Background Changes induced by intrinsic and extrinsic photoaging result in signs of skin aging including altered pigmentation and wrinkles. A 3‐in‐1 night facial serum (NFS) was developed to treat skin aging by antioxidative and retinoid‐like mechanisms. Objective To determine the clinical and histological effects of the 3‐in‐1 NFS on signs of skin aging, clinically and histologically. Methods & Materials Twenty‐four subjects applied serum nightly for 12 weeks, and 12 subjects continued an extension study to 24 weeks. Clinical assessment of skin quality was performed by dermatologists. Skin biopsy was performed at 12 weeks to assess histological changes. Results There was a global aesthetic improvement over the duration of the study: +1.21 points at 12 weeks; +1.25 at 24 weeks. Skin texture, pigmentation, erythema, skin tone, complexion, lines, and wrinkles all significantly improved (P < .05). There was also a significant reduction in photodamage, hyperpigmentation, and wrinkle scores, most notably horizontal forehead expression lines, and marionette lines (P < .05 for all). Dermal and epidermal thickness increased without reaching statistical significance. Conclusion The 3‐in‐1 NFS had clinically and statistically significant effects on signs of skin aging after 12 weeks, which became more pronounced after 24 weeks.