The "NAD+" sold in under-eye creams against dark circles is mostly a branding move: the clinical evidence specific to topical NAD+ is still early-stage, and the ingredient that actually has solid data for this same mechanism is called niacinamide.

noli's read

NAD+ genuinely plays a role in cellular aging, and in vitro research shows it protects fibroblasts from UV stress — but it's a large, charged molecule that doesn't cross the skin barrier well, which is why most "NAD+" products actually use precursor molecules like niacinamide (vitamin B3), itself extremely well documented by decades of clinical trials on pigmentation and barrier function — just under a different marketing name. No robust, controlled, published human trial specifically measures topical NAD+'s effect on dark circles; the studies found either address melasma via microneedling (a different indication and delivery method) or are cell-culture work. Other dark-circle formulations (vitamin C, arbutin, tranexamic acid) do have dedicated clinical trials with objectively measured reductions of 12-48% depending on the study — a standard of proof this product hasn't reached yet for its headline ingredient. Dark circles are multifactorial anyway (vascular, pigmentary, structural), so a single active is unlikely to fix all of it.

the sources

No named source held this one up — that absence is part of the verdict.