This scam has been around for a while. I'm embarrassed to admit that I once sent off a hair sample for testing. Pure hokum.
Check this out:
Commercial Hair Analysis: A Cardinal Sign of Quackery
"Proponents claim that hair analysis is useful for evaluating a person's general state of nutrition and health and is valuable in detecting predisposition to disease. They also claim that hair analysis enables a doctor to determine if mineral deficiency, mineral imbalance, or heavy metal pollutants in the body may be the cause of a patient's symptoms. These claims are false.
Hair analysis is not reliable for evaluating the nutritional status of individuals. In 1974, the AMA Committee on Cutaneous Health and Cosmetics noted: "The state of health of the body may be entirely unrelated to the physical and chemical condition of the hair . . . Although severe deficiency states of an essential element are often associated with low concentrations of the element in hair, there are no data that indicate that low concentrations of an element signify low tissue levels nor that high concentrations reflect high tissue stores. Therefore . . . hair metal levels would rarely help a physician select effective treatment." [3]
Most commercial hair analysis laboratories have not validated their analytical techniques by checking them against standard reference materials. The techniques typically used to prepare samples for analysis can introduce errors for many of the elements being determined.
Hair mineral content can be affected by exposure to various substances such as shampoos, bleaches and hair dyes. No analytic technique enables reliable determination of the source of specific levels of elements in hair as bodily or environmental.
The level of certain minerals can be affected by the color, diameter and rate of growth of an individual's hair, the season of the year, the geographic location, and the age and gender of the individual.
Normal ranges of hair minerals have not been defined.
For most elements, no correlation has been established between hair level and other known indicators of nutrition status. It is possible for hair concentration of an element (zinc, for example) to be high even though deficiency exists in the body.
Hair grows slowly (1 cm/month), so even hair closest to the scalp is several weeks old and thus may not reflect current body conditions for purposes of health diagnosis.
The use of a single multielemental hair analysis test as the sole means of diagnosis violates basic tenets of medical practice that laboratory findings should be considered together with the patient's history and physical examination, and that the practitioner should keep in mind that laboratory errors occur.
For these reasons, multielemental analysis of human hair is not a valid technique for identifying an individual's current bodily excesses or deficiencies of essential or nonessential elements. Nor does it provide a valid basis for recommending vitamins, minerals, or other dietary supplements [4,5]."]
I wish it was that simple 
