Earbud comfort and sleeping positions are both extremely personal. The Nighbuds rest in your ears rather than fitting deeply, with a tiny finger protruding from the silicon bud cover that hooks into the curves of your ear to keep them secure. There’s a good choice of both bud and finger size, so most people will find one that fits well (which might be different for each ear). However, that may not be enough to stop them falling off during the night or just slipping out enough to get turned off automatically to save batteries (a setting you can change if fiddling around to get them back in and turned on again wakes you up all over again). You may also end up leaving the silicon covers in your ears when you take the buds out in the morning, although they’re easy to pop back on. 
The wiggly wire between the buds expands to cope with most hairstyles, although I found it compressed the braids I’ve been sporting for the last decade and I ended up tucking them under my hair (alternatives like the Bose Sleepbuds II are fully wireless). As a side sleeper, the battery and volume pod at the back wasn’t in my way, just very awkward for turning the Nightbuds on and setting the volume. The earbuds are more comfortable to lie on than other tiny buds I’ve tried, but I was still very aware that I had something firmer than foam earplugs in my ears and I found I had to change my sleeping position somewhat to get comfortable. Again, this is so individual that you’re not going to know if the Nightbuds will suit you without trying them, and it may take a few nights to get used to them. 
Even if you find them comfortable, the Nightbuds are fiddly so it’s best to turn them on before you put them on, and maybe pick your audio first. 
What you hear through the Nightbuds could be your own favourite falling-asleep music, a Kokoon-curated playlist from a service like Spotify or Apple Music, or something from an app like Calm or Headspace that promises to help you sleep. But the companion app also includes Kokoon’s own audio experiences designed to help you drop off, wake you up or relax during the day. 
These are filed under Going to Sleep, Feeling Anxious, Disrupted Sleep and Brighter Mornings in the (subscription-based) MyKokoon app, which is available for iOS and Android. This offers a mix of coaching, meditations, storyscapes (like an imaginary shipping forecast) and music, which includes ‘binaural’ sounds that send each ear a slightly different tone, causing the brain to perceive a low-frequency tone that’s supposed to produce the theta and delta brainwaves that accompany sleep. There’s more hype than research about binaural sound, but listening to it in the office did make me yawn a lot. The coaching and meditation tracks will work best if you find the narrators’ voices soothing rather than annoying, which is again a personal thing. 
Whatever you’re listening to, you can set it to either fade out or have coloured noise added as the buds detect that you’re actually falling asleep. You can also add your choice of white, pink or brown noise, or sounds like rain, waves or a campfire, without waiting for the Nightbuds to notice you falling asleep. 
Slightly confusingly, you select the audio directly from the library but swipe the app background left or right to pick the added noise. This coloured noise masks any real background noise (rather than trying to cancel it out precisely, which takes more power), but you may have to experiment to find a noise colour or sound effect that works for you. You can set the volume for the added noise separately, which is helpful because at a volume that made the audio I’d chosen audible I found the coloured noise intensely annoying until I turned it down. SEE: The 5 best noise-canceling earbuds: Shut out the world Again, all this was very fiddly and got in the way of finding the Nightbuds experience relaxing until I’d invested quite a lot of time understanding what could be a much more intuitive interface. 
If you’re someone who turns your phone volume off at night, that will turn off the MyKokoon volume too, so you may want to take some time to turn off notifications that would wake you right up again. 
The battery pod in the middle of the wire packs enough power to let the Nightbuds stream audio from your phone rather than restricting you to sounds stored on the buds the way alternatives like the Bose Sleepbuds do, but the 10-hour battery life (if you’re lucky) means unless you routinely get by on only a few hours of sleep, you’re going to have to plug these in every morning. You can set them to turn off automatically when you take them off, but if you pull them out while you’re asleep the first thing you see when you look at the app in the morning will be a glaring reminder of your restless 4am removal, which can make you feel tired all over again. 
The sleep tracking is rather bare bones – fitness trackers that track more than your sleep have an advantage in that they gather data about the rest of your day to use in their analysis, but Kokoon doesn’t give you any details, just an overall efficiency score. Also, the insistence on setting what you want your sleep schedule to be can actually add to the anxiety of falling asleep. If you find the Nightbuds comfortable enough to fall asleep in but also find that you remove them (or they fall out) in the night, the tracking won’t be accurate. 
There’s an alarm option, but I didn’t manage to get it to actually wake me up (perhaps because the Nightbuds sometimes slipped out in my sleep). 
Audio quality is optimised for voice rather than music, so the Nightbuds are a better choice if you respond well to the coaching and soundscapes than if you want relaxing ambient tones and you’re not likely to reach for them during the day to listen to music. But assuming you don’t leave them in the bedroom, they come in handy if you need a quick nap or just to destress after a frustrating call or meeting, or to transition out of work mode when working from home. The Nightbuds could also be good to help you sleep on airplane journeys, assuming you find them comfortable enough. However, they don’t cut out the sound of a crying baby, a chatty passenger or engine noise the way custom in-ear buds do. 
At £229.99 with a two-year subscription to the MyKokoon app (discounted to £207 at the time of writing, or £169.99 reduced to £136 for the buds with an annual membership that auto-renews), the Nightbuds are pricey. If they help you sleep better that’s certainly worth it, but not everyone is going to find them useful. You need to find them comfortable and be someone who falls asleep better with the right sound than in silence. The 30-day trial does let you check that for yourself, though. 
Kokoon Nightbuds specifications

Alternatives to consider

Sleep earbuds can offer a range of functionality, including active noise cancelling, the ability to play soothing and noise-masking sounds, and your own sounds. Two of the leading alternatives to the Kokoon Nightbuds are from Amazefit and Bose. RECENT AND RELATED CONTENT Kokoon: The noise-canceling headphones that monitor brain activity and help you sleep  Kokoon noise-canceling headphones in pictures  Noise-canceling headphones that help you sleep through any snore Coros sports watch firmware update improves sleep and workout tracking Sleep better in any position with this self-cooling pillow Read more reviews

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