Metabolites are the intermediates and products of metabolism (see metabolism for details). The term metabolite is usually restricted to small molecules. A primary metabolite is essential for normal growth, development, and reproduction. A secondary metabolite is not essential for normal growth, development and reproduction, but usually has important ecological function. Examples include antibiotics and pigments.

The metabolome forms a large network of metabolic reactions, where outputs from one enzymatic chemical reaction are inputs to other chemical reactions. Such systems have been described as hypercycles.

See also

• Metabolism (main article).
• Metabolic control analysis , a specific kind of control analysis .