Valium stays in the body for quite a while compared to other benzos, and factors like body fat and age can make the drug remain even longer.

Article at a Glance:

  • Valium has an extremely long half-life, and the drug can stay in the body for up to 10 days.
  • The body breaks Valium down into different metabolites that are detectable for more than 10 days.
  • Different factors affect how long Valium stays in the body, including age, body fat and drug interactions.

Half-Life of Valium

Valium is the brand-name version of diazepam, a prescription benzodiazepine drug commonly used to treat anxiety and seizures. Valium stays in the body longer than many other benzos, which is one reason why it is so effective for seizure treatment. However, its long-lasting nature also makes it extremely risky to use with substances like alcohol or opioids. Understanding Valium’s duration of effects, its half-life and how it’s broken down in the body can help you avoid life-threatening risks like overdose.

How Long Does Diazepam Last?

The effects of diazepam can last as long as 12 hours after a single dose. However, diazepam stays in the system much longer than a person feels the effects. This is the reason why drugs like diazepam are involved in so many overdose deaths in the United States.

A study in North Carolina showed that the risk of death from opioid overdose is 10 times higher when a person is also taking a benzodiazepine like diazepam. Diazepam and other opioids are known to slow down the central nervous system; when combined, their effects are much greater than when taken alone.

Compared to other benzodiazepines, diazepam is fairly long-lasting. For example, the effects of Xanax, another benzodiazepine, are felt for only six hours.

How Long Does Valium Stay in Your System?

A drug’s half-life is a measurement of how long it takes the body to remove half of the drug from its system. A drug stays in the system for approximately five half-lives before it is completely eliminated from the body. The half-life of Valium is approximately 48 hours, regardless of its dosage. This means the drug will be present in the body for approximately 10 days. However, its metabolites can remain for much longer.

The body breaks down diazepam into a metabolite called desmethyldiazepam, which has a long half-life of up to 100 hours. This means that after you take a dose of diazepam, the drug and its metabolites can take up to 35 days to clear your body.

Factors that Affect How Long Valium Stays in the System

A variety of different factors can influence how long Valium remains in a person’s system, including body fat, age, dosage amounts, other medications and substance use.

Body Fat

Diazepam is a highly lipophilic drug, meaning it prefers to settle into fat tissue and does not absorb well into environments with a lot of water. Therefore, diazepam typically stays in the system longer if a person has a higher percentage of body fat.

Drug Interactions

Diazepam is mainly metabolized in the liver by different metabolic enzymes. If you are taking drugs that interfere with these enzymes, it may take more or less time for diazepam to be metabolized.

Drugs that commonly interact with Valium may include:

  • Opioids: This class of medications includes hydrocodone, oxycodone, fentanyl and heroin. Taking opioids and Valium together is extremely dangerous and can lead to respiratory depression.
  • Alcohol: Mixing alcohol and Valium increases the risk of overdose and death.
  • Antacids: These types of drugs increase the amount of time it takes Valium to start working.
  • Drugs that interact with cytochrome 3A4: Examples include ketoconazole, fluvoxamine and fluoxetine. Ask your doctor or pharmacist for a full list of interactive medications.
  • Phenytoin: This is an anti-seizure medication that can reach toxic levels if taken with Valium.

Dosage and Frequency

In general, a drug’s half-life is the same no matter what dosage is taken. Because diazepam has a 48-hour half-life, and it takes five half-lives for the body to completely eliminate a drug, diazepam is usually cleared within 10 days. However, since diazepam can accumulate in fat tissue, taking repeated doses can cause the drug to accumulate and increase its half-life.

These effects would not be evident after taking just one dose. If someone is taking diazepam every day for weeks, however, then the half-life will increase.


Older adults tend to have different types of body tissue than younger adults. In particular, older adults have more fat tissue and less lean muscle tissue. Because of this, diazepam is likely to stick around for longer in people aged 65 or older.

Find Treatment for Valium Addiction

If you or someone you love is struggling with Valium abuse or addiction, help is available at The Recovery Village. Our experts provide a full continuum of care for addiction treatment and can also address co-occurring mental health disorders like anxiety and depression. Contact us today to learn more about treatment programs that can work well for your situation.

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Editor – Jonathan Strum
Jonathan Strum graduated from the University of Nebraska Omaha with a Bachelor's in Communication in 2017 and has been writing professionally ever since. Read more
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Medically Reviewed By – Dr. Conor Sheehy, PharmD, BCPS, CACP
Dr. Sheehy completed his BS in Molecular Biology at the University of Idaho and went on to complete his Doctor of Pharmacy (PharmD) at the University of Washington in Seattle. Read more

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Food and Drug Administration. “Valium Package Insert.” 2016. Accessed November 9, 2021.

National Institute on Drug Abuse. “Benzodiazepines and Opioids.” February 2021. Accessed November 23, 2021.

George, Tobin; et al. “Alprazolam.” StatPearls, July 2021. Accessed November 23, 2021.

Dhaliwal, Jaberpreet; et al. “Diazepam.” StatPearls, September 2021. Accessed November 9, 2021.

Hallare, Jericho; et al. “Half Life.” StatPearls, August 23, 2021. Accessed November 23, 2021.

Temte, Vidar; et al. “An Experimental Study of Diazepam and Al[…]g Single Oral Doses.” Journal of Analytical Toxicology, March 2019. Accessed November 9, 2021.

Medical Disclaimer

The Recovery Village aims to improve the quality of life for people struggling with substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare providers.