Is aloe vera effective against melasma?

The pregnancy mask is one of the many skin concerns experienced by pregnant women. Also known as chloasma or melasma, it usually occurs from the second trimester of pregnancy and affects approximately 50 to 75% of women. The pregnancy mask appears as large dark areas on the face, more or less regular. While it generally disappears spontaneously in the months following childbirth, this is not systematic for all women.

A natural and non-hazardous topical treatment during pregnancy, the aloe vera gel is a true ally for expectant mothers. Hydrating and repairing, it improves skin elasticity and can easily be applied through massage. Moreover, a study has shown that it can help prevent stretch marks. The effectiveness of aloe vera gel on pregnancy mask, however, appears to be more measured, if not non-existent, despite the promising results obtained by in vitro studies. These have indeed shown that aloesin from aloe vera could inhibit the hydroxylation of tyrosine into DOPA and the oxidation of DOPA into dopachrome, a metabolite of melanin biosynthesis.

However, the main obstacle to the action of the aloe vera gel on brown spots is its highly hydrophilic nature. Predominantly composed of water and compounds only soluble in aqueous environments, this botanical extract remains on the skin's surface when applied topically and is unable to penetrate the stratum corneum, a layer rich in proteins and lipids. Therefore, it cannot reach the melanocytes, the cells that produce melanin, or even the keratinocytes, where the melanin synthesised in the melanosomes is subsequently transferred.

To circumvent this issue, researchers conceived the idea of encapsulating aloe vera in liposomes, lipid vesicles capable of penetrating the corneal layer and releasing the active ingredients they contain. They then recruited 180 pregnant women with melasma and divided them into two equal groups of 90 individuals. For 5 weeks, participants in the first group used the formulation based on encapsulated aloe vera, while those in the second group applied pure aloe vera gel. After 35 days, the scientists evaluated the women's melasma using the MASI (Melasma Area Severity Index) score and noted a significant average reduction of 32% in the first group of participants. No significant difference was observed in the second group. Thus, encapsulating aloe vera could allow the use of its depigmenting potential, which is inaccessible when used in its raw form.

Although the topical application of aloe vera gel is beneficial for pregnant women, it does not combat the mask of pregnancy.