Weight-loss injections vs tablets: efficacy, cost and convenience

For years, prescription weight-loss treatment in the UK meant one thing: a weekly injection. That is changing. There is now a needle-free tablet on the market, so the honest question for many people is no longer "which jab?" but "weight-loss injections vs tablets — which form suits me?" This guide compares the two across the three things that actually decide it: how much weight you can expect to lose, what it costs, and how it fits your life.

Every price below comes from our master dataset of 24 UK providers, last checked 4 July 2026. We have not rounded them up or invented any.

What each form actually is

There are three prescription options in play, spanning both classes.

Injections (the weekly jabs)

Mounjaro (tirzepatide) is a once-weekly injection given with a pre-filled KwikPen. It is the only dual-hormone option — it acts on two gut-hormone receptors (GIP and GLP-1) at once — and it produces the largest average weight loss of the current UK medicines.

Wegovy (semaglutide) is also a once-weekly injection, self-given with a pre-filled disposable pen. It is the most widely used dedicated weight-loss jab and the only one shown to cut heart-attack and stroke risk in people with existing heart disease (the SELECT trial).

Tablets (the needle-free route)

The Wegovy Pill (oral semaglutide) is the UK's first needle-free GLP-1: a daily tablet rather than a weekly injection, with results reported as close to the jab. The trade-off is a stricter routine — it must be taken first thing on an empty stomach with no more than a small sip of plain water, followed by at least a 30-minute wait before eating, drinking anything else or taking other tablets.

Efficacy: how much weight comes off

This is where most people start, so let's be plain about it. Head-to-head, the weekly injections generally lead.

• Mounjaro (injection) has the largest average weight loss of the current options; in its main obesity trial (SURMOUNT-1) participants lost roughly a fifth of their body weight at the top dose.
• Wegovy (injection) showed around 15% of body weight lost in its STEP 1 trial — substantial, and the most established track record.
• Wegovy Pill (tablet) lands close to the weekly semaglutide injection, but as a general rule sits a step behind the strongest jab.

Two caveats matter more than the headline numbers. First, trial averages are not promises — individual results vary widely, and lifestyle, dose reached and how long you stay on treatment all move the outcome. Second, the "best" medicine is the one you can actually tolerate and keep taking. A slightly lower-ceiling option you stick with beats a stronger one you abandon. Our complete UK weight-loss medications guide walks through the efficacy ladder in more depth.

Cost: injections vs tablets, side by side

A common assumption is that tablets must be cheaper because there's no pen. The data doesn't support that. Price is set by the provider and the dose you're on, not by the format. The table below shows the lowest ongoing four-weekly price we recorded for each option, alongside The Weight Clinic's price so you can see our recommended provider in context. Starter doses are cheaper than maintenance doses, so we've used a representative maintenance dose for each.

Two things stand out. The cheapest ongoing option in our data is actually an injection — the Wegovy pen from £109 for four weeks. And the tablet is not the budget choice: at a maintenance dose it starts from £119, similar to or above the Wegovy injection. The tablet is also stocked by only two of the 24 providers we track, which limits how far you can shop it around. For the full spread across every provider, see our cost comparison across 24 providers, and for the tablet specifically our Wegovy pen vs pill cost breakdown.

Watch the small print too: first-order promo codes, whether cold-chain delivery is charged, and whether there's a subscription all change the real monthly figure. A £10-off first order flatters month one but doesn't touch what you'll pay from month two onward.

Convenience: needle vs daily routine

This is where the two forms genuinely differ, and it's personal.

A weekly injection is a single action every seven days: same day each week, any time, with or without food, rotating the injection site on the tummy, thigh or upper arm. The obvious barrier is the needle — and for a meaningful number of people that barrier is real.

The daily tablet removes the needle entirely, which is its whole appeal. But "no needle" doesn't mean "no discipline". You take it every morning on an empty stomach after an overnight fast, with only a small sip of water, then wait at least 30 minutes before your coffee, breakfast or any other medicine. Miss the window or take it with food and it may not absorb properly. Seven mornings of that beats one weekly jab for some people and loses to it for others.

A simple way to decide: if needles are the dealbreaker, the tablet is worth asking about. If a fuss-free routine matters most, the weekly jab is hard to beat.

Side effects and safety are the same conversation

Both classes work on the same appetite-regulating hormone pathway, so the tolerability profile is broadly similar in character — most commonly gut-related, and usually eased by starting low and increasing the dose slowly. Whichever form you choose, all of these are prescription-only medicines, they are not suitable for everyone, and the decision belongs to a qualified prescriber after a proper consultation. Report any suspected side effects through the MHRA Yellow Card scheme. Whether you'll qualify at all is worth checking first — our UK eligibility guide covers the BMI thresholds and health checks.

So — injection or tablet?

If maximum average weight loss is the priority and you're comfortable with a weekly jab, the Mounjaro injection leads on results. If you want the longest safety track record or have heart-health considerations, the Wegovy injection is the established choice. If a needle is what's stopping you, the oral tablet is a genuine, if less widely stocked, alternative that gets you most of the way there. Cost shouldn't be assumed either way — check the current maintenance price for the exact option on our master comparison table before deciding.

Frequently asked questions