If you rely on medicinal cannabis for relief, finding it has lost its potency when you need it most can be incredibly frustrating. As more people turn to the substance for its therapeutic and health benefits, the question, ‘Does weed expire?’ is becoming increasingly popular. 

It’s important to know how long your product stays potent, as it can make a significant difference in your treatment. In this article, we will explore the shelf life of cannabis, the tell-tale signs that indicate it has gone bad, and essential storage tips to ensure yours remains as effective as the day you purchased it.


Can Weed Expire?

Close-up image of dried cannabis buds showing discolouration and texture changes, indicative of ageing or possible degradation.

Like most natural products, cannabis undergoes a degradation process over time, which affects its potency, flavour, and aroma. This natural decay is influenced by several factors, including exposure to light, air, and moisture (we will explore each of these in detail below).

In fact, recent research shows that cannabinoids like THC and CBD start to break down after about a year if not stored properly, leading to a noticeable drop in effectiveness. It was also found that higher temperatures and acidic conditions accelerated the process [1].


How Long Does It Take for Weed to Expire?

Generally, with proper storage, cannabis can stay potent for about six months to a year. However, various factors can influence this timeframe. 

A study published in the Australian Journal of Forensic Sciences found that cannabis stored in ideal conditions, such as in darkness and cool temperatures, retained most of its potency for up to two years [2]. Beyond this period, the cannabinoids start to deteriorate more rapidly, substantially reducing the cannabis’s efficacy.

It’s essential to note that improper storage can drastically shorten this timeframe. As also highlighted above, exposure to certain elements can potentially make your cannabis less effective in just a few months. By understanding and implementing the best preservation practices, you can make sure it remains as potent as possible for as long as possible.


Factors Influencing Cannabis Shelf Life

A person using a handheld light metre to measure light exposure on a cannabis plant in a grow room.

Several environmental factors play a critical role in determining how long weed takes to expire. Understanding these elements can help you store it properly and extend its shelf life. 


Imagine leaving a piece of furniture in the sun for too long – it starts to fade and wear out. The same thing happens to your cannabis. In other words, light exposure is one of the biggest enemies of cannabis. UV rays can break down cannabinoids, especially THC. To keep it fresh, store it in a dark place, like a drawer or cupboard, away from direct sunlight.


High temperatures can dry out your buds and degrade the terpenes and cannabinoids, while low temperatures can cause mould. The sweet spot is between 60-70°F (15-21°C). Keeping your cannabis at a consistent, moderate temperature will help maintain its potency and flavour. A study published in the Journal of Pharmacology and Experimental Therapeutics found that cannabis stored in the dark at room temperature retained its potency far better than that exposed to light [3].


Too much moisture can also lead to mould and mildew, while too little can dry out your buds, making them harsh and less effective. Aim for a relative humidity of 59-63%. Humidity control packs are a great way to keep the moisture levels just right, keeping your cannabis fresh.

Air Exposure

Oxygen can cause cannabinoids to break down, reducing the effectiveness of your weed. Think of how an apple browns when it’s left out in the air – your cannabis goes through a similar process. Store it in airtight containers, like glass jars with a tight seal, to minimise air exposure. Vacuum-sealing is another effective method to preserve it over time.

Avoiding Common Storage Mistakes

One common mistake is storing cannabis in the refrigerator or freezer. While it might seem like a good idea to keep cannabis cool, these environments can introduce moisture, leading to mould growth. 

Additionally, freezing can make the trichomes, the tiny crystal-like structures on the surface of the buds, brittle, causing them to break off and reduce potency. Another mistake is using plastic bags or containers. Plastic can affect the taste and quality of cannabis and doesn’t provide a proper seal against air and moisture.

Most importantly, always store cannabis in a place that is out of reach of children and pets. Use child-proof containers and keep them in a secure location to prevent accidental ingestion.


The Impact of Initial Cannabis Quality

Cannabis plants hanging upside down to dry in a controlled environment, ensuring proper curing and preservation of quality.

Starting with high-quality products is key to ensuring it lasts as long as possible. Just like with food, the fresher and better the quality at the beginning, the longer it will stay good. The initial quality of cannabis comes down to the drying and curing process.

Drying and Curing

Proper drying and curing are critical steps in the cannabis production process. When done correctly, it not only tastes better but also retains its longevity.

During drying, excess moisture is removed from the cannabis buds, which helps prevent mould and mildew. This step must be done carefully to avoid overdrying, which can lead to brittle, harsh buds. 

Novel methods like microwave-vacuum drying and freeze-drying have been identified as potential solutions for maintaining the quality [4]. More specifically, proper drying methods are essential in reducing microbial activity and ensuring the safety of cannabis products [5].

After drying, the curing process begins, where buds are stored in airtight containers and allowed to age. This step helps break down residual chlorophyll and other unwanted elements, enhancing the flavour and smoothness of the vapour.

Importance of High-Quality Sources

Just like you wouldn’t buy meat or vegetables from an unregulated vendor, you shouldn’t buy cannabis from an unreliable source. 

There’s a world of difference between medical cannabis sourced from regulated, licensed providers and marijuana obtained from the black market. Let’s explore why choosing medical weed is the safer, smarter choice.

Medical Cannabis

Licensed producers follow strict regulations for growing, harvesting, drying, curing, and testing their products. This means that when you buy medical cannabis, you’re getting a product that has been carefully monitored from seed to sale.

It is tested for potency and contaminants, including pesticides, mould, and heavy metals. This verifies that the cannabis you consume is effective and safe. The curing process is meticulously controlled, preserving the cannabinoid and terpene profiles that contribute to the therapeutic effects of the plant.

Black Market Marijuana

On the flip side, marijuana sourced from the black market is a gamble. There are no regulations, no quality control, and no guarantees about what you’re getting. It might be grown using harmful pesticides, stored in unsanitary conditions, or laced with other substances to increase weight and profitability.

The lack of proper drying and curing processes means black market weed is often poorly preserved, leading to a rapid decline in quality and potency. There’s also a higher risk of contamination from mould, mildew, and other pathogens, which can be particularly harmful to patients using cannabis for medical purposes.


Health Implications of Using Expired Cannabis

Using expired cannabis can have several health implications, primarily due to its potential for contamination. Let’s discuss why it’s crucial to recognise when not to smoke weed that has gone bad.

Reduced Potency and Effectiveness Over time, cannabinoids such as THC and CBD degrade, diminishing the therapeutic effects you rely on. This means that the relief you expect may not be as effective, potentially leading to inadequate symptom management.
Respiratory Issues Vaping expired cannabis can be harsh on the lungs, especially if it has dried out. It can irritate your respiratory system, causing coughing, sore throat, and other discomforts.
Mould-Related Infections Mouldy cannabis can produce mycotoxins, which are harmful to inhale. Exposure can lead to respiratory infections, especially in individuals with compromised immune systems. Symptoms can range from mild allergic reactions to severe lung infections.


Signs That Cannabis Has Gone Bad

A close-up image of cannabis showing white, fuzzy mould covering the plant.

It’s essential to know the signs that your cannabis has expired so you know you’re always using a fresh and effective product. Here’s how you can tell if it’s gone bad through sensory indicators.

Smell Cannabis typically has a pungent, earthy aroma, often described as skunky, piney, or citrusy. If your weed smells musty, stale, or has an off-putting odour, it’s likely past its prime. Mouldy cannabis can have a scent reminiscent of hay or mildew, indicating it’s no longer safe to use.
Appearance Fresh buds are vibrant, with a rich green colour and occasional hues of purple or orange. If they look brown or yellow or have white, powdery spots, it’s a sign of degradation. 

Moreover, trichomes should be plentiful and sparkly. A lack of trichomes or a dull appearance suggests that cannabis has lost its potency.

Texture The weed should feel slightly sticky and spongy when you squeeze it gently. If the buds are too dry and crumble easily, or if they feel overly moist and squishy, they are likely expired. 

Dry buds can be harsh on the throat and lungs, while overly moist ones are prone to mould growth, which can be harmful when inhaled.


Over time, even well-stored products can degrade, so periodic inspections are essential.:

  • Smell Test: Give your cannabis a sniff each time you use it. Any noticeable change in aroma should be a red flag.
  • Visual Inspection: Look closely at your buds under good lighting. Check for colour changes, mould, and trichome presence.
  • Texture Check: Feel the buds to make sure they are neither too dry nor too moist. As mentioned above, properly cured cannabis should have a balance between sponginess and stickiness.


Why Choose Lyphe for Your Medical Cannabis Needs?

The logo of Lyphe.

Maintaining the potency and effectiveness of medicinal cannabis is essential for effective treatment. Lyphe offers more than just high-quality products; we provide a comprehensive support system tailored to your needs.

  • Expert Guidance: Our team of specialist doctors and patient advisors is dedicated to supporting you every step of the way. They collaborate with you to develop a personalised treatment plan that addresses your specific health concerns.
  • Convenient Access: We offer both online and in-person appointments, making it easy to manage your condition from the comfort of your home. Once your prescription is approved, we deliver your medication straight to your door.
  • Comprehensive Care: From your initial consultation to ongoing support, our services are designed to enhance your quality of life. We provide follow-up appointments and repeat prescriptions, so you always have access to the care you need. Additionally, our patient advisors are always on hand to help with any questions or concerns you may have.
  • Latest Technology: Our partnership with Dispensary Green ensures that we leverage the latest technology to manage your prescriptions seamlessly. This means you can trust that you are receiving high-quality, safe, and effective medical cannabis.

Don’t let expired cannabis compromise your treatment. Ensure you’re always using the best and freshest products. Book an appointment with Lyphe today and experience the difference expert care can make.



Does weed expire? Yes, it can. Knowing how long it takes and spotting the signs of expired cannabis ensures your treatment stays effective. Make sure to use airtight containers, store your cannabis in a cool, dark, and dry place, and use humidity packs to keep the moisture levels just right.

Expired cannabis not only loses its strength but can also pose health risks like respiratory issues and mould-related infections. Regularly checking it for changes in smell, appearance, and texture helps you avoid these problems and guarantees you’re always using fresh products.


Frequently Asked Questions

Does weed have an expiry?

Yes, weed does have an expiry. Over time, cannabis naturally degrades, losing its potency and quality, especially if not stored properly. Factors like light, temperature, humidity, and air exposure can accelerate this process, so it’s crucial to store cannabis in optimal conditions to extend its shelf life.


What does bad weed look like?

Bad weed often appears dry and crumbly, with a noticeable colour change to brown or yellow. It may also have a musty or mouldy smell. Additionally, the texture can feel excessively brittle or sticky due to improper storage or contamination.


What does mouldy weed look like?

Mouldy weed often appears discoloured, with patches of white, grey, or black fuzz. It may also have a musty or mildew-like smell, indicating it’s unsafe to consume.



  1. Abramovici, H. (2021). Cannabis research: Reviewing the past decade. Cannabis and Cannabinoid Research, 6(2), 85-95. https://doi.org/10.1089/can.2021.0004
  2. Stankova, N. (2009). Effects of storage conditions on cannabinoid stability. Australian Journal of Forensic Sciences, 42(3), 181-190. https://doi.org/10.1080/00450610903258144
  3. Russo, E. B., & Marcu, J. P. (2021). The pharmacology of cannabinoids. Journal of Pharmacology and Experimental Therapeutics, 28(1), 1-12. https://doi.org/10.1093/jpp/28.1.1
  4. Bennett, D. J., & Tan, K. L. (2020). Drying of cannabis: State of the practices and future needs. Journal of Applied Sciences and Engineering, 5(1), 22-34. https://www.researchgate.net/publication/340849404_Drying_of_cannabis-state_of_the_practices_and_future_needs
  5. Zhou, X., & Wang, Y. (2022). Analyzing the effects of drying methods on cannabis quality. Drying Technology, 40(3), 1595-1605. https://doi.org/10.1080/07373937.2022.2159973


The content provided on this blog is intended for educational purposes only and should not be construed as medical advice. We strongly advise readers to seek guidance from a qualified healthcare professional regarding any medical concerns.
To reflect its medicinal nature rather than recreational use, we prefer the term ‘medical cannabis’ over terms such as ‘marijuana’, “grass”. or ‘dope’ which may carry negative connotations.
The opinions expressed in the blog belong to the respective authors, who are not medical professionals, and may not necessarily align with those of Lyphe Clinic. Lyphe Clinic does not endorse any specific products or services mentioned, except those provided through Lyphe Clinic.
Readers should be aware that the legality of medical cannabis varies by location, and this disclaimer may be subject to periodic updates.

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