Direct-to-consumer full-body scans have become a visible part of the prevention conversation — marketed as a way to catch problems years before symptoms appear. The idea is appealing, and worth understanding clearly, including what medical experts actually say about it, before spending anywhere from several hundred to several thousand dollars on one.
Full-body MRI: what it is and what it costs
A full-body MRI uses magnetic fields and radio waves (no ionizing radiation) to produce detailed images of soft tissue. A scan session commonly takes 45 to 90 minutes depending on the provider. Pricing varies widely — get a clear, itemized quote before booking, since "full body scan" packages vary considerably in what they actually cover.
Full-body CT: the key difference from MRI
A full-body CT scan uses X-rays (ionizing radiation) rather than magnetic fields. CT scans involve a real, cumulative radiation dose, and the FDA has issued public guidance specifically cautioning against unnecessary CT-based screening in people without symptoms or elevated risk factors.
What major medical organizations actually say about screening scans
- Limited evidence that population-wide screening in low-risk individuals reduces mortality.
- False positives and incidental findings are common, leading to additional tests, cost, and anxiety.
- Scans are a snapshot, not a diagnosis — findings still require clinical follow-up.
None of this means full-body scans have no value — for people with specific risk factors, family history, or symptoms, targeted imaging ordered by a physician is a completely different conversation.
Where a Comprehensive Metabolic Panel (CMP) fits in
A CMP is a far more modest, far more commonly ordered test than a full-body scan. See ONU's full guide to understanding a CMP and other blood test results.
What actually works well between scans and lab draws
The months between periodic testing are exactly where continuous tracking earns its value: watching HRV and resting heart rate trends, sleep quality, and stress patterns day to day means you're not waiting for the next scheduled test to notice that something has shifted.
How to think about your own prevention plan
- Talk to your doctor about your actual risk profile.
- Understand what a specific scan package actually includes before paying for it.
- Use routine, low-cost testing (like a CMP) as your baseline.
- Track continuously in between.
Frequently asked questions
Every claim, built on the same foundation
Plain-language, evidence-checked explanations of the biology behind your health data — organized by the kind of question that usually brings people here in the first place.
1Blood Test Results Explained
Cholesterol, non-HDL, A1C, and metabolic panels — decoded in plain English, including what a borderline number is actually worth flagging to your doctor.
2Sleep Score Explained
Deep sleep, REM, and why your score moves the way it does — plus research-backed ways to actually improve both, not just chase a higher number.
3Why Am I Always Tired?
Tired but can't sleep, dragging through mornings, waking up unrefreshed — the most common, evidence-backed explanations, in plain language.
4HRV Explained
What heart rate variability measures, what counts as a good resting heart rate, and how HRV connects to zone 2 training and real recovery.
5Cortisol and Stress
What cortisol actually does in your body, what the viral terms get right and wrong, and which foods and supplements genuinely affect stress.
6Acute vs. Chronic Stress
The actual difference between short-term stress and chronic burnout, and whether stress genuinely speeds up aging — without the scare tactics.
7Biological Age Testing
VO2 max, biological age calculators, and the longevity metrics everyone's suddenly discussing — what's evidence-backed, and what's still unproven.
8Full Body Scans & Preventive Checkups
What full-body MRI and CT scans actually involve, what physicians say about screening healthy adults, and where routine tracking fits in between.
9Magnesium & Ashwagandha: A Practical Guide
Which magnesium form actually helps sleep, when to take it, and how much ashwagandha is typically used in studies — no supplement-aisle guesswork.
How this library is built
Every article here goes through the same process: a claim isn't published until it's checked against a primary, authoritative source — the CDC, NIH, WHO, American Diabetes Association, American Heart Association, or peer-reviewed research, depending on the topic — and every article stays inside ONU's wellness-lane guardrail: educational and non-diagnostic, with no disease, treatment, or cure claims anywhere. Where the science is genuinely unsettled or still developing, these guides say so directly, rather than overstating certainty for the sake of a cleaner narrative.
Nothing in this library exists purely as content marketing disconnected from the product. Each article maps directly to something ONU's app actually measures and interprets: the HRV guide explains the exact metric behind your recovery score, the Blood Test Results guide explains the same interpretation logic your uploaded labs go through, and the Cortisol guide explains the physiology behind your daily stress signal. Reading a guide here should make your own ONU Score meaningfully easier to understand, not just deliver abstract information disconnected from your actual data.
If you want a broad orientation rather than jumping straight to one specific question, a reasonable starting sequence is: Blood Test Results Explained (the foundation for understanding any lab work), Sleep Score Explained and HRV Explained (the two most common wearable metrics people misunderstand), then Cortisol and Stress (the physiology behind the terminology dominating health conversations online right now). From there, the remaining guides go deeper into specific, related questions.
See how ONU turns this knowledge into your daily ONU Score in the full product overview.
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