'I'm a cosmetic doctor. Here's my verdict on the top LED masks to snap up in the sales.'

If I had a dollar every time someone asked me which LED mask to buy, I'd be a very rich beauty editor. So, I can only imagine how many DMs a skin expert would get on the daily, with people enquiring as to what at-home device is actually worth their cash. Especially as we're coming into sales season.

Juuust in case you missed it, Black Friday is kicking off on November 29, and then rolling into Cyber Monday on December 2. However, a lot of retailers have jumped on the bandwagon early. Meaning? There's an awful lot of good deals getting around. And if you're in the market for an LED mask, there's probably never been a better time to make the commitment.

However, while the market is positively bursting with options, they're usually quite pricey (even when they're discounted) — and you're often left wondering if there's any difference between them and if any of the more affordable ones are legit.

Well, in a recent episode of The Formula, that's exactly what I asked general practitioner and cosmetic physician Dr Prasanthi Purusothaman (who goes by Dr Prasanthi).

And she's done her research. In fact, Dr Prasanthi's written a whole comparison guide on it (you can sign up to view the whole thing here).

So, in the interest of helping you figure out which mask to cart in the sales, we've pulled together Dr Prasanthi's breakdown on some popular masks on the market, including which skin concerns each one targets and her review.

It's also worth noting that while some of these LED masks are currently on sale (ahem, looking at you Omnilux!), others aren't discounted just yet. So, just keep an eye out!

Watch: Speaking of beauty, here's Em Vernem and I chatting about the clever hack for smooth feet (and yes, you can get the product we're talking about on sale right now!). Post continues below.

Before we get into it, it's probably helpful to give you a quick refresher on what the different wavelengths are. This will help you know what you're looking for if you're in the market for an LED mask.

Let's start with red light. According to Dr Prasanthi, the optimal wavelength for red light is 633nm (it should say this somewhere on the box!).

According to Dr Prasanthi, this wavelength is able to reach the dermis increasing the production of collagen and aiding in the targeting of hyperpigmentation (in the right energy settings).

There's also another type of light called near-infrared light which works as an optimal wavelength 830nm. Best for wound healing, anti-inflammatory benefits and evening out skin tone, Dr Prasanthi said it may influence muscular tone and improve skin hydration.

Also on the light spectrum is blue light, with an optimal wavelength of 415nm. Dr Prasanthi said it has "anti-microbial properties, effective for treating inflammatory acne through destruction of C Acnes bacterial porphyrins leading to cell death."

Meaning? It kills the bacteria responsible for acne.

"The more specific a mask is at confirming wavelengths at the above nm, the better," she said. "If it reports anything more than +/-10nm, I would be cautious regarding efficacy as the specificity of wavelength is CRUCIAL for the stated benefits."

As Dr Prasanthi added, other wavelengths with less robust data include: amber/yellow light at 575nm to 590nm and green light at 500 to 560nm which is marketed to be beneficial in hyperpigmentation.

Without getting too deep on the science-y side of it all (so many numbers! So many symbols!), you'll also notice the word 'irradiance' in the below verdicts. This has to do with the power density i.e. the amount of energy a specific part of your body receives.

"This is perhaps the most defining factor when considering red light therapy at home since higher irradiance can result in better results in less time as more energy is delivered to the tissue. It is also important to note that most of the studies looking at the benefits of LED are based on clinic LED treatments," Dr Prasanthi said.

"Higher irradiance can reduce treatment time but also increase the risk of thermal damage if not controlled or inhibit activation of these responses if a dose higher than indicated is delivered. Similarly, light stimulus alone will be insufficient to trigger the beneficial cellular functions of LED if it is delivered below the recommended dose."

Still with us?

With all of this in mind, here's a summary of Dr Prasanthi's findings (because look — some of the numbers sound a bit complicated and confusing) when it comes to popular LED masks on the market.

Omnilux Clear, $605.

Treatment times: 10 minutes, four times a week for six weeksWavelengths: Red light 630 nm +/- 5 nm, blue light 412.5 nm+/- 7.5 nm.Mask type: FlexibleWarranty: 24 months

DR P verdict: "Good. Irradiance within range of clinical data — does not however have near infrared wavelength, which would be beneficial combined with either red or blue."

San Lueur Advanced LED Light Therapy Mask, $795.

Treatment time: 10 minutes three to four times a week.Wavelengths: Red light 633nm +/- 10nm, near-infrared light 830nm +/- 17.5nm, blue light 415nm +/- 10nm.Mask type: FlexibleWarranty: 12 months

Dr P verdict: "Great. Higher irradiance so caution in skin types prone to hyperpigmentation and rosacea, use lower settings and shorter contact time. Eye protection provided with blue light use. Some people may want the option to use near infrared separate to red. Near-infrared could be tighter within 10nm range."

Current Body Skin LED Light Therapy Mask, $585.

Treatment time: 10 minutesWavelengths: 633 nm, 830 nm.Mask type: FlexibleWarranty: 24 months

Dr P verdict: "Okay. Lower irradiance — may be better for darker skin types prone to hyperpigmentation."

Dermalux Flex MD LED Light Therapy Device, $5,487.

Treatment time: One to 30 minutes for acne and wrinkles, three to four times weekly for four weeks. For pain relief, three times weekly.Wavelengths: 415nm, 633nm, 830nm.Mask type: Rigid semi circleWarranty: 24 monthsDr P verdict: "Not good. Irradiance low, treatment duration too long for most people as a result to compensate and price point high."

Therabody TheraFace Mask, $899.

Treatment time: Three minutes each light mode for a total of nine minutes per treatment, recommended to use two to five times per week.Wavelengths: Red light 633nm, blue light 415nm, near infrared light 633nm/830nm.Mask type: RigidWarranty: 12 months limitedDr P verdict: "Great. Stronger mask in terms of irradiance, caution for over heating and especially skin types predisposed to vascular rosacea and hyperpigmentation and darker Fitzpatrick phototypes."

Dr Dennis Gross DrX SpectraLite Faceware Pro, $763.72.

Treatment time: Three minutesWavelengths: Red light 630nm, near infrared light 880nm, amber light 605nm, blue light 415nm.Mask type: HardWarranty: 12 months

Dr P verdict: "Great. Caution for overheating with higher irradiance settings and especially in skin types predisposed to rosacea and hyperpigmentation. Infrared should be closer to 830 nm most studied wavelength with benefit."

Dr Naomi LED It Glow, $595.

Treatment time: 10 minutesWavelength: 630 nm +/- 5 nm, near infrared light 830 nm.Style: FlexibleWarranty: 12 monthsDr P verdict: "Okay. Stronger irradiance masks on market, no blue light for acne sufferers. Good for people wanting general skin rejuvenation that need a milder irradiance."

If you would like to read Dr Prasanthi's full comparison guide that includes more popular LED masks, you can download it here. You can also check out her website here or follow her on Instagram.

Have you tried any of the above masks before? What are your thoughts? Share with us in the comment section below.

Feature image: Instagram/@drprasanthipuru.

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