CBD Oil Explained: What It Is, What the Research Says and How to Choose One

CBD oil is now sold everywhere from pharmacies to health food shops. But what exactly is it, does it work, and how do you tell a good product from a bad one? Here’s a straightforward guide.

What is CBD?

CBD (cannabidiol) is one of more than 100 cannabinoids found in the cannabis and hemp plant. Unlike THC, CBD is not intoxicating – it will not get you high. Most CBD sold legally is extracted from hemp, a variety of cannabis grown to contain only trace amounts of THC.

How is CBD oil made?

CBD is extracted from hemp flowers and leaves, usually with CO₂ or ethanol. The extract is then mixed with a carrier oil such as MCT (coconut) oil or hemp seed oil so it can be dosed with a dropper, typically under the tongue.

Full spectrum vs broad spectrum vs isolate

• Full spectrum: contains CBD plus other cannabinoids, terpenes and trace THC. Some people believe these compounds work together (the so-called “entourage effect”), though evidence is still limited.
• Broad spectrum: like full spectrum but with THC removed.
• Isolate: pure CBD with everything else removed.

In Ireland, products must not contain detectable, controlled levels of THC, so broad spectrum and isolate products are the safer choice legally.

What does the research actually say?

Research on CBD is growing, but it’s important to separate evidence from marketing:

• Epilepsy: the strongest evidence. A prescription CBD medicine (Epidyolex) is approved in Europe for certain rare, severe forms of childhood epilepsy, such as Dravet and Lennox-Gastaut syndromes.
• Anxiety and sleep: some small studies show promise, but results are mixed and doses used in trials are often much higher than those in shop-bought oils.
• Pain and inflammation: animal studies are encouraging; high-quality human evidence is still limited.
• Everything else: be wary of any product claiming to cure or treat disease. Those claims aren’t backed by solid evidence and aren’t permitted on food supplements in the EU.

Side effects and interactions

CBD is generally well tolerated, but it isn’t risk-free. Reported side effects include tiredness, diarrhoea, changes in appetite and, at high doses, changes in liver enzymes. Importantly, CBD can interact with other medicines – including blood thinners, some anti-epileptics and antidepressants – because it affects the liver enzymes (CYP450) that break many drugs down. Always check with your GP or pharmacist first.

How to choose a quality CBD oil

• Ask for a Certificate of Analysis (COA) from an independent lab. It should confirm the CBD content matches the label and that THC is not present at controlled levels.
• Check for contaminants: a good COA also tests for pesticides, heavy metals and residual solvents.
• Clear labelling: total CBD per bottle and per drop, batch number, ingredients and a best-before date.
• No medical claims: reputable sellers don’t promise to cure conditions.
• Avoid unusually cheap products – independent testing has repeatedly found that many CBD products contain far less CBD than advertised.

Is CBD oil legal in Ireland?

CBD itself is not a controlled drug in Ireland, but THC is. That means CBD products must be free of controlled levels of THC. In addition, CBD sold as a food or supplement is classed as a “novel food” under EU rules, and the Food Safety Authority of Ireland (FSAI) has flagged that many products on the market have not completed that authorisation process. Buy from established retailers who can show lab testing.

Key takeaways

• CBD is non-intoxicating and derived mostly from hemp.
• The strongest evidence is for specific forms of epilepsy; other uses are still being studied.
• It can interact with prescription medicines – speak to a professional first.
• Always look for independent lab results before buying.

This article is for general information only and is not medical or legal advice. Talk to your GP or pharmacist before using any cannabis or CBD product, especially if you take other medication, are pregnant or breastfeeding. Cannabis products are for adults 18+ only.