Botanical

Cannabis (THC)

Also known as THC, Delta-9-tetrahydrocannabinol, Marijuana, Cannabis sativa

Delta-9-tetrahydrocannabinol, the primary psychoactive cannabinoid in Cannabis sativa, acting as a partial agonist at CB1 receptors; used medically for chronic pain, chemotherapy-induced nausea, appetite stimulation, and spasticity. Subject to legal restrictions varying by jurisdiction.

5linked conditions

34linked studies

On this pageEvidence Availability Outcomes & conditions →

Evidence

What the research actually shows

We link to relevant studies and leave interpretation to you and your healthcare professional.

Evidence analytics

Where the evidence is concentrated

Number of audited published findings for Cannabis (THC) by condition. Drill into a pair page for the full breakdown.

Putative uses

Where people report using it and what trials suggest

Strong evidenceChemotherapy-induced nausea (Rx cannabinoids)
Strong evidenceMS spasticity (Rx, nabiximols)
Moderate evidenceChronic neuropathic pain adjunct

Where the evidence is negative

Common claims the trials do not support

For most chronic-pain conditions, guideline reviews find small/unreliable benefits vs harms.
Anxiety relief paradox: acute anxiolysis at low dose, anxiogenic and panic-inducing at higher doses/naive users.
Chronic use: dependence (~10%), cognitive impairment, psychosis risk in predisposed.
Depression and PTSD trials largely null.

Δ9-THC has real prescription indications (chemo nausea, spasticity, appetite in HIV/AIDS) alongside well-documented harms from recreational use.

Safety notes: Impairs driving. Interacts with alcohol/sedatives. UK: prescription-only; recreational possession illegal.

Evidence grades reflect study quality and consistency, not marketing claims.

34studies referenced

29journals

2014–2026publication range

01Cannabis-Based Products for Chronic Pain : An Updated Systematic ReviewChou R, et al. · Annals of internal medicine · 2026PMID 41429020 ↗

What trials found, in numbers

Summaries of published trial results for this compound, grouped by condition. Numbers are reported exactly as the researchers published them — we never calculate or convert.

How to read this table

Benefit: What the trial saw happen: whether the measured outcome moved in the helpful direction in that one study (the tag on each row: “Benefit seen”, “No clear benefit” or “Unclear”). It is a study result — not advice, and not a promise it will work for you.
Evidence: How strong the research behind that result is. A meta-analysis pools many studies (strongest); a systematic review collates them; an RCT tests against a control (placebo); observational studies only watch — they can suggest, not prove.
Effect size: How large the measured change was, exactly as the researchers published it. “No number reported” means the abstract gave no effect size — we never invent one.

In short: benefit is what was observed; evidence is how much you should trust the observation. A “Benefit seen” tag on a weak study counts for far less than the same tag on a meta-analysis.

Anxiety (4 outcomes)

Outcome measured	What trials found	Effect size	People studied	Duration	Type of evidence	Study
Anxiety	No significant association was found between cannabis use and anxiety risk compared with nonusers in 23 317 individuals. (95% CI, 0.84-1.67; I2=42%)No clear benefit	no number reported	23 317	—	Meta-analysis · 2019	PMID 30758486
Depression	Cannabis users had a 1.37 times higher risk of depression compared with nonusers in 23 317 individuals. (95% CI, 1.16-1.62; I2=0%)Unclear	1.37 OR	23 317	—	Meta-analysis · 2019	PMID 30758486

What publications report

Outcome summaries extracted from the linked papers' curated records. Educational, not medical advice.

01Chronic neuropathic pain, spasticity, and nausea/vomiting — Improved

May benefit (moderate-quality evidence)

Medical cannabinoid users · Systematic review & meta-analysis · PMID 26103030 ↗Strong evidenceImproved 02Chronic neuropathic pain — Reduced

Significantly reduced vs placebo (low-dose smoked cannabis)

Chronic neuropathic pain patients · Crossover RCT · PMID 25972454 ↗Moderate evidenceReduced

Figures are reported as published; study designs and populations vary. Works for Us does not interpret results or provide medical advice.

Outcomes & conditions

Why people look into Cannabis (THC) — and what they report

Associated conditions and community-reported outcomes, wrapped together on one page. Aggregates appear only once enough reports arrive.

Outcomes & conditions →

Important: This page reflects observational, aggregate-only community reporting and independent published research. It is not medical advice, and it does not claim any compound treats, cures, or is effective for any condition. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or treatment.

Availability

Where to get Cannabis (THC) (UK)

How this compound is sold in the UK, and where our readers typically find it.

Prescription-only in the UK

Cannabis (THC)can't legally be sold over the counter here. It's available only with a prescription, through a consultation with a doctor or qualified prescriber. We don't sell medicines and never will — our job is the evidence, not the dispensing.

How prescription-only compounds work →

Outcome measured	What trials found	Effect size	People studied	Duration	Type of evidence	Study
30% or greater pain relief	Cannabis-based medicines increased 30% pain relief to 39% versus 33% with placebo in 1586 participants. (95% CI 0.03 to 0.15)Benefit seen	39% versus 33%	1586 participants	—	Meta-analysis · 2018	PMID 29513392
50% or greater pain relief	Cannabis-based medicines increased 50% pain relief to 21% versus 17% with placebo in 1001 participants. (95% CI 0.00 to 0.09)Benefit seen	21% versus 17%	1001 participants	—	Meta-analysis · 2018	PMID 29513392
Mean pain intensity (herbal cannabis)	It is uncertain whether herbal cannabis reduces mean pain intensity compared to placebo due to very low-quality evidence.Unclear	no number reported	—	—	Meta-analysis · 2018	PMID 29513392
Nervous system adverse events	Cannabis-based medicines increased nervous system adverse events to 61% versus 29% with placebo in 1304 participants. (95% CI 0.18 to 0.58)Unclear	61% versus 29%	1304 participants	—	Meta-analysis · 2018	PMID 29513392
Patient Global Impression of Change (PGIC)	Cannabis-based medicines improved PGIC to 26% versus 21% with placebo in 1092 participants. (95% CI 0.01 to 0.17)Benefit seen	26% versus 21%	1092 participants	—	Meta-analysis · 2018	PMID 29513392
Psychiatric disorders	Cannabis-based medicines increased psychiatric disorders to 17% versus 5% with placebo in 1314 participants. (95% CI 0.06 to 0.15)Unclear	17% versus 5%	1314 participants	—	Meta-analysis · 2018	PMID 29513392
Serious adverse events	Evidence was insufficient to determine if cannabis-based medicines increased serious adverse events versus placebo in 1876 participants. (95% CI -0.01 to 0.03)Unclear	no number reported	1876 participants	—	Meta-analysis · 2018	PMID 29513392
Tolerability (herbal cannabis)	Herbal cannabis and placebo did not differ in tolerability based on very low-quality evidence.No clear benefit	no number reported	—	—	Meta-analysis · 2018	PMID 29513392
Withdrawal due to adverse events	Cannabis-based medicines caused withdrawal in 10% versus 5% with placebo in 1848 participants. (95% CI 0.02 to 0.07)Unclear	10% of participants versus 5% of participants	1848 participants	—	Meta-analysis · 2018	PMID 29513392
dizziness	Synthetic high THC products probably increase dizziness risk versus placebo in 1740 people over 1 to 6 months.Unclear	no number reported	1740	1 to 6 months	Systematic review · 2022	PMID 35667066
nausea	Sublingual spray with comparable THC-CBD ratio increases nausea risk versus placebo in 1740 people over 1 to 6 months.Unclear	no number reported	1740	1 to 6 months	Systematic review · 2022	PMID 35667066
pain severity and overall function	Sublingual spray with comparable THC-CBD ratio probably improves pain and function versus placebo in 1740 people over 1 to 6 months.Benefit seen	no number reported	1740	1 to 6 months	Systematic review · 2022	PMID 35667066
pain severity and response	Synthetic high THC products may moderately improve pain severity and response versus placebo in 1740 people over 1 to 6 months.Benefit seen	no number reported	1740	1 to 6 months	Systematic review · 2022	PMID 35667066
sedation	Synthetic high THC products increase sedation risk versus placebo in 1740 people over 1 to 6 months.Unclear	no number reported	1740	1 to 6 months	Systematic review · 2022	PMID 35667066
study withdrawal due to adverse events	Extracted high THC products increase withdrawal risk due to adverse events versus placebo in 1740 people over 1 to 6 months.Unclear	no number reported	1740	1 to 6 months	Systematic review · 2022	PMID 35667066