Medical Cannabis Reference
Evidence-based overview of conditions, delivery methods, and dosing principles — drawn from peer-reviewed research and clinical data.
Not medical advice. This content is for educational and informational purposes only. Always consult a licensed healthcare provider before using cannabis for any medical condition or alongside any medication. For adults 21+ (18+ in medical jurisdictions).
Evidence-Based Conditions
Conditions with meaningful clinical research supporting cannabis as a therapeutic option. Evidence strength varies significantly by condition.
Chronic Pain
THC and CBD both reduce pain — this is one of the most-studied uses of cannabis.
Both cannabinoids act on CB1 and CB2 receptors to modulate pain signaling. Neuropathic and inflammatory pain have the strongest supporting evidence.
Anxiety
CBD reduces anxiety; THC's effect depends heavily on dose.
CBD lowers anxiety without psychoactive effects. THC may help at low doses but can worsen anxiety at higher doses.
Low-THC, CBD-forward formulations are most commonly reported as effective.
Sleep Disorders
Cannabis may shorten sleep onset, but chronic use can reduce sleep quality.
THC reduces time to fall asleep; CBN is linked to sedation. Long-term high-THC use may suppress REM sleep.
Effect varies significantly by dose and product.
PTSD
Early research supports cannabinoids for reducing nightmares and hyperarousal.
CB1 receptors are involved in fear memory extinction — a key mechanism in PTSD treatment. Clinical research is ongoing.
PTSD is a qualifying condition in several US medical cannabis programs.
Nausea & Vomiting
This has some of the strongest clinical evidence — FDA-approved cannabinoid treatments exist.
Dronabinol (synthetic THC) is FDA-approved for chemotherapy-induced nausea and vomiting. Inhalation acts fastest; edibles provide more sustained relief.
Epilepsy
CBD is FDA-approved for two severe, treatment-resistant epilepsy syndromes.
Epidiolex (pharmaceutical-grade CBD) is approved for Dravet syndrome and Lennox-Gastaut syndrome. This is the clearest regulatory precedent for medical cannabis in the US.
Epidiolex is a CBD isolate — not whole-plant cannabis.
MS Spasticity
Sativex — an equal THC:CBD spray — is approved in multiple countries for MS spasticity.
MS spasticity has strong clinical evidence for cannabinoid therapy. Sativex (nabiximols) is approved in Canada, the UK, and parts of Europe.
Not yet FDA-approved in the US.
Crohn's Disease & IBD
Cannabinoids may ease GI symptoms, but remission evidence is mixed.
CB1 and CB2 receptors are densely expressed throughout the GI tract. Clinical trials show symptom improvement; cannabis has not been shown to reliably induce remission.
Typically used alongside conventional therapy, not as a replacement.
Delivery Methods
Onset, duration, and bioavailability differ significantly by delivery method — choosing the right one matters as much as strain or dose.
Inhalation (Smoked)
Fastest onset, lowest efficiency.
- •Fastest way to feel effects
- •Lowest bioavailability of all methods
- •Combustion produces respiratory irritants
Vaporization achieves the same speed with significantly less respiratory risk.
Vaporization
Fast, clean, and efficient.
- •Same speed as smoking, nearly 3× the bioavailability
- •No combustion — lower respiratory risk
- •Preferred delivery method for medical use
Oral / Edibles
Longest lasting, hardest to dose accurately.
- •Slowest and most variable onset of any method
- •First-pass metabolism converts THC to 11-OH-THC — a more potent form
- •Delayed onset is the leading cause of accidental overconsumption
Always wait the full onset window before redosing.
Sublingual (Tinctures)
Faster than edibles, more predictable.
- •Absorbed under the tongue directly into the bloodstream
- •Bypasses first-pass metabolism — more consistent than edibles
- •Good middle ground between speed and duration
Topical
Localized relief only — no psychoactive effects.
- •Does not enter the bloodstream
- •No psychoactive effects
- •Targets localized pain, inflammation, and skin conditions
Transdermal Patch
Slow, steady, and systemic.
- •Penetrates skin into the bloodstream — unlike topicals
- •Bypasses first-pass metabolism
- •Ideal for chronic conditions requiring stable, sustained dosing
Dosing Principles
Dosing is highly individual — body weight, metabolism, prior exposure, and genetics all affect response. Use these as starting points only.
Find Your Starting Dose
Inhaled / vaporized: Wait 15–30 minutes before assessing effect.
Edibles / sublingual: Wait at least 2 hours before taking more.
Experienced users may use higher doses (25 mg+). This guidance is for new users only.
Wait Before Taking More
Most overconsumption happens because effects are delayed. Do not take more during the onset window.
Edibles: effects may not appear for up to 2 hours.
Increase Slowly
Wait 24 hours before increasing your dose.
- Raise in 1–2.5 mg increments only
- Track your response each session
Check Drug Interactions
- CBD inhibits CYP3A4 and CYP2C19
- Affects blood thinners, antiepileptics, and immunosuppressants
- Interaction risk varies by medication and dose
Always disclose cannabis use to your prescribing physician.
Need a specific dose estimate?
The Dose Calculator walks through your consumption method, product potency, and experience level to give you a personalized starting-point recommendation.