A tablespoon amount of hair may be used for two investigations.

Mineral and toxic metal analysis Hair analysis for mineral deficiency or excess has a well-established scientific background but it is poorly used in orthodox medicine because of the marked underestimation of mineral deficiency, or toxic excess, as a cause of illness or disease. Samples sent to the 101 Group can be put through a simple analysis that can give a clear indication of mineral problems.

Food intolerance

I am highly sceptical of the use of hair analysis in food intolerance/allergy testing .