Misconception: Using lemon juice for radiant skin.

With its high content of vitamin C and citric acid (AHA), freshly squeezed lemon juice is often hailed as a natural alternative for preventing and correcting various skin issues (dull complexion, blackheads, brown spots, acne, etc.). Indeed, some assert that the various compounds contained in lemons make them theoretically beneficial for the skin. It is notably used to lighten brown spots, even out skin tone, soothe acne, slow down the appearance of wrinkles, and even remove dandruff. However, very few studies have demonstrated the positive effects of lemon juice on the skin.

However, it should be noted that the quantity of citric acid and vitamin C can vary from one lemon to another, which could potentially affect its effectiveness on the skin.

Furthermore, this practice would primarily pose risks. Its topical application could lead to several adverse effects and exacerbate the targeted skin conditions. Thus, the direct use of lemon juice on the skin would do more harm than good.

• Skin Irritation: Lemon has a pH ranging between 2 and 3, which can potentially make it problematic. Indeed, this extremely acidic nature of lemon juice can alter the physiological pH of the skin (between 4.5 and 5.5), thereby increasing the risk of skin irritation and inflammation. By lowering the skin's pH, the application of undiluted lemon juice directly onto the skin can lead to a weakening of the skin barrier, which ultimately results in redness, excessive skin dryness, tingling, flaking, and even burns.

• Photosensitisation: Along the same lines, applying lemon juice to the face also makes the skin much more sensitive to UV rays. In other words, this means that exposing the skin to the sun after applying pure lemon juice can increase the risk of sunburn. Indeed, lemon is composed of photosensitising molecules, the furocoumarins (psoralen, bergapten, xanthotoxin, isopimpinellin, etc.), which increase the skin's sensitivity to UV, and not because of the vitamin C as is often relayed.

  If you expose your face to the sun after applying lemon juice, the risks can be significantly increased. Indeed, the direct application of lemon juice on the skin can, in rare cases, lead to a condition called phytophotodermatitis, which is an erythematous skin rash followed by hyperpigmentation caused by the overproduction of melanin stimulated by photosensitising agents (furocoumarins).

• Chemical Leucoderma (vitiligo): Apart from this issue, large and widespread white patches of leucoderma can appear in areas where lemon juice has been in contact for a long period, as people often use it to lighten brown spots.

Considering these potential risks and limitations, lemon juice appears to have more drawbacks than benefits. Therefore, it is recommended not to use lemon juice on your skin. There are more effective and safer alternatives available on the market for pigmentation issues, to brighten the complexion, or to eliminate blemishes.

Even though lemon juice may be seen in the ingredient list of some topical products (INCI: Citrus Limon (Lemon) Fruit Water), this does not imply that applying it directly to the skin will provide the same benefits. Products based on lemon water have been meticulously formulated by scientists using ingredient concentrations that offer optimal and safe benefits, and are intended exclusively for topical use. Furthermore, the lemon water used in skincare products has a significantly less acidic pH and does not have the same phytochemical composition.

• ALWEIS R. & al. Lime-induced phytophotodermatitis. Journal of Community Hospital Internal Medicine Perspectives (2014).

• MYUNGHWA K. & al. Chemical leucoderma induced by homemade lemon toner. Australasian Journal of Dermatology (2014).

• HSIANG D. & al. Phytophotodermatitis: Rash with many faces. Canadian Family Physician (2017).

• GANGEMI S. & al. A spotlight on lime: A review about adverse reactions and clinical manifestations due to Citrus aurantiifolia. Clinical and Molecular Allergy (2021).