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Home » ‘Body hair’ can confirm drug use despite negative urine, hair tests

‘Body hair’ can confirm drug use despite negative urine, hair tests


1. Drug Allegations and Body Hair Testing in
Lee Sun-kyun’s Case

Korean actor Lee Sun-kyun was reported to have denied drug use allegations during a police investigation, claiming he was unaware of the substance being a drug and had been deceived into taking it. He previously showed negative reactions for drugs in urine and hair tests. Currently, there is a heightened interest in the results of his leg hair test, as it can provide information about drug use over a longer period than hair tests.

On April 4th, when interrogated by the police, Lee Sun-kyun stated that he was tricked by a manager at an entertainment establishment, who gave him a substance without his knowledge of it being a drug. He insists he did not intentionally use drugs, and the leg hair test results could be crucial in proving his claim. Leg hair testing can reveal drug use over a much longer period than hair tests, playing a significant role in this case.

2. Types of Drug Detection Methods – Urine Testing

The primary methods for detecting drugs include urine and hair tests. Urine testing, known as a reagent test, detects drugs through metabolites expelled from the body. This test can individually detect various drug components like amphetamines, methamphetamines, cocaine, MDMA, etc., and is known to have an accuracy rate of over 95%. However, a limitation of this method is the difficulty in detecting drugs after a week of use, as drug components are detectable in the blood for about a day and up to a week in urine.

3. Types of Drug Detection Methods – Hair Testing

Hair testing is one of the most precise and sensitive methods for tracing drugs. It is based on the physiological process where drug components move through the body’s capillaries to the hair roots, where they are absorbed and stored. The drug components in the hair are fixed during the keratinization process and can be detected in very low concentrations using equipment like Gas Chromatography-Mass Spectrometry (GC-MS). This equipment boasts high sensitivity, capable of measuring molecular weights as small as one picogram.

The average growth rate of hair is about 1 centimeter per month. Based on this, a general analysis of about 3-4 centimeters of hair can determine drug use over the past three months. For those with longer hair, it’s possible to trace drug use even further back.

4. Types of Drug Detection Methods – Body Hair Testing

In investigations, suspects often try to confuse the investigation by dying or bleaching their hair, or in some cases, shaving it off. However, in the absence of head hair, investigative agencies can collect body hair from legs, armpits, pubic areas, and even around the anus to detect drug components. This shows that various body hair can be used in investigations.

4. Types of Drug Detection Methods – Others

Advancements in forensic science now allow for the collection of other biological evidence like follicle cells or fingernail and toenail tissues for drug testing. These technological advancements have made it harder for criminals to conceal the truth.

5. Summary

Even if a hair test shows a negative result, it does not completely negate drug use, as drug components can still be detected in other body hair. For instance, in 2019, a famous actor tested negative for drugs in his head hair, but the leg hair test detected drug components, ultimately proving the allegations. This emphasizes the importance of not only hair testing but also other body hair tests.