SiPhox Health vs Function Health (2026): At-Home Simplicity vs the Full Membership
One mails a no-needle kit to your door for ~$99; the other is a $365/yr lab membership. Which serves longevity tracking better comes down to one question: breadth or frequency?
These two get compared a lot because they answer the same question - what are my biomarkers doing over time - in opposite ways. Function Health is a full lab membership: two clinic draws a year, 160+ markers, AI insights, physician review, $365/year. SiPhox is the at-home route: a no-needle upper-arm sample you collect yourself, up to 60 markers, AI action plan, from about $99 a kit.
The honest decision comes down to one trade: breadth or frequency.
The core trade
Function gives you the broadest single snapshot - 160+ markers, drawn at a lab, reviewed by a physician. SiPhox gives you a narrower panel (up to 60) but removes every point of friction: no lab visit, no needle, no appointment, and a low enough price that testing every quarter is realistic. For longevity tracking, the value is in the trend, and four data points a year at $99 each often beats two at $365 for watching a marker actually move.
Spec comparison
| Spec | SiPhox Health | Function Health |
|---|---|---|
| Price | ~$99+ per kit (memberships from ~$125) | $365/yr membership |
| Biomarkers | up to 60 | 160+ |
| Collection | At-home, no-needle (upper arm) | Lab draw (Quest/LabCorp) |
| Turnaround | ~7-10 days | ~1-2 weeks |
| Insights | AI summary + action plan | AI insights + physician review |
| Physician review | No (testing + insight only) | Yes |
| HSA/FSA | Yes | Yes |
| Best cadence | Quarterly or more | Twice a year |
Where Function wins
- Panel breadth: 160+ markers vs 60. If you want the widest one-time picture, Function covers more.
- Physician review: flagged results get a clinician look. SiPhox is testing and insight, not a review or prescribing relationship.
- Cohort data + brand: the largest member base and the category-defining brand.
Where SiPhox wins
- No needle, no lab: the whole draw happens at your kitchen table. For needle-averse buyers, this is the difference between testing and never testing.
- Price + frequency: ~$99 makes quarterly testing realistic, and trend lines need frequency.
- Speed to first test: kit ships in days, no appointment to book.
The middle option
If you want a membership with past-lab upload and a biological-age readout, the cleaner comparison is Mito Health - the same 100+ marker membership model at a near-identical price ($349 Core vs Function's $365). See Mito vs Function for that side.
The honest recommendation
- First comprehensive baseline, or you want physician review → Function (or Mito for the same thing cheaper)
- Ongoing, frequent, friction-free tracking, especially if needles are why you have not tested → SiPhox
- Many buyers run both: one broad annual panel for depth, SiPhox quarterly for the trend in between.
Biomarker tracking only pays off if you keep doing it. Pick the one you will actually run on schedule.
For the full membership-tier breakdown, see Best Diagnostic Platform 2026.
- Ryan, Founder
The products this post references
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