# Cosmeceuticals and Thalassotherapy: Recovering the Skin and Well-Being after Cancer Therapies
## 3 Cosmeceuticals for Skin Care of Oncologic Patient
### Vitamins
#### 3.2.2 B Vitamins  
B vitamins contribute to a greater or lesser extent to maintaining the health of the skin and hair; they are also coenzymes in energy production. They are water soluble and quite stable, penetrating through the stratum comeum, and are frequently used for the production of cellular energy and to improve the protection of the skin barrier.  
Vitamin B3 (Niacinamide) is perhaps the most studied in regard to treatment of skin inflammation and erythrocytes, calming irritation. Niacinamide exerts anti-inflammatory effects due to inhibition of proinflammatory factors, as well as its ability to increase the expression of serine palmitoyl transferase, the enzyme involved in ceramide synthesis [36]. Therefore, studies have been carried out to evaluate the protective effect of a cosmetic preparation with 4% niacinamide during radiotherapy, obtaining a significant improvement in symptoms [37].  
Vitamin B5 or D-Panthenol acts as a moisturizer, improving stratum comeum hydration, reducing tranepidermal water loss and maintaining skin softness and elasticity. It is also known to accelerate re-epithelialization in wound healing. Dexpanthenol has been shown to have an anti-inflammatory effect on experimental ultraviolet-induced erythema. The stimulation of epithelization, granulation and mitigation of itching were the most prominent effects of formulations containing dexamethasoneol, and also improved the symptoms of skin irritation, such as pruritus, erythema, roughness, scaling, and likewise erosion/fissures, after a few weeks [38]. Another study compared the reduction of incidence of moist desquamation with a hydroactive colloid gel versus dexamethasoneol; a clear clinical benefit of a hydroactive colloid gel over an oil-in-water emulsion containing 5% dexamethasoneol has been shown for the prevention of radiotherapy-induced moist desquamation [39].  
Vitamin B6 (pyridoxine pure crystalline powder or pyridoxine hydrochloride forms) acts as a coenzyme in numerous enzymatic reactions, many of them necessary for the maintenance of healthy skin. A review by [PERSON] et al. [40] concluded that, although there is insufficient scientific evidence, vitamin B6 in doses of more than 400 mg may improve some of the manifestations of hand-foot syndrome. Pyridoxine could be converted into pyridoxal phosphate in red blood cells, and it acts as a potent antagonist of P2X purinergic receptor, which accelerates the skin barrier repair and prevents epithelial hyperplasia [41].  
Biotin B7 is a water-soluble vitamin that acts as a prosthetic group of carboxyles. In addition to its function as an enzyme cofactor, it participates in embryonic development, cell proliferation, immune functions and metabolism, while pyridoxal participates in regeneration of tetrahydrofolate and in glutathione biosynthesis. Both vitamins play important roles in the energy metabolism. Further progress in biotin function investigation revealed its epigenetic properties and a role in cell signaling and in defense against reactive oxygen species [42; 43]. Using a PAMAM G3 dendrimer with measured linkages of nine biotin molecules and ten molecules of pyridoxal phosphate (BC-PAMAM), these authors carried out a study in which managed to reduce inflammation in HaCaT keratinocytes, which opens an interesting perspective for the treatment of skin inflammation [44].