No.5 Vitamin Concentrated Serum — Reddit Reviews

• Hyperpigmentation

  Strong evidence

  Tranexamic Acid: 16 studies tested it on its own. See all 21 studies→

  On Reddit: Acne marks slowly fade for some users, who also report reduced pigmentation and a subtle glow. 40 mentions

  Both ingredients for hyperpigmentation

  Tranexamic Acid · Strong evidence

  • Side effects on the skin were usually mild, such as burning or irritation

  Niacinamide · Some evidence

  5 studies tested it on its own. See all 20 studies→

  • All 5 studies that tested it on its own found it helped fade dark spots
  • On its own, it reduced facial darkening and made skin look lighter than a placebo
  • It also improved dark spots linked with sun damage in one clinical trial

• Acne

  Some evidence

  Niacinamide: 6 studies tested it on its own. See all 17 studies→

  On Reddit: Lingering marks from breakouts fade slowly, and one user reports improved acne-related hyperpigmentation. 4 mentions

  What the studies found

  • Most studies found niacinamide helped acne
  • It often cleared acne about as well as clindamycin when put on the skin
  • Some studies found it helped reduce red, sore spots and pimples
  • Some evidence is still uncertain because some studies found no clear difference

• Anti-Aging

  Some evidence

  Niacinamide: 3 studies tested it on its own. See all 9 studies→

  What the studies found

  • Another study found it helped skin hold more water and lowered water loss through the skin

• Dehydration

  Not proven yet

  Few or mixed studies. This claim isn't established.

  Panthenol: 2 studies tested it on its own. See all 3 studies→

• Skin Barrier

  Not proven yet

  Few or mixed studies. This claim isn't established.

  Niacinamide: 1 study tested it on its own. See all 17 studies→

  Both ingredients for skin barrier

  Niacinamide · Not proven yet

  • The one study that tested it on its own found it helped the skin barrier
  • It lowered water loss through the skin
  • It increased the thickness of the outer skin layer

  Panthenol · Not proven yet

  Few or mixed studies. This claim isn't established.

  1 study tested it on its own. See all 10 studies→

  • The one study that tested it on its own found it helped
  • Skin treated with panthenol lost less water through the skin
  • Higher strengths like 1.0% and 5.0% seemed to help the most

Research context, not treatment advice. Studies are about the ingredient, not necessarily this exact product.