This question is about Nutrition and Cycling
Yes, many cyclists use whey protein
Many athletes supplement their diets with whey protein after a ride to help with muscle recovery and repair. Whey protein is rich in leucine, an amino acid shown to stimulate muscle protein synthesis [1] here
[1] Kerksick, C.M., Wilborn, C.D., Roberts, M.D. et al. ISSN exercise & sports nutrition review update: research & recommendations. J Int Soc Sports Nutr 15, 38 (2018). https://doi.org/10.1186/s12970-018-0242-y