Everything you need to know about eyelash and eyebrow serums.

The function of eyelashes and eyebrows is to protect the eyes from dust and sweat droplets. On average, they reach a length of about ten millimetres. Their life cycle unfolds in three phases: the growth, stagnation (catagen phase) and shedding (telogen phase). Each eyelash and eyebrow independently follows its own cycle, which is why the eyes are continuously protected by long eyelashes and thick eyebrows.

The growth phase extends over one to two months. Hairs that have completed their growth enter the second phase (stagnation). During this transition period, the hair follicle shrinks. This period lasts approximately three weeks. During this transition phase, the eyelash can fall out prematurely and regrowth does not occur instantly. Regrowth will not commence until the end of the catagen phase.

Throughout this cycle, it is crucial to care for one's eyelashes and eyebrows to ensure they remain healthy and do not fall out prematurely. Hence, the usefulness of a fortifying serum for eyelashes and eyebrows!

Eyelash and eyebrow serums are most commonly direct aqueous or emulsified gels (with a majority aqueous phase and a minority oily phase). They contain various categories of ingredients:

• The solvent : Most often appearing first on the INCI list, thewater is the most common solvent in eyelash and eyebrow serums.

• Gelling Agents: The substantial texture is provided to eyelash and eyebrow serums via texturising agents, which are most often natural or synthetic polymers. Among the natural texturisers, we can mention sclerotium gum (INCI name: "Sclerotium Gum"), the xanthan gum (INCI name: "Xanthan Gum") or even tara gum (INCI name: "Caesalpinia Spinosa Gum").

• The active ingredients: Generally, those found in eyelash and eyebrow serums are fortifying and nourishing (e.g. castor oil, pea peptides, panthenol, biotinoyl-GHK...). They stimulate, strengthen and densify the cells of the eyelashes and eyebrows, while helping to keep them in good health.

• Humectant compounds: The humectant nature of an ingredient is based on its ability to retain water molecules due to its hygroscopic power (strong affinity for water). On the market, the potential humectant compounds present in an eyelash and eyebrow serum are the glycerine, the propylene glycol, polyethylene glycols (PEG) or even the pentylene glycol.

• Fatty substances: Some eyelash/brow serums contain vegetable oils, in order to nourish these hair follicles. For example, the eyelash serum Typology contains vegetable castor oil("Ricinus Communis (Castor) Seed Oil").

• Emulsifiers: The blending of fatty substances with water is made possible by the presence of surfactants, which disperse oil droplets in the aqueous solution to form a stable emulsion.

• Preservatives: The lash/brow serum is typically a gel aqueous, it is conducive to the growth of bacteria. In response to this, to maintain the effectiveness and safety of the product, it is essential to incorporate preservatives.