CBD has proven neuroprotective effects and its anti-cancer properties are being investigated at several academic research centers in the United States and elsewhere. A 2010 brain cancer study by California scientists found that CBD “enhances the inhibitory effects of THC on human glioblastoma cell proliferation and survival.” This means that CBD makes THC even more potent as an anticancer substance. Also in 2010, German researchers reported that CBD stimulates neurogenesis, the growth of new brain cells, in adult mammals.

People taking other medications: When side effects are reported, it’s often by this group. CBD appears to have a similar effect to grapefruit on the liver’s ability to metabolize certain drugs, which can lead to adverse side effects. Generally, if a medication has a grapefruit warning, you should avoid taking CBD. Although, if you are on any medication you should talk to your doctor before starting CBD, to ensure you won’t expect any negative interactions. 

According to the 4 Corners Cannabis website, co-owners Justin and Brian Jasiewicz have 30 years of cannabis growing experience between them. That expertise gives them the know-how, the company claims, to make sure that the entire production process of 4 Corners’ CBD oil is run correctly – all the way from field to store. And while that may result in products that are a little more expensive than equivalents on the market, there could be room for that to change if enough people lobby for lower prices; 4 Corners, for one, emphasizes that it “[listens] to the demands from [their] customers to better serve them in the future.” Meanwhile, the company makes picking the right product that little bit easier through its innovative labeling. This makes it plain at a glance for potential purchasers to see which of the 4 Corners range are designed to improve mental well-being and which, by contrast, are targeted at those with active lifestyles.
Transparency: Receptra Naturals’ website has a database where you can look up lab reports for their products. The first time we checked, we got some 404 errors for a couple of the lab reports, but these glitches seem to have been fixed since then. We were able to see third-party lab reports for all their tinctures (though, apparently not for their topicals). 

Nearly every expert Health spoke to agreed that your CBD products should be tested by a third party to confirm the label's accuracy. This is a real concern in the industry—take the 2017 Journal of the American Medical Association study, for example, which tested 84 CBD products and found that 26% contained lower doses than stated on the bottle. Look for a quality assurance stamp or certificate of analysis from a third party (aka not the actual brand) or check the retailer's website if you don't see it on the product's label.
Cost is another consideration. Most CBD oils are sold in concentrations of 300 to 750 mg, although this may range from less than 100 mg to more than 2,000. A good indicator of price-point is the cost per milligram. Low-cost CBD oils usually fall between five and 10 cents per mg; mid-range prices are 11 to 15 cents per mg; and higher-end oils cost 16 cents per mg or higher. Given these varying per-milligram costs, a bottle of CBD oil may be priced anywhere from $10 or less to $150 or more.
Lisa Hamilton, a jeweler and doula in Brooklyn, NY, knows about the side effects. She recently tried CBD for the shoulder pain that plagued her five years after an accident. Her doctor certified that she was in chronic pain, which under New York State law allowed her to buy from a state dispensary. One Friday, she swallowed two 10-mg capsules, the amount recommended at the dispensary, then took another two on Saturday. “By Sunday, it felt like I’d gotten hit by a truck. Every muscle and joint ached,” Hamilton says. She cut back to one pill a day the following week, but still felt hungover. She stopped after that.

To make matters more confusing, nine states (including California, Washington, and Colorado) let residents buy cannabis-based products with or without THC. Nearly two dozen other “medical marijuana states” allow the sale of cannabis, including capsules, tinctures, and other items containing CBD or THC, at licensed dispensaries to people whose doctors have certified that they have an approved condition (the list varies by state but includes chronic pain, PTSD, cancer, autism, Crohn’s disease, and multiple sclerosis). Sixteen more states legalized CBD for certain diseases.
Additionally, PlusCBD oil is incredibly rigorous and transparent when it comes to testing their products and sharing the results. They perform thorough in-house testing to verify potency and screen for contaminants. PlusCBD Oil also validates its own in-house testing with independent third-party testing via DB Labs to ensure all products are free of pesticides, fungicides, residual solvents, heavy metals, and microbiological contamination.

Is CBD Legal? Hemp-derived CBD products (with less than 0.3 percent THC) are legal on the federal level, but are still illegal under some state laws. Marijuana-derived CBD products are illegal on the federal level, but are legal under some state laws. Check your state’s laws and those of anywhere you travel. Keep in mind that nonprescription CBD products are not FDA-approved, and may be inaccurately labeled.

You’ve probably seen PureKana listed on several other “best CBD oils” lists, and it’s for good reason; in our experience (along with maybe a couple of other close competitors), they offer the best overall value in terms of potency, price, customer service, and most importantly, effectiveness. In fact, if I wasn’t continuously trying out new stuff and dedicated to reviewing every single hemp product on the market in an effort to reveal the absolute best CBD oil, I would probably use them exclusively for my lower back pain. Likewise, my partner has said several times that the 600 mg Vanilla tincture is one of his favorites for helping him sleep through the night.
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