THC (Delta-9-Tetrahydrocannabinol) | Cannabinoid Guide
Complete Guide to THC in Medical Cannabis
Pronounced: tee-aych-SEE
THC (Delta-9-Tetrahydrocannabinol) is a psychoactive major cannabinoid. Complete guide to THC, the primary psychoactive cannabinoid. Learn about medical uses, effects, dosing, side effects, and scientific research..
Boiling Point
315°F (157°C)
Formula
C₂₁H₃₀O₂
Legal Status
Schedule I federally; legal for medical use in 38+ states
May cause impairment. Do not drive or operate machinery after use.
Research Sources
7 peer-reviewed studies
Verified Via
PubMed / DOI
Evidence
Research-Backed
Updated
February 2026
What is THC?
THC (delta-9-tetrahydrocannabinol) is the primary psychoactive cannabinoid in cannabis, responsible for the "high" associated with marijuana use. Beyond its psychoactive effects, THC has been extensively studied for potential therapeutic applications including pain management, nausea reduction, and appetite stimulation.
How THC Works
THC acts primarily through CB1 receptors concentrated in the brain and central nervous system. When THC binds to CB1 receptors, it triggers the release of dopamine and alters neural communication in areas controlling memory, coordination, pleasure, and perception. THC also has some activity at CB2 receptors, which are involved in immune function.
Researched Effects
Pain Relief
Strong EvidenceExtensive clinical evidence supports THC for chronic pain management, particularly neuropathic pain.
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Clinical evidence supports pain-relieving properties
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Cures pain or replaces pain medication
Appetite Stimulation
Strong EvidenceWell-documented "munchies" effect; FDA-approved for AIDS wasting and chemotherapy-induced appetite loss.
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Clinically proven to stimulate appetite
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Cures eating disorders
Sources
Anti-nausea
Strong EvidenceHighly effective for chemotherapy-induced nausea and vomiting (CINV).
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FDA-approved for chemotherapy-induced nausea
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Cures nausea
Sources
Sleep
Moderate EvidenceMay reduce sleep onset time; effects on sleep architecture still being studied.
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May help with falling asleep
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Cures insomnia
Sources
Medical Applications
Chronic Pain
Strong EvidenceParticularly effective for neuropathic and cancer-related pain.
Chemotherapy Side Effects
Strong EvidenceFDA-approved (as Marinol/dronabinol) for CINV.
AIDS/HIV Wasting
Strong EvidenceFDA-approved for appetite stimulation in AIDS patients.
Multiple Sclerosis Spasticity
Strong EvidenceApproved in many countries as Sativex (THC:CBD combination).
Dosing Guidance
Start low (2.5-5mg), go slow. Effects typically begin within 5-15 minutes when inhaled, 30-90 minutes when ingested. Duration is 2-4 hours inhaled, 4-8 hours ingested. Tolerance develops with regular use.
Safety Information
THC can cause short-term memory impairment, increased heart rate, dry mouth, red eyes, and impaired coordination. High doses may cause anxiety or paranoia in some users. Not recommended during pregnancy. May interact with sedatives and other medications.
Potential Side Effects
- Short-term memory impairment
- Increased heart rate
- Dry mouth and eyes
- Impaired coordination
- Anxiety or paranoia (dose-dependent)
- Altered perception of time
Drug Interactions
THC is metabolized by CYP3A4 and CYP2C9 enzymes. May interact with sedatives, opioids, and blood thinners. Consult your physician if taking other medications.
Scientific References
7 peer-reviewed sources cited
- 1
Gaoni Y, Mechoulam R. Isolation, structure, and partial synthesis of an active constituent of hashish Journal of the American Chemical Society. 1964. doi:10.1021/ja01062a046
Landmark paper first identifying and synthesizing THC.
- 2
Whiting PF, et al. Cannabinoids for medical use: A systematic review and meta-analysis JAMA. 2015
Comprehensive review finding moderate evidence for chronic pain.
- 3
Aviram J, Samuelly-Leichtag G. Efficacy of Cannabis-Based Medicines for Pain Management: A Systematic Review and Meta-Analysis of Randomized Controlled Trials Pain Physician. 2017
Systematic review of clinical trials for neuropathic pain.
- 4
Lutge EE, et al. The medical use of cannabis for reducing morbidity and mortality in patients with HIV/AIDS Cochrane Database of Systematic Reviews. 2013
Systematic review of cannabis for HIV/AIDS symptoms including appetite.
- 5
Smith LA, et al. Cannabinoids for nausea and vomiting in adults with cancer receiving chemotherapy Cochrane Database of Systematic Reviews. 2015
High-quality evidence for CINV efficacy.
- 6
Kesner AJ, Lovinger DM. Cannabinoids, Endocannabinoids and Sleep Frontiers in Molecular Neuroscience. 2020
Review of THC effects on sleep architecture.
- 7
Novotna A, et al. A randomized, double-blind, placebo-controlled, parallel-group, enriched-design study of nabiximols (Sativex), as add-on therapy, in subjects with refractory spasticity caused by multiple sclerosis European Journal of Neurology. 2011
Phase III trial showing efficacy for MS spasticity.
Research Verification
All citations link directly to PubMed or the original source. You can verify any claim by clicking the reference link. Learn more about how we research.
Frequently Asked Questions
What is THC?
THC (delta-9-tetrahydrocannabinol) is the primary psychoactive compound in cannabis, responsible for the "high." It binds to CB1 receptors in the brain and has FDA-approved medical uses for pain, nausea, and appetite stimulation.
How long does THC stay in your system?
THC can be detected in urine for 3-30 days depending on usage frequency, in blood for 1-7 days, and in hair for up to 90 days. Factors include body fat percentage, metabolism, and hydration.
What are the medical uses of THC?
THC is FDA-approved (as Marinol) for chemotherapy-induced nausea and AIDS-related appetite loss. It's also used medically for chronic pain, MS spasticity, PTSD, and other conditions depending on state laws.
How much THC should I start with?
Start with 2.5-5mg for edibles or a single small inhalation. Wait at least 2 hours before redosing with edibles. Effects vary significantly based on tolerance, body weight, and consumption method.
Quick Facts
- Full Name
- Delta-9-Tetrahydrocannabinol
- Category
- major Cannabinoid
- Psychoactive
- Yes
- Boiling Point
- 315°F (157°C)
- Formula
- C₂₁H₃₀O₂
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Medical Disclaimer
This content is for educational purposes only and is not medical advice. Consult a healthcare provider before using cannabis products.
Individual Variation
Cannabis affects everyone differently based on genetics, tolerance, and other factors. What works for one person may not work for another.
Start Low, Go Slow
Always begin with the lowest effective dose and increase gradually to minimize risk of adverse effects.