Metamucil Fiber Thins Market Report: Sales Volume, Market Share, Leading Brands & Market Trends

Metamucil is the best-performing metamucil fiber thins brand in July 2026, moving 210,000 units across 5 ASINs for 63.6% of Top 10 volume. Physician's CHOICE follows with 40,000 units (12.1%), ahead of Benefiber on 40,000 units (12.1%).

With 5 brands splitting the Top 10 and 87.9% of volume sitting with three of them, this is a concentrated shelf — the leaders hold multiple listings or one very high-velocity ASIN, so a new entrant competes against established review moats rather than an open field. Average selling prices among the leaders run from $15.72 to $26.72, which frames the price band a competing listing has to justify.

Based on July 2026 data, this shortlist surfaces the two kinds of ASIN worth keeping an eye on — the ones that just broke into the Top 10, and the ones growing fastest month over month. Specifically, one ASIN forced its way in: B0FSWWF65H booked 10K units at $15.99. On the growth side, B07KYYP497 leads positive momentum with ▲ 233.3% MoM growth on 1K units, with B001TH7K0G close behind at ▲ 100.0% MoM on 40K units.

The two signals carry different weight. A fresh entrant means share has already changed hands — an incumbent gave up its place to make room, so any competitive set drawn up a month ago is now out of date. A steep growth rate works as the earlier warning: it marks demand that is still compounding, usually a month or two before the ranking catches up to it.