How we choose blood tests, biological-age kits and glucose monitors

What earns a place

This guide covers health tests you can order and pay for yourself in the US, at a published price. Function Health, Superpower and InsideTracker sell yearly blood-panel memberships with draws at a lab^{1, 4, 9}. Quest’s Elite Health Profile is a one-off lab panel at $399 plus a $6 physician fee²⁵. SiPhox Health mails a kit for a small sample from your upper arm, at $124 to start plus shipping^{27, 28}. Two kits estimate biological age: TruDiagnostic’s TruAge is a finger-prick kit scored for DNA methylation aging¹³, and Tally Health’s TallyAge reports an epigenetic age from a cheek swab³⁴.

Dexcom’s Stelo and Abbott’s Lingo are glucose monitors sold without a prescription^{15, 17}. If you want a dietitian to read your glucose data, Nutrisense sells Stelo sensors with access to dietitian video calls⁴¹. A first order across all ten ran from $54 to $499 when checked on October 13, 2026^{13, 17}. The FDA cleared Stelo in March 2024 as the first over-the-counter CGM, for adults 18 and older who don’t use insulin¹⁶. In June 2026 it widened Stelo’s clearance to anyone 2 or older who doesn’t use insulin³³. Lingo was cleared in May 2024 for adults 18 and older not on insulin¹⁹.

Tests your own clinician orders and bills to insurance are outside this guide. Our evidence review covers which of those have guideline support. Each pick names the need it serves, its trade-off and an alternative. Picks are for different needs, not a ranking.

What we weigh

Seven questions decide the picks. Each answer comes from the company’s own pages or terms, or from an FDA record, and carries the date it was checked.

• What it measures. We record the sample, the number of draws or sensors in an order and the tests or biomarkers per draw. Function lists 100+ lab tests at an annual visit and 60+ at a follow-up 3 to 6 months later². Quest lists 85+ markers from one visit²⁵. TruAge reports DNA methylation aging scores from a few drops of finger-prick blood¹³. TallyAge reports one epigenetic age from a cheek swab³⁴. Lingo’s 2-week plan is one sensor worn for up to 14 days¹⁷.
• How the sample is taken. We record whether you go to a lab, pay for a home draw or collect the sample yourself. InsideTracker charges $119 for a mobile draw⁹. Quest charges $79 for home collection where it’s offered²⁵. SiPhox’s upper-arm kit covers 25 biomarkers on its Longevity Essentials panel³¹, and SiPhox says upgrades reach up to 62²⁸. Tally’s cheek-swab kit goes back in the mail with a prepaid return label⁴⁶.
• What a year costs. A first-year price isn’t a yearly price. Function charges $365 for the first year and renews at the then-current price, which it doesn’t state¹. InsideTracker’s $489 bundle includes one test, and member retests cost $340 each^{9, 10}. TruDiagnostic says many customers retest every 3 to 6 months, which at $499 a kit is $998 to $1,996 a year¹³. Its online store also lists a 4-test subscription at $998 a year²⁴. Quest’s panel doesn’t renew, but each retest costs the same $399 plus $6²⁵. A TallyAge kit is $249³⁴. Tally’s membership costs $129 a month and includes a test every six months³⁵. Nutrisense keeps billing $249 a month until you cancel^{41, 43}.
• Who runs and reads the tests. We record the lab each company names, what it says about CLIA or CAP, and whether a clinician reviews results. Superpower names Labcorp, Quest Diagnostics or another third-party lab⁶. InsideTracker’s terms say a licensed clinician may order the tests where state law requires it, without forming a doctor-patient relationship¹². Function says clinicians review every result². With Quest, a provider licensed in your state reviews, approves and orders the test²⁶. Nutrisense sells access to 1:1 dietitian video calls, and its first call is free^{41, 44}.
• What a glucose monitor is cleared for, and what it doesn’t do. We record the FDA clearance and who it covers. The FDA said Stelo isn’t designed to alert users to problematic hypoglycemia¹⁶. Lingo’s 510(k) summary says its app gives no glucose or system alerts¹⁹. Nutrisense ships the same Stelo sensors and, like Dexcom’s buy page, still lists them for adults 18 and older not on insulin^{15, 41}.
• Who can use it, and where. State rules change both access and price. Function isn’t offered yet in Rhode Island, Hawai’i or Puerto Rico². Its $365 full access excludes New York and New Jersey, where its terms say some or all lab fees may be billed to you directly by the lab^{1, 3}. Superpower charges $599 a year in New York and New Jersey⁷. InsideTracker requires a $119 mobile draw in New York, New Jersey, Rhode Island, Hawaii, Arizona and Canada⁹. Quest can’t collect samples in Arizona, Hawaii or Puerto Rico²⁵, and SiPhox doesn’t serve Hawaii or New York yet³⁰. Nutrisense sells only in the US⁴¹.
• What you can get back. Refund terms differ more than prices. Function refunds in full only within 48 hours of purchase and before any specimen is collected³. InsideTracker may refund within 30 days if the test is unused, and says membership purchases aren’t refundable¹¹. Quest refunds a cancellation before collection, minus a $20 fee per order²⁶. TruAge sales are final once the order ships¹⁴, and SiPhox doesn’t refund a billing period once its kit ships²⁹. Lingo’s 30-day money-back guarantee covers only a first Lingo purchase^{17, 18}. Stelo’s sales are all final, with no returns or exchanges¹⁵. Tally may take back an unused kit in its original packaging if you email first, and its terms say membership fees aren’t refundable^{37, 38}. Nutrisense doesn’t refund a monthly charge once it’s made, and its sensors can’t be returned⁴².

What we don’t weigh

Marker counts don’t move a test up or down. Companies count differently, so a bigger number isn’t a like-for-like comparison. Function counts lab tests, and InsideTracker says its Ultimate test looks at up to 54 biomarkers without listing them^{2, 10}. Superpower’s own pages put its baseline draw anywhere from 87 to 101 markers^{4, 7}. Scores calculated from your results aren’t extra tests either, such as Quest’s Health Quotient Score²⁵ or InsideTracker’s healthspan scores⁹.

Health, healthspan and biological-age scores don’t decide picks, and neither do claims about outcomes. A Cochrane review of randomized trials found general health checks in adults had little or no effect on total mortality, with high-certainty evidence²⁰. A 2024 Nature Medicine review says there’s no consensus yet on how aging biomarkers should be validated before clinical use²¹.

Company figures about their own customers aren’t outcome evidence. InsideTracker says 80% of its customers improve at least one at-risk biomarker, with no method or comparison group⁹. A published analysis of its users was funded by the company²³. It had no control group and measured biomarker changes, not health outcomes²³.

Tally makes a similar kind of claim. It says over 62% of members lowered their epigenetic age by an average of 2+ years within 12 months, without saying how that was measured³⁴. Its own help center says swings of about two years between tests are normal, which is about the size of that average³⁶.

A regulator’s decision isn’t proof of benefit. An FDA clearance of a CGM concerns how it measures. Lingo’s 510(k) summary says accuracy met the iCGM special controls, based on FreeStyle Libre 2 study data, and gives no MARD or other accuracy figure¹⁹. CLIA, which CMS administers, regulates lab testing on people in the US²². It covers how testing is done, not whether a marker is worth testing in a healthy adult.

How facts are checked

Every fact in a product review cites the page it came from and the date it was checked. When a company’s own documents disagree, we record both versions. Superpower’s FAQ lists nine states it doesn’t serve, but its homepage’s list of live states differs^{4, 5}. Its FAQ says it doesn’t offer refunds, while its Membership Agreement describes a one-time Satisfaction Refund^{5, 6}. InsideTracker’s product page requires a mobile draw in Arizona, but its FAQ lists only four states⁹. Nutrisense lists iOS 16.2 or Android 12 as its minimum phone, while Dexcom’s Stelo page asks for iOS 18.6 or Android 13^{15, 41}.

Lab claims stay the company’s own until checked. TruDiagnostic and InsideTracker describe their labs as CLIA-certified^{12, 13}. Superpower describes many assays as run in CLIA-certified, CAP-accredited labs, and labels some as lab-developed tests not cleared or approved by the FDA⁸. Quest says it and certain affiliates are CLIA-certified labs^{25, 26, 32}. SiPhox says samples go to a CLIA-certified lab but doesn’t name the lab²⁷, and Tally doesn’t name its lab or mention CLIA³⁴.

CMS offers a CLIA Laboratory Lookup for checking a lab’s certification²². CMS’s provider file for clinical labs, checked on October 14, 2026, lists an active CLIA lab under the TruDiagnostic name in Lexington, Kentucky⁴⁷. Its certificate of compliance runs to December 28, 2026⁴⁷. We haven’t matched the other companies’ lab claims to a CMS record, so they appear as company statements. A figure a company doesn’t publish, such as Function’s renewal price or Lingo’s accuracy figures, is recorded as not stated, never as zero^{1, 19}.

We also record who owns what when it links two picks. Infinite Epigenetics, the parent of TruAge maker TruDiagnostic, bought Tally Health in a deal announced April 29, 2026^{39, 40}. Tally’s terms describe Tally Health as a brand owned and operated by an affiliate of TruDiagnostic³⁸. So the TruAge pick and its TallyAge alternative aren’t independent of each other.

How prices are checked

Prices are US list prices for the exact plan on the company’s official page on the check date, before tax. Promotional prices are noted but not used. Superpower’s comparison page showed a limited-time $199-a-year offer⁷. Function’s pricing page mentioned a Function Day offer that expired on October 8, 2026¹. Lingo’s Terms of Sale page carried a banner for an unspecified first-purchase discount¹⁸, and Quest offers 10% off a first purchase²⁵.

Subscriptions show as separate plans, such as Stelo’s $89 monthly and $252 three-month plans beside its $99 one-time box¹⁵. Where a company shows only a starting price, we say so. SiPhox shows $124 to start testing, plus shipping and handling, and doesn’t say whether later kits cost the same²⁸.

The three-year estimate adds the purchase, three years of consumables and three years of membership fees. A pure membership counts its yearly fee as a recurring cost. Where a company states only a first-year price, we assume renewal at that price and say so. Function’s three years show as $1,095, and years two and three may cost more¹. Extras with no published price, such as Function’s at-home draw, are left out and flagged, not counted as zero^{1, 3}.

Glucose monitor costs assume you wear one all year at the reviewed plan’s price. Each $99 Stelo box covers about 30 days, or about $1,205 a year¹⁵. Each $54 Lingo sensor covers up to 14 days, or about $1,408 a year¹⁷. Nutrisense’s $249 a month comes to $2,988 a year, before any calls your insurance doesn’t cover⁴¹. Its plan page showed $212 with an automatic 15% code, which we treat as a coupon, not a list price⁴¹.

What we don’t do

These limits apply to every testing review and pick.

• We don’t give scores, star ratings or a single overall winner.
• We don’t interpret anyone’s results or give medical advice. Function, Superpower and InsideTracker each say they don’t provide diagnosis or medical advice^{1, 3, 6, 12}. Lingo’s plan page says it isn’t intended to diagnose disease, including diabetes¹⁷. Tally’s terms say its products aren’t a diagnostic test, and Nutrisense’s say its wellness services aren’t medical advice^{38, 45}.
• We don’t rank by biological-age, health or healthspan scores, or by longevity claims.
• We don’t count an unknown cost as zero or present a promotional price as a list price.

Sources

1. Function Health pricing Function Health · manufacturer
2. Function Health FAQ Function Health · manufacturer
3. Function Health Terms of Service (updated October 7, 2026) Function Health · manufacturer
4. Superpower homepage and membership overview Superpower · manufacturer
5. Superpower FAQs Superpower · manufacturer
6. Superpower Membership Agreement (effective September 15, 2026) Superpower · manufacturer
7. Superpower vs SiPhox Health Superpower · manufacturer
8. Superpower biomarkers Superpower · manufacturer
9. InsideTracker Membership + Ultimate test InsideTracker · manufacturer
10. InsideTracker blood tests and membership options InsideTracker · manufacturer
11. Am I eligible for a refund? (InsideTracker help center) InsideTracker · manufacturer
12. InsideTracker terms of service InsideTracker · manufacturer
13. TruAge Test TruDiagnostic · manufacturer
14. TruDiagnostic refund policy (effective April 2, 2025) TruDiagnostic · manufacturer
15. Stelo Glucose Biosensor: one-time purchase Dexcom · manufacturer
16. FDA Clears First Over-the-Counter Continuous Glucose Monitor U.S. Food and Drug Administration, 2024 · regulator
17. Lingo: Select plan Abbott (Lingo) · manufacturer
18. Lingo Terms of Sale (last updated 18-Dec-2025) Abbott (Lingo) · manufacturer
19. 510(k) summary K233655: Lingo Glucose System U.S. Food and Drug Administration, 2024 · regulator
20. General health checks in adults for reducing morbidity and mortality from disease (Krogsbøll, Jørgensen, Gøtzsche) Cochrane Database of Systematic Reviews, 2019 · systematic review
21. Validation of biomarkers of aging (Moqri et al.) Nature Medicine, 2024
22. Clinical Laboratory Improvement Amendments (CLIA) Centers for Medicare & Medicaid Services · regulator
23. Longitudinal analysis of biomarker data from a personalized nutrition platform in healthy subjects (Westerman et al.) Scientific Reports, 2018 · cohort study
24. TruAge Test listing on TruDiagnostic's store (including the Annual Subscription) TruDiagnostic · manufacturer · data file
25. Quest Health: Elite Health Profile (18386M) Quest Diagnostics (Quest Health) · manufacturer
26. Quest Health consumer terms and conditions (last revised January 6, 2026) Quest Diagnostics (Quest Health) · manufacturer
27. SiPhox Health pricing SiPhox Health · manufacturer
28. SiPhox Health home page SiPhox Health · manufacturer
29. SiPhox Health Refund Policy (updated Feb 2, 2026) SiPhox Health · manufacturer
30. SiPhox Health State Coverage SiPhox Health · manufacturer
31. SiPhox Health: Longevity Essentials Program SiPhox Health · manufacturer
32. Quest Health home page Quest Diagnostics (Quest Health) · manufacturer
33. FDA Clears First Over-the-Counter Continuous Glucose Monitor for Children U.S. Food and Drug Administration, 2026 · regulator
34. TallyAge Test Kit Tally Health · manufacturer
35. Tally Health Membership Tally Health · manufacturer
36. Help center: How reliable are the TallyAge test results? Tally Health · manufacturer
37. Tally Health refund policy Tally Health · manufacturer
38. Tally Health terms of service (effective April 29, 2026) Tally Health · manufacturer
39. Infinite Epigenetics Acquires Tally Health to Accelerate the Future of Epigenetics-Driven Health and Longevity (PR Newswire release, April 29, 2026) Infinite Epigenetics via PR Newswire, 2026 · manufacturer
40. Infinite Epigenetics acquires Tally Health in 'largest epigenetic testing deal to date' NutraIngredients, 2026 · news
41. Nutrisense: 1-Month Set with Stelo Glucose Biosensors Nutrisense · manufacturer
42. Nutrisense Refund and Return Policy (updated Dec 23, 2025) Nutrisense · manufacturer
43. How to Cancel Your Nutrisense Subscription (updated Jan 7, 2026) Nutrisense · manufacturer
44. Insurance-Covered Nutritionist Consultations: Complete Guide (updated Aug 3, 2026) Nutrisense · manufacturer
45. Nutrisense Terms of Service (last updated Apr 13, 2026) Nutrisense · manufacturer
46. Help center: Purchasing and shipping logistics Tally Health · manufacturer
47. Provider of Services File: Clinical Laboratories (record for TruDiagnostic, CLIA 18D2183496) Centers for Medicare & Medicaid Services · regulator