Side Effects of GLP-1 Medications: What to Expect and How to Cope

Both GLP-1 medications can cause similar side effects, with nausea being the most common complaint, particularly when starting treatment or increasing doses. Other gastrointestinal side effects like diarrhoea, constipation, vomiting, and abdominal discomfort are also common. These effects usually reduce in frequency over time and are mainly seen during the first few months when you're gradually increasing your dose.

Nausea is by far the most frequently reported side effect, affecting nearly half of people taking GLP-1s at some point during their treatment. Most people find that whilst it might be noticeable during the first few weeks, it becomes much more manageable and often disappears entirely as treatment continues.

The nausea occurs because the medication slows down stomach emptying. When food sits in your stomach longer than usual, it can trigger feelings of queasiness, particularly if you eat larger portions or foods that are harder to digest. This is why the timing and content of your meals become so important when you're starting these medications.

The most effective strategy for managing nausea is adjusting how and what you eat. Smaller, more frequent meals work much better than larger portions. An empty stomach can actually worsen nausea, so having something light and easily digestible every few hours often helps more than trying to push through feeling sick. Cold foods tend to be better tolerated than hot foods, as they produce fewer aromas that might trigger nausea.

One of the key things to realise is that when on these medications, especially at the higher doses, you may not feel hungry at all. It can be very easy to miss meals and go most, if not the entire, day without eating. People often mistakenly see this as something positive as it means they lose weight very quickly. But this can cause real problems. The rapid weight loss that comes from such a drastic reduction in nutrition is not healthy.

The important thing to realise is that even though you no longer feel hungry, your body still needs nutrition, and is still going to have the same physical responses as it would if you were not on medication and had gone the entire day without eating. Problems like feeling faint, shaky, having problems concentrating and being irritable are actually the effects of not eating and having low blood sugar levels.

Both medications can also cause fatigue, headaches, and a general feeling of being unwell in the early stages. Some people describe feeling as though they have a mild flu for the first week or two. This usually improves with time. Understanding that these side effects represent your body's temporary adjustment period rather than signs that something is wrong can be incredibly reassuring. For most people, these early challenges are well worth pushing through for the benefits that follow.