Wegovy tablets or injections: differences in efficacy, side effects, how they're taken and price

In Spain, Wegovy comes in two forms containing the same active substance, semaglutide: a daily tablet that goes up to 25 mg, and a weekly pen with a 2.4 mg maintenance dose plus a further step up to 7.2 mg. No trial has compared them directly, but in their own separate trials average weight fell by 13.6% with the tablet and by 14.9% with the pen. What really sets them apart is day-to-day life: fasting and consistency with the tablet, a needle and a fridge with the pen. Both require a prescription and neither is funded by the Spanish National Health System.

Do you lose more weight with Wegovy tablets or injections?

The honest answer is that we can't know from a head-to-head trial, because there isn't one. What we have are two separate trials, each against placebo. In OASIS 4, a phase 3b trial, 307 adults with obesity, or with overweight and a related health condition, and without diabetes, took oral semaglutide 25 mg (205) or placebo (102): at 64 weeks, mean weight had fallen by 13.6% versus 2.2%. In STEP 1, 1,961 adults with a similar profile, also without diabetes, used the 2.4 mg pen or placebo: at 68 weeks, weight fell by 14.9% versus 2.4%.

The populations are similar, but not identical. Both trials excluded diabetes and started from a similar mean weight: 106.4 kg in the OASIS 4 tablet group and 105.4 kg in the STEP 1 pen group. But OASIS 4 was six times smaller and measured its outcome four weeks earlier. Subtracting 13.6 from 14.9 and concluding that the pen produces 1.3 points more weight loss would be asking more of the data than they can give. The Spanish summary of product characteristics (SmPC) for the tablets itself states that efficacy and safety were similar in the two trials.

There are two things that, for now, only the pen has. The first is cardiovascular evidence: in the SELECT trial, carried out in adults with overweight or obesity and pre-existing cardiovascular disease, injectable semaglutide 2.4 mg reduced major cardiovascular events by 20%, and there is no equivalent trial with the 25 mg tablet. The second is a higher step, 7.2 mg a week, which the SmPC restricts to adults with a BMI of 30 or more at the start of treatment; in the STEP UP trial, at 72 weeks, weight fell by 18.7% with 7.2 mg versus 15.6% with 2.4 mg.

Which one causes more digestive side effects?

They are very similar, because it is the same molecule. With the tablet, in OASIS 4, nausea occurred in 46.6% of participants (18.6% with placebo), vomiting in 30.9% (5.9%), constipation in 20.1% (9.8%) and diarrhoea in 17.6% (8.8%). For the pen, the SmPC gives pooled data from the 68-week STEP 1 to 4 trials: nausea in 43.9% (16.1%), diarrhoea in 29.7% (15.9%), vomiting in 24.5% (6.3%) and constipation in 24.2% (11.1%).

Again, these are different trials, and the pen figures pool four populations, so differences of a few tenths of a point can't be compared. What both SmPCs agree on is the pattern: most symptoms were mild or moderate and short-lived, except for constipation, and they were concentrated in the weeks when the dose is being increased. Digestive effects led to stopping treatment in 3.4% of people on the tablet in OASIS 4 and 4.3% of those on the pen in STEP 1-4. Where these symptoms come from and how they are usually managed is explained in our guide to the side effects of drugs in this class and how to manage them.

What changes day to day: fasting, needles and the fridge?

This is where the real difference lies. Semaglutide is very poorly absorbed through the stomach: the bioavailability of the tablet is around 1-2%, compared with 89% for the subcutaneous injection, and it also varies a great deal from one day to the next. That is why the SmPC is so strict about how it is taken: on an empty stomach, after a recommended fast of at least 8 hours; the tablet swallowed whole with a sip of water, up to half a glass (120 ml); and a wait of at least 30 minutes before eating, drinking or taking other oral medicines, because a shorter wait reduces absorption.

That discipline shows in your routine. Coffee or breakfast has to wait half an hour every morning. Anyone who takes other tablets on an empty stomach needs to work out the order with their doctor: in a study described in the SmPC, taking the tablet together with five others reduced semaglutide exposure by 34%. The SmPC also notes that semaglutide increased exposure to levothyroxine by 33%, so thyroid monitoring may be considered for people taking it.

The pen is used once a week, at any time of day and with or without food, in the abdomen, thigh or upper arm. The trade-off is the needle: each FlexTouch pen comes with 4 disposable needles, one for each weekly dose, and the 7.2 mg pen is a single-dose pen. And there's the fridge: before first use it is stored between 2 °C and 8 °C; once started, it lasts 6 weeks below 30 °C or in the fridge.

For travelling, the tablet is less demanding: it needs no special temperature, just its original packaging to protect it from light and moisture, and it has a 3-year shelf life. A pen in use keeps outside the fridge below 30 °C, but an unused spare pen has to be kept refrigerated.

How much does each form cost at the pharmacy?

Neither is paid for by the Spanish National Health System (Seguridad Social): BIFIMED, the Spanish Ministry of Health's funding database, lists both the tablets and the pens as 'No financiado por resolución' (not funded, by official decision). With a prescription, they are bought at the pharmacy at an unregulated price. This is what has been published:

• 25 mg tablet: the press reports €236.20 for a box of 30, which at one a day lasts 30 days. This is not an official price.
• 1.5, 4 and 9 mg tablets: there is no verified public price.
• 0.25, 0.5 and 1 mg pens: €179.89 each, according to Vademecum; the 1.7 mg pen, €200.19, and the 2.4 mg pen, €223.64. Each pen contains 4 weekly doses, i.e. 4 weeks.
• 7.2 mg pen: it is on the market, but we have not been able to find its price.

At maintenance doses, the difference is small: €236.20 for 30 days of tablets versus €223.64 for 4 weeks of the 2.4 mg pen, bearing in mind that the first figure comes from the press. Box-by-box details are in the price of Wegovy tablets, dose by dose, and how to get a prescription and in the monthly cost of each Wegovy pen.

Can you switch from the injection to the tablet, or the other way round?

The SmPC allows for both switches. You can move from the weekly 2.4 mg pen to the daily 25 mg tablet, starting one week after the last injection, and from the 25 mg tablet to the 2.4 mg pen, starting the day after the last tablet. Both SmPCs do warn, however, that the effect of switching is hard to predict, because absorption by mouth varies much more than absorption by injection. That is why 25 mg by mouth and 2.4 mg by injection can't be compared milligram for milligram: what reaches the bloodstream depends on the route.

Who is each one suited to?

There is no one-size-fits-all answer, and the SmPC doesn't make the choice for anyone. What we can describe is what each form requires:

• The tablet suits people who don't want needles, travel often or have no room in the fridge, and who can keep up the fast and the half-hour wait every day.
• The pen suits people who prefer to deal with it once a week, have irregular mornings or take other oral medicines first thing, and people whose doctor considers the cardiovascular evidence from SELECT or the 7.2 mg step relevant.
• Both share the same indication in adults: a BMI of 30 or more, or of 27 to 30 with a weight-related condition, alongside a reduced-calorie diet and increased physical activity. For under-18s, only the pen is indicated, from age 12; there are no data for the tablet.

With all this in mind, the choice is made by your doctor based on your history: your weight and health conditions, what you already take, how you tolerate digestive effects and what routine you can genuinely keep up for months.

For more detail on the tablet, how to take Wegovy tablets covers taking it on an empty stomach and what to do about a missed dose, and its side effects sets out what the SmPC says.

Key takeaways

Wegovy tablets and the Wegovy pen are the same semaglutide, with similar results in their trials and no direct comparison between them; what separates them is the fasting dose, the needle, the fridge and a few euros a month.

What is available in Spain today for people who want to lose weight with medical support is medical weight-loss treatment with a prior assessment, a prescription where appropriate from a doctor registered with the Spanish medical council, and ongoing follow-up. You can:

Check in a few minutes whether you're eligible