The excitement has been hard to miss. Last week Britain’s medicines regulator approved the world’s first weight-loss tablet – the Wegovy Pill.

The response was immediate. Online pharmacies have reported that they expect to have waiting lists of more than 100,000 patients who want to start taking the daily tablet, which will only be available privately at first.

At first glance, this excitement seems reasonable. At present, weight-loss drugs such as Wegovy and Mounjaro have to be self-injected, a task that many people find off-putting. 

The tablets are also expected to be roughly £40 less a month than the injections. 

No wonder then that, according to polling published last week, twice as many Britons say they would take a weight-loss pill than a jab.

However, I’m concerned that many patients are unaware that the Wegovy Pill is not the easy alternative that it appears. In fact, the vast majority of patients would be better off sticking with the injections.

To explain why, it’s important to understand how this drug works.

The Wegovy Pill contains semaglutide, the same drug that made the Wegovy injections famous. It works by mimicking a hormone called GLP-1, which your body releases naturally after eating. 

This makes you feel fuller for longer, reduces hunger and curbs cravings.

The reason semaglutide has always been given as an injection is that, taken orally, the drug is normally destroyed by stomach enzymes before it can reach the bloodstream.

The tablet gets around this with a special compound that briefly neutralises stomach acid and protects the drug long enough to be absorbed.

The science behind the formulation of this drug is ingenious – but it has its limits.

For one thing, it is markedly less effective than the most powerful injections. The Mounjaro jab typically triggers around 22 per cent weight-loss for obese patients.

By comparison, studies show the strongest dose of the Wegovy Pill leads to, at most, 17 per cent weight-loss, a meaningful result but one that falls short of Mounjaro.

This is all the more significant when you consider the fact that these are averages meaning that many patients who go on Mounjaro do not reach this amount. 

It’s common for patients to reach a weight plateau – where the jabs seem to stop having an effect.

Of course, any weight loss if you have obesity is good for your health, but it’s a frustrating experience and, with the pills, this plateau may occur even earlier.

Then there are the side-effects. While taking a daily pill may seem less intensive than self-injecting, the risk of complications is the same.

Regardless of which form of Wegovy patients take, they should expect to experience some uncomfortable symptoms including nausea, diarrhoea, abdominal pain, constipation and vomiting, particularly when starting or after the dose is increased.

Which brings me to my biggest concern about this drug. The Wegovy Pill has been pitched as a convenient and easy-to-use alternative to injections. However, it is far from it.

It cannot simply be swallowed with your morning coffee or alongside other medication.

It must be taken on a completely empty stomach, after fasting for at least eight hours.

It can only be taken with a small, specific amount of water – up to 120ml to be precise (half a cup apparently).

And then, after swallowing it, patients cannot eat or drink anything at all for 30 minutes.

Failure to follow these steps to the letter will affect how much of the drug is absorbed into the bloodstream – and therefore weaken its effect, limiting weight loss.

This is a daily commitment, without exception. For a pill marketed on the basis of simplicity, it’s a demanding routine – and I predict a lot of patients are going to struggle to stick with it.

There is also a further concern that has, so far, received relatively little attention.

The Wegovy Pill contains roughly 100 times as much semaglutide per dose as the injection. 

This is to make up for the fact that so much less of the drug survives the journey through the stomach. No matter which form you use, roughly the same amount of medication is absorbed into the bloodstream.

And herein lies the problem. In recent years, there have been repeated shortages of semaglutide, due to worldwide demand.

If the early figures from online pharmacies are to be believed, the demand for the Wegovy Pill is likely to outstrip that for the injections. 

And since the pills contain so much more semaglutide than the injections, it’s highly likely that shortages of the medicine will occur again.

When that happens, Wegovy Pill patients will be in a difficult position. Those who have been prescribed it cannot simply switch to an alternative tablet – there isn’t another one approved currently.

None of this means the Wegovy Pill has no place. For some patients it will not just be useful – it will be life-changing. 

I think of one patient I saw privately, a woman with obesity who had tried every diet and exercise approach she could find and was desperate for help.

She was also utterly terrified of needles. When I tried to teach her to self-inject, it was immediately clear she simply could not do it.

She came to the clinic week after week for months so that a healthcare professional could administer the injections for her, sweating and shaking each time in anticipation.

For a patient like her, a pill would have changed everything from day one.

For other people considering the Wegovy Pill, the lower efficacy, the strict daily timing regime and the very real risk of shortages make it a less attractive proposition than the injections it imitates.

The excitement is understandable. Just make sure you know what you’re actually signing up for.