Getting Started

Getting Started

Start your weight loss journey with simple guides on Mounjaro, Wegovy and eligibility in the UK. Learn how treatments work and what to expect before you begin.

Whether you have just decided to consider weight-loss injections or are halfway through researching them and not sure what to do next, this guide is a step-by-step getting started roadmap for Mounjaro or Wegovy in the UK. The aim is to help you go from "thinking about this" to "first injection at home" with realistic expectations and the right preparation. LetsLoseWeight is an independent comparison site; we do not prescribe medication, and the right treatment for you is a clinical decision with a regulated UK prescriber.

Step 1 — Check whether you might be eligible

The licensed indication for Mounjaro and Wegovy in the UK is broadly:

  • Adults with BMI ≥30, or
  • Adults with BMI ≥27 with at least one weight-related comorbidity (e.g. type 2 diabetes, hypertension, dyslipidaemia, obstructive sleep apnoea)

You can calculate your BMI on the NHS website. If you don't meet either threshold, regulated UK prescribers will not normally prescribe — and this is for your benefit, not an obstacle to work around.

NHS access criteria are tighter — see our private vs NHS guide for the specifics. For the full eligibility picture, see our who can take weight loss injections guide.

Step 2 — Decide between Mounjaro and Wegovy

The two medicines are similar but not identical. Quick summary:

  • Mounjaro has greater average weight loss in head-to-head trials and is increasingly the default first-line private choice
  • Wegovy has a longer track record (semaglutide has been used in diabetes since 2017) and is similarly priced

For most patients without a specific reason to prefer one, Mounjaro is a reasonable starting point. For specific clinical reasons (skin hypersensitivity history, existing semaglutide regimen for diabetes, particular cost considerations), Wegovy may be the better choice.

For a deeper comparison, see our Mounjaro vs Wegovy UK guide and our best weight loss injection UK decision framework.

Step 3 — Decide between NHS and private routes

If you meet NHS criteria and can wait for specialist services, NHS treatment is dramatically cheaper — only the standard prescription charge (£9.90 in 2025/26 in England; free in Scotland, Wales, and Northern Ireland). Many patients are eligible privately but not on the NHS, in which case the private route is the practical choice.

For a fuller comparison, see our private vs NHS guide.

Step 4 — Choose a regulated UK provider

The provider you buy from matters. Regulated UK pharmacies are registered with the General Pharmaceutical Council (GPhC) and use UK-registered prescribers.

Key checks before you buy:

  • GPhC number visible on the website (usually in the footer)
  • Named superintendent pharmacist
  • Real clinical assessment — not three checkboxes and a credit card field
  • Clear pricing and refund policy

Avoid: social media sellers, beauty clinics without a regulated pharmacy partner, anything with prices dramatically below the market rate.

For our full provider checklist, see our where to buy guide. For provider-by-provider profiles, see our provider directory.

Step 5 — Complete the online clinical assessment

Once you've shortlisted a provider, the clinical assessment typically takes 10–20 minutes and covers:

  • Medical history — including thyroid disease, pancreatitis, gallbladder problems, eating disorders, mental health
  • Current medications — both prescription and over-the-counter
  • Weight history — current weight, recent trend, target
  • Lifestyle and diet
  • Pregnancy plans and breastfeeding
  • Allergies and previous reactions to GLP-1 medicines

Be honest. The questionnaire is the prescriber's main source of information about you, and incomplete or inaccurate answers compromise their ability to prescribe safely. A decline based on a contraindication is a good outcome — it means the system is working.

You will also typically need to provide:

  • Photo identification (passport or driving licence)
  • A recent weight photo (full body or scale-with-feet, depending on provider)

Step 6 — Wait for prescriber approval

Most regulated UK providers turn around clinical reviews within 24–48 hours. Some are faster (a few hours); some take longer for complex cases. The prescriber may:

  • Approve and prescribe — usually with the standard starter dose
  • Request additional information — particularly if your medical history flags an area for clarification
  • Decline — for clinical reasons

If you are declined and want a second opinion, you can apply to a different regulated UK pharmacy — but disclose the previous decline. Going to an unregulated source after a regulated decline carries the safety risks the original prescriber was trying to protect you from.

Step 7 — Receive and store the medicine

Once prescribed, the medicine is dispatched in temperature-controlled packaging. Most providers offer next-day or 1–2 day delivery. On arrival:

  • Check the medicine — pen looks intact, in original packaging
  • Move to the fridge promptly — store at 2–8°C
  • Read the patient information leaflet — it has the specific instructions for your pen design

Most providers also include a sharps bin or arrangements for disposal. If yours doesn't, ask before you start injecting.

Step 8 — Prepare for the first injection

Before your first injection day:

  • Read the instructions inside the pen pack carefully
  • Watch the manufacturer's video (linked from the pen pack or pharmacy website)
  • Decide where you'll inject — abdomen, thigh, or upper arm. The abdomen is usually easiest for first-time self-injection
  • Choose a quiet day — first injections are easier without time pressure. A weekend morning works well for many people
  • Have a clean, well-lit space — your kitchen or bathroom is fine

For full technique, see our how to inject guide and where to inject guide.

Step 9 — The first injection

The first injection is psychologically the hardest. Practical tips:

  • Take the pen out of the fridge 15–30 minutes before — a cold injection is more uncomfortable
  • Don't rush — read each step in the pen instructions
  • Press firmly when injecting — the mechanism activates with proper pressure
  • Listen for the click — there's usually one to start and one to confirm completion
  • Hold for the full count specified in your pen instructions (usually 5–10 seconds)
  • Don't recap — used pens go straight into the sharps bin

Once you've done the first one, the rest are easier. Most patients find injecting themselves becomes routine within 2–4 weeks.

Step 10 — Manage the first weeks

The first 2–4 weeks on the starter dose are when you'll learn how the medicine affects you personally. What to expect:

  • Mild gastrointestinal effects — nausea, occasional loose stools, slight bloating
  • Reduced appetite — meals feel more filling, less interest in snacking
  • Variable energy — particularly the day or two after injecting
  • Minimal scale change — the starter dose is intentionally below the weight-loss threshold

For practical strategies, see our reduce side effects guide. For what to expect over time, see our when do you see results guide.

Step 11 — Plan dose increases

After 4 weeks at the starter dose, the standard schedule is to step up. Your prescriber will usually:

  • Confirm tolerability — sometimes via a brief follow-up consultation
  • Issue the next dose pen — at the dose level specified in the schedule
  • Adjust if needed — staying at the current dose for an additional 4 weeks if side effects are heavy is a normal option

For Mounjaro the schedule progresses through 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg, at minimum 4-week intervals. For Wegovy the schedule is 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg over 16 weeks.

What to expect — realistic expectations

Going in with the right expectations protects against disappointment and unnecessary stopping:

  • Most patients lose meaningful weight — typically 10–20% of starting weight on the maintenance dose, over 12–18 months
  • Real-world results are usually a bit lower than trial results
  • Progress is not linear — weeks of no scale change are normal
  • The medicine works alongside lifestyle change, not instead of it
  • Treatment is long-term — stopping usually means regaining

For full results context, see our how much weight can you lose guide.

What might go wrong, and how to handle it

Side effects that don't settle

If gastrointestinal side effects don't settle within 2–3 weeks at a stable dose, talk to your prescriber. Options include staying at the current dose longer, dropping back, or switching medicines.

Plateau or slower-than-expected progress

If you've not lost 5% by 12 weeks at the maintenance dose, the prescriber will usually want to review. See our plateau guide and what affects results guide.

Wanting to switch providers

Switching is straightforward at any regulated UK pharmacy. Keep records of your dose, start date, and side-effect history.

Wanting to stop

Stopping is your call, with prescriber input. The realistic outcome is gradual weight regain — see our stopping safely guide.

Frequently asked questions

How quickly can I get started?
From application to first injection is typically 3–7 days at most regulated UK providers. Some are faster.

Do I need to tell my GP?
It is recommended. Most regulated providers will offer to share a summary with your NHS GP if you consent — this keeps your medical record complete and helps avoid drug interactions.

Can I start straight away on the maintenance dose?
No. The licensed approach requires starting at the starter dose and titrating up. Skipping ahead significantly increases the risk of severe side effects and is not licensed.

What if I'm scared of needles?
The pen does most of the work — you don't actually see the needle if you don't want to. The first injection is the hardest; from there, it becomes routine. If needle anxiety is severe, talk to your provider before starting.

What if I don't lose weight?
Around 9–14% of trial participants did not lose meaningful weight even at the highest doses. The standard benchmark is at least 5% weight loss by 12 weeks at the maintenance dose; if you're below that, your prescriber will want to review.

Next steps

Sources

This guide is for general information only and is not a substitute for professional medical advice. Talk to a regulated UK prescriber about whether weight-loss injections are suitable for you.

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Getting Started with Weight Loss Injections UK | LetsLoseWeight