Drugs appear in hair through a process involving the bloodstream and hair follicles. After drug ingestion, the substance enters the bloodstream and subsequently transfers to the hair follicle, embedding itself within the growing hair strand.
Here's a more detailed breakdown:
- Drug Ingestion: A person consumes or is administered a drug.
- Absorption into Bloodstream: After taking a drug, the substance enters a person's bloodstream.
- Transfer to Hair Follicle: The drug molecules are carried through the bloodstream and reach the hair follicles.
- Incorporation into Hair: Next, the drug transfers to the hair follicle, and into the hair strand. As new hair cells are produced, the drug molecules become trapped within the protein structure of the hair.
- Hair Growth and Drug Location: As a result, the drug becomes trapped in the hair strand. As the hair strand grows, the drug will move further away from the scalp. This allows for a historical record of drug use to be analyzed based on the length of the hair.
In essence, hair acts as a recording device, capturing drug use over time, with segments of hair reflecting drug exposure during specific periods.
