Three dermatologist-recommended brands — CeraVe, EltaMD and La Roche-Posay — ranked third, fourth and fifth among Amazon's top beauty brands by share of sales in August, according to new data from Navigo Marketing. The findings show clinical positioning is no longer a niche play on the platform; it is the dominant structure of the beauty bestseller list.

Only two brands outranked them: Medicube, with 10.8 percent of the month's beauty sales, and Nutrafol, with 6.9 percent. Medicube held the number-one spot for a second consecutive August, per Navigo.

The August top 10 also included Eos and The Ordinary, while Hero Cosmetics took the number-10 spot on the strength of its signature pimple patches.

How big are the leaders' shares?

Medicube's 10.8 percent of August beauty sales makes it the single largest brand on the platform by monthly share, a position it has now held for two Augusts running. Nutrafol's 6.9 percent placed it second overall — and in hair care specifically, it ranks number one, with roughly 23.1 percent share. That figure is more than four times the share of the next-biggest hair brand, even though Nutrafol lost three share points year-over-year, Navigo's data shows.

The clinical trio of CeraVe, EltaMD and La Roche-Posay filled the third, fourth and fifth positions, meaning derm-positioned brands occupy the majority of the top five by sales share.

Who is growing fastest?

Movement within the top 10 points to two diverging dynamics: routine loyalty and short-term momentum.

• The Ordinary, now at number seven, posted the largest year-over-year growth in the ranking.
• Eos was the fastest mover month-over-month.
• Hero Cosmetics held steady at number 10, carried by its pimple patches.

"Consumers are increasingly building routines around trusted names instead of experimenting with individual products," said Meredith Matthes, director of operations at Navigo. Her read of the data: shoppers are consolidating around a shortlist of brands they trust, not sampling product by product.

Is advertising driving the clinical surge?

No — and that is the finding that separates the top two from the rest. Navigo founder Jacob St. John said demand for dermatologist-positioned brands on the platform is organic, noting that none of the top clinical players are also among the top advertisers on Amazon.

Medicube and Nutrafol, by contrast, are both top-10 beauty advertisers on the platform. Their first and second places come with paid support; CeraVe's, EltaMD's and La Roche-Posay's do not.

That split matters for brand strategists. A clinical recommendation, once established, appears to carry sales weight on Amazon without ongoing ad spend — at least for the brands that have earned it. For emerging clinical labels, the Navigo data suggests the ceiling is high: three of five top positions, held without top-tier advertising budgets. The question for the coming months is whether Nutrafol's three-point year-over-year share loss in hair signals the start of broader churn at the top of the list.