Gainful

What's in the box: A typical delivery holds a tub of unflavored protein in your chosen blend plus individual flavor packets, with pre-workout or hydration products as optional add-ons.

Gainful is a US supplement brand built around one simple idea: buy unflavored protein and add the flavor separately. You don't have to commit to a single flavored tub. Instead, you pick one of seven protein blends and pair it with individual flavor packets. The site lists eight flavors. The lineup covers whey, plant and collagen options, including Everyday Whey, Isolate-Only Whey, Lean Plant and a Performance Whey made with tart cherry powder. Each blend lists its protein and calories per serving clearly, ranging from 20 to 25 grams of protein and 80 to 140 calories. The shop also sells pre-workout and hydration products. A quiz helps new customers choose a blend based on their goals. The company says a large set of proprietary data shaped its formulas, but we cannot verify that claim. Subscribers get 25% off compared with one-time purchases. The flavor packets are useful if you tire of one taste, and unflavored protein works well in cooking or smoothies. The downside is that this is a supplement refill service, not a discovery box, so there is little surprise. Adding a packet to every shake is also an extra step that may not suit everyone. As with any supplement, check the ingredients against your own needs and talk to a professional if you have health concerns.