NUMBUZIN No.6 Deep Sleep Mask Serum (50ml)

Yes, generally. The serum contains niacinamide and vitamin C derivatives, both of which tend to sit well alongside retinoids and can support hydration and brightening while your skin adjusts.

A few things to keep in mind:

• Apply it as a calming, hydrating layer over tretinoin rather than treating it as another active.
• Start slowly, around 2 to 3 nights per week, before using both together more regularly.
• If you notice stinging, redness, or extra peeling, switch to using this serum on your non-tretinoin nights and keep things simple.

For advice specific to your tretinoin strength, it's worth checking with your prescribing dermatologist.

Apply it before your moisturiser. A simple PM routine would look like this:

• Cleanser
• Toner or essence (optional)
• No.6 Deep Sleep Mask Serum
• Moisturiser to seal everything in

If your skin is normal to combination, you can sometimes skip the moisturiser and use this as your last step instead.

Before moisturiser in most routines:

• Cleanser, toner/essence, serum, then moisturiser on top.

On nights you want extra hydration, you can also apply a slightly thicker layer as the very last step, after moisturiser, to use it as a sleeping mask.

Possibly, but go carefully. It contains niacinamide and vitamin C derivatives, which many people use alongside tretinoin without issue, but can be too much for skin that's already sensitised.

• Start by using it on nights when you're not using tretinoin
• If your skin settles well, you can try layering them, but stop if you notice stinging, redness, or extra peeling

As tretinoin is a prescription treatment, your prescriber's advice takes priority when it comes to mixing actives.

The formula combines hydration, brightening, and soothing ingredients:

• Icelandic Glacier Water: mineral-rich hydration that helps restore radiance to dull, tired skin.
• 5 types of Hyaluronic Acid: delivers moisture at multiple skin layers for a plump, bouncy look.
• Niacinamide: brightens overall tone and helps fade dark spots and pigmentation over time.
• Sea Buckthorn: antioxidant-rich and nourishing, supports skin repair and a healthy glow.
• Centella Asiatica & Chamomile: soothing duo that calms redness and irritation, gentle for sensitive skin.
• Green Tea & Licorice Root: help protect against environmental stressors and support even tone.
• Panthenol & Allantoin: support the skin barrier and keep skin comfortable overnight.

Yes. In your evening routine, apply retinal first and let it absorb for a minute or two, then follow with this serum as your hydrating and soothing layer. Finish with a moisturiser if needed.

If your skin is on the sensitive side, try alternating: retinal one night, this serum the next.

It's an evening-only product, used as your final step before bed.

• Normal/combination skin: cleanse, tone, optional lightweight serum, then apply this instead of a moisturiser.
• Dry skin: cleanse, tone, serum, moisturiser, then apply this on top to seal everything in.

Start with 2 to 3 nights a week and increase frequency if your skin is happy with it.

Introduce it slowly, especially alongside tretinoin.

• Weeks 1 to 3: use on non-tret nights only. Cleanser, toner (optional), No.6, moisturiser.
• If skin stays settled and your prescriber is happy, try one tret night per week: cleanser, No.6, moisturiser, tretinoin last.

If you notice extra stinging, redness, or peeling on tret nights, pull it back to non-tret nights only.