Lycopene- The only major carotenoid with zero vitamin A activity

Unlike beta-carotene, alpha-carotene, and beta-cryptoxanthin, lycopene has no provitamin A activity at all. Its 11 conjugated double bonds form a linear (acyclic) chain that cannot be enzymatically cleaved to retinal. This means lycopene's entire biological value comes from mechanisms other than vitamin A, singlet oxygen quenching, HMG-CoA reductase inhibition, and gap junction communication. Yet it's constantly grouped with "vitamin A carotenoids" in marketing.Publications of interest:https://pmc.ncbi.nlm.nih.gov/articles/PMC2854912/https://pmc.ncbi.nlm.nih.gov/articles/PMC11606860/https://pmc.ncbi.nlm.nih.gov/articles/PMC3679377/