The Short Answer
If your usual moisturizer keeps your skin comfortable, you can skip serum. If you want extra hydration, use a gentle hydrating serum your skin already tolerates, such as one with hyaluronic acid. Apply it after your red light session, then follow with moisturizer, and check your mask’s instructions before applying any product under it.
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What One Study Tells Us About Serum and Red Light Therapy
To decide whether a serum is worth buying, ask what benefit you expect. Hydration is a skincare goal. Getting better results from the light session is a separate claim that depends on how the serum and device were tested together.
In a 28-day study published in the Journal of Biophotonics, Guermonprez and colleagues studied 32 women using a split-face design. One side received a specific serum delivered with LED light and massage, and the other side received the serum base alone. The researchers reported greater improvement in measures of skin smoothness and crow’s feet on the side that received the combined treatment. Guermonprez et al., 2020
The study compared the full treatment with the serum base. It had no LED-only group, so it could not establish how much benefit the serum added to light treatment on its own. It also did not test a serum applied before or after a wearable mask, so it offers no basis for choosing either timing. Guermonprez et al., 2020
For a purchase decision, the useful comparison would be the same mask on the same schedule, with the serum as the only difference between groups. Without that comparison for the combination you’re considering, a study of a different system is a weak reason to replace the skincare you already use.
How INIA GLOW 4D Fits Into Your Routine
That distinction matters when you use INIA GLOW 4D. Its setup guide places your usual skincare after the session, so you can decide what to apply based on how your skin feels and what you already use. For skin preparation, mode selection, and timing, follow the instructions supplied with your unit. INIA GLOW 4D setup guide
GLOW 4D is a cordless LED face mask with a red and dual near-infrared setting for a cosmetic routine focused on the appearance of fine lines. The cordless design lets you use the mask away from an outlet, so you can fit a session into the time you already set aside for skincare. INIA GLOW 4D product information
A Simple Evening Routine With GLOW 4D
1. Cleanse and prepare your skin. Remove makeup and sunscreen as you normally would, then follow your mask’s directions for skin preparation. If those directions call for clean, dry skin, pat your face dry and leave serum, moisturizer, and other products for after the session. American Academy of Dermatology red light therapy guidance
2. Use the mask as directed. Fit the mask and choose the setting described in the instructions for your unit. Follow the recommended session length and schedule, then remove the mask and continue with your usual skincare. INIA GLOW 4D setup guide
3. Choose the amount of hydration your skin needs. If your moisturizer keeps your skin comfortable, apply it on its own. If you prefer an extra layer, apply a gentle hydrating serum you already tolerate and follow it with your moisturizer.
For example, if you usually wash your face and apply cream right away, set the cream next to the mask before you start. On mask nights, use the cream once you’ve removed the device. If you already use a hydrating serum on dry evenings, keep that option for the nights when your skin feels like it needs the extra layer.
If you’re shopping for a hydrating serum, hyaluronic acid is one ingredient to look for. If your skin often feels tight after using a light lotion, consider whether a cream would meet your needs before buying a serum. The American Academy of Dermatology recommends creams or ointments for dry skin because they tend to moisturize more effectively than lotions. American Academy of Dermatology tips for dry skin
If you buy a new serum, try it first on a night when you aren’t using the mask and keep the rest of your routine familiar. That makes it easier to tell how the new formula feels and whether it adds enough hydration to keep using it.
Give yourself a simple way to judge the purchase. If your skin feels just as comfortable with the moisturizer alone, you can leave the serum out of your regular routine.
Bottom Line
Keep the moisturizer you already use if it gives you enough hydration. If you want a serum, choose one your skin tolerates and apply it after your GLOW 4D session.
Frequently Asked Questions
Can I apply serum before a red light mask?
Apply serum beforehand only if the instructions for your exact device allow it, and check whether they specify a product or formula. A serum can feel fully absorbed while the directions still call for bare skin. American Academy of Dermatology red light therapy guidance
Does hyaluronic acid make a red light mask work better?
Choose hyaluronic acid for hydration. The study discussed here evaluated a specific serum, light, and massage system and did not test hyaluronic acid as an add-on to a wearable mask. Guermonprez et al., 2020
Where do retinol and exfoliating acids fit?
Follow both the skincare label and the device instructions when deciding whether to use these products on the same evening. If you use a prescription retinoid, check with your prescriber before changing its schedule. American Academy of Dermatology red light therapy guidance
References
- Guermonprez C, Declercq L, Decaux G, Grimaud J-A. (2020). Safety and efficacy of a novel home-use device for light-potentiated (LED) skin treatment. Journal of Biophotonics. 13(12), e202000230.
- American Academy of Dermatology. Is red light therapy right for your skin?
- American Academy of Dermatology. Dermatologists’ top tips for relieving dry skin.
- INIA. GLOW 4D product details and specifications.
- INIA. Red light therapy before or after skincare? GLOW 4D routine guide