At What Temperature Does THC Degrade? The Full Thermal Breakdown Timeline

THC begins to degrade measurably at around 300°F (149°C), but the process is gradual, not a single cliff-edge event. The cannabinoid is most stable below 250°F (121°C). Between 300°F and 315°F (149–157°C), decarboxylation converts THCA into active THC faster than THC itself is lost. Above 315°F, THC oxidation and evaporation accelerate, and by 392°F (200°C) significant losses occur within minutes. Prolonged exposure matters as much as peak temperature: at 230°F (110°C), roughly 10 percent of THC is lost per hour, while at 350°F (177°C) the same loss happens in under a minute.

The Molecular Mechanism Behind THC Degradation

THC degradation is not one reaction. It is at least three competing processes running at different rates, and understanding which one dominates at a given temperature explains why the "degradation temperature" is a range rather than a number.

The first process is decarboxylation. Raw cannabis contains mostly tetrahydrocannabinolic acid (THCA), which is not psychoactive. Heat removes a carboxyl group from THCA, releasing carbon dioxide and leaving delta-9-THC. This conversion is the goal of most heating, and it is fastest between 220°F and 280°F (104–138°C). Decarboxylation is not degradation, but the two are often confused because both are heat-driven.

The second process is oxidation. Once THC forms, oxygen attacks the molecule, converting it to cannabinol (CBN). CBN is mildly psychoactive but far less potent than THC, which is why old cannabis feels weak and sedating. Oxidation is temperature-dependent and accelerates roughly two to three times for every 18°F (10°C) rise, a standard rule of thumb for reaction kinetics. Light and air exposure compound it.

The third process is evaporation. THC has a boiling point of about 315°F (157°C) at standard atmospheric pressure. Above that temperature, unbound THC becomes volatile and physically leaves the material before it can chemically break down. This is why vaporizers and dab nails operate in specific windows: too cool and you leave cannabinoids behind, too hot and you destroy or volatilize them.

In plain terms: heat first activates THC, then oxidizes it, then boils it away, and the three overlap in a narrow band.

A fourth pathway, thermal decomposition into smaller fragments, only becomes significant above 450°F (232°C), where the molecule's ring structure itself begins to break apart. That threshold matters for combustion and for anyone torching a concentrate.

The Full Thermal Timeline: What Happens at Each Temperature

The table below reconciles the thresholds most commonly cited, which often conflict because they measure different endpoints. Some sources report the temperature at which THC loss begins, others the temperature at which half the THC is gone, and others the boiling point.

The key reconciliation: the widely quoted "THC degrades at 300°F" refers to the onset of measurable oxidative loss, while "THC boils at 315°F" refers to volatilization, and "half-life of minutes at 350°F" refers to combined loss. These are not contradictions; they describe different mechanisms at overlapping temperatures.

Why Time and Temperature Trade Off Against Each Other

The single most overlooked variable is duration. THC loss follows roughly first-order kinetics, meaning the rate of loss is proportional to how much THC remains and to a temperature-dependent rate constant. Doubling the time at a given temperature roughly doubles the fraction lost, but raising the temperature by 18°F can double the rate constant itself.

This produces a practical equivalence. Holding cannabis at 230°F (110°C) for one hour loses on the order of 10 percent of THC to oxidation. Holding it at 350°F (177°C) for one minute loses a comparable fraction, but the loss at higher temperature is split between oxidation and evaporation. The lower-temperature, longer-time route preserves more THC but takes far longer and may not fully decarboxylate if the material is dense.

For extraction and cooking, the practical lesson is that temperature near the decarboxylation optimum (around 240–250°F) paired with moderate time gives the highest retained THC. Pushing hotter to "finish faster" sacrifices cannabinoid content to save minutes.

How Degradation Varies by Product Form

The temperature at which THC degrades is not fixed across formats because the physical matrix changes how heat and oxygen reach the molecule.

Flower and ground plant material degrade slowly because plant tissue and moisture buffer heat and limit oxygen contact. A sealed jar stored at 70°F (21°C) loses minimal THC over a year, but the same flower exposed to 90°F (32°C) and light can lose 15 to 20 percent of its THC in months as oxidation proceeds.

Concentrates and oils have far more exposed surface area per unit mass and almost no moisture buffer. A distillate or shatter heated to 300°F (149°C) oxidizes faster than flower at the same temperature because there is no matrix slowing oxygen diffusion. This is why concentrate makers purge and store under inert gas or vacuum.

Edibles and infusions add another layer. THC dissolved in fat or alcohol is protected from evaporation until the carrier itself boils, but it remains vulnerable to oxidation. Butter and oil infusions held at 250°F (121°C) for long periods lose potency to oxidation even though the THC never approaches its boiling point.

Vaporization sits at the boundary. A dry-herb vaporizer set to 365°F (185°C) delivers a mix of cannabinoids and is hot enough to volatilize THC but not hot enough to decompose it, provided the material is not overheated at the element. Combustion at 1,200°F (650°C) or higher destroys most THC in the burning zone, which is why a joint delivers a smaller fraction of the plant's cannabinoid content than a vaporizer.

Correcting Common Misconceptions About THC and Heat

The most persistent misconception is that THC degrades instantly at one specific temperature, like a melting point. It does not. Degradation is a rate process spread across a range, and the dominant pathway changes as temperature climbs: oxidation first, then volatilization, then structural decomposition.

A second misconception is that higher heat always means more destruction. In the 220–280°F window, heat is constructive: it converts inactive THCA to active THC. Applying that heat is why decarboxylation exists as a step. The destructive phase only begins once most THCA has converted and THC sits exposed to oxygen and rising temperature.

A third error is ignoring CBN formation. Many people treat THC "loss" as simple disappearance, but a large share of the loss above 300°F is conversion to CBN rather than destruction. The material still contains a cannabinoid; it is just a less potent, more sedating one. This is the mechanism behind the sleepy reputation of aged cannabis and why a degraded product is not necessarily an empty one.

A fourth subtlety: the boiling point of 315°F applies to pure THC at standard pressure. In a sealed extraction vessel, pressure changes the effective boiling point, and in a plant matrix the cannabinoid is bound and releases at different rates. Laboratory boiling-point figures and kitchen behavior diverge for these reasons.

Practical Temperature Targets for Cooking and Storage

For decarboxylation before making edibles, target 240–250°F (116–121°C) for 30 to 45 minutes in an oven, which converts most THCA while minimizing oxidative loss. Above 280°F the loss rate climbs faster than the conversion gain, so there is little reason to go hotter.

For storage, keep cannabis below 77°F (25°C) and away from light and air. A sealed, opaque container at room temperature preserves THC for six to twelve months; refrigeration adds a few more months but risks condensation if the container is opened warm. Freezing works for long-term storage but repeated freeze-thaw cycles damage trichomes.

For vaporization, 340–365°F (171–185°C) balances cannabinoid release against thermal loss. Settings above 400°F (204°C) increasingly trade flavor and potency for a harsher, more degraded vapor.

Do not hold concentrates at or above 300°F (149°C) for extended periods without inert-atmosphere protection, and never assume a high-temperature purge is harmless; it costs measurable cannabinoid content for every minute above the oxidative threshold.

The Limits of What the Numbers Can Tell You

The temperatures and loss rates above are approximations drawn from kinetic studies and practical extraction experience, not a single standardized protocol. Real degradation depends on oxygen availability, moisture content, surface area, light exposure, and the exact starting cannabinoid profile, none of which a single temperature captures.

Consumer-grade ovens also cycle around their set point by 10 to 25°F, so an oven set to 240°F may oscillate enough to push part of the material into the oxidative range. Laboratory and industrial processes use controlled atmospheres and precise thermal baths that home cooks cannot replicate.

Finally, much of the fine-grained kinetic data on THC degradation comes from small studies and industry testing rather than large standardized trials, so specific loss percentages should be read as order-of-magnitude estimates. The reliable, established facts are the thresholds: decarboxylation optimizes near 240–250°F, oxidation accelerates above 300°F, THC volatilizes near 315°F, and structural decomposition dominates above 450°F. Everything between them is a gradient, and treating THC degradation as a curve rather than a switch is the difference between preserving potency and losing it.