The research behind the safety of injections for weight loss
A recent systematic review and meta-analysis of randomised controlled trials analysed the impact of semaglutide on weight loss and showed that 9.4% of participants experienced a serious adverse event that led to them stopping the medication.
The rate of serious adverse events in the placebo group was 6.6%. So, the in-treatment difference was just 2.8%.
Correspondingly, another study showed that participants on semaglutide (Wegovy/Ozempic) had a lower rate of serious adverse events occurring during a trial than those in the placebo group.
The results showed that the semaglutide group had a serious adverse event rate of 7.9% during the trial, compared to 11.8% in the placebo group.
The similar rates of adverse events are likely due to individuals living with obesity already having a lower health status, and the risk of serious adverse events occurring, medication or not, is higher than those not living with obesity.
There are other concerns around thyroid cancer and pancreatitis, which are mainly based on animal models and research on the older generation of injections for weight loss, like liraglutide and dulaglutide.
Additionally, recent reports suggested that semaglutide may increase the risk of mental health disorders and suicidal ideation.
However, research indicates that people taking semaglutide have a lower rate of suicidal ideation compared to those not taking the medication.
Correspondingly, some researchers are investigating the potential use of GLP-1s in treating depression, given their prospective role in supporting the central nervous system’s normal functioning.
Furthermore, other effects, like their ability to reduce inflammation by lowering body fat, could potentially alleviate depressive symptoms.
So, injections for weight loss are safe and effective for most people prescribed the medication, and there’s no reason to suggest that people couldn’t stay on them for the long term if they choose to.
Do weight-loss injections have side effects?
Weight-loss injections do have common side effects. Some are mild and transient; others can be more serious, but these are rare and only occur in less than 10% of people with the newer generation of injections for weight loss, like semaglutide and tirzepatide.
The most common side effects of weight-loss injections, like Wegovy, Mounjaro, and Saxenda, are GI-related, such as nausea, constipation, and diarrhoea.
Fatigue and feeling more tired than usual is another common side effect of weight-loss injections.
Studies suggest that over 90% of people on weight-loss injections will report experiencing side effects at least once when on the medication.
However, these side effects typically occur during dose escalation and ease after the body has adapted to the medication.
For example, a paper recently published by Second Nature found that 44% of people on our Wegovy weight-loss programme reported ‘feeling more tired than usual’ after four weeks on the medication.
However, our study showed that after eight weeks, the number of participants reporting ‘feeling more tired as usual’ had halved from 44% to 22%.
So, while side effects are common when using weight-loss injections, they’re typically mild and transient and ease over time as your body adjusts to the medication.
Do weight-loss injections really work?
Weight-loss injections do work. Particularly the newer generation of weight-loss injections, Wegovy and Mounjaro.
Research shows that Wegovy supports an average weight loss of around 16% of body weight after two years. On Mounjaro, the average weight loss is around 26%.
Compared to lifestyle interventions without medications, GLP-1-assisted programmes have been shown to lead to a more clinically significant weight loss of 10% or more.
Losing and maintaining weight loss of more than 10% is associated with significantly reducing complications associated with obesity, including hypertension, type 2 diabetes, and heart disease.
A recent paper published in The Lancet showed that nearly 20% of participants in lifestyle interventions without medications gain weight, around 40% lose between 1-10% of their body weight, and just 13% lose more than 10%.
In comparison, less than 5% of participants combining semaglutide with lifestyle interventions gain weight, around 10% lose between 1% and 10%, and 87% lose more than 10%.
On tirzepatide (Mounjaro), these numbers are even greater. Over 92% of participants lost more than 10% of their weight.
So, weight-loss injections lead to significant weight loss for people living with obesity.
Take home message
Weight-loss injections aren’t for everyone. Many people can lose weight sustainably without the assistance of weight-loss injections by introducing healthy habits like eating a healthy diet, exercising, and sleeping well.
However, there will be people who have made many failed attempts to lose weight and keep it off over the years, going through several periods of weight loss and weight regain.
This type of ‘yo-yo’ dieting can make it very challenging to maintain weight loss in the future.
Additionally, many people will have genetic predispositions to obesity where they struggle to eat at energy balance due to their brain not receiving the required signals from the body to trigger the feeling of fullness.
In these scenarios, weight-loss injections can calm the food noise, lower hunger, and enable people to develop sustainable healthy habits that can help them keep the weight off for good.
At Second Nature, we have extremely strict eligibility criteria for our medication weight-loss programmes.
Weight-loss injections are most effective when combined with developing healthy habits.
To check your eligibility for our Wegovy or Mounjaro weight-loss programmes, click here to take your health quiz.
