You may have already noticed that your CBD oil changes slightly in colour or smell after a few months sitting in a cupboard. That’s no coincidence. The molecules found in a cannabis extract are alive, in the chemical sense of the word: they evolve over time, and the conditions in which they are stored play a decisive role. A recent study looked at precisely this question. Researchers exposed different types of cannabis-based products — raw plant material, extracts, formulated oils, pure isolates — to three distinct temperatures over an extended period, to observe how the molecules behave. The findings are revealing: depending on whether a product is rich in CBD or THC, the ideal storage strategy is not the same at all. Here is what this research tells us, translated into everyday language.

Why a molecule like CBD or THC can break down over time

Before diving into the results, a useful bit of context. Cannabis contains several dozen active molecules called cannabinoids — among which CBD (cannabidiol) and THC (tetrahydrocannabinol) are the best known. These molecules are not fixed in time: like any organic substance, they can transform under the effects of heat, light, humidity, or simply the passage of time.

This process of chemical transformation is called degradation. In practical terms, a molecule can lose its original structure and convert into another molecule, different in form and in properties. For an extract or an oil, this means that the chemical profile measured at production may no longer match what is actually inside the bottle a few months later.

This is precisely what the researchers set out to document rigorously, as long-term data comparing different types of products side by side was still missing from the scientific literature.

How the study was conducted

The researchers selected several types of matrices — the technical term for the “medium” in which the molecules are contained: dried leaves and flowers, concentrated extracts, isolates (i.e. molecules purified to a near-pure state), and ready-to-use formulated oils.

Three plant varieties were included, representing three distinct chemical profiles: a THC-rich variety, a CBD-rich variety, and an intermediate variety with a balance between the two. These products were then placed in three controlled-temperature environments:

• Room temperature — what we commonly call “ambient,” around 20–25 °C.
• Refrigeration — between 2 and 8 °C, like a standard household fridge.
• Freezing — at −20 °C, like a standard domestic freezer.

The samples were analysed at regular intervals using a technique called gas chromatography — think of a machine capable of “separating” all the molecules in a mixture, much like sorting objects on a conveyor belt, then weighing each one individually. This makes it possible to know precisely which molecules are present and in what quantity at each stage of monitoring.

CBD and THC do not age in the same way

CBD: a remarkably stable molecule

The first major finding of this research: CBD proved surprisingly resistant to the effects of time, including when stored at room temperature. The researchers report that CBD-dominant products maintained good chemical integrity over the study period, regardless of the form of the product — plant material, extract, or isolate.

To put it in everyday terms: CBD behaves a bit like a well-sterilised homemade jam. Even left out in your kitchen, it stays stable far longer than you might expect, as long as you keep it away from direct heat sources and intense light.

This relative stability of CBD at room temperature is useful information for understanding why storing CBD-dominant oils in a dark cupboard remains a perfectly reasonable approach — provided the product is not exposed to sudden temperature changes or direct sunlight.

THC: a far more fragile molecule at room temperature

The picture is very different for THC-rich matrices. The authors note that these products are significantly more susceptible to degradation at room temperature. The main phenomenon observed is the conversion of THC into another molecule called cannabinol — a substance that forms naturally when THC oxidises, meaning when it reacts with oxygen in the air. This transformation substantially alters the chemical profile of the product over time.

The researchers report that this degradation was significantly accelerated at room temperature, and significantly slowed by cold. The best results were obtained with solutions stored in an ethanol solvent (a form of alcohol used as a stabiliser) and kept at −20 °C: it is under these conditions that the THC molecule showed the greatest longevity.

Freezing: the clear winner for complex matrices

Overall, the authors highlight that storage at −20 °C consistently preserved the integrity of cannabinoids across all products tested, regardless of their composition. Freezing acts as a chemical “pause”: by significantly lowering the temperature, it slows down the reactions that transform molecules from one form into another.

This is the same principle that explains why certain medicines are kept in the freezer, or why pharmaceutical laboratories work with strict cold chains to ensure the stability of their formulations.

What this means in practice: the idea of tailored storage

The researchers’ main conclusion is stated clearly: the ideal storage temperature must be chosen based on the composition of the product. There is no single universal rule that applies to all cannabis extracts. A CBD-dominant product can reasonably tolerate storage at room temperature under good conditions (away from light and heat). A THC-rich product, on the other hand, requires stricter cold management to preserve its original chemical profile.

The authors even use the expression “cold chain management” for THC-rich matrices — a term borrowed from the pharmaceutical and food industries. It refers to keeping a product at a controlled temperature throughout its entire life, from production through to use.

The limitations the authors themselves acknowledge

This study provides solid and welcome data, but its authors are the first to point out its limitations. A few important points to keep in mind:

• The conditions tested are controlled laboratory settings: in reality, products are exposed to temperature fluctuations, humidity, and light far more complex than a stable cold chamber.
• The diversity of products on the market is vast: formulations, excipients (the ingredients that accompany the active molecules), packaging, and manufacturing processes vary considerably from one producer to another. The findings of this study do not cover all of this variety.
• The observation period, though extended, has its limits: the authors note that additional data over even longer periods would be helpful to refine the recommendations.
• The interactions between molecules — between cannabinoids, terpenes, and other components — have not all been analysed in detail. A full extract is far more complex than a pure isolate, and its behaviour may differ accordingly.

These caveats do not diminish the value of the findings, but they serve as a reminder that science advances step by step, and that every study opens as many new questions as it closes.

Conclusion

What this study teaches us: the researchers report a clear difference in behaviour between cannabinoids when faced with time and temperature. CBD demonstrates robust stability even at room temperature, while THC-rich matrices break down significantly faster without cold management. Storage at −20 °C proved the most effective across all matrices tested.

What the authors themselves qualify: these results were obtained under controlled laboratory conditions, on a limited panel of matrices. The variability of real-world products — their formulations, packaging, and transport conditions — introduces a level of complexity that this study does not fully cover. Further research remains necessary.

What this tells us about extract composition: this study is a reminder that the balance between the cannabinoids present in an extract — CBD, CBG, CBC — and their surrounding environment of terpenes and flavonoids (the pigments and aromatic molecules naturally found in the plant) is a defining characteristic of a product. Two oils displaying the same CBD percentage can be built on very different phytochemical profiles, and can behave quite differently over time.

At TheGreenLab, this reality is reflected in the way our oils are crafted. The vast majority of our CBD oil range goes through a fractional distillation process: a technique that refines and stabilises the cannabinoid profile, giving the oil its characteristic light colour and mild taste. At the other end of the spectrum, our X-Strong 45% oil is based on a raw, undistilled extract, preserving the plant’s complete phytochemical profile — hence its deep, pronounced colour, its bold aromatic character, and its richness in full natural compounds. These are two different approaches, two distinct profiles, designed to suit different preferences.

Keen to explore our range? Discover our CBD oils, our CBD flowers, our CBD hash, or browse our full online shop.

Source: “Long-term cannabinoid stability in Cannabis sativa plant material, extracts, oil formulations, and isolates under distinct temperature conditions,” study published with gas chromatography analysis. DOI or full reference not available in the excerpt provided.

META TITLE: CBD Stability and Temperature: What the Science Says

META DESCRIPTION: A study compares the stability of CBD and THC at different temperatures. Findings, limitations, and what this means for storing your extracts.

FAQ

Does CBD break down over time?

The researchers report that CBD displays remarkable stability over the long term, including at room temperature — provided it is kept away from direct light and heat sources. This is one of the most striking findings of the study, clearly distinguishing CBD from other cannabinoids such as THC, which is far more sensitive to environmental conditions.

Should you keep your CBD oil in the fridge?

Based on the study’s findings, CBD-dominant products maintain their chemical integrity even at room temperature. The fridge or freezer offers an added layer of security, particularly for full-spectrum extracts that contain a broad range of molecules. In any case, a dark, cool cupboard away from heat sources remains a perfectly reasonable option for a CBD-dominant oil.

What is the difference between a distilled oil and a raw extract?

Fractional distillation is a process that separates and refines the molecules in a raw extract. It produces an oil with a stabilised profile, a light colour, and a mild taste. A raw extract, on the other hand, retains all of the compounds present in the plant — cannabinoids, terpenes, flavonoids — without any separation or removal. Its colour is darker, its aromatic profile more complex and pronounced. These are two complementary approaches, neither one inherently better than the other.

What is a terpene and why does it matter in an extract?

Terpenes are aromatic molecules naturally present in many plants, including cannabis. They are what give a variety its characteristic scent — woody, citrusy, floral, or earthy. In a cannabis extract, they form an integral part of the phytochemical profile, alongside cannabinoids such as CBD, CBG, or CBC. The terpene composition helps to distinguish one extract from another, even when the displayed CBD percentage is identical.

Should all CBD products be stored the same way?

No — and that is precisely the central message of this study. The researchers emphasise that the storage strategy must be adapted to the composition of the product. A CBD-rich extract can tolerate reasonable ambient conditions, while a product with a more complex chemical profile that includes THC requires stricter temperature management. Reading the storage recommendations provided by the manufacturer is, in all cases, the best approach.