CBD Guides

CBD carrier oils explained: what the 4.5x absorption figure really shows

By the Honest CBD Co team · 24th September 2026 · Updated 1st October 2026

MCT and hemp seed oil are the two carrier oils you will meet most often in UK CBD products, and the honest answer is that both do the job well. MCT is thin and flavourless; hemp seed oil brings a nutty, whole-food profile from the same plant the extract comes from. We use both across our own range, matched to what each product is for. You may also have seen a headline claiming formulation can raise CBD absorption by 455%. There is a real study behind that number, but it is a rat study of one emulsified formulation, the figure describes peak levels relative to a plain oil control (about 4.5 times), and it says almost nothing about which carrier oil you should pick. The rest of this guide explains what a carrier oil actually does, what the research really shows, and how to choose for your own priorities.

TL;DR:

MCT oil is virtually flavourless, sits easily under the tongue, and holds onto a full spectrum product’s terpenes better in storage than olive oil does.

Hemp seed oil offers a natural, whole-food profile with balanced omega fatty acids, and pairs naturally with hemp-derived CBD extract. It is what we use in our Full Spectrum CBD Oil.

Formulation, especially droplet size, has a far bigger effect on absorption than which carrier oil is used. The much-quoted 4.5x figure came from an emulsion study in rats, not from swapping one oil for another.

Anyone with a coconut allergy should avoid MCT (it is usually coconut-derived) and choose a hemp seed oil product instead. Anyone on prescription medication should speak to a GP or pharmacist before starting CBD.

Choose a product with a clear ingredient list from a brand with a track record you can check.

Honestcbdco

Honestly Made CBD, Matched to the Job

Small-batch full spectrum CBD from a husband-and-wife business in Bolton, trading since 2018. Honest prices and free UK delivery.

Visit Honest CBD Co

What is a carrier oil in CBD products?
How do carrier oils affect CBD absorption?
MCT, hemp seed, olive and other carrier oils compared
How to choose the right carrier oil for your CBD
Allergies, drug interactions and how to store CBD oil safely
How Honest CBD Co chooses carrier oils for its products
What nutritional benefits do carrier oils add beyond dilution?
Why formulation matters more than the oil itself
Honest CBD Co’s carrier oil range and where to find it
Sources
FAQ

What is a carrier oil in CBD products?

A carrier oil is simply the base liquid that CBD extract gets mixed into before it reaches a bottle or capsule. CBD itself is a waxy, concentrated substance that is fat soluble, meaning it dissolves into oils rather than water. Diluting it into a carrier turns an unmanageable extract into something you can dose with a dropper, swallow comfortably, and store for months without it degrading on the shelf.

There are three practical jobs a carrier oil does beyond simply holding the CBD:

Dosing control: a measured dropper of oil gives a repeatable dose every time, rather than guessing at a smear of raw extract.
Taste masking: raw hemp extract is bitter and resinous; the right oil softens that considerably.
Stability: oils protect cannabinoids from oxygen and light exposure that would otherwise break them down faster.

Walk down the label of most tinctures on sale in the UK and you will see one of three names repeated: MCT (often listed as fractionated coconut oil), hemp seed oil, or olive oil. Occasionally you will spot palm-derived variants or black cumin oil, which we cover later. Each carries its own trade-offs in flavour, absorption and shelf life, which is where the real decision starts.

How do carrier oils affect CBD absorption?

Absorption starts with how the body handles fat. When you swallow an oil-based CBD product, it travels through the digestive tract and gets packaged with dietary fats into structures called chylomicrons, which the lymphatic system carries directly into the bloodstream, partially bypassing the liver’s first-pass processing. This is why taking CBD with food, particularly fatty food, measurably improves how much reaches circulation, an effect we have written about in more detail in our piece on CBD bioavailability.

Statistic Callout: Formulation matters more than most people realise, and more than the oil itself. In a rat study comparing ten CBD formulations, an emulsion with carefully sized droplets reached peak blood levels around 4.5 times those of plain CBD in oil (455% of the reference), with total absorption nearly three times higher. Tellingly, the same study found next to no difference between the two carrier oils it tested. The gain came from droplet engineering, not oil choice, and rat results do not translate directly to people.

This is not a new idea in pharmaceutical science either. Certain licensed clinical formulations have used sesame oil specifically because it supports lymphatic transport and systemic uptake, long before CBD products existed. The takeaway for anyone comparing bottles on a shelf: look at how the product is actually made, not just which oil is listed first on the ingredients panel.

MCT, hemp seed, olive and other carrier oils compared

Every oil brings something different to the bottle. Here is how the common options actually compare, based on what formulation research consistently shows.

MCT oil (fractionated coconut): virtually flavourless, thin enough to sit comfortably under the tongue, and one of the most common carriers in tinctures precisely because manufacturers want broad consumer acceptance. Research also suggests MCT preserves volatile terpenes better during storage than olive oil, which matters if you value a full spectrum product’s natural aroma compounds staying intact. We use C8 MCT in our own Pure CBD Isolate Oil for exactly these reasons.
Hemp seed oil: a natural pairing with hemp-derived CBD extract, since both come from the same plant. It carries a mild, nutty, slightly grassy flavour and brings its own fatty acid profile, though it is not as neutral as MCT if you dislike the taste of hemp. It is the base we chose for our Full Spectrum CBD Oil, where the whole-plant character is the point.
Olive oil: thicker in texture, with a distinctive savoury flavour that suits people who want something closer to a whole-food product. Its antioxidant content may help protect other compounds in the extract from degrading, even if it is less effective than MCT at holding onto terpenes over time.
Palm-derived and niche carriers: fractionated palm oil behaves similarly to MCT but raises sustainability questions depending on sourcing, so check for certified sourcing if this matters to you. Black cumin oil appears occasionally on UK labels as a niche alternative, chosen more for its own reputed properties than for absorption performance, and sesame oil turns up mainly in pharmaceutical-style formulations rather than consumer tinctures.

Pro Tip: If you are torn between two oils, taste-test the plain oil itself before buying a CBD product with it. A carrier you find unpleasant on its own will not improve once cannabinoids are added.

Quick pick for typical priorities: if you want the most neutral, discreet daily tincture, choose MCT; if you want a whole-plant, “closer to nature” feel, hemp seed or olive oil suit you better. On absorption, the evidence does not crown a clear winner between them, so let taste and dietary fit decide.

How to choose the right carrier oil for your CBD

Picking confidently comes down to matching the oil to your actual priority, then checking the label does what it claims.

Decide your main priority first. If neutral taste tops your list, MCT-based products are the sensible starting point. If you prefer a whole-food ingredient list or enjoy a more savoury flavour, hemp seed or olive oil fit better.
Read the full ingredient list, not just the marketing copy. The label should state the exact carrier oil and the CBD content in milligrams, so you can work out exactly what you are paying per mg.
Buy from a brand with a track record you can check. Years of trading, genuine customer reviews and a registered UK company all tell you more than marketing copy ever will.
Skip vague labels. Unsupported potency claims or woolly sourcing language (“natural oils” with no specifics) are reasons to look elsewhere.

Getting this right takes two minutes at most once you know what to look for, and it saves you from buying a product that does not suit your actual needs.

Allergies, drug interactions and how to store CBD oil safely

Coconut-derived MCT oil is generally well tolerated, but anyone with a genuine coconut allergy should check the label carefully, since MCT is typically sourced from coconut or palm kernel oil. We have covered this in more depth in our guide to coconut allergy and CBD. In our own range, the Full Spectrum CBD Oil (organic hemp seed oil), the capsules, the whole plant paste, the 85% distillate and the isolate crystals are all free of coconut-derived ingredients; the Pure CBD Isolate Oil and 50% Amber Oil use coconut-derived C8 MCT, and the Body Salve contains coconut oil, so those three are the ones to avoid with a coconut allergy.

CBD itself can also interact with several prescription medicines by affecting the liver enzymes that metabolise them. Anyone taking prescribed medication should speak with a GP or pharmacist before starting CBD regularly, a point covered further in our article on CBD and drug interactions.

Storage matters more than most buyers expect:

Keep bottles away from direct heat and sunlight; both accelerate cannabinoid and terpene breakdown.
Store upright with the cap tightly closed to limit oxygen exposure.
MCT-based oils tend to hold onto volatile terpenes for longer in storage than olive oil, so if aroma and flavour intensity matter to you, factor that into how you store and how quickly you use the bottle.

How Honest CBD Co chooses carrier oils for its products

Honest CBD Co is a husband-and-wife business in Bolton making full spectrum CBD in small batches in the UK, registered at Companies House since January 2018. Our CBD is lab tested at source, we are happy to share the certificates of analysis, and we are rated Excellent on Trustpilot across more than 700 reviews.

The oil choice is never an afterthought. We match the carrier to what each product is for:

Full Spectrum CBD Oil: uses organic hemp seed oil, so the whole bottle comes from the hemp plant. The mild nutty base suits the whole-plant character customers buy it for, and a measured dropper keeps dosing precise.
Pure CBD Isolate Oil and 50% Amber Oil: use C8 MCT, the thin, flavourless carrier, because these products are built for people who want cannabinoids with as little taste interference as possible.
Full Spectrum CBD Capsules: carry the extract in hemp oils inside a plant cellulose shell, so there is no taste to mask at all.
Full Spectrum Whole Plant Paste: is the raw extract itself, with no carrier added, for customers who want the extract’s own natural composition rather than a diluted format.

What nutritional benefits do carrier oils add beyond dilution?

Carrier oils are not inert filler. Hemp seed oil carries a naturally balanced ratio of omega-3 and omega-6 fatty acids, a profile nutritionists have long pointed to for supporting general cardiovascular health, independent of anything it is mixed with. That is one reason hemp seed pairs so naturally with CBD extract, and one reason we chose it for our Full Spectrum CBD Oil: the base oil already brings something useful to the bottle.

Olive oil brings a different strength. Its antioxidant compounds, the same ones behind olive oil’s reputation in Mediterranean diets, may help protect other constituents in a CBD extract from oxidative degradation over the product’s shelf life. That is a nutritional and a preservation benefit rolled into one.

MCT oil’s advantage is more metabolic than nutritional in the traditional sense. Medium-chain triglycerides are processed differently to long-chain fats, absorbed quickly and used readily for energy, which is part of why MCT has its own following in sports and ketogenic nutrition circles entirely separate from CBD.

None of this means you should choose a carrier oil purely for its background nutrition profile; the CBD dose and product quality still come first. But it explains why “just a filler” is the wrong way to think about the oil sitting alongside your CBD, and why we are deliberate about which one goes into which product.

Why formulation matters more than the oil itself

The biggest misconception in this space is that picking the “best” oil is mostly about the oil. It is not. The research on emulsions and droplet size makes that clear: the celebrated 4.5x peak came from how one formulation was engineered, in rats, not from which oil went into it, and the same study found the two carrier oils it compared performed almost identically. I would rather see a customer choose a sensibly made oil from a brand with a track record than chase a niche carrier on the promise of marginal absorption gains that formulation, not oil selection, actually drives.

That said, oil choice still matters at the margins, for taste, for allergy avoidance, for how long a product holds its terpene profile in the cupboard. My honest recommendation is to pick by taste and dietary fit: MCT if you want no flavour at all, hemp seed if you like the whole-plant profile, and either way take your CBD with or after a meal that contains some fat. If you take prescribed medication, talk to a GP or pharmacist first. No carrier oil, however well chosen, changes that advice.

Richard

Honest CBD Co’s carrier oil range and where to find it

Honest CBD Co is the straightforward alternative to guesswork shopping: every product page states its carrier plainly.

The Full Spectrum CBD Oil, from £25.99, uses an organic hemp seed oil base for a true whole-plant bottle with accurate dropper dosing, browsable alongside the rest of the range in the CBD oils category. If you prefer the extract completely undiluted, the Full Spectrum Whole Plant Paste, from £17.99, keeps the extract’s own natural composition intact with no carrier at all. For anyone who wants cannabinoids with no taste, the flavourless Pure CBD Isolate Oil, from £14.99, uses a neutral C8 MCT base and is THC-free. Every order comes with free UK delivery from a family business rated Excellent on Trustpilot across 700+ reviews. Browse the full shop to compare strengths and find the format that matches your carrier oil preference.

This article is general information, not a substitute for advice from a qualified doctor. Consult a qualified healthcare professional about your own circumstances before acting on anything here.

Sources

FAQ

Which CBD is best for arthritis pain?

There is no single “best” CBD product for arthritis, but full spectrum oils are a common starting point because a measured dropper gives accurate, repeatable dosing; the carrier oil matters less than getting the dose consistent. Anyone managing arthritis alongside prescribed medication should check for potential drug interactions with a clinician first.

Which CBD oil is best for nerve pain?

Formulation and dose consistency matter more than the specific carrier oil when it comes to nerve pain. A consistent full spectrum oil gives you a reliable, repeatable dose to work from, though individual results vary and evidence in this area remains limited.

Is CBD oil good for panic attacks?

Some people use CBD oil as part of a broader approach to anxiety, though the research specific to panic attacks is still developing and not conclusive. If panic attacks are frequent or severe, speak with a doctor rather than relying on CBD alone.

Which CBD oil is best for back pain?

A full spectrum oil such as Honest CBD Co’s Full Spectrum CBD Oil, made with an organic hemp seed oil base, is a sensible default for back pain because it combines dependable dropper dosing with a mild, nutty flavour. As with any persistent pain, it is worth discussing alongside your existing treatment plan with a clinician.