How Much Weight Can You Lose on Ozempic, Wegovy & Mounjaro?

It is the first question almost everyone asks, and it deserves a straight answer rather than a sales pitch. The honest version is this: the clinical trials tell us what large groups of people averaged over a year or more, under close medical supervision. They cannot tell you what you will lose. What they can do is show you the realistic range, how quickly it tends to arrive, and what separates the people who keep the weight off from the people who do not.

This guide sets out the published figures for semaglutide and tirzepatide, then does the more useful thing: explains the spread hiding behind each average, and what the month-by-month reality usually looks like.

The Short Answer

Across the major trials, average total body weight reduction after roughly 14 to 17 months of treatment looked like this.

Two things are worth noticing immediately. The first is that the dose matters more than the brand — tirzepatide at 5 mg and semaglutide at 2.4 mg land in much the same place. The second is that these are averages of large groups, and an average is a poor description of any single person.

What the Averages Hide

If you take one idea from this article, make it this one. When a trial reports "15% average weight loss," that figure is the midpoint of an enormous spread. Some participants lost a third of their body weight. Others lost almost nothing. Quoting only the mean makes a wide, messy distribution look like a promise.

Both landmark trials published the proportion of participants who reached each threshold, which tells you far more than the headline number does:

Proportion of trial participants reaching each weight-loss threshold

Adults with obesity or overweight, without type 2 diabetes · treatment arms only

Semaglutide 2.4 mg

STEP 1 · 68 weeks · n = 1,961

Tirzepatide 15 mg

SURMOUNT-1 · 72 weeks · n = 2,539

Read the left-hand chart carefully. Roughly one participant in three on semaglutide 2.4 mg reached 20% or more, which is an outstanding result by any historical standard. But roughly one in seven did not reach even the 5% mark — the threshold most clinicians treat as the minimum for a medication to be worth continuing. On tirzepatide 15 mg the whole distribution shifts upward, and around a third of participants exceeded 25%. The same caveat still applies at the bottom of the range.

The Timeline: What the First Year Usually Looks Like

Weight loss on a GLP-1 is not linear, and the first weeks are almost always the slowest. This is deliberate: every one of these medications starts at a low, intentionally sub-therapeutic dose and steps up gradually so your gut can adapt. People who give up in month one have usually given up before the medicine has properly started working.

• Weeks 1–4 · Starter dose

  Ozempic and Wegovy start at 0.25 mg; Mounjaro at 2.5 mg. These are tolerance-building doses, not treatment doses. Appetite suppression is often noticeable, but weight change is usually modest — and some of it is fluid. Nausea, if it appears, tends to peak here.

• Months 2–3 · Titration

  The dose steps up roughly every four weeks. A steadier pattern usually establishes itself in this window. Most people notice the constant thinking about food quietening down before they notice the scale moving.

• Months 4–9 · The main phase

  You are at or near your maintenance dose, and this is where the bulk of the total loss accumulates. In both trials, the steepest part of the curve sits here.

• Months 9–16 · Flattening

  The curve bends. Losses slow substantially and then largely stop. In STEP 1 and SURMOUNT-1 alike, the group averages had essentially plateaued before the trials ended.

Why Two People on the Same Dose Get Different Results

The variation in those charts is not random noise. The factors that consistently predict where someone lands include:

• Whether you have type 2 diabetes. This is the single largest predictable difference. STEP 2 studied the same semaglutide 2.4 mg dose in people with type 2 diabetes and found average loss closer to 10% than the ~15% of STEP 1. If you are diabetic, calibrate to the lower figure — this is a well-documented physiological effect, not a personal failure.
• The dose you actually reach. Many people stop escalating early because of side effects or cost. Results at 5 mg of tirzepatide are genuinely good, but they are not the 15 mg results.
• Protein intake and resistance training. A meaningful share of the weight lost on a GLP-1 is lean muscle. Protecting it changes both your body composition and how well you hold the result later. Our guide to Nigerian foods on GLP-1 therapy covers hitting protein targets on a suppressed appetite.
• Consistency of dosing. Missed weeks — usually from supply gaps or cash-flow gaps — blunt results more than most people expect.
• Starting weight. Percentages are percentages: a higher starting weight generally means more absolute kilogrammes for the same proportional loss.
• Sleep, stress and other medications. Some antidepressants, steroids and beta-blockers work against you. Worth reviewing with your doctor before concluding the drug is not working.

The Plateau Is Normal, Not a Malfunction

Almost everyone plateaus somewhere between nine and fifteen months. Carrying less weight means burning fewer calories at rest, and your energy requirement falls until it meets your intake. The loss stops because a new equilibrium has been reached — not because the medication has stopped working.

The plateau is where the goal changes from losing weight to holding the loss. That is a genuine clinical outcome in its own right: a sustained 10–15% reduction is associated with meaningful improvement in blood pressure, blood glucose and sleep apnoea, which for most patients is the actual reason for treating in the first place.

What Happens If You Stop

This is the part most sellers leave out, and you should know it before you spend a naira.

These medications treat obesity as a chronic condition. They do not permanently reset anything. In the STEP 1 extension study, participants who came off semaglutide regained roughly two-thirds of the weight they had lost within about a year, and much of the improvement in their blood pressure and metabolic markers reversed alongside it. Withdrawal data from the tirzepatide programme point in the same direction. Appetite returns, and it tends to return to roughly where it started.

Trial Conditions Are Not Ordinary Conditions

One last piece of context for reading any of these numbers. Participants in STEP and SURMOUNT received structured lifestyle support throughout — regular counselling, a modest calorie deficit, an activity target, and the considerable motivational effect of being monitored by a research team. The medication was never tested as a standalone intervention.

Real-world studies generally report somewhat smaller average losses than the trials do, largely because of lower adherence and less support. That is not a reason for pessimism. It is a reason to treat the medication as one component of a plan rather than as the whole plan.

A Realistic Frame for Nigerian Patients

Because these medications represent a significant monthly commitment here, the question worth asking is not "which one produces the biggest number" but "what can I realistically sustain, and for how long."

A patient who reaches 10 mg of tirzepatide and stays there consistently for a year will almost certainly finish ahead of one who reaches 15 mg for two months and then stops. Consistency beats peak dose. If budget is your constraint, a lower dose maintained without interruption is usually the better clinical strategy — and it is worth raising openly with your doctor, because it genuinely changes what they would recommend.