InBody or DEXA: Which Scan to Use and When

People often ask which body composition scan is better. The honest answer is that InBody and DEXA do different jobs. One is a precise measurement you take a couple of times a year. The other is a quick check you can repeat often enough to see a trend.

DEXA: the precise checkpoint

DEXA uses two low energy X ray beams. Fat, lean tissue and bone absorb them differently, so the scanner can measure each tissue directly across your whole body. You lie still for about 10 minutes, and the radiation is a small fraction of a chest X ray.

What DEXA does well:

• Fat mass and lean mass with high precision.
• Bone density, which InBody does not measure.
• Regional numbers for the arms, legs and trunk.
• An estimate of visceral fat around the organs.

We repeat DEXA about every 6 months. It costs $199.

InBody: the frequent check

InBody uses bioelectrical impedance. You stand on the device and hold the handles while a small current passes through your hands and feet. Water and muscle conduct current well and fat does not, so the device estimates your body fat, lean mass by arm, leg and trunk, visceral fat level and body water. It takes about a minute and costs $39.

The tradeoff is that InBody is sensitive to conditions. A big meal, a hard workout or a day of poor hydration can shift the result. That is why it is better for trends than for a single reading. We repeat it about monthly.

To keep InBody readings comparable:

• Scan at the same time of day each time.
• Skip food and exercise for a few hours beforehand.
• Use the bathroom first.

Using them together

For most members we use DEXA as the baseline and the 6 month checkpoint, and InBody in between to see whether the plan is moving in the right direction. A hypothetical 45 year old woman starting a strength program might get a DEXA in January, InBody scans each month, and a second DEXA in July to confirm what the monthly trend suggested.

One caution. Compare each tool only with itself. An InBody and a DEXA taken the same day will rarely give the same body fat percentage, because they measure in different ways. The change from one InBody to the next, or one DEXA to the next, is what matters.

That's how we track body composition. Purchasing either scan takes you straight to scheduling.

Book a DEXA scan at HYBRD Health ($199)

Book an InBody scan at HYBRD Health ($39)

This article is educational and is not medical advice.