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ChatGPT · measured July 2026

The ChatGPT Shelf for Vitamin C Serums

CeraVe leads on an affordability question

CeraVe 60%, The Ordinary 47%, La Roche-Posay 38%. Worth reading with the prompt framing in mind — these questions asked for affordable serums, so this ranks the value shelf, not the whole category. Ulta carries 57% of the offers and brand-direct is 6 offers out of 3,756.

Questions asked
653
Brands seen
132
Offers recorded
3,756
Through a feed
84%

Who ChatGPT names

Share of shelf is the percentage of answers a brand appeared in. It is not a rank of quality or sales — it is how often the model brought the brand up when someone asked about an affordable vitamin C serum.

  1. 1 CeraVe 60%
  2. 2 The Ordinary 47%
  3. 3 La Roche-Posay 38%
  4. 4 Naturium 24%
  5. 5 The INKEY List 24%
  6. 6 Good Molecules 23%
  7. 7 e.l.f. 19%
  8. 8 Vanicream 16%

Where the offers come from

Every product ChatGPT showed came from somewhere. Brand-direct means the offer pointed at the brand's own store rather than a retailer.

  • Ulta 57% · 1,803 offers
  • Walmart 13% · 418 offers
  • Target 13% · 412 offers
  • Sephora 11% · 343 offers
  • CVS 3% · 93 offers

How the shelf gets built

84% of the offers here arrived through a product feed rather than a page crawl, and 6 of them came direct from a brand.

Shelf position Offers Through a feed Brand named
Top of shelf 1,745 84% 83%
Positions 2–3 1,513 84% 84%
Position 4 and below 498 84% 83%

Who writes this shelf

Before ChatGPT names a an affordable vitamin C serum brand, it reads. These are the sources it cited most when building this shelf.

See every source that writes the shelf →

How we measured this

  • We asked ChatGPT 653 shopping questions about an affordable vitamin C serum in July 2026. The questions never named a brand, so nothing here was prompted into the answer.
  • Questions were repeated. ChatGPT does not answer the same way twice, so a single ask tells you nothing — share of shelf is the pattern across all 653 of them.
  • We recorded every brand mentioned and every product offer shown, 3,756 offers across 132 brands.
  • This is one engine, one country, one point in time. It is a snapshot of a shelf that moves.

Questions about the method, or think a number is wrong? Tell us — we will check it against the raw data and correct the page.

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Other shelves we measured