Which active ingredient(s) should be used against dark circles and bags under the eyes?

Dark circles , also known as periorbital/periocular hyperpigmentation, periorbital melanosis, infra-orbital darkening, infra-orbital discolouration, or idiopathic cutaneous hyperchromia of the orbital region, is a common issue that results in a darkening of the skin covering the periorbital area and/or the depression of the lower eyelid. They present as bilateral, round or semi-circular, and homogeneous macules, giving the subject a tired appearance.

Dark circles are caused by various exogenous and endogenous factors. Causal factors include genetics, excessive pigmentation, fragility of blood vessels, poor blood circulation, skin laxity associated with ageing, hormonal fluctuations, sun exposure, rubbing and scratching of the skin around the eyes, and the use of certain ocular hypotensive medications. Other lifestyle-related factors can also contribute to the development of dark circles, including lack of sleep, stress, excessive alcohol consumption and smoking, although this is not clinically proven. Furthermore, the thinness of the eyelid skin makes the small blood vessels under the eyes highly visible.

The etiology and structural variations of dark circles have been subject to classification, thus aiding in the introduction of appropriate modalities based on the type of dark circles, as different forms of dark circles respond to different types of care.

• Vascular dark circles can be identified by a blue/pink/purple infra-orbital discolouration, caused by poor circulation leading to a decrease in blood oxygenation. They particularly manifest after significant fatigue and/or stress and are generally accentuated with age or during menstruation;

• Generated by an overproduction or a distribution issue of melanin, the pigmented dark circles display a brown/black hue. The appearance of dark circles can also result from the fragility of blood vessels: these can easily rupture, leading to the leakage of haemoglobin into the surrounding area. However, when haemoglobin breaks down, pigmented degradation products form and accumulate locally in the dermis and epidermis, thereby causing a dark discolouration around the eye. This type of dark circle is more prevalent in individuals with medium to dark skin tones;

• There also exist structural dark circles which are characterised by a hollow in the periocular region . This phenomenon also causes, depending on lighting conditions, a structural shadow. This change is related to skin ageing, occurring primarily due to the thinning of the dermis, combined with a thinning and loosening of the collagen and elastin fibre network;

• Mixed dark circles are a combination of pigmented type dark circles and vascular type ones, to varying degrees of prominence.

As for eye bags, they are identified by observing a periorbital puffiness with a high pre-septal thickness, with or without discolouration. They result either from the accumulation of fluid or fat. Factors that can trigger the formation of bags under the eyes include fatigue, a diet high in salt, the intake of certain muscle-relaxing medications, and excessive consumption of alcoholic beverages...

• The adipose pockets are characterised by fatty pads on the periorbital area. They result from a loss of fat with bony prominence ;

• The aqueous bags are caused by a dysfunction of the lymphatic tissues, leading to the infiltration of fluid at the infra-orbital edge. Indeed, the eyelid region has a spongy property, which can lead to an accumulation of biological fluid. Compared to fatty bags, malar bags are always present when looking down and do not change much when looking up.

To limit the pigmentation of dark circles and the swelling of bags around the eye contour, the use of specific topical actives that have shown significant benefits in managing dark circles and bags is among the possible options to mitigate their appearance. However, the type of active chosen depends on the nature of the dark circles and bags.

• Arbutin Acid : Extracted from the leaves of bearberry, cranberry, pear or blueberry, alpha-arbutin inhibits the activity of tyrosinase, as well as the maturation of melanosomes. Although one study has demonstrated the effectiveness of arbutin acid on melasma, it can potentially be used in other cases of facial hyperpigmentation such as on brown under-eye circles;

• Azelaic Acid : Initially developed as a topical anti-acne agent, azelaic acid can also be used due to its effect on tyrosinase. Indeed, it has proven effective in reducing pigmentation in patients suffering frompost-inflammatory hyperpigmentation on the face or melasma. Thus, it represents a potentially promising agent for pigmented dark circles. Its mechanism of action includes its interference with the synthesis of DNA and mitochondrial enzymes in melanocytes;

• Exfoliating agents (glycolic acid, lactic acid, mandelic acid, citric acid...): The practice of chemical peels is a good alternative for improving the aesthetic appearance of the skin around the eyes, particularly with the use of high-concentration alpha-hydroxy acid (AHA) products. However, for darker skin tones, it is preferable to extend the peel to the entire face to avoid post-peel demarcation.

  For optimal results, it is often recommended to apply treatments containing depigmenting agents for several weeks before undergoing a chemical peel. However, this type of procedure has drawbacks such as the occurrence of post-inflammatory hyperpigmentation, hence the importance of wearing sunglasses which can be paired with the application of a sun protection product around the eyes, but also the fact that they can be irritating. This is why they must be used with caution and under dermatological control, especially at high concentrations;

• Caffeine : This is an alkaloid designed to stimulate blood circulation around the eyes and also accelerates blood flow in the capillaries, thereby preventing the accumulation of plasma and subcutaneous pigments to prevent the formation of dark circles. It also improves the lymphatic microcirculation of the eye contour, thus reducing the swollen appearance of the eyes and fading under-eye oedema. Its effectiveness is observed after an average of 12 weeks of application, morning and evening. However, the studies conducted on this molecule are insufficient to fully measure its effectiveness on the eye contour;

• Niacinamide : More commonly known as vitamin B3, niacinamide aims to even out the complexion through its anti-spot action. Indeed, it has the ability to modulate the biosynthesis pathway of melanin (melanogenesis), which is involved in the pathophysiology of brown circles, by acting on the transfer of melanin granules to the basal epidermis. Furthermore, it stimulates blood microcirculation, helping to reduce the appearance of bluish circles and watery bags under the eyes;

• Vitamin C and its derivatives : This skin antioxidant is also capable of correcting pigmentation under the lower eyelids. It is particularly effective at trapping free radicals that can trigger melanogenesis. Furthermore, Vitamin C is also able to stimulate collagen production and thus mask the colour, improving the appearance of dark circles due to an increase in dermal thickness which helps to conceal the dark pigmentation under the eyes caused by congested blood.

  Similarly, a study has also demonstrated that the use of a lotion containing 10% vitamin C (INCI name: Ascorbic Acid) or its esterified derivatives, such as ascorbyl palmitate (INCI name: Ascorbyl Palmitate), ascorbyl glucoside (INCI name: Ascorbyl Glucoside) or even magnesium ascorbyl phosphate (INCI name: Magnesium Ascorbyl Phosphate), could inhibit the production of melanin by inhibiting the enzyme tyrosinase, thereby preventing the conversion of dopa into melanin. This therefore results in a reduction of melanin content in the epidermis and a lightening of the periorbital area.