Nutrabolt has launched C4 Sparkling Protein, a caffeine-free ready-to-drink beverage delivering 20 grams of protein, zero sugar, and five essential vitamins and minerals in a carbonated format — a direct play on one of the fastest-growing segments in the functional beverage market.
The launch signals a deliberate pivot for Nutrabolt, whose C4 brand has long been synonymous with pre-workout powders and high-stimulant energy drinks. By entering the sparkling protein RTD space without caffeine, Nutrabolt is widening the consumption occasion from gym bag to any-time-of-day, targeting both core sports nutrition consumers and the broader wellness audience driving protein's mainstream breakout.
Formulation and Format
The finished formulation takes direct aim at a persistent quality gap in the clear protein beverage segment. Protein-fortified sparkling drinks have historically struggled with astringency and chalky aftertaste — a function of the interaction between carbonation and whey or whey hydrolysate at higher protein concentrations. Emily Hoyle, Senior Vice President of Marketing at Nutrabolt, emphasized that the brand applied its flavor development capabilities specifically to overcome that barrier. "Sparkling and clear protein drinks have a reputation for tasting flat or leaving behind a chalky mouthfeel, and we knew that wasn't good enough for C4," Hoyle said. The result is three flavor SKUs — Cherry Vanilla (a Walmart exclusive), Strawberry Watermelon, and Lemon Lime Fizz — all built on the brand's existing flavor platform.
At $27.99 per unit, C4 Sparkling Protein occupies the premium tier of the RTD protein category, consistent with the brand's positioning across its sports nutrition portfolio.
Market Context
The RTD protein beverage category has expanded well beyond traditional post-workout shakes, driven by broader consumer interest in protein as a weight-management, satiety, and GLP-1-adjacent wellness tool. Sparkling and clear protein formats have attracted particular attention from operators and retailers looking to capture consumers who associate fizz with refreshment rather than function — a crossover opportunity between the energy drink and protein supplement aisles where C4 already holds significant shelf space.
Nutrabolt's distribution infrastructure gives C4 Sparkling Protein immediate scale. The product launches at Walmart and on the brand's direct-to-consumer platform at cellucor.com, with Amazon availability set to follow. Nutrabolt's broader portfolio — which includes XTEND, Cellucor, and Bloom — is already distributed in more than 125 countries across top U.S. retailers including Target, Kroger, Walgreens, GNC, and The Vitamin Shoppe, giving the sparkling protein SKU a credible path to rapid national velocity.
For category buyers and co-manufacturers watching the functional RTD space, the launch illustrates how heritage sports nutrition brands are using reformulation and format innovation to compete in protein and performance beverages while simultaneously reaching the wellness-first consumer segments that have driven explosive growth in functional and fortified beverages.
Written by Michael Politz, Author of Guide to Restaurant Success: The Proven Process for Starting Any Restaurant Business From Scratch to Success (ISBN: 978-1-119-66896-1), Founder of Food & Beverage Magazine, the leading online magazine and resource in the industry. Designer of the Bluetooth logo and recognized in Entrepreneur Magazine's "Top 40 Under 40" for founding American Wholesale Floral, Politz is also the Co-founder of the Proof Awards and the CPG Awards and a partner in numerous consumer brands across the food and beverage sector.
