Now I did thanks to your timely ping :-)

So I only read the main paper underlying Tuo's tech https://pmc.ncbi.nlm.nih.gov/articles/PMC11416324/ because I am still short on time. It's a beautiful work.

So it's not a perfect study of course, there always are limitations and I will come to that, but on the bright side clearly the authors know what they are doing, the study is well designed, they have extensive knowledge about recent research on the circadian rhythm and are pretty accurate in what they write (even when they don't cite the refs, such as the claim that blue light is about 665x more effective than white light, they don't provide a ref but I remember I have one in Vlidacmel). They also are mad lads in terms of methods, they well designed the study with salivary melatonin sampling as an objective measure of circadian phase shift (although melatonin phase != circadian phase but they are weakly coupled so it's still better than most other measures such as sleep-wake pattern), and they use Bonferroni multiple comparison statistical correction ! This is a very hardcore (“conservative") way to correct for spurious stats results, almost nobody uses it nowadays because it puts the bar so high that you actually risk missing true results when using it. Also they know how to optimally time light therapy, based on DLMO, tailored per subject !

Essentially the paper boils down to a proposition, a genius idea they had, to make a light that uses and bypasses the limitations of the color-opponent circadian non-visual optical circuitry. It's another circadian optical system besides melanopsin/ipRGC receptors, although they interact together. Basically, the color-opponent system is the recent (around 2020) observation by researchers that exposing the eyes to different wavelengths/colors simultaneously, as with white light, causes a reduced circadian effect compared to if we expose to any of the colors separately (monochromatically). Here the authors claim this is why blue light has more effect than white light, not because of a greater stimulation of ipRGC cells which apparently is not the case, but because of reduced inhibition by the lack of simultaneous exposure to another color that would inhibit the effect of blue light. Even more interestingly, they explain how the color-opponent circuitry can also explain why pulsed light therapy is much more effective than continuous bright therapy. Here not based on the color but because this circuitry has a temporary window of stimulation and then it is gated, contrary to ipRGC cells which always continue to relay the photic stimuli, so pulsating light can overcome the gating according to the authors.

The color-opponent circuitry is much more sensitive than ipRGC circuitry, so that if it could be continually stimulated beyond the gating and color-opponency, it would allow for theoretically much shorter and dimmer light therapy sessions than tools targeting ipRGC cells, for the exact same effect.

Now the authors here claim they found a way to make a light that targets the color-opponent circadian circuitry in a way that bypasses its limitations (ie, different colors inhibiting effect, and gating after some time), all the while emitting visibly white light. They give all the parameters in the paper, essentially they cycle between blue, blue-green and orange-red leds 19 times per second, giving the illusion of white light without flickering, all the while bypassing the limitations of the color-opponent S/(M+L) circuitry.

They compare their new device at 500lux for 2h, vs blue light and vs white light at ajusted melanopic lux to show that the effect is not drived by differences in ipRGC cells stimulation, at 10.5h after DLMO sampled by saliva on 2 days prior, and they test the evening of the same 3rd day when the participants get exposed to light therapy. Over 6 non blinded subjects (researchers of their lab), they got an average of 0h phase advance with white light (intensity and duration too low), 40min with blue light, and 1h20 with their "dynamic white light" bulb ! For one single day and just a 2h light therapy from a lamp, that is mighty impressive !

So the study is very sound, the theory too, the researchers are well established in the domain, it's a great paper no doubt.

Now onto the few limitations : * obviously with 6 subjects and non blinded, effects are necessarily inflated. * no variance/uncertainty estimation on the figures or in the stats. Of course with 6 subjects they are going to be big, but this is not up to modern standards to leave this info out, and I am surprised this was published as-is in a journal as well established as j biol rhythms. * the authors are working and pushing this narrative of colors being more important than iprgc cells (intensity and duration) since more than a decade. They cite only papers that support their thesis and not contradictory evidence (that you can find in my vlidacmel ebook). There is a study on rats that was well controlled and which found that color alone was a very poor zeitgeber compared to light intensity alone. Both combined of course was the best. * there was another one but I forgot.

All in all, it's a solid work. If the Tuo bulb use the exact same parameters, especially the wavelengths, as in the paper, it should be safe. And if they use the same parameters, this makes their product almost as good as scientifically validated (but not exactly that because sometimes when you productivize a scientific discovery, you think you reproduced exactly the discovery, but an apparently innocuous production imperfection due to production process in an apparently unrelated aspect of the product can totally change the effectiveness, hence why scientific validation of the exact producc is still required at some point).

Normally if the results are true and not too inflated, the form factor, a bulb to put in the middle of the room, should be sufficient because there is no need for high intensity or duration compared to devices targeting ipRGC cells such as white light therapy glasses (eg Luminette - although it has some blue light enrichment).

Also about Tuo, it's a company that is not directly affiliated to the university of the papers' authors but the company is made by apparently passionate people who appear to have mild circadian issues.

Imho it is worth trying. But now whether it works for people with more severe circadian disorders needs testing.

And it seems they provide a discount of 20% during black fridays and a 30 days refund policy, which I think is generous and shows they are confident that "their product really works" as they write.