THE REASONS BEHIND THE PICKS
What matters.
And what doesn't.
Five things decide these picks: what a test measures, how the sample is taken, what a year costs, who reads the results and what you can get back. We don't rank by how many markers a company counts. We don't rank by biological-age or health scores, or by longevity claims, either. Randomized trials of general health checks found little or no effect on deaths. An FDA clearance covers how a glucose monitor measures, not whether wearing one helps. A lab's CLIA certification covers how it runs tests, not whether a test is worth taking.
01Membership or one-off
Function, Superpower and InsideTracker renew every year, and none promises its renewal price. Function charges $365 for the first year. Superpower lists $349 a year, or $599 in New York and New Jersey. InsideTracker's $489 bundle includes one test, and member retests cost $340 each. SiPhox charges per kit, $124 to start plus shipping, as often as monthly. Quest's panel ($405) and a TruAge kit ($499) are one-off buys, but every retest costs the same again. A TallyAge kit is a $249 one-off too. Tally's membership costs $129 a month and includes a test every six months. Wearing a glucose monitor all year costs about $1,022 to $1,408, depending on brand and plan. If you want a dietitian to read your glucose data, Nutrisense's program comes to $2,988 a year at list.
What to checkAdd up the renewal and every retest you plan, not just the first order. Note the date any membership renews.
02How the sample is collected
Function, Superpower, InsideTracker and Quest draw blood at a lab. Function and Quest use Quest centers, InsideTracker most often does, and Superpower uses Labcorp, Quest or another lab. A home draw costs $119 extra at Superpower and InsideTracker, and $79 at Quest. Function sells one in select areas but shows no price. InsideTracker requires the home draw in New York, New Jersey, Rhode Island, Hawaii, Arizona and Canada. SiPhox's kit takes a small sample from your upper arm at home, and its Longevity Essentials panel covers 25 biomarkers. TruAge uses a few drops of finger-prick blood you mail back, and TallyAge a cheek swab sent back with a prepaid label. Lingo and Stelo are sensors you wear on the back of your upper arm.
What to checkIf you won't go to a lab, price the home draw or kit. Then compare what that sample actually tests.
03Measured directly or calculated
Headline counts don't compare well. Function counts lab tests, while Superpower and SiPhox count biomarkers. Superpower's own pages give four different baseline counts, and InsideTracker says up to 54 biomarkers without listing them. Several services also add scores calculated from your results. Examples are Quest's Health Quotient Score, InsideTracker's healthspan scores and Superpower's biological age estimate. TallyAge reports a single epigenetic age, and Tally says results can swing by about two years between tests. TruDiagnostic doesn't say whether its telomere, CRP and IL-6 results are measured or estimated from DNA methylation.
What to checkAsk for the list of what the lab actually measures. Treat scores built from those results as summaries, not extra tests.
04FDA-cleared sensor or lab test
Lingo and Stelo are FDA-cleared devices. The clearance covers how they measure glucose, not any health benefit. Neither the FDA records nor the makers' pages give an accuracy figure such as MARD. Lingo is cleared for adults 18 and older not on insulin. Stelo was cleared for the same group in 2024. In June 2026 the FDA widened Stelo's clearance to anyone 2 or older not on insulin, with an adult caregiver supervising children. None of the lab tests here claims FDA clearance. TruDiagnostic, InsideTracker, Quest and SiPhox say a CLIA-certified lab runs their tests. Tally doesn't name its lab or mention CLIA. Superpower says some of its tests are lab-developed and not cleared or approved by the FDA. Function's pages don't state CLIA or CAP status.
What to checkRead an FDA clearance as a statement about measurement. Look up a named lab in CMS's free QCOR CLIA lookup. SiPhox and Tally don't name their labs, so you can't check them.
05Who reads your results
Function says clinicians review every result and add a summary and action items. Superpower has a care team of physicians, nurse practitioners and pharmacists, and says its concierge replies within one business day. With Quest, a provider licensed in your state approves the order, and you can discuss results with an independent provider at no extra cost. InsideTracker's terms say a clinician may order tests without forming a doctor-patient relationship. It doesn't say whether one reviews results. SiPhox calls itself a wellness-only service. If you want a dietitian to read your glucose data, Nutrisense ships two Stelo sensors a month for $249, with access to 1:1 dietitian video calls. That's $150 more than Dexcom charges for the sensors, and charges aren't refundable. Lingo also offers dietitian visits through Berry Street, and Stelo lists 1:1 calls with a dietitian or nutrition specialist. What you pay for calls depends on your insurance. Nutrisense's first call is free, and Stelo offers one free 30-minute call without coverage.
What to checkAsk who follows up an abnormal result, how and how fast. A score or a glucose trace on its own isn't a diagnosis.
06Your state, and what you can get back
Function isn't offered in Rhode Island, Hawai'i or Puerto Rico. Superpower's FAQ lists nine states it doesn't serve, and its homepage disagrees. SiPhox doesn't serve Hawaii or New York, and Quest can't collect in Arizona, Hawaii or Puerto Rico. Function refunds only within 48 hours and before any sample. Superpower's agreement offers a one-time refund in the first term, though its FAQ says it doesn't refund. InsideTracker may refund within 30 days if the test is unused. Quest refunds before collection, minus a $20 fee. TruAge and SiPhox don't refund once a kit ships, and Stelo's sales are all final. Tally takes back unused kits in their original packaging if you email first, but gives no return window. Lingo's 30-day guarantee covers a first purchase only.
What to checkConfirm your state is served before you pay. Read the refund clause and note when its window closes.
