It can take a little while to get it right, so be patient. Many people do not see a difference in symptoms after one or two doses of CBD. It can take up to eight weeks of regular use to feel an impact, says Bridget Seritt, co-founder of the Canna-Patient Resource Connection, a Colorado-based organization that is working to protect patient rights and end stigma against those who choose cannabis as medicine.
“There are no standard doses for patients,” says Rachna Patel, DO, a physician who does consultations about medical marijuana and CBD and sells her own line of CBD products. “Ultimately, it’s trial and error, but you have to go about it in a methodical way.”
No two patients respond to CBD in the same way. You and your doctor will probably need to adjust the dose either up or down until you hit the right balance of benefits without side effects. “A lot of it depends on your biochemistry and the way your liver breaks down these chemicals. There’s a wide variety of factors that come into play,” says Dr. Patel.
“I wouldn’t recommend starting CBD without the supervision of a physician,” says Dr. Patel, author of The CBD Solution. “Many times people purchase a CBD product, try a dose that that doesn’t work for them, switch products and spin their wheels. Or, worse, they develop side effects.”
3. Expect some trial and error
Many factors, such as your body mass index (BMI), specific health condition(s) you have, medications you take, your health history, and the form of CBD you plan to use can influence how much CBD you may need to treat your symptoms. Although CBD is different than medical marijuana — which contains CBD as well as THC, an intoxicating ingredient — a doctor who’s well-versed in cannabis (marijuana) is probably the best person to help you help you sort it out.
Oils and tinctures can be trickier because the packaging often states the amount of CBD in the entire bottle, not in a dropper. This calculator can help you figure out how many drops you need based on the strength of the product.
Let’s say you and your doctor settle on a dose of 30 mg of CBD per day. Now what? The answer depends on which form of CBD you take.
1. Work with an expert
When it comes to CBD in topical form (creams, lotions, and salves), you’ll probably see the total amount of CBD in the container listed on the label. You’ll then have to divide that total by the number of millimeters in the package to determine how much is in each milliliter. For example, if you have a 50 ml jar of salve that contains 200 mg of CBD, there’s 4 mg per ml. You should then use a metric measuring spoon to scoop out 7.5 ml to get a 30 mg dose of CBD.
CBD won’t get you high the way that cannabis with THC can, but it may still cause side effects. “The most common side effects are fatigue and lethargy, and in rare cases diarrhea,” says Dr. Patel, who notes that CBD that’s taken topically less commonly causes side effects. Topical CBD is best used to address pain in a single joint, rather than widespread pain, she adds.
Despite the prevalence of CBD use and current hype, guidance on dose recommendations has not advanced and is not clear, additionally hampered by the striking lack of accessible pharmacokinetic and bioavailability data of CBD in humans.8 No published study to date has reported the absolute oral bioavailability of CBD in humans.8 Limited dose‐determination studies have left a paucity in data surrounding desired plasma concentrations to achieve minimum effective doses. Additionally, the lack of information on the role of different formulations and routes of administration on absorption are also apparent. The aim of this review was to comprehensively collate all published data relating to CBD administration in clinical populations to describe the range of CBD doses assessed across different pathological states.
Summary of included studies: randomised controlled trials
Clinically, CBD is being investigated in multiple disease states including neurodegeneration, anxiety disorder, orphan childhood diseases with a prevalence of <5 in 10 000 individuals (e.g. tuberous sclerosis complex) and addiction (ongoing trials in cannabis and cocaine craving).4, 5, 6 Epidiolex has recently become the first Food and Drug Administration‐approved CBD medicine, indicated for use in Lennox–Gastaut or Dravet syndrome (childhood epilepsy) by oral administration. Sativex is an oromucosal spray containing both CBD and δ‐9‐tetrahydrocannibinol, which is licenced in the EU and Canada for the treatment of multiple sclerosis associated spasticity. At the time of writing, there are 49 clinical trials registered on clinicaltrials.gov investigating CBD alone (either not yet recruiting, recruiting or active) and there have been at least a further 100 clinical trials previously registered containing CBD, indicating a significant clinical interest with an ongoing need to ensure that human volunteers engaged in these trials are given doses that are optimised for efficacy and safety. Surprisingly, none of the 49 currently registered trials have explicitly included a study design to investigate the dose‐ranging efficacy of CBD.
2.3. Data acquisition and analysis
CBD did not change therapeutic outcome variables in a double‐blind RCT in Huntington disease patients compared to placebo (n = 15; 10 mg/kg/d for 6 weeks),23 but improved dystonia disability in an open pilot study (n = 5; 10 mg/kg/d for 6 weeks),32 and improved spasm frequency and severity in a case report in 1 patient with Meige syndrome (7 mg/kg/d).43