The low certainty of evidence and small sample size limit our confidence in the results.

The apparent lack of benefit from protein supplementation could be related to the studies being too short for significant changes to occur in bone mineral content. Other possibilities include the dosage of protein being insufficient or the participants already getting adequate protein: the participants’ average protein intake at baseline ranged from 0.81 to 1.3 grams per kilogram of body weight per day (the RDA is generally 0.8 grams per kilogram).^[1]

Does protein powder enhance the effect of resistance training on bone mineral content? Original paper