What happens when you stop taking weight loss injections?

Are weight loss injections short-term or long-term?

There are no strict rules on how long you can take any of the four approved weight loss medicines currently available in the UK. However, NHS guidance suggests that, to stay within the safety limits tested in clinical trials, most should be used for no longer than two years.

You may also be taken off the medicine if you have not lost a significant amount of weight within the first few months of starting treatment.

There may be reasons for stopping weight loss medicine that are not directly related to weight loss. Your doctor might determine that the treatment isn’t providing you with sufficient health benefits, or you may experience side effects that make it difficult or unsafe to continue.

However, coming off weight loss medicine after you achieve long-term weight loss can lead to rapid weight regain if your lifestyle habits haven’t been changed alongside treatment.

Weight regain

Without sustained lifestyle changes, you will quickly regain some or all of the weight you lost once your treatment ends.

Dr Hazel Parkinson, a GP based in Long Itchington, UK, says that one of the biggest misconceptions about taking weight loss medicine is that the results are permanent.

"Weight loss treatments may suppress your appetite, but they don't 'reset' your metabolism for habits," she explains. "Stopping the medicines can also lead to loss of motivation, or rebound eating, so a clear exit strategy and long-term support are essential."

Muscle loss

Some weight loss medicines can contribute to the loss of not only body fat but also muscle mass, which may harm your health.

"These medicines don't discriminate between fat and muscle," says Parkinson. "So, unless you're eating enough protein and doing resistance training, you have a high chance of losing your body mass. This can affect your strength, metabolism, and even bone health - especially if you're a woman approaching menopause."

Dr Ramit Singh Sambyal, Head of Emergency Medicine, Metro Hospitals and Heart Institute, India, adds that during rapid weight loss, your body naturally reduces its energy expenditure to conserve calories.

"Without building muscle through strength training, your metabolic rate remains lower even after stopping the medicine," he says. "This makes it easier to regain weight."

Increased appetite

One of the most immediate and noticeable effects after stopping weight loss medicine is a sharp increase in appetite.

Sambyal explains that weight loss medicines work by slowing gastric emptying and influencing appetite-regulating hormones in your brain, which helps you feel fuller for longer.

Sambyal adds that if you don't make any long-term changes to your eating patterns or daily activity, it is highly likely you will struggle to maintain proper portion control. This can lead to cravings for high-calorie comfort foods, and you'll regain the weight you lost within months.

Cambios hormonales

When you stop taking weight loss medicine, your hunger hormones - such as ghrelin - rise, causing increased and persistent feelings of hunger.

Sambyal says this leads to frequent snacking and larger meal portions - often without you even realising it.

Emotional eating patterns

Many people with emotional eating patterns may not have addressed the underlying causes of their behaviour.

Sambyal warns: "Without the appetite-suppressing effect of the medicine, it's easy to fall back into old habits of using food for comfort or stress relief."

Experts advise viewing weight loss medicine as a supportive tool for long-term behavioural change - not as a quick fix.

Sambyal emphasises the importance of having a structured, step-by-step plan before coming off weight loss medicine.

"Abruptly stopping without building healthier routines almost always leads to weight regain," he says.

As our experts emphasise, weight loss medicine should be seen as a supportive bridge towards developing healthier habits - not as a long-term solution.

"The key is to build healthier behaviours while the medicine is helping manage your appetite," says Sambyal. "This is so that when it’s time to stop, the transition feels smoother and more manageable."

According to Sambyal, seeking ongoing support is essential. This support can come from various sources, such as terapia cognitivo-conductual, weight loss support groups, or consultations with a nutritionist. These resources offer the emotional support and accountability needed to maintain consistent lifestyle changes.