How Long Does THC Stay In Saliva Glands?
Cannabis use has become increasingly common in Australia, with the 2022–23 National Drug Strategy Household Survey reporting that 11.5% of Australians used cannabis in the past 12 months. As attitudes shift and medicinal cannabis prescriptions grow, questions about how cannabis affects workplace drug testing are becoming more frequent.
One of the most common queries, especially from employees preparing for a screening or HR teams managing safety programs, is how long tetrahydrocannabinol (THC) remains detectable in the saliva glands. Unlike alcohol, where impairment often correlates closely with blood alcohol concentration, cannabis metabolites behave differently in the body. This can make detection timelines confusing if you’re not familiar with the science behind testing.
In this guide, we break down everything you need to know about THC, how it’s detected in saliva and must-know information about drug testing for employees and employers.
What is THC?
THC is the main psychoactive compound in cannabis plants. It binds to cannabinoid receptors in the brain and nervous system, particularly CB1 receptors, producing psychological and physiological effects. These can include relaxation, altered sensory perception, reduced coordination, and slowed reaction time – which is why its presence in safety-sensitive work environments is monitored.
When cannabis is consumed, THC enters the body in different ways depending on the method:
- Smoking or vaping: THC travels from the lungs directly into the bloodstream, reaching the brain in seconds.
- Edibles, oils or capsules: THC is processed through the digestive system and liver, taking longer to produce effects – often 30 minutes to 2 hours.
Once absorbed, THC and its metabolites are distributed to various tissues. It is fat-soluble, meaning it can be stored in fat cells and gradually released back into the bloodstream, which is one reason detection windows can vary. Even after the “high” wears off, small amounts may still be detectable for a period.
How Long THC Stays In Saliva (and Why Detection Times Vary)
Saliva drug testing is designed to detect recent cannabis use. However, how long THC remains detectable can differ significantly between individuals. Factors influencing this include:
- Frequency of cannabis use
- Metabolism and body mass
- Amount consumed
- Potency of the product
- Method of consumption
- Hydration and oral hygiene
- Individual biological differences
While no timeframe applies universally, research and workplace testing standards suggest:
| User Type | Approx. Detection Window in Saliva |
| Single or occasional use | 12-24 hours |
| Frequent use (several times weekly) | 24-48 hours |
| Daily or heavy use | Up to 72 hours, or longer |
Saliva drug tests are preferred in many workplace settings because they more closely correlate to recent use and potential impairment, rather than past exposure.
Why Do Workplaces Test For THC?
Work health and safety (WHS) obligations require employers to provide a safe working environment. Industries such as mining, transportation, logistics, construction, and manufacturing often involve machinery, vehicles, or other hazards where impaired judgment or reduced reaction time can lead to serious incidents.
Even if someone doesn’t feel impaired, THC can impact cognitive and physical abilities, including:
- Reduced coordination and motor control
- Delayed reaction times
- Impaired decision-making and memory
- Altered perception and concentration
Can You Remove THC From Saliva Faster?
Many online resources recommend quick fixes: drinking water, special mouthwashes, gums, and even supplements. However, there is no scientifically reliable method to rapidly eliminate THC from saliva once it is present. Most “detox hacks” are ineffective and may be considered tampering.
The only proven way to reduce THC levels is time.
Some general health behaviours (hydration, oral hygiene, time between use and testing) may influence superficial detection conditions, but none guarantee a negative result if THC is still present in the saliva glands.
If you’re concerned that THC may be detected in your test:
- Review your company’s drug and alcohol policy – Many policies outline expectations, support pathways and disclosure requirements.
- Do not attempt to falsify results – Tampering can undermine trust and may result in disciplinary action.
- Seek guidance discreetly – A HR representative, supervisor or medical professional can provide advice.
- Access support if needed – Workplace Employee Assistance Programs (EAP) offer confidential counselling and assistance.
Safely Delivering The Best Results
THC can typically be detected in saliva for 12 to 72 hours, depending on frequency and method of use, metabolism and individual factors. Understanding how long cannabis remains in the system helps employees make informed choices and supports HR teams in promoting a secure and productive workplace.
If your organisation needs reliable drug and alcohol testing, medical assessments or workplace training, Safework Health is here to assist. Safework Health is a trusted national provider of drug and alcohol testing, medical assessments and workplace health services. We work with organisations of all sizes, from small businesses to large industrial sites, to create safer, healthier workplaces.
We understand that drug testing can be a sensitive topic. That’s why we prioritise discretion, employee dignity, and education, helping organisations maintain compliance while fostering trust and wellbeing.
Get in touch with our team today to learn how we can support a safer, healthier workplace.