As temperatures are set to reach 33°C this bank holiday weekend, a GP has warned that people taking weight loss jabs containing GLP-1 receptor agonists, such as semaglutide, face a higher risk of dehydration. Dr Suzanne Wylie, a GP and medical advisor for IQdoctor, explained that common side effects like nausea, vomiting, and diarrhoea can lead to significant fluid loss, while the medication's effect of slowing gastric emptying may cause individuals to eat and drink less overall.
Dehydration can lead to heat exhaustion or, in severe cases, heatstroke. Symptoms include headaches, fatigue, dizziness, dry mouth, and darker urine. More serious signs include confusion, weakness, muscle cramps, or feeling faint. Dr Wylie emphasised that thirst is a late indicator, so people should drink regularly throughout the day, aiming for at least 1.5–2 litres of fluid, and more during hot weather.
Dr Wylie also highlighted a lesser-known risk: dehydration may increase the likelihood of gallstones, a rare side effect associated with rapid weight loss and some weight-loss medications. Dehydration can reduce bile flow and concentrate bile within the gallbladder. Anyone experiencing persistent dizziness, severe fatigue, worsening nausea, or dehydration symptoms should seek medical advice.
