Overview
Medical cannabis is not a single product — it encompasses a wide range of formulations with different onset times, durations, and delivery methods. Your prescribing doctor will recommend the most appropriate type based on your condition, symptoms, and lifestyle.
Dried Flower (Herbal Cannabis)
Dried cannabis flower is the most common form of medical cannabis prescribed in the UK. It is typically vaporised (not smoked) using a medical-grade dry herb vaporiser. Vaporisation heats the flower to a temperature that releases cannabinoids as vapour without combustion, reducing the harmful by-products associated with smoking.
Onset: 5–15 minutes
Duration: 2–4 hours
Best for: Acute pain, nausea, rapid anxiety relief, sleep onset
Cannabis Oils (Sublingual Drops)
Cannabis oil extracts are administered by placing drops under the tongue (sublingually), where they are absorbed through mucous membranes into the bloodstream. Oils provide more predictable dosing than flower and have a longer onset time but a more sustained effect.
Onset: 15–45 minutes
Duration: 4–8 hours
Best for: Chronic conditions requiring sustained relief, daytime use, patients who prefer not to inhale
Capsules and Softgels
Cannabis capsules contain measured doses of cannabis extract in an oil base, swallowed like any other tablet. They offer the most consistent dosing and are easy to incorporate into a daily medication routine. The onset is slower as they must pass through the digestive system.
Onset: 30–90 minutes
Duration: 6–10 hours
Best for: Consistent daily dosing, chronic conditions, patients requiring long-lasting relief
Vape Cartridges
Pre-filled vape cartridges contain cannabis extract (usually a distillate or full-spectrum oil) compatible with a vape pen device. They offer convenience and discretion but have faced scrutiny over additive safety. Always ensure vape products are pharmacy-dispensed and free from vitamin E acetate and other harmful additives.
Onset: 5–10 minutes
Duration: 2–3 hours
Best for: Rapid relief, on-the-go use
Wafers and Lozenges
Some manufacturers produce cannabis in dissolvable wafer or lozenge form for sublingual or buccal (cheek) absorption. Sativex, the only fully licensed cannabis medicine in the UK, is delivered as an oromucosal spray. These formulations offer accurate dosing and discreet administration.
Understanding THC and CBD Ratios
Medical cannabis products are classified primarily by their THC (psychoactive) to CBD (non-intoxicating) content:
- CBD dominant (e.g. 1:20 THC:CBD) — minimal psychoactive effects, suitable for daytime use and patients sensitive to THC
- Balanced (e.g. 1:1 THC:CBD) — moderate effects, CBD moderates the psychoactive impact of THC
- THC dominant (e.g. 20:1 THC:CBD) — stronger psychoactive effects, typically reserved for pain and sleep conditions
Strain Types: Sativa, Indica and Hybrid
Medical cannabis flower is commonly categorised by strain type, which reflects the likely effects profile:
- Sativa-dominant strains tend to produce more energising, cerebral effects and are often prescribed for daytime use, depression, and fatigue.
- Indica-dominant strains are typically more sedating and are often preferred for pain, sleep, and evening use.
- Hybrid strains combine characteristics of both, offering a more balanced profile.
Note that the sativa/indica distinction is a simplification — terpene profile and cannabinoid content are more reliable predictors of a product's effects.
Which Product Is Right for You?
Your prescribing doctor will guide you to the most appropriate formulation. Key factors include the severity and timing of your symptoms, whether you need rapid-onset or sustained relief, your sensitivity to THC, your lifestyle, and whether inhalation is suitable for your respiratory health.