Vyvanse is typically detectable in urine for about 2.5 days (roughly 60 hours) after your last dose. That number can shift significantly in either direction depending on your body chemistry, how much you take, and even what you eat and drink.
Why Vyvanse Shows Up as Amphetamine
Vyvanse itself isn’t what drug tests look for. The capsule contains lisdexamfetamine, a prodrug that does nothing on its own. After you swallow it, red blood cells in your bloodstream strip off an amino acid (lysine) and convert it into dextroamphetamine, the compound that actually treats ADHD. Your body clears the original lisdexamfetamine very quickly, with a half-life under one hour. But the dextroamphetamine it produces sticks around much longer, with a half-life averaging about 11 hours in adults.
Standard urine drug panels screen for amphetamines as a class. Because Vyvanse converts entirely into dextroamphetamine, it will trigger a positive result on any test that screens for amphetamines. About 96% of a dose is eventually recovered in urine, with almost nothing exiting through feces.
The 2.5-Day Average and How It’s Calculated
Pharmacologists estimate clearance time by multiplying a drug’s half-life by 5.5. Each half-life cuts the remaining concentration roughly in half, so after 5.5 cycles almost all of the substance is gone. For dextroamphetamine, that math works out to about 60 hours: 11 hours multiplied by 5.5. That’s where the 2.5-day figure comes from.
Peak blood levels of dextroamphetamine occur about 3.5 hours after taking Vyvanse. From that point, concentrations decline steadily. By 60 hours, levels in most people fall below the detection threshold used in standard workplace testing, which is set at 1,000 nanograms per milliliter for the initial screening.
Factors That Shorten or Extend Detection
Urine pH
This is the single most influential variable, and most people don’t know about it. Dextroamphetamine is a weak base, which means acidic urine causes your kidneys to flush it out faster, while alkaline urine lets it get reabsorbed back into the bloodstream. The difference is dramatic. Shifting from alkaline urine (pH around 8) to acidic urine (pH around 5) can increase the amount of amphetamine excreted by up to 11-fold. In practical terms, someone with consistently alkaline urine could test positive well beyond the 2.5-day average, while someone with acidic urine might clear the drug noticeably faster.
Your urine pH fluctuates based on diet, hydration, and other factors. Diets high in meat and grains tend to acidify urine, while vegetable-heavy and plant-based diets push it toward alkaline. Certain medications, particularly antacids and bicarbonate supplements, can also make urine more alkaline and slow excretion.
Dose and Frequency
Higher doses mean more dextroamphetamine circulating in your system, which takes longer to clear below detectable levels. If you take Vyvanse daily, the drug accumulates to some degree between doses, so chronic use extends the detection window compared to a single one-time dose.
Age and Kidney Function
Your kidneys do the heavy lifting in clearing amphetamines. Reduced kidney function, whether from aging or a medical condition, slows excretion and extends how long the drug remains detectable. Older adults generally clear amphetamines more slowly than younger adults for this reason.
Body Composition and Metabolism
Individual metabolic rate, body weight, and hydration status all play a role. People with faster metabolisms and those who are well-hydrated tend to process and excrete drugs more efficiently, though these effects are smaller than urine pH or kidney function.
What Happens During Testing
Most workplace and clinical drug tests use a two-step process. The initial screening is an immunoassay that flags samples above the 1,000 ng/mL cutoff for amphetamines. If that first test comes back positive, a second, more precise confirmatory test is run. The confirmatory test can distinguish between different types of amphetamines, which is relevant if you have a valid prescription.
If you take Vyvanse with a legitimate prescription, a positive amphetamine result is expected. You’ll typically be asked to provide proof of your prescription to the Medical Review Officer who oversees the testing process. The result is then reported as negative. The important thing is having documentation readily available, since the test itself cannot tell the difference between prescribed and non-prescribed use without that context.
Detection in Other Types of Tests
Urine is the most common testing method, but amphetamines can also be detected in blood, saliva, and hair. Blood tests have the shortest detection window, typically 24 hours or less, because they measure active circulating drug rather than accumulated metabolites. Saliva tests generally detect amphetamines for one to two days. Hair tests have the longest window by far, potentially picking up use from the past 90 days, though they reflect patterns of use rather than a single dose.
For the vast majority of employment and clinical screening scenarios, urine remains the standard. If you’re taking Vyvanse as prescribed and your last dose was more than three days ago, it’s unlikely to show up on a standard urine panel. For heavy, long-term use or individuals with alkaline urine or impaired kidney function, allowing four or more days provides a wider margin.