GLP-1's What Dose is Right for ME?
Graham Phillips
FRPharmS • Founder
GLP-1s – What’s The Right Starting Dose?
One of the most common (and important) questions in this group is:
“What dose should I start on – and how quickly should I go up?”
Let’s break it down in a clear, practical way, using Ozempic, Wegovy and Mounjaro as examples, and then I’ll explain why, in our clinic, we start at half the official starting dose.
1. Same Drug, Different Licences, Different Doses
Two key facts that often surprise people:
Ozempic and Wegovy are the same drug – semaglutide.
Ozempic is licensed for type 2 diabetes.
Wegovy is licensed for obesity / weight management.
You might expect the diabetes dose to be higher, but it’s actually the other way round:
Ozempic usually tops out at 1.0 mg weekly for diabetes.
Wegovy can go up to 2.4 mg weekly for obesity.
So for weight loss, the official “target” dose is more than double the diabetes dose, even though it’s exactly the same molecule acting on the same receptor.
2. How Long Do These Drugs Stay In Your System?
Another key piece of context is how long the drug hangs around:
Both Semaglutide (Ozempic / Wegovy) and Tirzepatide (Mounjaro) have a half-life of about 5 days.
It takes at least 20 days (maybe longer) for a given dose to mostly wash out of your system. So when you take a dose every week, the drug actually builds up in your body.
What this means in real life:
If you “overshoot” the dose and feel awful, you can’t just stop and feel normal in a couple of days because the effect can linger for days or even weeks.
That’s one of the reasons why precise dose and titration speed are so critical.
3. What Do The Official Leaflets Say?
The product information and trial protocols all take a broadly similar approach:
Start low, then increase every few weeks, provided you’re tolerating it.
For example (simplified):
Wegovy (semaglutide for obesity)
0.25 mg weekly → 0.5 mg → 1.0 mg → 1.7 mg → 2.4 mg
Each step is normally 4 weeks apart if tolerated.
Ozempic (semaglutide for diabetes)
0.25 mg weekly → 0.5 mg → 1.0 mg (some markets 2.0 mg)
Mounjaro (tirzepatide)
2.5 mg → 5 mg → 7.5 mg → 10 mg → 12.5 mg → 15 mg
Again, typically 4-weekly dose increases if tolerated.
All of this is evidence-based: these are the schedules used in the big clinical trials that got the drugs licensed in the first place. But remember the clinical trials are devised to help the manufacturer obtain a product license… so they can sell their product. It’s at least as much to do with marketing as patient benefit
4. But Real Life Is Much Messier Than The Trials
- In carefully run trials, you have:
- Highly selected patients
- Lots of support and monitoring
- Very structured protocols
- In the real world we see:
- People who are older, more fragile, or on many other medicines
- People with very low caloric intake once the drug kicks in
- Huge variation in how sensitive people are
So although the official starting dose for Wegovy is 0.25 mg, many people find even this too much at the beginning – especially if:
- They’re already small / older / medically complex
- They’re told to jump up the dose every 4 weeks regardless of how they feel
- They aren’t given good support around protein intake, hydration, and micronutrients
The result?
- Crushing nausea
- Vomiting
- Being unable to eat properly
- Diarrhoea, Constipation - maybe both!
Sometimes ending up in A&E with Gallstones or Pancreatitis or maybe stopping the drug altogether. And remember: because the drug stays in your system for weeks, a bad dose decision can have long-lasting consequences.
5. Our Clinical Approach: “Start Low And Go Slow”
This is where a more personalised strategy comes in.
In our clinic, with all the GLP-1s (Ozempic, Wegovy, Mounjaro, etc.), we use a simple principle:
“Start low, go slow – and only go higher if you need to.”
For obesity treatment, that often means: We generally start at around half the official starting dose (for example, a smaller number of pen clicks than the full 0.25 mg for Wegovy), especially in more sensitive people.
We stay longer at each step if side-effects are an issue, instead of automatically increasing every 4 weeks.
Sometimes we delay or skip a dose if appetite suppression is extreme or side-effects flare up.
This has a few important consequences:
- Fewer side-effects → people are more likely to stay on treatment.
- Less drug wasted → you’re not paying for doses your body can’t handle.
- Better long-term adherence → which is what actually drives health benefits.
However, it’s really important to stress:
This kind of micro-titration is off-label – it’s more flexible than the exact schedule in the leaflet.
It should only be done under the guidance of a prescriber who understands GLP-1s and can look at your medical history, other medications, and lab results.
This group is great for sharing experiences, but it can’t replace proper, individual medical advice.
6. So What Is The “Right” Starting Dose For Me?
There isn’t a single “right” number for everyone, but there are some solid principles:
For diabetes (e.g. Ozempic):
The licensed doses are lower; side-effects tend to be milder, but we still sometimes need to slow down titration.
For obesity (e.g. Wegovy, Mounjaro):
Licensed “target” doses are higher, so tolerance matters even more.
Starting at half the official starting dose can be very reasonable in sensitive patients – if done under proper supervision.
If you’re struggling on the standard schedule:
That doesn’t mean you’ve “failed” or that GLP-1s “aren’t for you”.
It may simply mean the dose, timing or support (nutrition, electrolytes, etc.) needs to be adjusted.
Key Take-Home Messages
Ozempic and Wegovy are the same drug (semaglutide), but obesity licences use higher doses than diabetes.
These drugs stay in your system for weeks, so dose mistakes can have long-lasting effects.
The official titration schedules are based on good evidence, but real patients vary enormously.
A “start low, go slow” approach – often starting at around half the official starting dose for obesity – can reduce side-effects and improve adherence, if it’s done with proper medical oversight.
Please don’t adjust your own dose radically without speaking to a prescriber who understands these medications.
If people find this helpful, I can follow up with a post on “How do I know if my GLP-1 dose is too high?” – looking at red-flag symptoms and when to seek urgent help.
About Graham Phillips
Graham Phillips is a registered pharmacist (FRPharmS) with over 35 years of experience. Frustrated by “pill for every ill” medicine, he founded ProLongevity to help people reverse chronic disease and lose weight through precision lifestyle medicine.
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