DEXA Body Composition

What your body is actually made of.

Lean mass declines roughly 3–8% per decade after 30, and the scale cannot see any of it. DEXA measures fat, lean tissue and bone as three separate things — region by region, down to the gram. Body composition we can measure — not a number that went down.

Scan 10–15 min • open table

Measures • fat • lean • bone • region by region

Results • same day • in the same visit

Why We Measure It

The scale measures weight. Nothing else.

Two people at the same weight and the same height can carry entirely different risk. What separates them is composition, and composition is invisible to every bathroom scale ever made.

Where fat sits matters more than how much of it there is. Visceral fat — the fat packed around your organs rather than under your skin — behaves like an endocrine organ, releasing inflammatory signals that track with insulin resistance and cardiovascular risk. Someone can look lean and carry a great deal of it. DEXA quantifies it directly.

Lean mass is the other half of the picture, and it is the half people lose without noticing. Muscle is where glucose gets disposed of, and it is the difference between recovering from a fall in your seventies and not. A patient who loses 15 pounds and feels successful may have given up a meaningful share of it from muscle — and no scale, no mirror and no clothing size will tell them that happened.

Bone is measured on the same scan. Bone loss produces no symptoms whatsoever until something breaks, which makes it one of the few conditions where the first sign is also the consequence you were trying to avoid.

What We Measure

One scan. Four answers.

Measure 01

Fat and lean mass, total and regional

Body fat percentage, then lean mass broken out by arms, legs and trunk, with left-to-right symmetry. The regional data is what makes the scan useful for training rather than just for reassurance.

Measure 02

Visceral adipose tissue and fat distribution

The fat around your organs, reported as its own value rather than folded into a single body-fat percentage, alongside the pattern of where the rest of it sits.

Measure 03

Relative skeletal muscle index

Muscle mass scaled to your frame. This is the measurement early sarcopenia is identified by, and it is the one that predicts function later.

Measure 04

Bone mineral density at hip, spine and total body

With T-scores and Z-scores where indicated, and a baseline fracture-risk picture to track against. The WHO thresholds are standard: a T-score between −1.0 and −2.5 is osteopenia, and −2.5 or below is osteoporosis.

The Appointment

Ten minutes, fully clothed.

You lie on an open table while a scanning arm passes above you. Nothing encloses you, nothing touches you, and nothing about it is uncomfortable — the most common remark is that patients expected more. It takes 10 to 15 minutes from lying down to standing up.

The radiation dose is very low. No fasting is required. Wear clothing without metal — no zips, underwire or heavy buttons — and tell us if you have had contrast imaging or a nuclear medicine study in the past week, since either can affect the reading.

Result timing

You do not wait for results. Your scan is read and explained the same day, in the same visit — which is the point of doing this in a physician’s office rather than at a scan-and-email service.

Not eligible

DEXA is not performed during pregnancy. If there is any chance you are pregnant, tell us and we will reschedule.

Interpretation

The scan is the starting point.

A first DEXA tells you where you are. The second one tells you whether what you are doing is working.

The scan is read against your labs, your training history and your goals. In practice that produces a small number of specific decisions: whether protein intake needs to go up, whether resistance training needs to be added or restructured, whether visceral fat warrants a closer look at insulin and lipids, and whether bone density calls for intervention now or monitoring on an interval.

For patients losing weight, DEXA is how we hold the protocol accountable. Paired with a measured resting metabolic rate, it answers the only question that matters during a deficit: is the weight coming off the right tissue? If it is not, the protocol changes.

Body composition sits across two of the Peak Longevity Six — Metabolic and Strength. It is measured alongside the other four, because a good composition number does not offset a poor result elsewhere.

Retest cadence

We do not scan more often than quarterly unless there is a clinical reason to. Composition does not change fast enough for it to tell you anything.

Pricing

Priced plainly.

DEXA scan

$150

DEXA + VO₂ max + RMR together

$325

DEXA is included in Peak Longevity and Peak Elite, repeated on the cadence your protocol calls for. Peak Foundations patients can add it at the à la carte price. Most patients use FSA or HSA funds.

The scanner is in our Meridian office, and patients travel to it from across Boise, Meridian and Eagle. No referral is required.

Begin

Lean mass is the thing you cannot get back easily later. Measure it before you need it.

The information on this page is for educational purposes and is not medical advice. Testing and treatment decisions are made by a physician in the context of your individual history.