Weight Gainer Market Report: Sales Volume, Market Share, Leading Brands & Market Trends

Optimum Nutrition is the best-performing weight gainer brand in July 2026, moving 150,000 units across 3 ASINs for 46.0% of Top 10 volume. Core Power follows with 100,000 units (30.7%), ahead of Premier Protein on 30,000 units (9.2%).

With 7 brands splitting the Top 10 and 85.9% 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 $27.57 to $47.98, 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. On the growth side, B06ZZ3PJQD leads positive momentum with ▲ 200.0% MoM growth on 30K units, with B07CZTHCXQ close behind at ▲ 166.7% MoM on 800 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already changed hands — an incumbent gave up its place to make room, so any competitive set drawn up a month ago is now out of date.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.