Pea protein is increasingly used as a dietary supplement to support weight gain, particularly among individuals seeking to build muscle mass or those who require additional caloric intake due to medical or lifestyle needs. The scientific rationale stems from its rich amino acid profile, relatively high digestibility, and plant-based origin, making it suitable for vegetarians and those with dairy allergies. Several clinical studies and reviews have demonstrated that protein supplementation, including from pea protein, can facilitate increases in lean body mass when combined with resistance training or increased caloric intake (Babault et al., 2015).

Pea protein specifically has been shown to be as effective as whey protein in promoting muscle thickness and strength gains over a period of weeks in resistance-trained individuals. While most research has focused on muscle mass gains rather than generalized weight gain (which also includes fat mass), increased muscle mass does contribute to healthy weight gain. Importantly, pea protein is rich in branched-chain amino acids (BCAAs), particularly lysine and arginine, which are important for muscle growth and repair.

While the evidence base is still growing, and long-term studies on diverse populations are limited, the use of pea protein for supporting weight gain, especially in the context of muscle-building, is supported by a moderate level of scientific evidence. It is not used traditionally for this purpose, but rather as a result of modern nutritional research.