The question of whether consuming common seeds can cause a failed drug test is a source of anxiety for many people facing employment or medical screening. This concern is based on a phenomenon that links certain seeds to temporary positive opiate results. The definitive answer is that sesame seeds do not contain the compounds necessary to trigger a positive result for opiates on a drug test.
The Definite Answer on Sesame Seeds
The reason sesame seeds are safe to consume before a drug test is rooted in their botanical origin and chemical composition. Sesame seeds come from the Sesamum indicum plant, which is entirely unrelated to the poppy plant that produces opium. The seeds are primarily composed of healthy fats, protein, and unique compounds called lignans.
The lignans found in sesame, such as sesamin and sesamolin, are structurally distinct from the alkaloids screened for in drug tests. Therefore, sesame seeds do not naturally contain or produce morphine, codeine, or any other opiate alkaloids derived from opium. There is no credible scientific evidence or documented case where the consumption of sesame seeds has led to a positive test result for opiates.
Origin of the Confusion: Poppy Seeds and Opiates
The confusion regarding seeds and drug tests stems entirely from the established link between poppy seeds and opiate detection. Poppy seeds are harvested from the opium poppy plant, Papaver somniferum, the natural source of opium. While the seeds themselves do not contain psychoactive compounds, they become contaminated with the plant’s milky latex during harvesting.
This contaminated latex contains opiate alkaloids, specifically morphine and codeine. When a person consumes a large quantity of poppy seeds, these trace amounts of alkaloids are metabolized by the body. This process introduces detectable levels of morphine and codeine into the urine.
This temporary spike in opiate metabolites can be high enough to trigger a “presumptive positive” on an initial drug screening. Depending on the poppy seed batch, which varies significantly in opiate contamination levels, these compounds can remain detectable for up to 48 hours after consumption.
How Drug Testing Cutoff Levels Work
Modern drug testing protocols use specific thresholds and a two-step analysis to differentiate between incidental food consumption and actual drug use. The initial step is typically a rapid immunoassay screening, which is highly sensitive and detects broad classes of compounds. This screen can sometimes react to trace opiates from poppy seeds, resulting in a presumptive positive.
A presumptive positive result does not automatically equate to a failed test and is always followed by a confirmation test. The second step is a highly specific and accurate method called Gas Chromatography-Mass Spectrometry (GC/MS). This test precisely identifies the molecular structure and quantifies the concentration of the substance found in the sample.
To account for false positives caused by food, federal workplace testing guidelines raised the opiate cutoff concentration for the initial screen to 2,000 nanograms per milliliter (ng/mL). This significantly higher threshold filters out the low concentrations that typically result from eating poppy seeds. Before this change, the cutoff was often as low as 300 ng/mL, which was easily surpassed by poppy seed ingestion.
Furthermore, a lab can differentiate between incidental morphine/codeine and actual heroin use by testing for the specific metabolite 6-acetylmorphine (6-AM). This compound is a direct breakdown product of heroin and is not found in poppy seeds or any other food source. If a sample is confirmed positive for opiates but lacks the presence of 6-AM, and the morphine or codeine level is below the higher cutoff, the positive result is likely due to food ingestion.