24. BrainGain: How unit economics by SKU turned a loss-making bestseller profitable

Kareem Raslan and his co-founder bought 25 pairs of adjustable dumbbells off a Facebook ad and sold them out of their parents' garages in two days. No business plan, no outside capital, no idea how importing worked. Just a product people wanted — and a £500-a-month side hustle in mind.

Five years later, BrainGain has passed 100,000 customers across 30 countries and ships every order in a 40-kilo box.

In this episode, host Peter Beckman sits down with Kareem — a 13-year banker who learned e-commerce on nights and weekends — to walk through the exercise line by line: gross sales, VAT, COGS, fulfilment, payment processing, returns, affiliate commission. Every product, every market, every channel. The bestseller turned out to be losing €30 a unit at a thousand units a month, while the model nobody was advertising made £50. And most of the margin that fixed it was hiding in places that had nothing to do with marketing.