Short answer: if you're over 40, trying to lose weight, on a GLP-1 or starting hormones, probably yes.
Here's why.
What a DEXA scan is
DEXA stands for dual-energy X-ray absorptiometry. You lie on a table for about 10 minutes while a scanner passes over you. The radiation dose is very low, a small fraction of a chest X-ray.
It measures what your body is actually made of:
Muscle, by region, so I can see your arms and legs separately.
Fat, and where it sits.
Visceral fat, the fat around your organs that’s most tied to heart disease and diabetes.
Bone density.
Why the scale isn't enough
The scale gives you one number. It can't tell you whether you lost 5 pounds of fat or 5 pounds of muscle. That difference matters. Losing muscle slows your metabolism, worsens your blood sugar and raises your risk of falls and frailty later.
BMI is no better. Two women can have the same BMI and very different health. One has plenty of muscle. The other has a normal weight and too much visceral fat.
Who should get one
Women in perimenopause or menopause. Body composition and bone both change fast in these years.
Anyone on a GLP-1. These medications work, but some of the weight lost can be muscle. A DEXA tells us whether we’re protecting it.
Anyone starting a serious strength or weight loss plan, so you know your starting point.
Anyone with a family history of osteoporosis or early heart disease.
What the numbers actually mean
A DEXA report is long. These are the numbers I focus on.
Visceral fat. The fat around your organs, reported in pounds or grams. There’s no single perfect number, so I care most about the trend. If it’s going down, your risk is going down, even if the scale barely moves.
Appendicular lean mass. The muscle in your arms and legs, adjusted for your height. This is the number used to screen for low muscle mass (sarcopenia), and it’s the one I protect most on a GLP-1.
Android to gynoid ratio. Belly fat compared with hip fat. A higher ratio means more fat stored around your middle, which is tied to higher heart and metabolic risk. It often rises in perimenopause.
Body fat percentage. Useful, but less important than where the fat sits.
Bone density. A whole-body estimate. It can flag a problem early, but it isn’t the diagnostic test (more on that below).
The point isn't to hit a perfect number. It's to know whether what we're doing is building muscle and losing the right fat.
How often
While we're actively changing things (starting a GLP-1, adjusting hormones, a new training plan), I repeat it every 3 months. That lines up with your biomarker rechecks, so we see your body composition and your labs move together. If muscle starts slipping, we catch it in weeks, not a year later. Once you're stable, we space it out.
One thing most people don't know
A body composition DEXA isn't the same as the bone density scan used to diagnose osteoporosis. That one looks closely at your hip and spine. If you need an osteoporosis workup, I order it separately.
How to get an accurate scan
Small changes in hydration and food can shift your numbers, especially lean mass. To compare one scan with the next:
Go at the same time of day, ideally in the morning before eating.
Drink normally the day before. Don’t over or under hydrate.
Skip hard workouts that morning.
Use the same machine each time when you can.
Wear clothes with no metal.
Even then, a change of a pound or so can be noise. That's why I look at the trend over several scans, not one result on its own.
How I use it
A DEXA is a starting point, not an answer. I read it next to your labs, your hormones and your wearable data. Then we set targets: how much visceral fat to lose, how much muscle to build, and when we'll check.
I coordinate DEXA scans in Los Angeles as part of care. If you want to know what you're actually made of, start with a call.
This is general education, not medical advice for your situation.
