Quest Diagnostics in a slick wrapper. The right product for the broad US biohacking-curious audience. Not the right product for someone who already knows which markers they care about and wants depth on a few.
What Function Health is.
Function Health is a US direct-to-consumer subscription. Pay one annual fee, get two comprehensive blood draws per year (~100+ biomarkers each), with results landing in a polished mobile app. Co-founded by Mark Hyman, MD; the venture brings concierge-style preventive testing to a price point closer to a gym membership than to an executive physical.
The pitch is unapologetically broad: get every marker, see your levels, track over time. That breadth is the differentiator versus single-issue tests like Cleerly or Galleri, and the price-per-marker is genuinely hard to beat in the US.
The phlebotomy experience.
This is where Function Health's product reveals its underlying chassis. The actual draw runs through Quest Diagnostics — the same chair, same staff, same waiting room as any insurance-routed lab visit in the US. Quest is enormous, well-validated, and clinically reliable, but it is not a premium experience. Wait times can be substantial. Phlebotomist quality varies with location. Reference ranges and assay families are what every other Quest-backed test gets.
The polish is on the software side, not the chair. That's a reasonable product decision — building in-house phlebotomy doesn't scale — but it's worth knowing going in. If you're paying because the marketing implied a boutique health concierge, the in-person reality is a strip-mall lab.
The data and the app.
The breadth is real. A standard Function panel covers the cardiometabolic basics (lipids including ApoB, glucose, HbA1c, HOMA-derived metrics), thyroid (TSH, fT3, fT4, antibodies), kidney/liver, full sex hormones with LC-MS testosterone, vitamins (D, B12, folate, magnesium), heavy metals, hs-CRP, and a long tail of less-validated markers. Twice-yearly cadence is sensible for catching real change.
The app does the trend visualisation well. Where it under-performs is the insights layer. Markers flagged "out of range" rarely come with a meaningful next step — most "high X / low Y" callouts could apply to half the user base and rarely translate into "do this specific thing for the next 12 weeks and retest." The result is information overflow without prioritisation: you finish a blood draw with 20 yellow flags and no idea which two matter.
"100+ markers without prioritisation creates anxiety more than insight."
This is the structural problem with broad DTC testing — the platform optimises for "comprehensive" because that's what justifies the subscription. A smaller curated panel with a clinician's interpretation would be more useful for most people, but it would also make the product less obviously different from a regular doctor's visit. Function picked breadth.
Pros
- Comprehensive panel — 100+ biomarkers twice yearly, hard to beat on breadth-per-dollar
- Easy access to clinical-grade testing without insurance gatekeeping
- Polished mobile app with clean trend lines and history
- Twice-yearly cadence makes real change detectable
- Some markers (LC-MS testosterone, ApoB, Lp(a)) are properly assayed, not surrogates
Cons
- Phlebotomy is Quest Diagnostics — mass-market chair, not premium
- App insights are broad — most flagged markers don't translate to a clear action
- Information overflow can produce anxiety without prioritisation
- No clinician in the loop — you read the numbers yourself or take them to your own doctor
- US only at time of writing
Who it's for.
Function Health is the best mass-market option in the US for someone new to preventive testing who wants broad coverage at a sensible price. It's also a good adjunct for people who already work with a clinician and just want longitudinal data between visits.
It's the wrong product if you want clinician-led interpretation built in (try YEARS if you can fly to Berlin), if you want a smaller curated panel with cleaner insights (try Aware if you're in the EU), or if you want a single deep-dive test like cardiac CT or genetic risk panel — Function isn't structured for that.
Verdict · 4 / 5
The category-defining DTC US product. Loses one star for the gap between marketing premium and Quest-chair reality, and for app insights that flag without actioning. Still the right answer if you live in the US and want broad twice-yearly biomarker coverage in one place. Pair it with a clinician who actually reads the data, or you'll generate trend lines without knowing what to do about them.
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Reviewed by Niko Hems · Last updated