Benefits
Lean mass and strength gains similar to whey with training
In two 8-week trials in resistance-trained men (24 men in each), rice protein taken with training gave gains in lean mass and strength that did not differ from an equal dose of whey, at 48 g after workouts and at 24 g a day. Neither trial had a placebo group, both were small, and both used rice protein from one supplier, which funded one of them.
Post-workout soreness and recovery ratings
In 24 trained men, 48 g of rice protein isolate or whey taken after one hard training session gave similar soreness, perceived recovery and readiness to train 48 hours later. Soreness rose in both groups, and with no placebo group the study cannot show that either protein speeds recovery; it shows only that rice protein did about as well as whey.
Muscle strength and function in older adults who exercise
In a 6-month pilot trial, 70 pre-frail or frail adults (average age 73) did a group exercise program with 20 g of rice or whey protein twice a day. The study found no differences between the rice and whey groups in gait speed, grip strength, physical performance or muscle mass. There was no group without protein, so the effect of the protein itself is unknown.
Pairs with pea protein to balance amino acids
Rice protein is low in lysine but higher in methionine, while pea protein is the reverse, so blending them gives a more even profile on paper. In 10 trained adults, 32 g of a pea, brown rice and canola blend raised muscle protein building after exercise as much as whey, though blood amino acids rose less. In another small study, a pea and rice blend did not raise blood amino acids more than pea alone.
Dairy-free protein option
Rice protein contains no milk protein or lactose, so it is an option for people who avoid dairy for allergy, intolerance or personal choice. In the 6-month trial in older adults, whey caused about twice as many digestive symptoms as rice protein. That is one small trial, and it did not test people with a diagnosed milk allergy.
Smaller insulin rise than whey after a protein shake
In 9 healthy men who drank equal-calorie protein shakes on separate days, whey raised blood insulin more than rice protein isolate over 3 hours, while appetite ratings did not differ between the proteins. This was a single-dose study in a few people, and it does not show that a smaller insulin rise changes health or training results.
Mechanism of action
Leucine and the muscle-building signal
Leucine helps switch on muscle protein building after a meal. Rice protein has less leucine per gram than whey: one analysis estimated that about 37 g of brown rice protein (about 47 g of the powder tested) is needed to supply the 2.7 g of leucine in 25 g of whey. In the 8-week trials, 48 g of rice protein gave about 3.8 g of leucine and 24 g gave about 2.1 g.
Low lysine, higher methionine
Lysine is the limiting amino acid in rice protein, measured at 2.4% of protein against a requirement of 4.5%, while its methionine content meets the requirement. Pea and soy proteins show the opposite pattern, which is why rice is commonly blended with pea, or eaten as part of a varied diet.
Digestibility below dairy protein
In a digestion study in growing pigs, brown rice protein concentrate had lower amino acid digestibility than heat-treated rapeseed protein, and its protein-quality score (DIAAS) was below 75, while whey protein isolate scored 100 or more. In people, blood essential amino acids rose less after a pea, rice and canola blend than after the same dose of whey.
Clinical trials
Randomized, double-blind trial comparing 48 g of rice protein isolate (Growing Naturals, made with Oryzatein from Axiom Foods) with 48 g of whey protein isolate taken right after each training session, 3 days a week for 8 weeks. Funded by Increnovo LLC, whose staff were co-authors (Joy et al. 2013, Nutr J).
24 college-aged men with at least 1 year of resistance training experience, 12 per group, on a dietitian-set diet.
Both groups gained lean mass (about 2.5 kg rice, 3.2 kg whey), gained muscle thickness, strength and sprint power, and lost fat, with no significant differences between groups. Soreness and perceived recovery 48 hours after a single hard session were also similar. There was no placebo group, and the trial was small.
Randomized trial of 24 g a day of rice protein concentrate (Growing Naturals, Axiom Foods) or whey protein concentrate during an 8-week standardized resistance training program, retroactively registered as NCT04411173. Funded by an unrestricted grant from Axiom Foods (Moon et al. 2020, J Int Soc Sports Nutr).
24 healthy resistance-trained men (average age about 33), 12 per group, eating about 1.9 g/kg/day of total protein.
Body mass, lean mass, fat-free mass, bench press and leg press strength rose over time, with no significant differences between rice and whey for any body composition, strength, endurance or Wingate power outcome. Whey supplied about 22% more leucine per gram of protein. No placebo group.
Randomized controlled pilot trial of a 6-month multi-component exercise program combined with 20 g of rice or whey protein twice daily (Jadczak et al. 2021, J Nutr Gerontol Geriatr).
70 community-dwelling pre-frail or frail older adults, average age about 73 (36 rice, 34 whey).
No differences between the rice and whey groups in gait speed, grip strength, physical performance, frailty score, muscle mass or other secondary outcomes, except that energy and fat intake were lower in the whey group. Whey caused about twice as many digestive symptoms as rice protein. There was no exercise-only group, so the trial cannot show what the protein added.
Randomized, double-blind crossover study of 32 g of protein from whey or from a blend of 39.5% pea, 39.5% brown rice and 21% canola protein isolates after leg resistance exercise. Funded by Science in Sport PLC (van der Heijden et al. 2024, Med Sci Sports Exerc).
10 healthy resistance-trained young adults (8 men, 2 women).
Muscle protein synthesis rose after exercise with no difference between the blend and whey over 4 hours, although blood essential amino acid availability was about 44% higher with whey. A one-session lab study of a blend, not of rice protein alone.
Randomized, double-blind crossover study of 0.3 g/kg body weight of a pea-rice protein blend, pea protein isolate or whey protein concentrate (Rogers et al. 2024, Br J Nutr).
10 healthy young adults (4 men, 6 women).
Blood essential amino acids rose more after whey than after either plant protein, and the pea-rice blend did not raise them more than pea alone. Appetite hormones, hunger ratings and food eaten at a buffet meal did not differ between the three proteins.
Single-blind, randomized three-way crossover study of equal-calorie shakes of whey, rice or potato protein isolate, with blood sampled for 3 hours. The rice protein isolate (Oryzatein Silk 90) was supplied by Axiom Foods, and the study reported no external funding (Tiekou Lorinczova et al. 2021, Nutrients).
9 healthy men (average age about 31).
Whey produced a larger overall insulin response than rice protein (p = 0.010) and potato protein. Average appetite ratings did not differ between the proteins. A single-dose study in a small group.