Minimum number of hairs for a hair sample?

• A. 5
• B. 50
• C. 20
• D. 100

Answer: (C)

The number of hairs needed is driven by the need for a representative sample that can support reliable analysis. For typical hair comparison work, about 20 hairs provide enough shafts to examine the range of characteristics—such as color distribution, shaft diameter, cuticle structure, and medulla pattern—while still leaving material for any additional tests if roots are present. This quantity balances obtaining a thorough microscopic assessment with not oversampling the evidence. Fewer hairs, like five, risk missing variation in the sample and could lead to a less reliable conclusion. More hairs, such as 50 or 100, aren’t usually necessary for standard hair analysis and can be impractical or unnecessary; they may also reduce the amount of other evidence that could be tested. If follicles are available, a smaller subset can still yield DNA, but the key point is that roughly 20 hairs are typically considered the practical minimum to perform a solid routine analysis.