If you’re a first time user of cannabidiol (CBD) — a cannabinoid found within the hemp plant that has been scientifically proven to provide health benefits for a number of different medical conditions — you may be wondering how long it will take before you’re able to realize its full effects.
The answer to this question depends on quite a few factors. This is mainly because each factor has the ability to impact CBD’s bioavailability, which is the human body’s ability to actually absorb and use this active ingredient.
With this thought in mind, and with regard to CBD specifically, bioavailability changes based on factors such as your diet, the condition or conditions you’re taking the CBD oil to treat, method of consumption, type of CBD oil, and the CBD oil dosage.
Some pieces of research have connected diet with how efficiently the body is able to use CBD oils and other products.
For instance, one animal study published in the American Journal of Translational Research found that consuming fat along with CBD can help enhance the effects of both CBD and tetrahydrocannabinol (THC)—the two main cannabinoids in the cannabis plant—by as much as 2.5 and 3 times, respectively.
Thus, researchers concluded that “co-administration of dietary lipids or pharmaceutical lipid excipients has the potential to substantially increase the exposure to orally administered cannabis and cannabis-based medicines.”  In simple terms, this means that taking CBD along with fatty acids can increase its effectiveness.
That’s why many CBD experts recommend that, if you take CBD oil orally, it is better to take it with food instead of consuming it on an empty stomach. Foods that seem to offer the best effects include oils (namely coconut, olive, soybean, and sesame), as well as other foods high in long-chain fatty acids, such as fish, nuts, avocado, meat, and eggs. 
Another factor to consider is the reason you’re taking the CBD oil as research has found that certain conditions tend to respond more quickly to CBD products than others.
As an example, one study of individuals with seasonal affective disorder found that participants receiving a single dose of CBD noticed positive anti-anxiety effects within just 80 minutes. 
Conversely, if you’re using it for pain relief or pain management, studies show that it may take a week or more (and multiple doses) before you notice the positive effects of CBD.  In this latter example, the CBD must build up in your system over a period of time before providing beneficial effects.
When considering how long it will take the CBD oil to work, your method of consumption matters too. Some of the most common ways people get CBD into their systems include:
When it comes to bioavailability, CBD tinctures typically work the quickest, which is likely why this is the method of consumption most people choose to use.  This is because tinctures involve placing the hemp oil under the tongue, where it is able to enter the bloodstream faster and more easily.
Plus, by not letting the CBD enter your digestive system, you avoid decreasing bioavailability due to first-pass metabolism. First pass metabolism is when either your gut or liver destroy some of the CBD taken orally before it is able to be absorbed and used. 
Certain types of CBD oil products are also more effective than others. Specifically, full-spectrum CBD is better than CBD isolates. What’s the difference?
If your product is a CBD isolate, that means that it only has one hemp extract beneficial to your health: cannabidiol. Yet, if it is full-spectrum hemp oil, the CBD product contains multiple ingredients from within the cannabis plant that are known to positively interact with your endocannabinoid system.
In addition to CBD, other healthy extracts found in full-spectrum CBD oils include a variety of other cannabinoids (such as CBG and CBN), terpenes, and flavonoids, each one offering its own medical benefits. Together, these work synergistically to provide more noticeable effects.
For this reason, you may feel the effects of CBD quicker when taking a full-spectrum CBD oil than if you take a CBD isolate.
The length of time before realizing the benefits of CBD may also be impacted based on your CBD oil dosage. In other words, if you’re not taking an amount of CBD that is large enough based on factors such as body weight and your individual level of sensitivity to this hemp plant extract, you may not notice this cannabinoid’s effects as quickly, if you notice them at all.
How much CBD oil should you take? Ultimately, taking an effective dosage of CBD depends on factors such as how much you weigh (the higher your body weight, the more you’ll likely need), whether you’ve used CBD before (new users may notice benefits from smaller dosages), and the quality of the industrial hemp the CBD is sourced from.
Therefore, the first step is to select a high-quality CBD product, which is one that uses lab-grade CBD extracted from cannabis plants grown within the U.S. and a manufacturer which engages in third-party testing. All of these ensure that the CBD in your product is high in quality and better for you.
Next, if you’re new to using CBD oil, start with a small dose that is roughly 1-6 mg for every 10 pounds you weigh. Give it a couple of days to see whether you notice any side effects. If it doesn’t seem to be working, increase your dosage and give it more time.
Follow this pattern until you reach a dosage amount that provides the desired effects. And if you max out on the CBD product’s suggested dosage amount, you may want to choose a higher potency CBD, again starting with a small dosage and working your way up if need be.
 Zgair, A, et al. “Dietary Fats and Pharmaceutical Lipid Excipients Increase Systemic Exposure to Orally Administered Cannabis and Cannabis-Based Medicines.” American Journal of Translational Research. 2016; 8(8): 3448-3459. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5009397/
 “Should I Take CBD Oil With Food?” Medical Marijuana, Inc. Apr 12, 2018. https://www.medicalmarijuanainc.com/take-cbd-oil-food/
 Bergamaschi, M, et al. “Cannabidiol Reduces the Anxiety Induced by Simulated Public Speaking in Treatment-Naïve Social Phobia Patients.” Neuropsychopharmacology. May 2011; 36(6): 1219-1226. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3079847/
 De Gregorio, D, et al. “Cannabidiol modulates serotonergic transmission and reverses both allodynia and anxiety-like behavior in a model of neuropathic pain.” PAIN. Jan 2019; 160(1): 136-150. https://journals.lww.com/pain/Fulltext/2019/01000/Cannabidiol_modulates_serotonergic_transmission.16.aspx
 Corroon, J, & Phillips, J. “A Cross-Sectional Study of Cannabidiol Users.” Cannabis and Cannabinoid Research. 2018; 3(1): 152-161. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6043845/
 Robertson, D. “First Pass Metabolism.” Nurse Prescribing. Jun 8, 2017; 15(6). https://www.magonlinelibrary.com/doi/abs/10.12968/npre.2017.15.6.303