How we research devices
By Kirill Gissa · Published · Updated Where the numbers come from
Brand sites and manuals
Wavelengths, irradiance, heater and wood specs, warranty and return terms come from the brand's own pages and manuals. Every number on a model page names its source and the date it was checked.
The FDA databases
Each red light device is looked up in the FDA 510(k) database and in the registration and listing database. “FDA cleared” appears only with a 510(k) K number. A device that is only registered and listed has no K number.
Independent measurements
Irradiance measured by third parties, with who measured it, the meter and the distance. It is shown next to the brand figure with a link and the date. Where sources disagree, both numbers are shown.
Prices
From the store page linked next to each price, with the date it was checked. Prices and FDA status are rechecked once a month.
Owner reviews
From Amazon, other stores and the brand's own site. We read the ratings and the reviews, look for praise and complaints that come up again and again, quote only word for word, and link to each review we quote. Reviews written for a free product (Amazon Vine) or marked as paid for aren't used, and neither are quotes that make health claims.
Reading FDA records
For every red light device I search the FDA's 510(k) database and its registration and listing database by company and device name, then match the record to the exact model. Saunas carry no FDA label here: a search of the 510(k) database for “sauna” returns no records, and none of the saunas we track has one.
Each red light device gets one of four labels. The count is how many of the 124 red light devices in the database have it today. Of these, 2 are 250-watt heat lamps sold as ordinary bulbs and get no label.
| Label | What it means | Devices |
|---|---|---|
| FDA cleared | A 510(k) record matches the brand and the device. The K number on our page links to that record. | 55 |
| FDA listed · no 510(k) | The company has registered with the FDA and listed the device, but there's no 510(k). Listing tells the FDA a device is on the market; it isn't a review of the device. | 42 |
| Clearance not confirmed | The brand says the device is FDA cleared, and I couldn't match it to a 510(k) record. | 9 |
| Not in FDA database | No 510(k) record and no listing found under the brand or the device name. | 16 |
No device page here says a device was approved by the FDA. Approval (premarket approval, or PMA) is a separate, stricter FDA process meant for higher-risk devices.
How the score works
Every model is scored on five criteria. Each criterion gives 2, 1.75 or 1.5 points, so the score out of 10 runs from 7.5 to 10. There are no weights. Each criterion is worked out from the database fields, and the category median is taken over models of the same type in the database.
Owner reviews: “mostly positive” means a store other than the brand's own site shows at least 25 ratings averaging 4.3 or higher, and no such store averages under 4.0. “Repeated complaints about breakdowns” means that on such a store at least 10 reviews about reliability or durability are negative, they make up 40% or more of the reviews on that topic and 2% or more of all its ratings, or that at least 3 of the reviews we read, and 5% or more of them, describe a unit that stopped working. Ratings on the brand's own site alone give 1.75 points, because the brand decides which reviews it shows; so do fewer than 25 ratings on other stores. A model whose reviews we haven't gathered yet also gets 1.75 points. The independent irradiance measurement is not part of the score; it is shown next to the brand figure.
Whether a brand pays us a commission plays no part in the score. It does affect the order: by default, lists show models with a “Check price” button first and the rest after them, and our picks come only from models with a button. Inside each group, models go by score; when two tie, the cheaper one comes first. To see a whole list by score alone, sort it by “Highest score”.
Red light devices
| Criterion | 2 points | 1.75 points | 1.5 points |
|---|---|---|---|
| FDA record | Cleared, with a 510(k) K number | Listed only, no 510(k). Devices for pets and horses all get 1.75, since the FDA doesn't review them | No record, or not confirmed |
| Published specs | Wavelengths and irradiance with the distance | Only one of the two | Neither |
| Price | At or below the category median | Up to 1.5× the category median | More than that |
| Warranty and returns | Warranty at least the category median and returns of 30 days or more | One of the two | Neither, or final sale |
| Owner reviews | Mostly positive | Mixed, or no reviews | Repeated complaints about breakdowns |
Saunas
| Criterion | 2 points | 1.75 points | 1.5 points |
|---|---|---|---|
| Heat figures | Max temperature and heat-up time both stated | One of the two | Neither |
| Published specs | Material and heater type or power; for infrared, EMF as a number | Part of it | None |
| Price per person | At or below the category median | Up to 1.5× the category median | More than that |
| Warranty and returns | Same as red light | Same as red light | Same as red light |
| Owner reviews | Same as red light | Same as red light | Same as red light |
PEMF devices and infrared mats
| Criterion | 2 points | 1.75 points | 1.5 points |
|---|---|---|---|
| FDA record | Cleared, with a 510(k) K number | Listed only, no 510(k). Animal devices all get 1.75, since the FDA doesn't review them | No record |
| Published specs | PEMF: frequency and field strength. Infrared mat: max temperature and wattage | Only one of the two | Neither |
| Price | At or below the category median | Up to 1.5× the category median | More than that |
| Warranty and returns | Same as red light | Same as red light | Same as red light |
| Owner reviews | Same as red light | Same as red light | Same as red light |
Evidence levels
When a page says what red light or a sauna might do for you, it links the study and says what kind of study it was and how many people took part. Across a whole use, such as skin or hair, the evidence gets one of four levels.
If a benefit has no published study behind it, the page says whose claim it is: “the brand says…” or “owners on Reddit report…”. A study result describes the people in that study. It isn't a promise for any device.
Updates
Prices and FDA status are rechecked once a month, on the 1st. A page's “Updated” date moves only when something on it changes: a price, a spec, a new measurement or a new model. Every price shows the date it was checked.
How we make money
Some links on this site are affiliate links: we may earn a commission when you buy through one. The commission does not change a score, and brands do not pay placement fees. It does change the order: models with a button come first in a list, and our picks come only from them.
Affiliate disclosureCorrections
If a number is wrong or out of date, tell us through the contact page. We check it against the source, fix the page and move its “Updated” date.
Report a numberHow to cite
You're welcome to quote figures and short passages from WellSpecs with a link to the page you took them from. A format that works:
WellSpecs, “<page title>”, <page URL>, accessed <date>.
Most figures on our pages come from somewhere else first: a brand, the FDA or an independent tester. If a number matters to your piece, cite that original source as well; each one is linked next to the number. Copying whole tables or the database needs permission, as the terms of use explain.