Choosing an At-Home NAD+ or Longevity Test: What to Check Before You Pay
At-home NAD+ and biological-age tests are easy to order and hard to interpret. Before you buy one, check what sample it uses, which lab runs it, whether you can repeat it the same way, and what you would actually do with the result.
By Kymata Health Editorial Published Last checked
This guide
Blood Testing & Biomarkers- Question
- How do I choose an at-home NAD+ or longevity test?
- Sources
- 7 cited
- Quick answers
- 3 questions
- Clinician review
- None; sources cited inline
Key takeaways
5 points- NAD+ is unstable once blood is drawn, and results differ by sample type and lab method, so a number only means something next to the same lab's own method and ranges1.
- A dried-blood-spot method kept NAD+ at 85% or more for at least 1 week at room temperature, which is why finger-prick kits can work at all3.
- Epigenetic age clocks can disagree by up to 9 years when the same sample is run twice, a noise level that swamps most changes you would hope to see4.
- We found no guideline that sets a target NAD+ level, and pooled NMN trials found no improvement in blood sugar or lipids5.
- A lab can hold CLIA certification for quality while the claims on its report have never been through FDA review; FDA's 2024 rule on laboratory developed tests was vacated in 202567.
What these kits actually sell
Consumer longevity tests fall into three groups: NAD+ tests (usually a finger-prick blood spot), biological-age tests built on DNA methylation (epigenetic clocks), and broad blood panels sold as healthy-aging checkups. Our explainer on what an NAD+ blood test shows covers the NAD+ science itself; this page is the buying checklist.
Each answers a narrower question than the marketing suggests. An NAD+ test tells you how much of one coenzyme was in your sample on one day. It does not diagnose a disease, and the evidence that NAD+ falls steadily with age in humans is very limited, so a flag saying you are low for your age rests on thin data2.
Five things to check before you buy
Use these questions to compare kits. If a company cannot answer them on its own site, treat that as an answer:
- Sample and method. Whole blood, plasma and blood spots are different measurements, and cheaper enzyme kits lack the specificity of liquid chromatography-mass spectrometry1. The company should name both.
- Sample stability. NAD+ degrades after collection; a published dried-blood-spot method held it stable for 2 weeks refrigerated and 1 week at room temperature3. That method was developed by employees of Teijin, two of whom applied for a patent on it3. Ask how long your sample can sit in the mail.
- The lab. CLIA, run by CMS, sets quality standards so lab results are accurate, reliable and timely7. Ask for the lab's name and CLIA number; you can look a lab up for free in CMS's QCOR database7.
- Regulatory status. FDA's 2024 rule that treated laboratory developed tests as medical devices was vacated by a federal court on March 31, 2025, and FDA reverted its regulation on Sept. 19, 20256. That rule would have treated labs that make their own tests as device manufacturers6; with it gone, do not assume FDA has reviewed a kit's claims.
- Repeatability. One reading tells you little. Check whether you can retest with the same lab, sample type and timing, and what a second kit costs.
Biological-age tests: the noise problem
Epigenetic clocks estimate age from DNA methylation. In a 2022 analysis, technical noise alone produced deviations of up to 9 years between replicate measurements of the same samples for six prominent clocks4. A reworked principal-component version brought most replicates within 1.5 years4.
The practical point: if a kit says your biological age dropped by two years after a new routine, that change can sit inside the test's own error. Ask whether the company uses a clock with published replicate reliability, and do not read one result as a trend. Some of the study authors license clock technology commercially, as their paper discloses4.
Decide what you will do with the number
The most defensible use of an NAD+ test is narrow: checking whether an NAD+ precursor raises your blood level, using the same lab before and on a steady dose. Even then, a higher number is not a health result. Across 8 randomized NMN trials, fasting glucose, insulin, HbA1c and lipids did not improve5.
Jinfiniti, for example, sells an intracellular NAD+ test and also sells NAD+ precursor supplements. When the same company sells the test and the product, read any advice to buy more alongside the result with care. Broad blood panels compared on our blood-testing hub answer more routine questions, such as cholesterol, blood sugar and kidney function.
Who should skip it, or talk to a clinician first
Skip testing as a reason to start or stop medicines; we found no guideline that acts on an NAD+ or biological-age result, and the precursor trials found no metabolic benefit5. If you are pregnant, breastfeeding, being managed for cancer, or taking prescription drugs, ask your clinician before adding an NAD+ precursor, since the trials behind these products were small and short5. If you have symptoms such as fatigue or weight change, a standard workup through your own blood work or a clinician is more useful than a longevity score.
Quick answers
Questions
3 answersIs an at-home NAD+ test accurate?
It can be precise within one lab's method, but results vary by sample type and assay, so they are not comparable across companies13.
Are biological-age tests reliable enough to track progress?
Standard epigenetic clocks varied by up to 9 years between technical replicates in one analysis, so small changes are hard to trust4.
More in Blood Testing & Biomarkers
Keep reading
5 pages- Blood Testing & Biomarkers hubEvery guide, regulatory notes and sources
- The 5 Best Blood-Test Services for Value and Trust, Scored on One Rubric
- How We Score Blood-Test Services: The 100-Point Rubric
- Who Runs the Blood-Test Companies: Founders, Funding, Privacy and Lawsuits
- Pharmacogenomic (PGx) Testing: What a DNA Medication-Response Test Shows, What the FDA Says, and Its Limits
Keep reading: Supplements and vitamins
Supplements and vitamins: every pageSupplement & Nutrient EncyclopediaBrowse all topics
- Previous in this topicWho Runs the Blood-Test Companies: Founders, Funding, Privacy and LawsuitsThe company checks behind our blood-test rankings: who founded each service, what backs it, how long it has sold tests, how it handles health data, and any lawsuits or breaches…
- Next in this topicPharmacogenomic (PGx) Testing: What a DNA Medication-Response Test Shows, What the FDA Says, and Its LimitsA pharmacogenomic test reads genes that change how your body handles certain drugs.
- Omega-3 (fish oil, krill oil, algal oil)Omega-3 supplements supply the long-chain fatty acids EPA and DHA from fish oil, krill oil or algae, or ALA from plant oils.
- Online TRT Compared (2026): 9 Clinics on Price, Labs and TrustOnline testosterone therapy from providers we vet, compared on published monthly price, labs, states and trust signals, with a re-weightable score.
- Metabolic Health and Blood Sugar: Prediabetes, Glucose Monitors and Supplements, by the EvidenceLifestyle change cut new diabetes by 58% in the landmark prevention trial, more than metformin.
References
Every study and document cited in this guide, numbered as in the text.
Sources
7 sources- 1NADomics: Measuring NAD(+) and Related Metabolites Using Liquid Chromatography Mass Spectrometry. Life (Basel), 2021. PMID 34073099
- 2Age-Dependent Decline of NAD(+)-Universal Truth or Confounded Consensus?. Nutrients, 2021. PMID 35010977
- 3Stabilization and quantitative measurement of nicotinamide adenine dinucleotide in human whole blood using dried blood spot sampling. Anal Bioanal Chem, 2023. PMID 36504284
- 4A computational solution for bolstering reliability of epigenetic clocks: Implications for clinical trials and longitudinal tracking. Nat Aging, 2022. PMID 36277076
- 5Effects of Nicotinamide Mononucleotide on Glucose and Lipid Metabolism in Adults: A Systematic Review and Meta-analysis of Randomised Controlled Trials. Curr Diab Rep, 2024. PMID 39531138
- 6Laboratory Developed Tests. U.S. Food and Drug Administration, 2025.
- 7Clinical Laboratory Improvement Amendments (CLIA). Centers for Medicare & Medicaid Services, 2026.
Dietary supplements are not intended to diagnose, treat, cure or prevent any disease, and these statements have not been evaluated by the FDA. Prescription options need a licensed clinician. Talk to your clinician or pharmacist before starting anything new, especially if you take prescription medicines, are pregnant or breastfeeding.