The science
The evidence in this jar divides cleanly into an active with human trials and a hero with laboratory ones. The active is niacinamide. In a 2005 Dermatologic Surgery paper, Bissett, Oblong and Berge ran a double-blind, left-right randomised study in 50 women with facial photoaging, applying 5 percent niacinamide to one side and vehicle to the other twice daily for 12 weeks, with imaging and instrumental readings every four weeks; the niacinamide side showed significant reductions in fine lines and wrinkles, hyperpigmented spots, red blotchiness and yellowing, and improved elasticity on cutometry. The mechanisms — reduced melanosome transfer to keratinocytes, increased ceramide and barrier-protein synthesis, more dermal collagen via NAD-dependent pathways, less glycation yellowing — map onto the 'more even', 'radiance' and 'skin quality' language of Nuxe's 28-day panel, though the trial's disclosed 5 percent and 12-week endpoint both outrun what this cream states or promises.
The hero is Chlorella vulgaris. A 2025 study in Marine Drugs by Masoumifeshani and colleagues extracted and enzymatically hydrolysed proteins from Chlorella vulgaris and Spirulina platensis and found that the sub-3-kilodalton peptide fractions showed strong antioxidant activity in DPPH, ABTS and FRAP assays and inhibited the skin-ageing enzymes elastase, collagenase and tyrosinase in vitro, identifying several di- and tri-peptides as likely contributors. That is a plausible basis for calling the alga 'anti-ageing' in a laboratory, and it is the level at which the evidence currently sits: hydrolysed peptide fractions in a test tube, not a whole-cell extract at twenty-third position in a cream on human skin. The '4 billion active cells' count is a statement about how small microalgal cells are, not about dose or effect.
The vehicle decides who can wear it. Squalane at second supplies a saturated, sebum-compatible emollient; alcohol denat at fifth is the volatile carrier behind the flash-dry, velvety set, and a known contributor to barrier disruption and stinging on compromised skin when used repeatedly; polyacrylate crosspolymer-6 structures the finish; shea butter, caprylic/capric triglyceride and sunflower oil restore a modest occlusive and linoleic layer; tocopherol and rosemary extract stabilise the oils. Fragrance at ninth with Citrus aurantium peel oil and nine declared allergen components — limonene, linalool, linalyl acetate, alpha-isomethyl ionone, geraniol, citronellol, terpineol, a musk and benzyl alcohol — is a substantial sensitiser load for a leave-on applied twice daily, and the citrus oil adds a small photosensitivity consideration that a morning sunscreen resolves.