitivity improve.

It is important to note that aloe vera gel is not suitable for severe sunburns (blistered skin, intense pain, fever or chills), which require medical attention.

• VONGTONGSRI R. & al. Efficacy of aloe vera cream in prevention and treatment of sunburn and suntan. Journal of the Medical Association of Thailand (2005).

• CAMPOS M. & al. Moisturizing effect of cosmetic formulations containing aloe vera extract in different concentrations assessed by skin bioengineering techniques. Skin Research and Technology (2006).

• HUSSANA A. & al. The administration of topical aloe vera extract reduce the number of sunburn cells and expression of caspase-3 on post UVB-light-exposure epidermis. Jurnal Kedokteran dan Kesehatan (2020).

• LI J. & al. Aloe vera: a medicinal plant used in skin wound healing. Tissue Engineering (2021).

• BAZYLKO A. & al. The potential of medicinal plants and natural products in the treatment of burns and sunburn – a review. Pharmaceutics (2023).