Which other active ingredients can caffeine be combined with?

caffeine is no exception to this rule.

• Caffeine and Hyaluronic Acid: The development of a formula combining hyaluronic acid and caffeine helps to achieve a refreshed and rested look. The addition of hyaluronic acid, referred to as a "filler substance", helps to fill and reduce the dehydration lines of the delicate skin around the eyes in the long term, in addition to hydrating the skin and improving its elasticity. Caffeine, on the other hand, protects the thin skin under the eyes from free radicals, thus preventing skin ageing.

• Caffeine and other draining actives: In anti-cellulite treatments or for eye contour care, combining caffeine with draining actives, such as theguarana extract (INCI: Paullinia Cupana Seed Extract), butcher's broom extract (INCI: Ruscus Aculeatus Root Extract), ivy extract (INCI: Hedera Helix Leaf Extract), etc., enhances drainage. In other words, these active ingredients facilitate the elimination of free fatty acid clusters post-lipolysis, as well as the pigmented degradation products accumulated in the dermis and epidermis, which are responsible for the dark colouration around the eye. In addition, they promote the decongestion of the eye contour and combat water retention.

• Caffeine and its natural derivatives: To supplement the activity of caffeine and enhance lipolysis action, it can be combined in the same cosmetic formula with extracts of plants naturally rich in native caffeine such as tea extract (INCI: Camelia Sinensis Leaf Extract) with theine, Yerba mate extract (INCI: Ilex Paraguariensis Leaf Extract) with mateine, guarana extract with guaranine... This combination thus promotes the hydrolysis of triglycerides accumulated in adipocytes into free fatty acids and helps to reduce the "orange peel" appearance.

• Caffeine and Niacinamide: In addition to its lipolytic and stimulating properties, caffeine is capable of reducing and preventing inflammatory reactions and skin redness. However, the combination of caffeine with other anti-inflammatory agents such as niacinamide significantly enhances its effectiveness.

• Caffeine and antioxidants ( epigallocatechin gallate glucoside (EGCG), vitamin C, ferulic acid...): This combination enhances the antioxidant action of a skincare product, given that these molecules both act on free radicals. It is thus used to protect the skin from signs of premature ageing and to brighten the complexion.

• Caffeine and Retinol: Caffeine is also credited with antioxidant properties. On the other hand, the retinol helps to firm the skin. This formulation device thus allows the skin to benefit from the "anti-ageing" potential of these active ingredients. This combination is particularly sought after to tighten the skin, and regain supple and toned skin.

A study conducted in 2015 assessed the use of 3% caffeine combined with 1% vitamin K in an emu oil base on the eye contour. More specifically, this trial in vivo was carried out to investigate the anti-wrinkle and anti-dark circle efficacy of this active ingredient combination on the right eye contour of 11 women over a four-week period. The study was controlled and compared with a placebo composed of water and applied under the left eye.

Caffeine is known for both tightening capillaries and increasing overall skin blood flow, effects that could enhance the appearance of the eye contour. It also helps to neutralise harmful free radicals that can cause collagen degradation and lead to the formation of wrinkles. Vitamin K, on the other hand, helps to strengthen capillary walls and reduce the visibility of blood vessels through the thin skin under the eyes.

After four weeks, the skin around the right eye of all subjects experienced a reduction in wrinkle depth and dark circles, and from a subjective standpoint, the appearance and elasticity of the skin were improved. Thus, the clinical study demonstrated that the application of the active formulation had a cumulative effect on hydration, pigmentation, and elasticity, thereby enhancing the appearance of the eye contour.

Note : emu oil is capable of penetrating through the dermal layer to prevent cells from dehydrating due to its high levels of unsaturated fatty acids (linolenic acid, oleic acid), enhancing the structure and function of cell membranes, as well as the skin's barrier function.

What are the limitations of this study?

However, these results need to be considered with caution. Indeed, the "depigmenting" power of this formula is far from established. In fact, the data presented on pigmentation show a high variability, illustrated by long confidence intervals, indicating that the values are more dispersed and there is a large uncertainty in the measurements presented. Moreover, the study was only conducted on 11 candidates, which represents a small sample size. Thus, although the results obtained seem encouraging regarding the corrective action of caffeine on wrinkles and brown circles, further research would be necessary to confirm its effects.

• SHATALEBI M. A. & co. Assessment of the clinical effectiveness and safety of an eye counter pad infused with caffeine and vitamin K in an emulsified Emu oil base. Advanced Biomedical Research (2015).