What is the shortest time period that can be accurately evaluated?
The minimum time period is approximately 1 month (1/2 inch). Body hair can be used if head hair is too short for a test. If body hair is used the timeframe represented by the test is approximately one year, due to the different growth pattern in hair below the neck.
"It is so much easier ordering online than adding to the gasoline fumes driving to the store, fighting traffic, finding a parking place, then finding the store is out of what you want. When one can avoid all of this and save money too, what could be better?" (Harry S.)