Function Health vs InsideTracker: 114 biomarkers or 48?
One tests more than twice as many markers for roughly half the money. That sounds like an easy verdict — until you work out what happens statistically when you run 114 tests on a healthy person. We did the arithmetic, and it changes the recommendation.
Function Health is far better value; InsideTracker gives you a clearer plan for fewer markers. Function runs 114 biomarkers across two panels a year for $365 — about $1.60 per result. InsideTracker's Ultimate panel is 48 markers for roughly $638 including membership, about $13.29 each. But with 114 markers, the chance that at least one comes back outside its reference range is about 99.7%, and neither company prepares you for that.
Function Health
$365/yr · 114 biomarkers · two panels a year
Wins on valueInsideTracker
$149 membership + ≈$489 per Ultimate panel · 48 biomarkers
Wins on action plansThe 60-second scorecard
| What you care about | Function Health | InsideTracker |
|---|---|---|
| Biomarkers per panel | 114 | 48 |
| Panels included per year | 2 | 1 (add-ons cost extra) |
| Annual price | $365 | $149 + ≈$489 |
| Cost per result | $1.60 | $13.29 |
| Clinician review of results | Included | Algorithmic, clinician optional |
| Action plan quality | Per-marker suggestions | Prioritised, intervention-linked |
| Interventions cited to literature | Partly | Yes, explicitly |
| DNA testing | No | Available as paid add-on |
| Biological age estimate | Included, from blood | InnerAge, paid add-on |
| Athlete-focused targets | General optimal ranges | Sport-specific |
| 24-month cost | $730 | $1,276 |
What does each one really cost per biomarker?
Both companies price in a way that makes comparison awkward, so here's the same arithmetic applied to both. Function lowered its annual price to $365 in 2026, down from $499, and includes a mid-year retest. InsideTracker charges a $149 membership plus a per-panel fee, with its Ultimate panel landing around $489.
| Metric | Function Health | InsideTracker |
|---|---|---|
| Year-one outlay | $365 | $638 |
| Marker-results in year one | 228 (114 × 2) | 48 |
| Cost per marker-result | $1.60 | $13.29 |
| Cost per distinct marker | $3.20 | $13.29 |
| Two-year outlay | $730 | $1,276 |
Verified 1 September 2026. Excludes phlebotomy fees where charged separately, and InsideTracker's DNA and InnerAge add-ons.
On raw data-per-dollar this is a rout: Function delivers roughly eight times more result per dollar. If your question is "how much of my blood chemistry can I see for the money", the answer is Function and there's no serious argument.
The 99.7% problem nobody mentions
Now the part that neither company's marketing addresses, and the reason this comparison isn't a rout after all.
A laboratory reference range is conventionally defined as the central 95% of results in a healthy reference population. That means a perfectly healthy person has, by construction, a 5% chance of falling outside the range on any single marker — not because anything is wrong, but because that's what "range" means.
Run that across a large panel and the arithmetic is unforgiving:
| Markers tested | Chance at least one is "abnormal" | Expected number flagged |
|---|---|---|
| 5 | 22.6% | 0.3 |
| 10 | 40.1% | 0.5 |
| 20 | 64.2% | 1.0 |
| 48 (InsideTracker Ultimate) | 91.5% | 2.4 |
| 114 (Function Health) | 99.7% | 5.7 |
Calculated as 1 − 0.95^n, assuming independent markers and a 95% reference interval. Real biomarkers correlate within panels, so the true figures are somewhat lower — but the direction and rough magnitude hold.
the approximate chance that a completely healthy person gets at least one out-of-range result from a 114-marker panel. Expect roughly six flagged markers. That's not the lab failing; it's the definition of a reference range. It is also the number that should appear on the results screen, and doesn't.Applandica calculation, 1 − 0.95114
This matters for real reasons, not pedantic ones:
- Cascade testing. A flagged marker leads to a repeat test, then an imaging scan, then a specialist referral. Each step carries cost, time and its own false-positive rate.
- Anxiety is a side effect. Six red numbers on a dashboard produce a feeling that no amount of small-print context undoes.
- It gets worse on repeat. Function's two-panels-a-year model doubles your annual exposure to the same statistics.
The mitigation is straightforward and both companies could ship it tomorrow: show the expected number of out-of-range results before you show the results. Rank flags by clinical significance rather than by how red they look. Say plainly which markers are screening-grade and which are noise until repeated. Function's included clinician review is the closest thing either offers, and it's a real point in its favour.
Data versus a plan
InsideTracker's defence of its price is that it isn't selling markers, it's selling prioritisation. Its output links your specific out-of-range results to interventions with citations attached and ranks them, with targets that adjust for athletic context. That's a genuinely different product from a wall of 114 numbers, and for someone who wants to be told what to do on Monday it's worth something.
Whether it's worth $546 more over two years is the actual question. Our answer: for most people, no — but for a serious endurance or strength athlete tuning ferritin, vitamin D and inflammatory markers around a training block, plausibly yes.
Neither product replaces a clinician, and both are clearest about this in their terms of service and vaguest about it in their advertising. Broad biomarker screening in asymptomatic adults is not currently recommended by major preventive-health guidelines, which is a fact worth knowing before you spend either amount.
Priya's take
Co-founder & Head of Testing · former clinical data scientistI spent years building reference intervals for a clinical lab, so I'll admit a bias: this category makes me twitchy in a specific way. Not because the tests are bad — the assays are the same ones your doctor orders, run by the same reference labs — but because the interpretation layer is where consumer health products consistently fail, and interpretation is the entire product here.
Here's what I'd actually buy. Function, once. Not as a subscription — as a single, deliberate snapshot in a year when you have a reason to look. Take the results to a clinician who knows you, and let them tell you which of your six flags is signal. That's roughly $365 for a genuinely comprehensive baseline, which is remarkable value compared with what the same panel costs paid privately.
What I would not do is run it twice a year indefinitely. Repeated broad screening on an asymptomatic person is how you end up with a scan you didn't need, and I've watched that happen to people who could well afford the test and could not afford the following six months of worry.
On InsideTracker: I like the prioritisation, I like that interventions are cited, and I think the price is difficult to defend for a general audience at $13 a marker. If you're an athlete with a specific question, it's a reasonable buy. If you're a curious person with a credit card, you're paying a large premium for a nicer explanation of fewer numbers.
The thing I want from both, and would raise their scores five points tomorrow: put the multiple-comparisons maths on the results screen. "You tested 114 markers. About six will read out-of-range by chance alone. Here are the two that matter." That is one paragraph of copy and it would make these products meaningfully safer.
Who should buy which
Buy Function Health if…
- You want the broadest baseline for the money
- You'll take results to a clinician who knows you
- You value the included clinician review
- You want biological age without an add-on fee
Buy InsideTracker if…
- You're an athlete tuning a training block
- You want prioritised, cited interventions
- You want DNA or InnerAge alongside blood work
- Fewer, better-explained markers suit you
Buy neither if…
- You're anxious about health — this category reliably makes that worse
- You have symptoms; see a clinician, who can order the right tests
- Your insurance already covers the panel your doctor would choose
- You won't act on the results either way
Not medical advice, and not a screening programme. Broad biomarker panels in asymptomatic adults are not recommended by major preventive-health guidelines, and neither product diagnoses anything. If a result worries you, the next step is a clinician — not a second panel.
Frequently asked questions
Is Function Health or InsideTracker better value?
Function Health, by a wide margin on data-per-dollar. It covers 114 biomarkers across two panels a year for $365 — about $1.60 per result — against InsideTracker's 48 markers for roughly $638 including membership, about $13.29 per result. InsideTracker's argument is prioritisation and cited action plans rather than raw coverage.
Why do so many of my biomarkers come back abnormal?
Because a reference range is defined as the central 95% of a healthy population, so each marker has a 5% chance of falling outside it by chance. Across 114 markers the probability of at least one out-of-range result is about 99.7%, with roughly six flags expected. Across 48 markers it's about 91.5%, with about two expected.
How many biomarkers does Function Health test?
114 distinct biomarkers, run twice a year within the $365 annual membership, with clinician-reviewed notes and a blood-based biological age included at no extra cost.
Does InsideTracker include DNA testing?
Not by default. DNA analysis and InnerAge are paid add-ons on top of the $149 membership and the panel fee.
Can these replace a doctor's blood work?
No. The assays are standard and run by reference laboratories, but neither service diagnoses conditions, and broad screening in people without symptoms isn't recommended by major preventive-health guidelines. Treat the results as a conversation-starter with a clinician who knows your history.
Should I test twice a year?
Only if you have a reason — a treated deficiency you're re-checking, a medication change, a training block. Repeat broad screening on an asymptomatic person doubles your annual exposure to false positives and the cascade of follow-up testing they trigger.
Sources
- Function Health — annual membership pricing ($365 in 2026, reduced from $499), 114 biomarkers, two panels per year, clinician-reviewed results. Verified 1 Sep 2026
- InsideTracker — $149 membership plus per-panel pricing; Ultimate panel ≈$489 for 48 biomarkers; DNA and InnerAge as paid add-ons. Verified 1 Sep 2026
- Applandica calculation: probability of at least one out-of-range result = 1 − 0.95n, assuming a 95% reference interval and independent markers. n = 48 → 91.5%; n = 114 → 99.7%. Method published here so you can check it
- Clinical and Laboratory Standards Institute convention for reference intervals: central 95% of a healthy reference population.