I tested popular functional coffee supplements for a week each (2026)

First the influencers and the loons of the manosphere were adding protein to the ice cream, and I didn’t care because I rarely eat ice cream. Then they added it to the popcorn, and I didn’t care because I rarely eat popcorn. Now they add it to coffee creamer, and I’m forced to care because I’m hopelessly addicted to coffee, caffeine, and anything even remotely fancy in this space.

Memes aside, protein is everywhere these days. The usual suspects blame the rise of wellness culture, the rightward shift in American political gestalt, and the noxious fumes emitted by the late-stage, sputtering capitalist machine into which we are all strapped, whether we like it or not. The proverbial ship is sinking. You might as well get robbed and do your part to keep the economy going while you can.

Protein isn’t the only thing intrepid Shopify-powered wellness brands are encouraging you to add to coffee, but it’s certainly the hottest, most contemporary supplement to pour into your daily brew. Mushroom extracts, nootropics, amino acids, collagen, and a host of other chemical compounds believed to get your brain firing on all cylinders are all fair game here, meaning the possibilities in this space are nearly endless. Coffee may be the final frontier in protein leakage, and we’re absolutely here for it.

To get a lay of the land, I rigorously tested eight readily available functional coffee supplements to determine which ones are legit and which ones are losers. I spent a week with each, adding the dose detailed in the serving size section of the Nutrition Facts panel to an 8-ounce cup of coffee. A few explicitly asked us to add the dose to a larger cup of liquid, in which case we increased the amount of coffee used as the base. The coffee I used was a single origin Guatemalan bean roasted by Atlas Coffee Club. It was brewed in a Fellow Aiden on the light roast Guided Brew setting in 5-cup batches.

Be sure to check out our many coffee-related buying guides, including the Best filter coffee makersTHE Best Coffee SubscriptionsTHE Best Coffee Concentratesand the Best Gifts for Coffee Lovers.