Overnight “bio-collagen” masks — a hydrogel sheet worn until it turns clear — became one of the most-shared skincare products of the past two years, and “collagen face mask” and its variants draw about 13,000 US searches a month (clickstream estimate, October 2026). The first page of search is mostly shop listings and roundups. This page reads the masks' own ingredient lists, works through the dalton figures they advertise, and sets out what the published mask studies measured, as of 14 October 2026. It does not rank or recommend any product, and no product here has been tested by us.
Four masks, read from their own pages
We read the full ingredient list each brand publishes on its US product page. Position matters: in the US and EU, cosmetic ingredients above 1% are listed in descending order of amount, and those at 1% or less may follow in any order.
| Mask (brand page, US price) | Ingredients | First five after water | Where collagen sits | Other actives named |
|---|---|---|---|---|
| Biodance Bio-Collagen Real Deep Mask ($19) | 34 | glycerin, acrylates copolymer, niacinamide, carob gum, Chondrus crispus (seaweed) extract | “collagen extract”, 24th | hydrolysed hyaluronic acid, niacinamide, ferments |
| Medicube Collagen Night Wrapping Mask ($24) | 26 | polyvinyl alcohol, glycerin, agave extract, niacinamide, sodium hyaluronate | “collagen extract”, 25th | ceramide NP, niacinamide |
| Medicube Collagen Milky Glow Daytime Wrapping Mask ($24) | 52 | “collagen water”, octyldodecanol, polyvinyl alcohol, niacinamide, methylpropanediol | “collagen water” 2nd; “collagen amino acids” 44th | glutathione, alpha-arbutin |
| Medicube Salmon PDRN Pink Collagen Jelly Gel Mask | 43 | glycerin, methylpropanediol, an acrylates copolymer, niacinamide, Chondrus crispus powder | “hydrolyzed collagen”, 26th | sodium DNA (PDRN), 13 peptides from 31st onward, fragrance 21st |
Three patterns stand out. The gel is the product. Every mask is built on water held by glycerin and a gel former — seaweed gums, agar and an acrylate polymer in the hydrogel sheets, polyvinyl alcohol in the wrapping masks that dry to a peelable film. Collagen is a minor ingredient in three of the four, placed among the extracts at the end of the list. And “collagen water”, second on the Milky Glow label, is not a standard name for a defined ingredient; the label does not say what it contains or at what strength. None of the four states a collagen percentage. The PDRN mask's peptides are read in detail on our analysis of that mask.
What “ultra-low molecular collagen” can mean
Collagen is a very large protein. A single chain of type I collagen weighs roughly 139,000 daltons, and the three-chain molecule several times that — which is why whole collagen cannot pass into intact skin, as our peptides vs collagen page sets out. The size usually cited as the practical limit for passing through the skin's outer layer is about 500 daltons (Bos and Meinardi, Experimental Dermatology 2000).
Brands answer the size problem by advertising very small fragments. Biodance's page says its collagen is 243 daltons and that “collagen skincare products are effective at a molecular weight of 500 daltons or less”. Medicube's Milky Glow page advertises “130Da ultra-low molecular collagen”, adding that “most collagen masks … stop at 300Da”. Set against the masses of collagen's own building blocks (PubChem, read 14 October 2026), those numbers say something the pages do not:
| Unit | Mass (daltons) |
|---|---|
| Glycine, the most common amino acid in collagen | 75.07 |
| Proline | 115.13 |
| Hydroxyproline | 131.13 |
| Smallest possible dipeptide, glycine–glycine (our arithmetic) | about 132 |
| Collagen's repeating tripeptide, glycine–proline–hydroxyproline (our arithmetic) | about 285 |
| One collagen chain | about 139,000 |
A 243-dalton fragment is smaller than collagen's repeating three-amino-acid unit — two or three amino acids at most. A 130-dalton “collagen” is smaller than any two amino acids joined together; it is the size of a single amino acid such as hydroxyproline, which fits the Milky Glow label's own wording, “collagen amino acids”. Neither is collagen in any structural sense, and a fragment that small reaching the skin is not the same as collagen being restored in it. Whether such fragments do anything after they arrive has not been tested in a controlled trial of these masks; the 500-dalton figure is a rule about what can enter skin, not evidence that what enters works.
What mask studies measure
A PubMed search on 14 October 2026 for facial, sheet or hydrogel masks with skin, hydration or wrinkle outcomes returned 152 records, 11 tagged as randomized controlled trials and one retracted. Read for collagen, two are directly relevant.
- A native collagen sheet. A 2024 paper evaluated a sheet made of more than 92% native bovine collagen — a freeze-dried collagen fleece, a different product from the gel masks above — across five clinical studies, and reported better hydration and smaller eye-wrinkle volume than a pre-soaked cellulose sheet (Janssens-Böcker et al., Journal of Cosmetic Dermatology 2024). All three authors are at MedSkin Solutions Dr. Suwelack, the sheet's maker, and the abstract itself notes that “the scientific evidence for the efficacy of collagen sheet masks remains limited”.
- A hydrogel mask with no collagen. A 2026 pilot of a radiation-crosslinked hydrogel mask (PVP, PEG and agar, with hyaluronic acid, ectoine, allantoin and tocopherol) in 15 people with sensitive skin over six weeks, with no control group, reported progressive improvement in hydration and firmness. Its authors describe the short-term effects as “consistent with occlusion-driven modulation” of the skin rather than lasting changes after removal (Rokita et al., International Journal of Cosmetic Science 2026).
That second finding describes what any of these masks is mechanically: a wet, occlusive layer that slows water loss while it is on. That is a real, measurable cosmetic effect, and it does not depend on collagen. The brands' own claims are framed the same way — Biodance's page describes a 166% increase in moisturisation lasting 150 hours, without naming the study or its design.
Overnight wear and irritation
The viral way to use these masks is to sleep in them. No study located measured overnight wear specifically. What overnight occlusion does do is keep every ingredient — including fragrance, which Medicube's PDRN mask lists 21st, preservatives such as 1,2-hexanediol and ethylhexylglycerin, and acrylate polymers — on the skin for many hours. PubMed held 15 records on face or sheet masks and allergy or contact dermatitis on 14 October 2026. Anyone who reacts to cosmetics, or who has eczema or rosacea, is better placed asking a dermatologist than following an overnight trend; our pages on peptides for eczema and peptides for rosacea cover what is known for those skin types.
Collagen lip and eye masks
The same format is sold for lips and under the eyes. The question is the same — where the collagen sits on the label and what the gel does — and our reading of what the under-eye patch trials actually tested and of one peptide-collagen hydrogel eye patch applies the same method to those products.
What the labels do not show
They do not show how much collagen any mask contains. They do not show that the collagen, or its fragments, does anything a glycerin gel would not. They do not show what happens with nightly use over months. They do show that the masks are hydrating gels with collagen named on the label, and that the smallest “collagen” sizes advertised are the size of single amino acids. For what peptides and collagen are claimed to do for skin more generally, see what peptides do for skin.
Sources and dates
Opened 14 October 2026: brand product pages for Biodance Bio-Collagen Real Deep Mask and Medicube Collagen Night Wrapping, Milky Glow Daytime Wrapping and Salmon PDRN Pink Collagen Jelly Gel masks; PubChem records for glycine (CID 750), proline (CID 145742) and hydroxyproline (CID 5810); PubMed records 38279521, 42521242 and 10839713 and the counts stated. Dipeptide and tripeptide masses are our arithmetic from the PubChem masses less the water released at each bond. Corrections go to the contact page.