What six months on tirzepatide did to my lean mass
TLDR: If you are using GLP-1–based medications, you need a deliberate strategy to preserve lean mass.
These medications are powerful. That is part of what makes them so useful, but also why I think they deserve a little more respect than simply celebrating the number on the scale.
Why I ran this on myself
At the start of November, I began taking the minimum dose of tirzepatide, 2.5 mg once per week. Part of the reason was personal, but part of it was professional curiosity. I am a strength coach, and several of my clients had started using these medications. I wanted to better understand the experience for myself, including the physical and behavioural side of appetite suppression and weight loss.
My own relationship with food is probably not unusual for someone who came through football. I deliberately gained a large amount of bodyweight to play offensive line, and after that, body composition became something that tended to oscillate depending on what I was training for.
So I decided to treat this like a small personal case study. The protocol was simple:
- DEXA scan before starting
- Tirzepatide 2.5 mg once per week
- Train 3 to 5 times per week
- Repeat the DEXA roughly 6 months later
What the two scans showed
| Measure | Oct 27, 2025 | Apr 15, 2026 | Change |
|---|---|---|---|
| Body weight | 252.1 lb | 216.0 lb | −36.1 lb |
| Fat mass | 66.7 lb | 43.1 lb | −23.6 lb |
| Lean mass | 176.7 lb | 164.2 lb | −12.5 lb |
| Body fat | 27.4% | 20.8% | −6.6 pts |
| Visceral adipose tissue | 8.18 in² | 1.76 in² | −6.42 in² |
Most of that table is good news. The fat loss is substantial, and the drop in visceral adipose tissue is the kind of change that matters well beyond appearance.
But the lean mass row is the reason I am writing this.
A third of what I lost was lean tissue
DEXA lean mass is not the same thing as skeletal muscle mass alone. It includes other lean tissues and fluid, so I do not want to overstate what the scan can tell us. But the direction is still important: I lost a meaningful amount of lean tissue over the same period that I lost a large amount of fat.
And I was trying not to.
I have a training background. I was still training. I was thinking about this problem in advance. Even then, preserving lean mass was not automatic.
To be fair, this was not the most consistent training block of my life. I started the period while rehabbing a medial hamstring injury, and there was a stretch where I was doing several hours of hatha yoga each week instead of more traditional strength training. Still, I was training regularly and using a structured upper/lower split for much of the period.
That is what made the result useful to me.
The medication made weight loss easier. It did not make tissue selection intelligent.
What I take from it
Your body does not necessarily know that you only want to lose fat. If energy intake drops enough, and the training stimulus is not strong enough or consistent enough, lean tissue can come along for the ride.
That is where I think some caution is warranted.
I am not anti-GLP-1. Quite the opposite. These medications are clearly powerful tools. But powerful tools should probably come with equally serious strategies. If preserving lean mass matters to you, then these should not be afterthoughts:
- Resistance training, with real progression
- Protein intake
- Recovery
- Objective monitoring, so you find out what is actually happening
You do not just want to lose weight. You want to influence what kind of weight you are losing.
That is also the idea behind Lucky Health, a remote training service I am building for people using GLP-1 medications. The goal is not just to “stay active.” It is to train with enough structure and intent to preserve as much lean mass as reasonably possible while body composition is changing.
Because these medications are powerful. And that is exactly why I think the training side needs to be taken seriously too.
This is a personal account of one person’s experience, not medical advice, and a single case is not evidence of what will happen to anyone else. Decisions about GLP-1 medications belong with your own physician.