What should one know about the use of green algae in cosmetics?

In cosmetics, we typically use green algae of the type Chlorella. Appearing 2.5 billion years ago, these are freshwater micro-algae (lakes, ponds, and marshes), invisible to the naked eye. Their name comes from their very high concentration of chlorophyll compared to other micro-algae. Also known as the "green gem", green algae is prized by Asians for its nutritional and therapeutic properties, as it has significant nutritional capabilities due to its richness in plant proteins.

Since its discovery, a large number of studies have been conducted on chlorella and it is currently being cultivated. The main varieties exploited are Chlorella vulgaris and Chlorella pyrenoidosa. At present, the majority of the crops are found in Asia, with a large portion of the global production coming from Japan and China. However, it is important to note that there are numerous "algae farms" in Europe that cultivate chlorella, notably in Germany, Spain, Portugal and France.

The numerous benefits of green algae are made possible by the bioactive compounds they contain.

Note : The biochemical composition of green algae can vary depending on the cultivation method and extraction process.

Green algae can be used in topical application or hair care, found in skincare products such as creams, masks or serums. Due to its chlorophyll content, it can also be used in tinted cosmetic products. It offers various benefits for the skin and hair.

• Slowing down skin ageing.

  Indeed, green algae could potentially slow down skin ageing. By reducing the expression of matrix metalloproteinase-1 (MMP-1), which is responsible for collagen degradation, green algae could therefore improve skin elasticity.

  Furthermore, chlorella inhibits lipid peroxidation, thus preventing their degradation through resistance to oxidative stress. Free radicals are produced by this stress (pollution, tobacco, UV, etc.), which accelerate skin ageing.

  The antioxidants found in chlorella, including carotenoids, astaxanthin, canthaxanthin, and flavoxanthin, will capture these free radicals by trapping the single oxygen, which can prevent the damage caused by oxidation on the skin and slow down skin ageing.

• Reducing vascular imperfections.

  Through the reduction of angiogenesis, green algae could potentially decrease the redness associated with dilated blood vessels (telangiectasias), as seen in conditions such as rosacea for example. It may also lead to the formation of a "sheath" of collagen around the dilated blood vessels to reduce their appearance and thus the associated redness.

  However, these results have only been demonstrated once. Further studies are necessary to confirm these hypotheses.

  Green algae can also promote the reduction of redness through the neutralisation of the colour red. Indeed, green algae is rich in chlorophyll, a green pigment. According to the colour wheel, red and green are complementary colours, and when mixed, their hues cancel each other out. Green algae in green tint correctors, for example, could "cancel out" the red colour of redness.

• Promote and accelerate the healing process.

  The topical application of chlorella on lesions increases the number of fibroblasts, likely through the stimulation of the fibroblast growth factor (FGF), which in turn boosts the production of collagen fibres by the fibroblasts. This action facilitates the formation of connective tissue, enabling the wound to heal quickly and properly.

• Boosting skin hydration.

  Green algae in cream form can increase the skin's water content, allowing for better skin hydration. No mechanism has yet been determined. However, we can hypothesise that the omega-3s contained in chlorella may contribute to this. They are essential for the regulation of skin lipids, such as ceramides, which maintain a healthy skin barrier. Omega-3s promote the formation of a protective lipid barrier on the skin, which maintains hydration and increases its suppleness.

• Slowing down the appearance of white hair.

  No study has demonstrated any effect of green algae on hair. However, we can hypothesize that the antioxidant properties of green algae may play a role in hair condition. Drying and stiffening of the hair fibre, linked to lipid oxidation, are part of photo-aggravation (UV-related oxidation) of hair ageing, according to studies. Hair proteins, such as keratin, are photochemically protected by hair pigments.

  However, when pigments act to protect these proteins, they themselves can be degraded or discoloured, resulting in white hair. It can be hypothesised that green algae, through its antioxidant effect and by preventing lipoperoxidation, can protect the hair from oxidative stress. It may help to preserve hair pigments by limiting or slowing the onset of white or grey hair.

These organisms are generally safe to use. However, due to the lack of scientific evidence on the subject, we cannot assert whether the application of green algae could pose problems. Nevertheless, their potential comedogenicity could cause concern. Indeed, algae in general could present a risk of comedogenicity. They would penetrate the pores and accelerate the growth of micro-comedones.

However, this concept is debatable: no study has shown a comedogenic effect of green algae. Most green algae on the market are in the form of extracts, too small to "block" the pores; what is "comedogenic" for one person is not necessarily so for another, and the fact that an ingredient is "comedogenic" does not mean that the product containing it necessarily is.

To maximise the benefits of green algae, it is crucial to use it correctly. Ensure you strictly follow the usage instructions of skincare products containing green algae. Although its use is generally problem-free, you can perform a skin test by applying a product containing green algae to the inside of your elbow, the inner side of your wrist, or behind your ear to observe any potential skin reactions.

Do not hesitate to consult your doctor at the slightest doubt.

Suitable for all skin types, particularly sensitive skin, our anti-redness corrector is the ally of skin prone to localised redness. Upon application, its characteristic green colour, combined with the presence ofgreen algae extract (INCI: Chlorella Vulgaris Extract) diminishes the appearance of redness by neutralising red, according to the colour wheel. This shade is light and natural, providing flexible coverage, without the need to apply foundation afterwards.

In the long run, the corrector reduces vascular imperfections : the green algae extract prevents the formation of new blood vessels and visibly diminishes the appearance of redness, while the niacinamide, present at 2%, soothes inflammations and restores the skin's membrane through the synthesis of intercellular lipids.

We recommend applying small dabs with the applicator to the red areas of the face, and using your fingertip or a brush to blend. This product can be easily removed with a makeup remover oil or micellar water.

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• LEE W. S. Photoaggravation of hair aging. International Journal of Trichology (2009).

• VACA-GARCIA C. & al. Morphology, composition, production, processing and applications of Chlorella vulgaris: A review. Renewable and Sustainable Energy Reviews (2014).

• ACHMAD H. & al. Effect of the application of Chlorella vulgaris ointment to the number of fibroblast cells as an indicator of wound healing in the soft tissue of pig ears. Pesquisa Brasileira em Odontopediatria e Clínica Integrada (2020).

• MORADI A. M. & al. Effect of microalga Chlorella vulgaris extract compared to vitamin C on collagen І and MMP-1 genes expression in human skin fibroblast cells. Journal of Animal Environment (2020).

• NAYARANAN V. Holistic skin care and selection of skin care products in acne. Archives of Clinical & Experimental Dermatology (2020).

• RAYA I. & al. The effectiveness of Chlorella vulgaris cream applied to male and female rats. National Journal of Physiology, Pharmacy and Pharmacology (2020).