No.5 Vitamin Concentrated Serum — Reddit Reviews

• Hyperpigmentation

  Strong evidence

  Tranexamic Acid: 12 studies tested it on its own. See all 21 studies→

  On Reddit: Vitamin C combined with tranexamic acid targets dark spots by inhibiting melanin production for visible fade. 36 mentions

  Both ingredients for hyperpigmentation

  Tranexamic Acid · Strong evidence

  • Most studies found tranexamic acid helped fade dark patches, especially in melasma
  • Some studies found it worked better than a placebo
  • It often worked about as well as hydroquinone
  • Used with laser or microneedling, it sometimes faded patches more than those treatments alone

  Niacinamide · Some evidence

  5 studies tested it on its own. See all 24 studies→

  • All of these studies found niacinamide helped fade dark spots or patches
  • In clinical trials, 5% niacinamide faded dark spots more than a placebo
  • It also helped when used with salicylic acid peels, more than peels alone
  • Used on its own, it helped, but one study found a niacinamide mix worked better
  • One study found the fading effect reversed after stopping niacinamide

• Acne

  Some evidence

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

  What the studies found

  • Most studies found niacinamide helped acne
  • Some studies found 4% niacinamide cleared acne about as well as clindamycin
  • One study found 4% niacinamide improved red, sore spots, but IPL worked better
  • Some research found no clear difference, and a large review said the effects were uncertain

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