Can I start Wegovy at 0.5 mg?

Standard UK instructions start at 0.25 mg once weekly and step up gradually to improve comfort and reduce tummy side effects. Starting at 0.5 mg is not the routine plan and tends to increase nausea for first-time GLP-1 users. If you’ve previously tolerated a GLP-1, your prescriber will still weigh the pros and cons before deviating from the usual start.

Why titration matters

Wegovy contains semaglutide, a GLP-1 receptor agonist that acts on appetite control centres in the brain and slows digestion. These effects are very effective for weight loss but can cause uncomfortable gastrointestinal side effects, especially in the early stages. People often report nausea, bloating, reflux, or diarrhoea as the body adapts. If the dose is increased too quickly, these symptoms can be more intense and discouraging. This is why NICE and the manufacturer recommend starting with a very low dose and slowly working up to the full strength. The idea is to help the body adjust gradually, allowing people to stay on treatment long enough to benefit.

The cautious start also reflects how the STEP clinical trials were run. In those studies, which provided the evidence for approval, participants always began at the 0.25 mg dose. The trial design showed that tolerability was far better when people were introduced slowly, even though the final goal was a 2.4 mg weekly maintenance dose. The NHS follows this same evidence-based schedule in clinical services.

The standard escalation schedule

The licensed pathway moves upward step by step over 16 weeks:

• Weeks 1–4: 0.25 mg once weekly

• Weeks 5–8: 0.5 mg once weekly

• Weeks 9–12: 1.0 mg once weekly

• Weeks 13–16: 1.7 mg once weekly

• Week 17 onwards: 2.4 mg (maintenance dose)

This slow increase is not about delaying results. It is about reducing the chance of side effects so that patients can actually reach and tolerate the highest effective dose. The STEP-1 trial, which included more than 1,900 participants, showed that people who followed the escalation plan achieved average weight losses of around 15% of their body weight after 68 weeks. These results depended on patients sticking with treatment, which was more likely if early nausea was manageable.

Why not start higher?

Some people ask whether skipping the first step and beginning at 0.5 mg would bring faster results. The answer is that it usually just brings faster side effects. Gastrointestinal upset is dose-related. Clinical experience shows that people who jump straight to 0.5 mg are more likely to suffer stronger nausea or vomiting. That discomfort can be demoralising, and it is a common reason people stop taking GLP-1 medicines.

There is no evidence that starting higher improves long-term weight loss. The maintenance dose of 2.4 mg is the same whether you begin at 0.25 mg or 0.5 mg. What matters is reaching and staying on that full dose, not how quickly you begin. For most people, patience in the first month pays off in long-term success.

Possible exceptions

There are circumstances where a prescriber might consider starting directly at 0.5 mg, though this is not routine. If someone has already used another GLP-1 medicine, such as Ozempic (semaglutide at lower diabetes doses) or Saxenda (liraglutide), and tolerated it well, the clinician may judge that the cautious first step is unnecessary. For example, a person who has taken 1.0 mg of Ozempic weekly for diabetes may not need to start at 0.25 mg when moving onto Wegovy. Even so, this decision rests with the prescriber, who will balance the potential benefits against the increased risk of nausea.

It is worth stressing that this is the exception, not the rule. The NHS pathway expects most people to begin at 0.25 mg. Deviations are based on individual medical judgement, not patient choice alone.

What if side effects are difficult?

The structured escalation is designed to minimise problems, but some people still find the jump from one stage to the next uncomfortable. Rather than splitting a weekly dose into two smaller ones — which is not recommended — the safe adjustment is to stay longer at a lower step. For instance, if nausea is significant at 0.5 mg, a prescriber may advise continuing that dose for another month before moving to 1.0 mg. This approach is supported in clinical guidance and allows the body more time to adapt.

It is also important to follow the practical advice given in clinics: eat smaller meals, chew slowly, avoid very fatty foods during escalation, and stay well hydrated. These habits make it easier to tolerate the medicine and improve comfort while moving up the schedule.

Safety considerations

Skipping the lowest starting dose is not just about side effects. There are safety reasons too. Rapid dose escalation has been linked with increased risks of gallbladder problems, dehydration, and discontinuation. Severe vomiting or diarrhoea can lead to electrolyte imbalances, especially in older adults or those with other health conditions. NICE guidance exists to reduce these risks, and clinicians are expected to follow it closely.

Another risk of ignoring the structured pathway is confusion over how to manage missed doses or pen strengths. Starting at 0.25 mg allows people to learn the routine with the least pressure from side effects, building confidence before the higher strengths are introduced.

NHS perspective

NHS weight-management services base their protocols on NICE’s Technology Appraisal TA875. The guidance specifies the starting dose of 0.25 mg, rising to 2.4 mg over sixteen weeks. Local services may add extra reviews during escalation to support people with side effects. Prescribers are generally cautious about moving away from the licensed schedule. Adjustments are made only when there is strong clinical justification, such as prior GLP-1 use with proven tolerance.

What this means in practice

The short answer is no: most people should not start Wegovy at 0.5 mg. The evidence and guidance point to beginning at 0.25 mg, then stepping up gradually. Starting higher increases the likelihood of nausea without improving long-term outcomes. There are occasional exceptions for people who have already used similar drugs, but these decisions belong to prescribers, not patients. For the majority, patience at the beginning ensures comfort, safety, and the best chance of reaching the full effective dose.