Dear Alice- is there a difference or clear winner between Dermalux Flex, Celluma or Lyma light therapy units? They are all v.expensive so any guidance would be helpful. Are you familiar with Lyma unit? Thanks Alice

Yes – the Celluma and the Dermalux Flex MD are certified medical devices that use gold-standard LED technology and are hugely popular across the aesthetics industry. When something like this is a ‘certified medical device’, it means it is a medically recognised treatment for conditions such as psoriasis, acne and pain relief. Everyone who sells an LED device bangs on about how it’s ‘NASA-derived technology’ which, yes, that’s technically correct, but they leave you to infer that you are getting top quality scientifically outstanding technology in their device which you generally aren’t. But with these two, you are. I would be very happy with either.

Editor’s note. I had previously written that in a head-to-head comparison carried out by an independent lab, the Dermalux Flex came out on top, and scored more highly in terms of power output. I had understood that this was because Dermalux uses single-wavelength bulbs, whereas Celluma puts multiple wavelengths through the same bulbs, which makes for a less effective result. BUT! I now stand corrected, as Celluma, which is backed by peer-reviewed and published studies, also uses single-wave-length LEDs, and the company has pointed out to me that power output does not directly equate to efficacy, as efficacy is a function of the amount of energy available for absorption at the surface of the skin.

And as for the Lyma, it is not a medically certified device. I tried it for months on end without getting any results, and all my laser-manufacturer acquaintances laugh at it when I ask them what they think of its supposed powers of rejuvenation. It makes enormous claims and has the flimsiest scientific backup  – and despite making these claims the company hasn’t risked putting the product through a single clinical trial or comparison with other devices. It’s been brilliantly and stylishly marketed and it has persuaded a lot of journalists who should have asked a few more questions to repeat the marketing claims without asking any difficult questions. Or even the basic questions, like, how can a device the size of a torch with a rechargeable battery generate enough power to do what it says it does? Or how can any light which is allegedly strong enough to prompt healing deep within the skin be safe to use around the eyes/ shine directly in your eyes without protection?  Keep well clear.