Dose, Not Session Length: Why Irradiance Matters

You have been told to run your mask for ten minutes.

You have not been told how much light arrives during those ten minutes. And in this category, that is not a small gap. LED mask irradiance is the entire measurement, and it is the number that goes missing most often.

Dose is not a feeling. It is a multiplication.

The amount of light your skin receives in a session is called dose, and it is calculated the same way every time:

Dose = output × time.

Output is irradiance, stated in milliwatts per square centimeter (mW/cm²). Time is the length of the session. Multiply them and you get dose, stated in joules per square centimeter (J/cm²). That is the figure that actually describes what happened to your skin.

Which means a session length, on its own, is half of a calculation. It is the half that costs a brand nothing to publish.

Consider two masks. Both instruct a ten-minute session. Both look similar on a face.

• One delivers 50 mW/cm² at the worn position. Ten minutes at that output is 30 J/cm².
• One delivers 15 mW/cm² at the worn position. Ten minutes at that output is 9 J/cm².

Same instruction. Same ten minutes. Roughly a third of the light.

Neither buyer can tell the difference by looking. The only thing that separates them is a number, and only one of those two brands has to publish it for the difference to become visible.

The part worth paying attention to

Something has started happening in this category that deserves to be said out loud.

Brands are building branded technologies around the concept of dose. Systems with names. Apps that calculate your optimal dose for you. The language is confident and the engineering is often real.

And in several cases, the LED mask irradiance figure does not appear anywhere on the product page, in the FAQ, or in the manual.

Sit with the shape of that. A dose is an output multiplied by a time. A company can market a dose-calculation technology while declining to publish the output half of the multiplication. The calculation may well be correct. You simply have no way to check it, because the input was never disclosed.

If a brand markets a dose technology and won't publish mW/cm², it is asking you to trust a calculation you are not allowed to check.

That is not an accusation of dishonesty. It is a description of an unverifiable claim. Those are different things, and the distinction matters — but a buyer spending five or six hundred dollars is entitled to notice the difference between a number and a reassurance.

And when the number is published, ask where the meter was

The second half of the problem is that irradiance figures are not comparable unless you know the measurement position.

Press a sensor directly against the brightest diode on a mask and you can report a number several times higher than what reaches a cheekbone at normal wearing distance. Both readings come off the same device. Both are technically real. Only one describes your session.

So the useful question is not what is your irradiance. It is where did you measure it.

In our own review of the category in August 2026, we looked for that disclosure across the premium tier and found two consistent patterns. A meaningful share of brands publish no irradiance figure at all. And of the figures that are published, we could not find one — other than our own — that stated the measurement position or offered third-party verification.

That is the gap this brand exists inside. It is also question two of the four questions we think every buyer should ask before comparing masks.

Our arithmetic, shown

We will not ask a question we won't answer.

These are two different classes of device and their numbers should be read that way — one is an LED mask, one is a VCSEL laser device with zone-mapped output. Comparing their irradiance figures to each other is a category error, which is exactly why we state the technology alongside the number.

RADIANCE — LED mask. Five wavelengths, 415, 590, 625, 830 and 1072nm, across 400 individual LEDs. Even, whole-face coverage. Up to 50 mW/cm², measured at the worn position, not at the diode. A ten-minute session at that output is approximately 30 J/cm². RADIANCE is FDA Cleared under K242385, model M5.

Contour PRO — VCSEL laser device, zone-mapped. 460, 665, 850 and 1064nm, with the 1064nm channel delivered by 72 quad-chip VCSEL emitters. VCSEL stands for Vertical-Cavity Surface-Emitting Laser: genuine laser chip diodes in the home-use, low-emission class, which is why we describe them plainly rather than dressing the word up or hiding from it.

Contour PRO was measured across 36 separate positions on the mask. VCSEL zones read 84 to 95 mW/cm², with a mean of 91.5. LED zones read 33 to 47. A ten-minute session at the VCSEL zone mean works out to roughly 55 J/cm².

The spread across those 36 positions is not an inconsistency — it is the design. VCSEL output is concentrated along the jawline and the structural perimeter, where we want the deepest-penetrating wavelength doing its work. We publish the lower zone readings alongside the higher ones because a scan that only reports its best position is a marketing asset, not a measurement.

Contour PRO is FDA Registered, with 510(k) clearance in progress for the VCSEL model. We state that exactly as it is. Registration is not clearance, and we will not let a customer believe otherwise in order to close a sale. Both clearance records are public and searchable in the FDA's 510(k) database.

What to do with this

Take one question to every mask you are considering, including this one:

"What is your irradiance in mW/cm², and at what position was it measured?"

A brand that has the number will give it to you in a sentence. A brand that has measured honestly will tell you where the meter was without being pushed. And a brand that answers with an adjective has answered the question anyway.

You are not under qualified to evaluate this category. You were just never given the input.

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NuYOU360 is a women-owned developer of home-use red light therapy devices. The brand publishes wavelength specifications, measurement-position-stated irradiance, and exact FDA status for every device it sells. RADIANCE and the NuYOU360 LED Red Light Therapy Face Mask are FDA Cleared under K242385. Contour PRO is FDA Registered, with 510(k) clearance in progress for the VCSEL model.

"I spent close to a decade using this technology every night before I ever sold it, starting with a back injury in 2016. The devices were never the problem. What I could not find as a buyer was a company willing to tell me where they put the meter." — Dora Tzotchevska, Founder and CEO, NuYOU360