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

Metamucil is the best-performing fiber capsules brand in July 2026, moving 160,000 units across 3 ASINs for 45.8% of Top 10 volume. Amazon Basics follows with 60,000 units (17.2%), ahead of Physician's CHOICE on 40,000 units (11.5%).

With 8 brands splitting the Top 10 and 74.5% 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 $9.74 to $28.14, 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: B01BMQRQ3E booked 9K units at $21.95, with ▲ 12.5% MoM change. On the growth side, B001TH7K0G leads positive momentum with ▲ 100.0% MoM growth on 40K units, with B0GS3PZP83 close behind at ▲ 100.0% MoM on 2K 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already changed hands — an incumbent gave up its place to make room, so any competitive set drawn up a month ago is now out of date.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.