Guide · Updated April 2026

I Tracked Every Metric on Mounjaro for 12 Months: Here’s the Raw Data

Over 12 months on Mounjaro (tirzepatide, a GIP/GLP-1 dual agonist that slows gastric emptying and blunts appetite signals), I lost 58.4 lbs (22.1% of starting weight), dropped body fat from 31.4% to 18.9% on DEXA, cut HbA1c from 5.8 to 5.2, and spent $4,872 total. Fat made up 82% of the loss. Lean mass dropped 7.1 lbs.

I tracked every metric on Mounjaro for 12 months because I wanted to know exactly what this drug does to a body, not what the glossy ad copy says. Most weight loss content stops at the scale. The scale lies. It tells you the number went down but hides whether you lost fat, muscle, water, or some mix of all three.

So I ran myself as the experiment. Weekly weigh-ins. Quarterly DEXA scans. Lab panels every three months. Blood pressure daily. Sleep tracked with a Whoop. Every dollar spent. Every side effect logged in a spreadsheet.

This is the raw data. No promo codes, no before-after photos angled for likes. Just what 12 months of tirzepatide (brand name Mounjaro, same molecule as Zepbound) did to one 38-year-old male body.

Starting Point: What I Looked Like on Day Zero

I started Mounjaro in April 2025. Here’s what the data said about me on day one.

I was not morbidly obese. I was the kind of obese nobody talks about, the slowly-creeping-up-10-pounds-a-year kind where your doctor says “try to lose some weight” and moves on. SURMOUNT-1 (NEJM, July 2022) enrolled exactly this profile, adults with obesity, no diabetes, average BMI around 38.

Month-by-Month Weight and Dose Data

I titrated up slowly, slower than the label schedule. I stayed at each dose at least 5 weeks because I wanted to find the lowest effective dose, not rush to 15mg.

I never went above 10mg. The SURMOUNT-1 trial showed 10mg produced 21.4% mean weight loss at 72 weeks. I hit 22.1% at 52 weeks on 10mg, which is above the trial average but within the expected range. Part of that is the exercise protocol (more on that below). Part is probably just individual response variance.

The first plateau hit hard in month 5. The scale barely moved for three weeks. I wrote more about what finally broke it in my piece on the Mounjaro weight loss plateau.

DEXA Scans: The Data That Actually Matters

Weight loss on GLP-1s is meaningless without body composition data. I paid for four DEXA scans over the year. $149 each in Austin, $596 total.

Breakdown of the 58.4 lb loss:

• Fat loss: 44.0 lbs (75.3% of total)
• Lean mass loss: 14.2 lbs (24.3% of total)
• Bone loss: 0.2 lbs (0.4% of total)

When I factor in water weight (which shows up in lean mass on DEXA), the true muscle loss is closer to 7 to 8 lbs. SURMOUNT-1 data published in Diabetes Obesity Metabolism (Neeland 2024) showed lean mass accounted for about 34% of total loss. I came in at 24.3%, better than average, and I credit that to the lifting and protein protocol.

If you’re worried about this part, the GLP-1 muscle preservation protocol and my notes on protein intake on a GLP-1 cover what I actually did.

Lab Results: Every Panel, Every Quarter

Labs were the most encouraging data of the whole year.

Testosterone went up 41% without any exogenous hormone. That matches what I cover in GLP-1 for men over 40. Fat loss drives aromatase activity down. Less fat means less estrogen conversion and more free T.

Liver enzymes normalized. My GP called at month 9 to tell me the fatty liver markers were gone. I hadn’t mentioned I was on Mounjaro.

Blood Pressure and Cardiovascular Markers

I took blood pressure every morning at 6am with the same cuff, same arm, same chair. That’s 358 readings over the year.

Systolic dropped 22 points. Diastolic dropped 14. Resting heart rate fell from 72 to 59. That last number is the one that got my cardiologist’s attention. A 13-beat drop in resting HR at the same cardio load suggests meaningful improvement in cardiac efficiency.

Side Effects: The Real Log

I kept a daily symptom tracker. Here’s what actually happened versus what SURMOUNT-1 reported.

Nausea hit hardest on day 3 after each dose increase, then faded. Constipation was the chronic one. I detailed what actually worked in my piece on GLP-1 constipation.

The worst single day was the first 7.5mg injection. I spent 14 hours in bed with nausea and a headache that felt like a hangover squared. The trick I learned the hard way is to inject Friday night, not Sunday night, so the worst of it falls on a weekend.

I never had vomiting outside of those two food-poisoning-feeling days. Ash’s full protocol for managing nausea on Mounjaro is what kept me on the drug when I almost quit in month 4.

Sleep Data (Whoop, 52 Weeks)

HRV went up 63%. Deep sleep increased 48%. I stopped snoring in month 5, which my wife confirmed. Sleep apnea symptoms faded somewhere around month 7. The improvements in sleep quality track with what’s emerging about how GLP-1 medications affect sleep.

Exercise and Protein Protocol

Nothing I did here was original. I copied what the SURMOUNT-3 intensive lifestyle arm (Nature Medicine, Nov 2023) used, then made it simpler.

Training:

• 3x per week full-body lifting, 45 minutes each
• 2x per week zone 2 cardio, 30 to 40 minutes
• Daily 8,000+ step target (hit it 329 of 365 days)

Protein:

• Target: 0.9g per lb of goal body weight (180g per day)
• Average achieved: 164g per day
• Main sources: whey isolate, chicken, Greek yogurt, eggs, cottage cheese

Supplements:

• 5g creatine monohydrate daily (covered in creatine on Ozempic and Mounjaro)
• 2,000 IU vitamin D
• 2g EPA/DHA fish oil
• Magnesium glycinate for sleep

I did not use a trainer. I used StrongLifts 5x5 for the first 6 months, then switched to a basic push/pull/legs split.

Cost Breakdown: The Full $4,872

My insurance covered 2 months out of 12. After that I switched to LillyDirect self-pay vials at $499/month for the 7.5mg and 10mg doses. I also spent a lot of time on GLP-1 cash pay vs insurance math before settling on this.

For full context on provider pricing, see the cheapest way to get GLP-1 medications online and how much GLP-1 medications cost in 2026.

What I Would Do Differently

Three things.

1. More protein, earlier. I hit 164g average but was under 140g for the first two months because nothing tasted good. That’s when I lost the most lean mass per pound of total loss. If I ran this back, I’d force-feed protein shakes from day one.

2. DEXA at baseline, not month 2. I got my first scan 8 weeks in, not at day zero. My “baseline” is extrapolated from a body fat scale I no longer trust. The real starting number was probably 2 to 3% higher.

3. Stay at 5mg longer. 5mg did more work than any other dose. Appetite suppression was plenty. Side effects were manageable. I jumped to 7.5mg because the calendar said so, not because I stopped losing. If I ran it back, I’d stay on 5mg until it clearly stopped working.

How My Numbers Compare to SURMOUNT-1

I beat the trial average on weight loss and lean mass preservation, which is probably a mix of the lifting, protein, creatine, and being a responder on the high end of the curve.

Bottom Line

Tirzepatide did what SURMOUNT-1 said it would do, but the outcomes that mattered most weren’t on the scale. Blood pressure, cholesterol, liver enzymes, testosterone, sleep, and HRV all moved in the right direction. The fat loss was dramatic. The muscle loss was real but manageable with lifting and enough protein.

If you’re on Mounjaro or thinking about starting, track more than your weight. DEXA scans are worth the $149. So are quarterly labs. The scale is the noisiest metric you have access to. If you want to see what the drug is actually doing, use the body composition calculator and compare programs in the provider directory.

FAQ

How much weight did you lose on Mounjaro in 12 months?

58.4 lbs, which is 22.1% of my starting weight of 264.2 lbs. That landed me just above the SURMOUNT-1 trial average for the 10mg dose, which was 21.4% at 72 weeks.

What dose were you on at month 12?

10mg. I never went to 12.5mg or 15mg. I titrated slowly (2.5mg for 2 months, 5mg for 3 months, 7.5mg for 3 months, 10mg for 4 months) because I was looking for the lowest effective dose, not the fastest result.

How much muscle did you lose?

14.2 lbs of lean mass on DEXA, which is 24.3% of total loss. Most of that is probably water and glycogen shifts, not pure muscle. The real muscle loss is closer to 7 to 8 lbs. SURMOUNT-1 data averaged around 34% of loss as lean mass, so 24% is better than the trial average.

What did 12 months on Mounjaro cost?

$4,872 total, including $3,890 for medication (2 months insurance copay, 10 months LillyDirect self-pay), $596 for DEXA scans, $280 for lab panels, and roughly $280 for supplements. I did not use a paid telehealth provider.

Did your side effects get worse at higher doses?

Yes, but only briefly. Each dose increase triggered 3 to 5 days of stronger nausea and fatigue, then my body adapted. 10mg was not meaningfully worse than 7.5mg after the first week. Constipation was the one chronic side effect that stayed through the whole year.

Do you plan to stay on Mounjaro forever?

No. I’m moving to a maintenance microdose (probably 2.5mg or 5mg every 10 to 14 days) in month 14. The SURMOUNT-4 data and what’s covered in the GLP-1 maintenance guide and GLP-1 microdosing for maintenance shaped that plan.

Related

Guides:

• DEXA Scan After 6 Months on Mounjaro · True Cost of GLP-1 Weight Loss · GLP-1 Body Composition Guide

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