The measurement of 500 milligrams (mg) of weed almost universally refers to the quantity of Delta-9-tetrahydrocannabinol (THC), the primary psychoactive compound in cannabis. This high dose is typically found in concentrated products like edibles, tinctures, or potent concentrates, not in raw cannabis flower. Five hundred milligrams of THC is an exceptionally high quantity, far exceeding a standard recreational dose for any user. The magnitude of this dose means its effects will be severe and prolonged, which consumers must understand.
Understanding THC Dosage Measurement
The effects of a THC dose depend heavily on the method of consumption, a concept known as bioavailability. Bioavailability is the proportion of the drug that enters circulation and has an active effect. When cannabis is inhaled (smoked or vaped), THC enters the bloodstream rapidly through the lungs, with peak concentrations reached within minutes. Average bioavailability for inhalation ranges from 10% to 35%.
Ingesting THC, especially through edibles, involves a different process resulting in a delayed but often more intense experience. Oral consumption requires THC to pass through the digestive system and be metabolized by the liver before entering the bloodstream. This metabolism converts THC into a more potent psychoactive metabolite, 11-hydroxy-THC (11-OH-THC). This metabolite crosses the blood-brain barrier more easily and produces a stronger effect.
The bioavailability of ingested THC is lower, typically 4% to 12%, but the 11-OH-THC metabolite causes a profound difference in effect. Onset is significantly delayed, often taking 30 minutes to two hours, with the full effect sometimes not felt for up to four hours. This delayed onset is a common reason for accidental overconsumption.
Standard Doses Compared to 500mg
To contextualize 500mg of THC, standard benchmarks for edible consumption must be established. A microdose, sought for mild relief without intoxication, is typically 1 to 2.5mg of THC. A standard recreational dose for a novice consumer is 2.5 to 5mg, providing noticeable effects like euphoria and altered perception.
An experienced user with moderate tolerance might use 10 to 20mg of THC. Doses exceeding 50mg are considered high, often reserved for those with significant tolerance or specific medical needs. Some sources define a very high dose as 50 to 100mg.
Five hundred milligrams is equivalent to 50 to 100 times the standard recreational dose. This quantity is overwhelmingly potent for the vast majority of consumers, even those with high tolerance. This amount is not intended for casual recreational use and is only considered in highly specialized medical contexts or for individuals with exceptionally high tolerance from chronic use.
The Acute Effects of High-Dose THC
Consuming 500mg of THC, especially as an edible, will likely result in an acute, unpleasant intoxication for almost any user. The intensity of the dose triggers intense psychoactivity, manifesting as anxiety, confusion, and paranoia. Users may experience a loss of their sense of time and space, leading to disorientation.
Physical symptoms are also present, including dizziness, impaired motor function, and increased heart rate. High doses can sometimes lead to temporary hallucinations, delusional thoughts, or a brief episode of psychosis. Due to the oral route of administration, the duration of these effects is extended, often lasting 8 to 12 hours, with residual effects persisting for up to 24 hours.
The combination of psychological distress and prolonged duration makes a 500mg experience overwhelming. While a fatal overdose from THC alone is impossible, the intense physical and mental distress can be severe enough to require emergency medical attention. Adverse effects from consuming too much cannabis are sometimes described as “cannabis poisoning.”
Individual Factors Influencing Response
The severity of the response to 500mg of THC varies based on physiological and experiential factors. Tolerance is the most significant factor, as regular, chronic use builds tolerance, requiring higher doses for the same effect. An individual with high tolerance may handle this dose better than an occasional user, for whom it would be incapacitating.
Metabolism speed, body weight, and body chemistry also influence how THC is processed. The liver enzyme Cytochrome P450 2C9 (CYP2C9) is primarily responsible for metabolizing THC into the active metabolite 11-OH-THC, and then into the inactive metabolite THC-COOH. Genetic variations in the CYP2C9 gene significantly impact how quickly a person metabolizes THC.
Individuals with less active variants of the CYP2C9 enzyme, such as the 3/3 genotype, metabolize THC slower. This results in higher blood levels of THC and a stronger, longer-lasting effect. This genetic difference can make a 500mg dose profoundly intense and prolonged for slow metabolizers compared to those with a faster metabolic profile.
Safety, Risk Management, and Mitigation
Approaching any high dose of THC requires strict adherence to safety principles, primarily to “start low and go slow.” Given the potency of 500mg, this dose should be avoided entirely by all but the most experienced users with specific medical needs and high tolerance. If a dose this high is accidentally consumed, the first step is to remain calm, recognizing that the intense effects are temporary.
Managing overconsumption involves finding a safe, quiet, and familiar environment to reduce overstimulation, which exacerbates paranoia and anxiety. Hydration is important, and having a trusted individual present provides reassurance and support. Seek medical attention immediately if symptoms include:
- Severe vomiting
- Prolonged cardiac distress
- Extreme confusion
- Inability to stay awake
Chronic, long-term use of high-dose cannabis, even below 500mg, carries the risk of developing Cannabinoid Hyperemesis Syndrome (CHS). CHS is characterized by cyclical episodes of severe nausea, vomiting, and abdominal pain. The only known curative treatment for CHS is complete and sustained abstinence from all cannabis use.