Abstract
The need for alternative skin rejuvenation approaches to treat intrinsic and photoaging is increasing. The oceans are a huge, largely untapped source of bioactive compounds (e.g., mycosporine-like amino acids, phlorotannins, carotenoids, sulfated polysaccharides) which are active in regulating oxidative stress, inflammation and extracellular matrix (ECM) degradation. Despite the vast in vitro evidence, very few marine compounds have investigated advanced clinical trials (randomized controlled trials (RCT) or regulatory approval for clinical anti-aging claims. This review examines marine compounds with established clinical evidence (RCT or splitface, or histologically verified studies) for skin rejuvenation, such as wrinkles, hydration, elasticity, and pigmentation. Skin rejuvenation effects of topical astaxanthin (antioxidant), oral marine collagen peptides (collagen synthesis), and some phlorotannin-containing extracts (MMPs) are confirmed by clinical studies. But there is considerable variation in trial designs, product stability, and endpoints, impeding meta-analysis. Gaps in translating mechanistic in vitro and animal discovery (e.g., novel MAAs, bromophenols) to clinical practice are attributed to low bioavailability, unstandardised preparations, and no regulatory pathways for "anti-aging" claims. To drive innovation, phase-aligned clinical advancement of promising marine leads through drug-development approaches, rather than nutraceutical strategies, is needed.