numbuzin No.6 Deep Sleep Mask Serum 80ml Set (+ No.4 SOS Ice-Cold Sheet Mask)
10 Olive Young reviews read first-hand · average 4.7 among them · 90% ★4–5 (our own tally) · a No.6 serum used like a mask + free No.4 sheet mask set · small sample, for trends only
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Community summary
The most frequently mentioned point is hydration. 'Skin stays moist until morning,' 'I'm dehydrated-oily so hydration matters, and this suits me,' and 'just the right moisture for oily skin' came up in 6 of 10 reviews. One review says that even in winter, layering about three coats left their cheeks bouncy without cream. That said, these are users' own impressions and depend on skin condition.
What shows this product's character is how it's used. Three reviews describe not a sheet you apply but a serum layered in two or three thin coats — sometimes three or four — before sleeping, and the phrase 'for when you can't be bothered with a sheet mask' recurs. Long-term users who have used numbuzin since its early days or repurchased it are common, at 5 reviews, and there's a pattern of switching to No.6 in summer because, compared with the No.3 serum, it's lighter and more hydration-focused.
The downsides are clear too. Two reviews say breakouts appeared at first use, so they paused for about a week before using it again (they say it was fine afterward); one combination-skin reviewer found it slightly drying and layers a light cream on top; and one ★2 review says it 'doesn't make you feel like you slept deeply.' The free No.4 mask splits opinions. Above all, the sample is just 10 reviews, so rather than reading too much into each percentage, it's best used as a reference for 'what people talk about.'
These are counts taken directly from all 10 reviews read, counting only clearly worded mentions. If anything, we undercounted rather than inflated — it's a minimum. With such a small sample, one review moves the figure by 10 percentage points.
By skin type
Star distribution — our own tally based on 10 reviews read first-hand, not Olive Young official. With such a small sample, one review equals 10 percentage points.
Expressions found in the reviews read (original tone kept, shortened)
Strengths reviewers kept mentioning
- Hydration — the most-mentioned pointSix of 10 reviews talk about hydration: skin stays moist until morning, and it adds just the right moisture to dehydrated-oily and oily skin. One review says layering about three coats left their cheeks bouncy without cream even in winter.
- Layering as a mask substitute — for lazy daysThree reviews describe a routine of layering two or three thin coats of serum instead of applying a sheet, then sleeping, which feels like you've done a mask. The phrase 'a product for people who can't be bothered with sheet masks' recurs.
- Light texture — summer and before makeupThree reviews say they switch to it in summer because it's lighter and more hydration-focused than the No.3 serum, and two say it sinks in well and doesn't pill even when applied before makeup.
- Long-term users and repurchasersFive of 10 reviews are from people who have used numbuzin since its early days, or tried it before and bought it again. Two also say they pack it for when their skin acts up while traveling.
Downsides (mentioned repeatedly)
- Reviews of pausing after early breakoutsTwo reviews say breakouts appeared when they first used it, so they paused for about a week before using it again (they say it was fine afterward). It's better to start with a small amount and watch how your skin reacts.
- The 'deep sleep' feel varies by personOne ★2 review says it didn't make them feel like they'd slept deeply. The 'deep sleep' in the product name is best taken as a description of the feel, not a promise.
- Dry areas need a cream on topOne combination-skin reviewer says it's slightly drying, so they apply a light cream only to dry areas, and another says cream is probably a must for dry skin.
- Free No.4 mask and bottle are hit-or-missThe No.4 mask included in the set got one positive review and one saying the scent wasn't great so they wouldn't buy it. One review also says the bottle is heavy and a travel-size container would be nice.
- Small sample, based on users' own impressionsWith only 10 reviews read, the percentages are for trends only. Comments about hydration and soothing are users' own impressions and vary by person, and we make no efficacy claims.
Best for
- When applying a sheet mask feels like a chore but you want to top up moisture before bed. The thin-layering routine comes up repeatedly
- When you have dehydrated-oily or oily skin and want a hydrating serum that isn't heavy. Hydration reviews are the most common
- When you need a light serum for summer or before makeup. Some say it doesn't pill
- When you've been using the numbuzin No.3 serum and want to try a lighter, more hydration-focused option
May not suit you if: When you're looking for an actual sheet mask. The main product is a serum, and the sheet mask (No.4) is a free add-on / When you have dry skin and want a serum alone to cover all your moisturizing. Some reviews say they layered cream on dry areas / Skin that tends to break out with new products. Two reviews say they paused because of early breakouts
How to Use numbuzin No.6 Deep Sleep Mask Serum 80ml Set (+ No.4 SOS Ice-Cold Sheet Mask)
- The common routine in reviews: after cleansing, apply a small amount thinly, and once it absorbs, add another coat — layering two or three coats (sometimes three or four) this way before sleeping
- The shared lesson from the early-breakout reviews is to start with a small amount over a short period to see how your skin reacts
- One combination-skin reviewer adjusts by layering a light cream only on dry areas like the cheeks and around the mouth
- One review also says they soak a cotton pad with it and leave it on the skin
Price & buying tips
- This set is the No.6 serum 80ml full size with a free No.4 SOS Ice-Cold Sheet Mask, so if you plan to try the sheet mask too, it's better to check the set rather than the single item
- The reviews read didn't mention prices or discounts. Olive Young sale prices and Coupang prices vary over time, so we recommend comparing them right before buying Check the price on Coupang →
Compared with other Sheet masks picks
Real-user and in-store trend tally for the sheet mask category (Olive Young JJintem's own data)
See the full Sheet masks ranking →
FAQ
Q. Is the numbuzin No.6 mask a sheet mask or a serum?
The main product is an 80ml serum named 'Deep Sleep Mask Serum,' and this set also includes a free No.4 SOS Ice-Cold Sheet Mask. Most reviews are about the serum, and the routine of layering the serum in several thin coats and sleeping in it, instead of applying a sheet, to get a 'just did a mask' feel comes up repeatedly.
Q. How to use the numbuzin No.6 serum — how much and how?
The method that recurs in reviews is to apply a thin layer after cleansing, add another coat once it absorbs, and layer two or three coats (sometimes three or four) this way before sleeping. Some reviews say it didn't pill even when applied before makeup in the morning. Others say they adjust by layering a light cream on dry areas.
Q. Can it cause breakouts?
Two of the 10 reviews read say breakouts appeared when they first used it, so they paused for about a week before using it again, and it was fine after that. Some call it gentle, but every skin reacts differently, so we recommend using a small amount for a few days at first to check how your skin responds. We make no safety or efficacy guarantees.
Q. How is it different from the numbuzin No.3 serum?
Reviewers who have used both compared No.3 as leaning toward moisture and skin texture, and No.6 as lighter and focused on filling in hydration, which is why they switch to No.6 in summer. One long-term user said, 'If I had to pick one, No.3 — but No.6 is a close second.' These are purely users' own comparisons.
Q. What about the free No.4 SOS Ice-Cold Sheet Mask?
Only 2 of the reviews read mention the No.4 mask — one positive, and one saying the scent wasn't great so they wouldn't buy it separately. The sample is too small to judge, so it's best seen as a bonus attached to the main No.6 serum.
Q. Where does it rank among Olive Young sheet mask recommendations?
In the Olive Young JJintem sheet mask tally, the numbuzin No.6 mask still has relatively few mentions. It's a serum you apply and sleep in rather than a sheet mask, so it's a slightly different kind of product, and rankings change depending on when they're tallied. For the latest comparison by condition — soothing, hydration, and so on — check the Olive Young sheet mask recommendation ranking page. We don't assign star ratings on our own.
Q. Where does the data on this page come from?
It's the result of us reading all 10 real Olive Young purchase reviews first-hand. The 4.7 average, 90% ★4–5, and star distribution were calculated directly from the star ratings of these 10 reviews and are not Olive Young's official tally. The keyword numbers are also minimums, counting only clearly worded mentions. The sample is small, so please treat it as a reference for trends. We don't reproduce the original review text — only the analysis — and we don't assign star ratings or make efficacy claims.
Starting from a viral Threads post with over 1.85M views, we collected real Korean users' recommendation comments on Olive Young posts, merged different spellings of the same product, and tallied mentions, likes, and staff endorsements. No ads or sponsorships — rankings come from real recommendation data only.
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