Phosphorus is an essential yet often overlooked element in terms of daily need. According to the national academy of science dietary reference intakes, the daily recommended intake for phosphorus has been determined based on serum (blood) levels of inorganic phosphate. We now know that the body wants to maintain blood mineral homeostasis, which implies that blood levels should be relatively stable, and will only infrequently show out of range phosphorus levels. The unanswered question is how much phosphorus do we really need? A lot depends on the amount of absorbable calcium and phosphorus we consume daily and the effective functioning of the thyroid and parathyroid. They all interact to create an optimal functioning energy system. The primary indicators of inadequate levels of phosphorus are: Inability to gain weight Loss of energy Muscle weakness Softening of bones General debility and fatigue Easy on the stomach. Safe for all ages no color or scent.