CBD oil strengths explained | Percentage, amount in mg, volume, pure v full-spectrum | Jersey Hemp

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Understanding CBD oil strengths

Close up of the label of a bottle of CBD oilHow should you judge the strength of a CBD oil? Is it down to the total amount of CBD a product contains? The percentage of CBD in relation to the volume of oil? Whether it uses ‘pure’ CBD or full-spectrum?

With so many CBD oil brands on the market, and so many different factors highlighted on packaging and in marketing material, you’d be forgiven for feeling confused. Yet if you take CBD oil, you need to know what makes one product more potent than another.

Below we’ll look at what the different numbers and terms mean and what’s most important when it comes to understanding the strength of a CBD oil.

What is CBD oil?

CBD, aka cannabidiol, is one of a number of chemical compounds known as cannabinoids found in the cannabis sativa plant. CBD is generally obtained from cannabis strains known as hemp, which contain very low levels of the psychoactive cannabinoid THC, so it won’t get you high.

CBD is marketed as a food supplement in the UK and individual products cannot legally make medical claims. However, many users believe that it improves their sense of wellbeing and helps with certain ailments, while research has suggested that CBD has therapeutic potential in some areas.

CBD oil itself is a bottled solution of CBD extract in a carrier oil such as hemp seed, olive or coconut. CBD oils usually come with built-in droppers, allowing measured doses to be added to food and drink or administered orally or sublingually. Sublingual application means holding droplets of oil under the tongue for a minute or two before swallowing. It allows for more rapid and efficient absorption via the capillary-rich mucous membrane.

Understanding CBD oil labelling

To determine the strength of a CBD oil, you’ll need to understand the different numbers commonly found on product labels and packaging, how they relate to one another and which is the most important when it comes to potency. Let’s look at each of them in turn.

CBD volume in millilitres

No major surprises here – the volume in millilitres (ml) (or, in the US, in fluid ounces) tells you the total amount of liquid in the product. That means the carrier oil, which makes up the vast majority of the volume, as well as the CBD that’s dissolved in it. Of course, volume of oil on its own doesn’t tell you anything about strength. For that you’ll also need to know how much CBD is in your oil.

CBD content in milligrams

A number you’ll often see displayed on the front of a bottle of CBD oil is the total amount of CBD it contains in milligrams (mg). The higher the number, the stronger the oil, right? Well, not necessarily. You can’t tell the strength, or potency, of the oil without looking at the amount of CBD in relation to the overall volume of oil.

Compare, for instance, a 30ml bottle of CBD oil containing 2,000mg of CBD with a 10ml bottle also containing 2,000mg of CBD. The 10ml bottle is smaller but it has the same amount of CBD in only one third of the oil, making it three times more concentrated than the 30ml oil.

So what you really need to know to understand the strength of an oil is the proportion of CBD to oil – that is, the percentage of CBD in the solution.

CBD oil percentage

A greater volume of CBD oil may last you longer (depending on the dose you choose), more milligrams of CBD in a bottle may be better value for money – but when you want to know the strength of your oil the number you really need is the percentage of CBD.

The percentage is often less prominent on the labelling than the amount of CBD and doesn’t appear at all on some products. However, you can calculate it by multiplying the volume of oil in ml by 10, then dividing the amount of CBD in mg by that number. So, using the same examples as above:

30ml bottle containing 2,000mg

  • 30ml x 10 = 300
  • 2,000mg / 300 = 6.66%

10ml bottle containing 2,000mg

  • 10ml x 10 = 100
  • 2,000mg / 100 = 20%

The smaller bottle is much stronger than the larger one because it contains the same amount of CBD but in less oil – and that in turn means that each droplet of the 10ml oil contains more CBD (in this case, three times as much).

How much CBD is in a droplet of oil?

A single droplet of oil from any dropper is always the same size – approximately 0.05ml. But, as we’ve seen, the concentration of CBD in different oils – and therefore the amount of CBD in a droplet – can vary hugely. If you don’t know the percentage of your oil, you can work out the approximate amount of CBD per droplet in any given bottle using the following formula:

  • Volume of bottle in ml / 0.05ml = number of droplets in bottle
  • Total amount of CBD in mg / number of droplets = amount of CBD in mg in each droplet

If you already know the percentage of your CBD oil, it’s much simpler. All you need to remember is that every 1% percent of the strength of your oil is equal to roughly 0.5mg CBD per drop. So you just half the percentage to get the amount of CBD per drop. In the examples we’ve used above, that means that the 10ml bottle at 20% would contain a very potent 10mg per drop, while the 6.66% would contain around 3.3mg per drop. Here are some other examples:

  • 3% - 1.5mg per droplet
  • 5% - 2.5mg per droplet
  • 10% - 5mg per droplet
  • 15% – 7.5mg per droplet

CBD oil dosage

Since the amount of CBD in a single drop of oil can vary greatly depending on the strength of the oil, you can't simply decide that your dosage will be, say, 5 droplets and leave it at that. The number of droplets you require will depend on the percentage of CBD in the oil. For example, if the dose you’ve chosen is 30mg, that means 12 drops of a 5% oil but only 3 drops of a 20% oil. Always bear this in mind when switching to a different strength of CBD oil.

When it comes to deciding on the right milligram dosage for you, it’s best to start small and work your way up. That’s because everyone is different and factors including weight, personal body chemistry and any side-effects you might experience can all have an impact.

Begin with perhaps 10mg per day, recording how you feel each day. Increase the amount in similar increments every few days until you find the optimum dosage.

The Jersey Hemp CBD oil calculator can give you an idea of the amount of CBD you may want to work towards. It calculates low, medium and high dosages based on a range of 1-6mg of CBD for every 10 pounds of body weight and for 5% and 10% oils. But bear in mind that the UK’s Food Standards Agency recommends as a precaution that healthy adults do not take more than 70mg of CBD a day.

CBD Calculator

Pure CBD oil v full-spectrum

For some CBD users, the concentration of CBD in an oil is not the only measure of its potency – it also depends on the type of CBD the oil is made with.

CBD isolate is the crystalline powdered form of CBD. It contains only trace amounts of other substances, usually totalling only a fraction of a percent, so if you’re looking for a ‘pure’ form of CBD, this is it.

Full-spectrum and broad-spectrum CBD, meanwhile, are made from the whole hemp plant and contain numerous naturally occurring compounds including other cannabinoids and substances known as flavonoids and terpenes, which have been shown to have their own health benefits.

The only difference between full- and broad-spectrum CBD is that full-spectrum contains non-intoxicating levels of THC – up to 0.2% in many European countries and 0.3% in the United States – while broad-spectrum does not. However, because of the stricter laws around THC levels in the UK, even oils labelled full-spectrum here often contain only trace amounts of THC, so the two terms are sometimes conflated.

When it comes to these ‘whole-plant’ forms of CBD, some people subscribe to a theory known as the entourage effect. This says that the different cannabis compounds work together to produce actions that are greater than the sum of their parts, giving a boost to any benefits of the CBD itself.

Although the entourage effect is still only a theory, there is some evidence to support it, with one wide-ranging review of studies concluding that the complementary activities of cannabinoids and terpenes in cannabis may increase their therapeutic effectiveness.

So when deciding which strength of CBD oil is right for you, you may also want to consider testing out full-spectrum oils against those made with CBD isolate.

What is the strongest CBD oil and which strength is right for you?

CBD oils can range from 250mg per bottle to a huge 7,000mg or more. Of course, as we’ve seen, the highest total CBD content doesn’t necessarily mean the greatest potency. When it comes to percentages of CBD in oils – which is what really tells you how strong they are – they rarely go above the 25% mark, delivering around 12.5mg of CBD per droplet.

There are pros and cons of choosing a high-strength oil. If you’ve already decided on a dosage, a higher concentration could mean you’ll need fewer droplets, which may be slightly easier to administer, especially if you are taking them sublingually. However, if you’re still working out what is the right dose for you – or sometimes want to take a smaller amount – you’ll want the flexibility of a less concentrated oil. Remember, you can never take less CBD than the amount contained in a single droplet of your chosen oil.

There are financial considerations around which strength of oil you choose, too. On one hand, you may not want to commit to the initial expense of a very high-percentage or high-mg oil; on the other, if you’re taking CBD longer term, there may be a saving in buying a higher strength oil that works out cheaper per mg of CBD.

Other things to consider when choosing CBD oil

In the UK and, more slowly, in Europe, the CBD industry is undergoing a process of improved regulation. This means that, eventually, only CBD products of a certain standard will be allowed on the market. At the moment, however, quality can vary hugely between brands and the strength that a CBD oil claims on its label may not always be the strength you get.

A report by the Centre for Medical Cannabis showed that while the best products available were “very high quality and… good options for today’s consumers”, more than a third of those tested had less than 50% of the advertised CBD content, and one contained no CBD at all. Meanwhile, almost half of the products had detectable levels of THC.

It’s therefore important to choose a trustworthy brand of CBD oil. Here are some things to look out for in order to ensure you’re getting a quality, reliable product:

Good provenance

It’s important that a CBD oil brand can demonstrate where its raw ingredients come from and how they are produced. In the United Kingdom, CBD should be made from strains of hemp containing no more than 2% THC. The best extraction and processing methods ensure no contamination with unwanted substances and reduce the level of THC even further.

Organic farming methods

If you’re looking for a high-quality wellness product, it makes sense that you’d want it grown without the use of chemical pesticides or fertilisers. Green practices like this also help take care of the environment and the long-term health of the soil.

Independent laboratory tests

Always check that a CBD oil brand shares third-party laboratory tests on its website. These give a full rundown of the levels of each substance in the product, including THC and CBD itself. In full-spectrum oils, they’ll show the extra plant substances, which have their own health benefits.

Jersey Hemp was the first company in the British Isles to be granted a licence to harvest hemp for CBD production. The hemp seed oil and much of the CBD used in its products comes from its own fields and every batch undergoes third-party lab tests, with results available to view on the website.

The Centre for Medical Cannabis called Jersey Hemp “one of the most compliant, high quality and accurately labelled products that we tested.”

What are the benefits of CBD oil?

People take CBD hoping to treat a wide range of ailments, as well as to improve their general sense of well-being, and often judge it to produce positive results. Scientific research suggests there is a basis for some of this anecdotal evidence, with studies involving human subjects having demonstrated beneficial effects on conditions including anxiety, sleeping disorders and pain. Initial laboratory tests also suggest there is value in further studying CBD’s effects on a number of other illnesses.

CBD is an active ingredient in two medications available by special prescription on the NHS. Epidyolex, which contains pure CBD, is used to treat rare forms of epilepsy, while Nabiximols, brand name Sativex, combines CBD with THC to help combat muscle stiffening in multiple sclerosis patients.

CBD safety and side-effects

Both the World Health Organization and the European Union have said that CBD is safe, while scientists conducting research into its potential benefits generally consider it ‘well tolerated’ by patients, meaning it is rare for subjects to drop out of trials due to adverse effects.

However, a minority of CBD users do experience side-effects – most commonly dry mouth and tiredness / fatigue, as well as appetite changes, diarrhoea, nausea and irritability.

The UK’s Food Standards Agency also recommends that pregnant or breastfeeding women do not take CBD.

CBD drug interactions

Perhaps the biggest safety issue regarding CBD is its interactions with medication. CBD can inhibit enzymes that metabolise certain drugs, potentially leading to unsafe levels in the body.

Drugs affected include those that carry a grapefruit warning, such as some statins and blood pressure medications. However, CBD also interacts with drugs that do not come with a warning. If you are on any medication, you should therefore not use CBD without first consulting your doctor.


The author of this article is not a medical expert and nothing in this article constitutes medical advice or gives rise to a medical practitioner/patient relationship. You should seek specialist medical advice where required. Never disregard professional medical advice or refrain from seeking it because of something you have read here.

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