Ingredient/brand reputation
Many buyers cite The Ordinary's reputation and niacinamide's well-known reputation for oil control and pore care as their reason for purchase, often having read positive reviews before buying.
Repurchase/loyalty
A very large share of reviews are repeat purchases (2nd-10th bottle), with some customers using the product continuously for 3-10 years.
Price-to-volume value
Reviewers repeatedly note the 60mL size is affordable relative to other niacinamide serums and cheaper than buying locally (e.g., in Japan or the US).
Influencer/word-of-mouth recommendation
Several buyers mention purchasing based on beauty blogger recommendations, friend/family suggestions, or Korean/Japanese online reviews.
Gifting
Some reviewers purchased it as a gift for family members (spouse, sibling, teenage child) who were also satisfied with results.