Nitrogen Balance
Nitrogen balance compares the nitrogen you take in (almost entirely from dietary protein) against the nitrogen you excrete (mostly through urine and sweat). Positive balance means your body is building tissue; negative balance means you are losing it.
Why It Matters
Nitrogen balance is the original method researchers used to estimate protein needs. The classic 0.8 grams per kilogram of body weight RDA was derived from balance studies in mostly sedentary adults. Active people, particularly resistance trainers, need more (1.6 to 2.2 g per kg) to maintain positive balance during heavy training.
While balance studies have known limitations (they often underestimate true requirements), the concept remains useful as a mental model: eat enough total protein over the day to stay in net positive nitrogen, and your body has what it needs to grow.
How to Spot It on a Label
Nitrogen balance is rarely printed on supplement labels but often referenced in scientific marketing copy. Look for claims tied to specific protein amounts (e.g., 25g per serving) rather than vague nitrogen-retention promises.
Examples from real products
Related Terms
Keep learning with these closely-linked entries: