The sports nutrition company said it has recorded a 50% sales growth to £70m in the past year as more Britons buy protein shakes and energy bars.
However, only 15% of the growth had come from the big four multiples the bulk had come through sports shops and health food stores.
With "different retailers stocking different sports nutrition products in different areas of the store", shoppers often had trouble locating Maximuscle during shopping visits, said sales director Mark Langley.
Retailers were missing out on "huge profit margins" by not expanding their offering of sports products, he claimed.
"We'd like supermarkets to consider creating a specific area for sports nutrition ranges, like they do in the US, where the category is recognised as a normal food product," said Langley. "We are not really making a dent in the bigger customers, which is surprising as Maximuscle offers a big sales opportunity for the mults. Many of our users get through a £40 tub of Maximuscle Promax in 10 days. When an average shopping basket costs around £35, this is a serious cash opportunity."
The British company predicted strong consumer interest in its water-based shake launched this week. Promax RTD (rsp: £2.49 per bottle) is available in orange and lemon & lime flavours and marks a departure from the "conventional, milk-based" protein shakes.