How we verify optimal ranges
Each optimal range on this site names who holds it and is checked against the document that states it. Rows with no named holder are labeled as general guidance. This page explains the rules, what gets withheld, and how to tell us when we are wrong.
Why we show more than one optimal range
A lab's reference range tells you where 95 percent of the tested population falls. An optimal range is a claim about where you should be, and there is no single authority for that. Clinical bodies, cohort researchers, and individual practitioners draw the line in different places for the same marker, often for defensible reasons.
Most sites pick one number and present it as settled. We do the opposite: each position is listed with the name of who holds it and, where a document states it, a link. When sources disagree, you see the disagreement instead of our average of it.
Example: vitamin D (25-hydroxy), ng/mL
- National Academies: 20 or above is sufficient for bone health
- Endocrine Society: 30 to 100
- Rhonda Patrick: 40 to 60
- Life Extension: 50 to 80
All four appear on the vitamin D page, attributed. We do not pick a winner.
The three kinds of range you will see
| Kind | Where it comes from | How it is checked |
|---|---|---|
| Guideline ranges | Clinical bodies such as the AHA/ACC, ESC/EAS, Endocrine Society, KDIGO, and the National Academies. | Linked to the guideline document or its PubMed record. We cite the document that sets the threshold, not a secondary write-up of it. |
| Curated targets | Bands tighter than the lab reference range, where cohort evidence supports them. Each row states its basis in plain words. | 108 of 229 rows link to a PubMed record we read against the paper's abstract before publishing, and 17 link to a guideline or standards-body document. 41 rows state that no target is established. The rest describe their basis in words; we are replacing the ones that do not name who holds the position. |
| Expert targets | Positions stated in published articles by named clinicians, researchers, and labs. | Verified mechanically against the article, as described below. 75 claims currently pass. |
How expert claims are verified
Expert targets are the easiest kind of range to get wrong. Numbers get copied between sites, rounded, and attributed to the wrong article. So every expert claim on this site goes through the same check before it renders:
- The claim is recorded with the exact URL of the article that states it. Not the author's homepage, not a podcast transcript, the page where the number appears.
- A script fetches that page and looks for the claim's numbers in its text. A range like 4.6 to 5.3 percent must show both numbers on the page. A claim whose only number is 1, such as "under 1 mg/L", must appear with the same comparator or unit, since a bare 1 proves nothing.
- The unit must be one the marker is measured in. The claim is stored as the article words it, and the page shows a reviewed display form. Dr. Mark Hyman writes fasting insulin as "2-5 mIU/dL", a unit no lab reports; the page shows 2-5 μIU/mL and says why. A claim in an unknown unit is withheld until it is restated.
- Lab reference intervals are not expert targets. When a practitioner site quotes a standard lab interval or a regulatory threshold, it is listed with the institutional positions and labeled as a reference interval or threshold, not as a target. 12 verified claims are in that group.
- Claims that fail are withheld. They are not rounded, softened, or re-attributed. They stay off the site until the source is fixed or the claim is dropped.
- The check re-runs whenever the source list changes, and the results are kept as a file that the site build reads. A claim cannot render unless its row in that file says it passed.
The last full run was on September 23, 2026. 75 claims from 12 sources passed.
What the check has caught
This gate exists because it found real errors in our own data. A fasting glucose target had been recorded as under 85 when the source article says under 80. A cholesterol ratio of 3.5 was matched to a page whose only "3.5" turned out to be the stroke width of a decorative graphic. An A1c target was linked to a podcast transcript about breakfast that never mentions A1c. None of those are on the site now.
What the check does not do
- It confirms that the source says what we say it says. It does not confirm that the source is right. Attribution is the point: you can see who holds the position and decide what that is worth.
- It cannot check claims made only in audio or video. Positions stated on podcasts and YouTube are not listed as targets. Episodes that discuss a marker appear on that marker's page as discussion, clearly separated from the ranges.
- Pages that block automated access cannot be checked. A claim we verified on an earlier run keeps that earlier verification and its date; a claim we have never been able to check is withheld, even when we believe it.
Commercial ties are disclosed, not hidden
Several of the loudest voices on optimal ranges sell products that appear in our comparisons: lab panels, glucose monitors, sleep trackers, fatty acid tests. Their ranges still appear, because readers ask about them. Each one carries a disclosure line stating the tie, right next to the number. The same applies to podcast hosts with an ownership stake in a company we compare.
We would rather show a vendor's position with the relationship stated than pretend the position does not exist. 8 sources currently carry a disclosure.
What we do not do
- We do not blend sources into a single "optimal" number.
- We do not publish a range without a source line. Some older rows describe their evidence without naming a body; we are replacing those with named sources.
- We do not accept payment for the placement or wording of any range. Affiliate links appear on provider comparisons, deals, best-of lists and the at-home testing page, are marked sponsored in the page code, and have no effect on which ranges appear.
- We do not give medical advice. A range on this page is a published position, not a recommendation for you.
Pricing and fees are checked the same way
Provider prices and hidden fees are read off each provider's own pages, and each provider page says when that was last confirmed. Where a provider's marketing and its checkout disagree, both are recorded. The Hidden Cost Index collects those findings across every provider we checked.
Corrections
If a range is misattributed, out of date, or missing a position you think belongs, write to hello@optimizebiomarkers.com with the source. We would rather fix it than defend it, and a correction that comes with a URL usually goes live the same day.