Spirulina stands out as a sustainable bioactive microalga with health-promoting properties, and an important active ingredient of natural cosmetics products. Currently, Spirulina has been incorporated in topical skin-care formulations, such as a moisturizing, antiwrinkles, antiaging and antiacne agent. Furthermore, this microalga is used by cosmetic formulators to promote healthy sunscreen protection, to treat skin pigmentation disorders and to heal wounds. Most of commercial cosmetics claim a large range of Spirulina properties, including antioxidant, revitalizing, remineralizing, moisturizing, protecting alongside cleansing and shining action, both for hair and for skin. In this review, recent cosmetic applications of Spirulina are revised, by highlighting its ability in improving skin appearance and health. Additionally, the analysis of the Spirulina cosmetic benchmark is discussed. Looking at the current emergence of the beauty industry, many Spirulina extracts and dry powder/flakes, both the starting ingredient and final Spirulina-based cosmetic products, are available on the market. In this industrial field, Spirulina—mainly Spirulina platensis and Spirulina maxima—is used either as a powder, like in the case of cheaper products, or as a phycocyanin-rich blue extract, particularly in the luxury market. It is likely that, in the coming years, diversity, quality and topical applications of Spirulina will rapidly increase.

Carnitines play a key physiological role in oocyte metabolism and redox homeostasis. In clinical and animal studies, carnitine administration alleviated metabolic and reproductive dysfunction associated with polycystic ovarian syndrome (PCOS). Oxidative stress (OS) at systemic, intraovarian, and intrafollicular levels is one of the main factors involved in the pathogenesis of PCOS. We investigated the ability of different acyl-carnitines to act at the oocyte level by counteracting the effects of OS on carnitine shuttle system and mitochondrial activity in mouse oocytes. Germinal vesicle (GV) oocytes were exposed to hydrogen peroxide and propionyl-l-carnitine (PLC) alone or in association with l-carnitine (LC) and acetyl-l-carnitine (ALC) under different conditions. Expression of carnitine palmitoyltransferase-1 (Cpt1) was monitored by RT-PCR. In in vitro matured oocytes, metaphase II (MII) apparatus was assessed by immunofluorescence. Oocyte mitochondrial respiration was evaluated by Seahorse Cell Mito Stress Test. We found that Cpt1a and Cpt1c isoforms increased under prooxidant conditions. PLC alone significantly improved meiosis completion and oocyte quality with a synergistic effect when combined with LC + ALC. Acyl-carnitines prevented Cpt1c increased expression, modifications of oocyte respiration, and ATP production observed upon OS. Specific effects of PLC on spare respiratory capacity were observed. Therefore, carnitine supplementation modulated the intramitochondrial transfer of fatty acids with positive effects on mitochondrial activity under OS. This knowledge contributes to defining molecular mechanism underlying carnitine efficacy on PCOS.

Arthrospira platensis (commonly known as Spirulina platensis) is a blue-green microalga increasingly used in skincare due to its antioxidant and dermo-protective properties, primarily attributed to components such as phycocyanin and carotenoids. However, the intense blue color of phycocyanin can limit its cosmetic appeal. In this study, we investigated the antioxidant, anti-inflammatory, skin lightening and photoprotective activity of Elixspir^®, a novel light-colored aqueous extract of Spirulina, using both 2D and 3D skin cell models. We demonstrated that Elixspir^® exerts strong antioxidant and cytoprotective effects by reducing intracellular ROS levels and modulating cellular thiol redox state. Its anti-pigmentation potential was supported by tyrosinase inhibition, while anti-inflammatory activity was principally due to ability to reduce PGE2 levels. Finally, we demonstrated an unprecedented photoprotective effect of Elixspir^®, highlighting its potential as a novel active ingredient for skin defense against environmental stressors. Overall, these results provide a molecular-level understanding of Elixspir^® multifunctional bioactivity and support its application as a skin-lightening, anti-inflammatory, antioxidant, and photoprotective ingredient in the formulation of innovative skin anti-aging treatments.