Which method is best for longevity tracking?

It depends on the question. Use the method you can repeat under the same conditions, and keep the same one across scans.

Can a 3D scan replace DEXA?

They measure different things. A 3D scan reports posture, circumferences and BIA composition, while DEXA uses X-rays. Choose by the question you need answered.

How often can I repeat BIA or a 3D scan?

Both are quick, so a re-scan every 12 weeks is a common rhythm.

DEXA vs BIA vs 3D Scan for Longevity Tracking

DEXA vs BIA vs 3D scan for longevity tracking

Three common ways to measure the body over time. Each answers a different question.

Short answer

DEXA uses low-dose X-rays and is usually done at a medical or specialist site. BIA estimates composition with a small electrical current and is quick to repeat, and a 3D scan adds posture and circumferences. For tracking over time, the best method is the one you can repeat under the same conditions. Reports are for reference, not a medical diagnosis.

Last updated: November 2026

Side by side

	DEXA	BIA	3D scan
Method	Low-dose X-ray absorptiometry	Small electrical current through electrodes	Optical 3D capture
Typical setting	Medical or specialist site	Clinic, gym or studio	Clinic, gym or studio
What it adds	Bone and regional composition	Fat, muscle and water, by segment	Posture and circumferences
Repeating it	Depends on access and cost	Quick to repeat	Quick to repeat

What each is good for

DEXA is often used when a bone or regional composition read-out is wanted. BIA and 3D scanning suit regular check-ins because they are quick and can be repeated every 12 weeks. Visbody combines 8-electrode BIA with a 3D scan in one session.

Personal trainer coaching a client through dumbbell exercises

Consistency beats a single number

Whatever the method, repeat it under similar conditions: same time of day, hydration and clothing. The trend over time matters more than one reading. Reports are for reference, not a medical diagnosis.

For a wider comparison of the three methods, see our guide to BIA, 3D body scanning and DEXA.

BIA vs 3D body scan vs DEXA Visbody for longevity

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