Reading a semaglutide units chart: what the dose markings really tell you

The decision you're actually making: licensed pen or unlicensed vial?

The reason people search for a semaglutide units chart almost always comes down to one fork in the road. Licensed Wegovy, supplied through a GPhC-registered pharmacy in the UK, arrives as a pre-filled, pre-dosed injection pen. There is nothing to measure. The prescriber decides your dose; the pen delivers it. No chart required.

The units chart question arises when someone is drawing from a vial using a syringe, or when they have been given a compounded preparation. In those cases, concentration matters enormously. A vial labelled at 5 mg/ml gives you a different number of units per milligram than one formulated at 2 mg/ml. Applying a chart written for one concentration to a vial of another is a genuine safety risk, an overdose is not a theoretical concern.

Compounded semaglutide is not a licensed medicine in the UK for weight management. The NHS patient information page for semaglutide covers the licensed forms: Wegovy for weight management and Ozempic for type 2 diabetes. Compounded preparations sit outside that framework, without the manufacturing controls, stability testing or pharmacovigilance that licensed products carry. That is the core safety context behind every units chart you might find online.

If your treatment is licensed Wegovy, the dose-in-units breakdown for licensed pens explains the specific markings on the authorised pen.

How licensed Wegovy doses work, and why there is no chart to read

Wegovy's titration schedule runs from a 0.25 mg starting dose through 0.5 mg, 1.0 mg and 1.7 mg, arriving at a 2.4 mg maintenance dose. More recently, a 7.2 mg maintenance dose has been approved by the MHRA. Each step is decided by your prescriber, and each pen is manufactured to deliver precisely that amount. The pen mechanism locks after use and dispenses automatically, you press the button, the dose goes in.

There is no dial, no graduation to read, no syringe to fill. The practical implication is that a semaglutide units chart has no role in a correctly supervised licensed-pen regimen. If someone has handed you a chart and told you to measure your Wegovy dose, something has gone wrong in the supply chain or in the advice you have received.

A quick check worth doing before any injection: confirm the pen name, strength and expiry date on the label match what your prescriber discussed with you. That takes under a minute and catches labelling errors before they matter. If anything does not match, contact your pharmacy before injecting.

For a broader overview of how semaglutide works and the current licensed options in the UK, our semaglutide guide covers the treatment landscape, including the difference between Wegovy and Ozempic.

Why unlicensed compounded preparations carry extra risk

The MHRA has issued public warnings about fake and unlicensed weight-loss injectables sold online, noting that counterfeit pens have in some cases contained insulin rather than the labelled medicine. The risk with any unlicensed compounded preparation is related but distinct: it may be produced without pharmaceutical-grade manufacturing controls, meaning concentration, sterility and stability are not independently verified.

If you are relying on a units chart to determine your dose because you purchased a vial rather than a licensed pen, you are simultaneously navigating an unverified concentration and an unlicensed supply. The margin for error is narrow. A ten-unit miscalculation at one concentration can translate to a meaningful milligram discrepancy at another, which is why our semaglutide chart page sets out exactly how dose, concentration and volume relate across different preparations.

The MHRA's Yellow Card scheme allows anyone to report suspected side effects or to flag a suspect product, including unlicensed sellers. If you have concerns about a product you have been supplied, that is the right place to start alongside speaking to a pharmacist or GP.

Pricing questions sometimes lead people toward non-licensed sources. A realistic look at Wegovy costs in the UK sets out what legitimate private treatment actually involves and why the cheapest option is rarely the safest one for a prescription medicine.

What a prescriber-led route actually looks like

Getting semaglutide through a regulated UK pharmacy means a named clinician reviews your health history, confirms eligibility, and decides the appropriate starting dose. Titration (moving from one dose to the next) happens on a schedule they set, based on how you are tolerating treatment, not on a chart you found online.

At nume, every consultation is reviewed by a GPhC-registered Independent Prescriber. A real clinician reads your answers. If your dose needs adjusting, that happens through a clinical review, not a self-calculated conversion.

If you are weighing up how Wegovy fits into your options, our Wegovy treatment page explains eligibility, how the pen works and what to expect from a private prescription route, including guidance on whether you can take Wegovy abroad if you are planning to travel during treatment. The broader weight-loss treatments overview compares the licensed options currently available.

If you have questions that go beyond what a page can answer, our clinical team is available seven days a week. When you are ready to take the next step, you can start a free consultation with no commitment required.