Variability

Dietary supplements are natural substances that may contain variable amounts of active and inactive ingredients. These amounts depend on several factors, including the age and specific part of the plant, the composition of the soil in which it was grown, the time of year it was harvested, and how the substance was processed and stored. While manufacturers must label their products with the contents, the recommended daily dose, and how much of the active ingredient each dose contains, dietary supplement composition can vary widely. From bottle to bottle, batch to batch, year to year, and company to company, consumers may not be aware of exactly what they are consuming.