Topicals and the Systemic Question: What a CBD Balm Can and Cannot Claim

Walk along any UK high street and the shelf arranges itself into a silent argument. On one side, a jar of CBD balm declaring 500mg. On the other, a dropper bottle declaring 500mg. The numbers match; the products do not. One is designed to sit on the skin, the other to be swallowed. Treating the figures as interchangeable is the most common mistake in the category, and it is a mistake the packaging rarely corrects.

Two products, two regulatory lanes

In the UK, a leave-on skin product is regulated as a cosmetic. Cosmetic claims are about the surface and the appearance: moisturising, conditioning, softening, improving the look of the skin. A claim to treat a condition — to relieve pain, reduce inflammation, manage a skin disease — moves a product into the medicinal category, which requires a marketing authorisation from the MHRA. Very few CBD products hold one. The only licensed cannabidiol medicine available in the UK is a prescription-only product for specific forms of epilepsy, which is a world away from a balm on a pharmacy shelf.

Oral CBD oils usually sit in a different lane again, sold as food supplements, subject to the novel food framework and the FSA's public list. That route also restricts medicinal claims. The point is not that one category is more honest than another. It is that the category determines what a brand is allowed to say, and readers are entitled to know which rulebook is in play.

Why 500mg in a balm is not 500mg in a dropper

Three different quantities get collapsed into one number.

Total content is the milligrams in the whole container. Concentration is that amount expressed against the volume or weight — a percentage, or milligrams per millilitre. Delivered dose is what actually crosses a biological barrier per application.

The first two are arithmetic. The third is pharmacology, and it depends on the formulation, the vehicle, whether the product is occluded under clothing, the area of skin, the condition of that skin, and how long it stays there. A balm is largely a stay-put product: much of what you apply remains on the surface, is transferred to clothing, or is washed away. An ingested oil is swallowed and processed systemically. The same headline milligram figure therefore describes two very different exposures.

Consider the arithmetic that rarely appears on pack. Five hundred milligrams in a 100ml balm is a 0.5% product. Five hundred milligrams in a 10ml oil is 5%. Same number, tenfold difference in concentration. Even within balms, a 50ml jar and a 15ml jar at the same milligram content are not the same strength.

The word 'transdermal' deserves scrutiny

A genuine transdermal delivery system — designed and licensed to move a drug into the bloodstream at a controlled rate — is a medicine. Balms described as transdermal are usually making a marketing point about penetration rather than a pharmaceutical claim. Some formulations do include penetration enhancers, and some evidence exists that certain vehicles improve skin permeation. That is not the same as demonstrating a meaningful systemic effect, and the published literature on topical CBD in humans remains small, heterogeneous and frequently industry-linked.

Reading the label the way a pharmacist would

Find the CBD. UK cosmetic labelling lists ingredients present above 1% in descending order, with anything below that permitted in any order. Where cannabidiol appears tells you roughly how much of the formulation it represents. Watch for hemp seed oil or Cannabis sativa seed oil near the top — these are carrier oils and contain effectively no cannabinoids.

Distinguish milligrams from percentage. A product quoting only one of the two is telling you half a story. Multiply out to work out what a typical application contains, not what the tub contains.

Identify the other actives. Menthol, camphor, capsaicin and essential oils produce cooling, warming or tingling sensations that many users attribute to CBD. In some products they are doing most of the perceptible work.

Check the batch and the certificate. A certificate of analysis should match the batch on the pack, state the cannabinoid profile and the testing laboratory, and be dated. A cosmetic product does not legally require this, but a brand serious about quality will provide it.

Note the expiry and the period-after-opening symbol. Cannabinoids degrade, and an old jar is not a reliable jar.

A patch test, realistically understood

A patch test is a check for irritation and contact allergy. It is not a test of efficacy, and a negative result does not mean the product will work.

Apply a small amount to the inner forearm, leave it uncovered and unwashed for 24 to 48 hours, and check for redness, itching, swelling or discomfort. Repeat if you switch formulation or buy a new batch with a changed ingredient list. Avoid broken, cracked or inflamed skin, and keep products away from the eyes and mucous membranes. If you are using prescription creams or are taking anticoagulant medication, it is worth a conversation with a pharmacist before layering anything new onto the same area.

Claims that quietly blur the line

A cosmetic balm cannot lawfully claim to treat arthritis, soothe a medical condition or reduce inflammation in a clinical sense. Phrases such as 'clinically proven', 'pharmaceutical-grade' and 'doctor-formulated' are often unverifiable, and 'FDA approved' is simply a category error in a UK context. Before-and-after photography implies a medicinal benefit that a cosmetic has not established.

The honest position is narrower and less exciting: a well-made balm can be a pleasant emollient with a declared cannabinoid content, and some users report subjective comfort. That is a reasonable thing to buy. It is not the same thing as a systemic treatment.

Questions to ask before you buy

Is this a cosmetic, a food supplement or a medicine, and what is it permitted to claim? What does one application contain, rather than the whole tub? Is the CBD an isolate or part of an extract, and is the profile declared? Does the certificate match the batch? What else in the formula is producing the sensation you notice? And is there any evidence for this specific formulation, or only for cannabidiol in general?

A balm is a local product. An oil is a systemic one. Keeping those two ideas separate is most of the battle.