Sericin.
A silk protein about a third serine. Taken by mouth it's digested like any protein and contributes amino acids. On skin it dries into a water-holding film.
- Category
- Compound
What Sericin is, and what it does.
- Does it work
- Suits someone building a skin-focused routine or curious about a serine-rich protein. Anyone reacting to silk, dust mite or other insect proteins should avoid it.
- How much to take
- No dose figure is on record for oral use, so we won't invent one. Topical products carry their own concentration. Start with what the product in front of you states.
- Time to feel it
- On skin, the film forms immediately and you notice it after one application. Oral timing hasn't been mapped in people.
- The first dose
- Topically, skin feels smoother and holds water within minutes. Taken by mouth, day one adds serine and glycine to your amino acid pool.
- With regular use
- Weeks of topical use is where the hydration work sits. For weeks of oral use, nobody has measured the outcome in people yet.
- How well tolerated
- Well tolerated on skin for most people. It is a known occupational allergen around silk processing, so anyone sensitive to insect or dust mite proteins should avoid it.
- How it feels
- On skin, a light slippery film that dries soft rather than tacky. Swallowed, it behaves like any dietary protein, so the effect sits in your amino acid intake.
- The overlooked benefit
- Serine feeds glycine and cysteine production, so a protein that is a third serine contributes to pathways well past simple tissue building.
The proof, claim by claim.
These words describe the research, not the molecule's worth. Research strength is how much work stands behind one claim, and it is never a product score.
- Skin hydration with topical useRandomised trial
- Serine-rich amino acid contribution from oral proteinNarrative review
- Metal chelation and slowed oxidation in laboratory systemsIn vitro study
- Glucose metabolism markers in animal modelsAnimal study
- Occupational allergen in silk processingNarrative review
Why these belong in the same formula. Each row says what the basis is, from settled biochemistry through to a trial that measured the pair.
Roughly a third of sericin's amino acid residues are serine, with aspartic acid and glycine making up much of the rest. Digested sericin therefore delivers serine, which SHMT converts to glycine while transferring a one-carbon unit to folate. Glycine supplementation feeds the same interconversion from the other side. This is amino acid biochemistry, not a demonstrated clinical pairing.
Oral sericin is digested to peptides and free amino acids like any other protein. Because of its composition, the amino acid it supplies most is serine. Free L-serine supplies the same residue without the peptide step. Which of the two is preferable depends on whether the peptide fraction is wanted, and that has not been settled.
The work was done in rats and measured chromium exposure and downstream metabolic markers rather than clinical outcomes in people. Peptides can enhance trace mineral uptake by keeping the metal soluble in the intestinal lumen, which is a known mechanism for other peptide fractions. Whether this holds in humans has not been tested. Read it as mechanistic rather than clinical.
Peptide fractions that resist upper gut digestion become substrate for colonic bacteria. The human work reported shifts in microbiota composition alongside gastrointestinal tolerability data. A change in composition is a marker, not an outcome, and the direction of any benefit was not established. The pairing with a defined probiotic strain has not been tested at all.
Sericin's hydroxyl-rich serine residues bind water and leave a flexible film on drying. Hyaluronic acid holds water in the same layer through a different polymer chemistry. Combining them is standard practice in hydrogel and topical formulation for humectancy and film integrity. This is a formulation property and says nothing about oral use.
Collagen peptides supply glycine, proline and hydroxyproline. Sericin supplies serine, aspartate and glycine. The amino acid profiles complement rather than duplicate each other. In topical and hydrogel work they also co-form films. The combination is a formulation choice, and no trial has tested the pair for any endpoint.
The reported antioxidant behaviour of sericin comes from cell-free and cell culture systems, where its hydroxyl-rich residues chelate transition metals and slow metal-catalysed oxidation. Glutathione works enzymatically inside cells, which is a different compartment and a different mechanism. Any additive effect is theoretical at this point. Do not read laboratory antioxidant activity as an effect in people.
Nothing specific on file for Sericin. Match the label to the daily amount above, and tell your doctor what you take.
Not medical advice. Show the label to your pharmacist.What Sericin actually does.
Sericin is the sticky protein that glues silk fibers together in the cocoon. the process that softens silk washes this protein away, which is why it used to just be a waste byproduct rather than something sold on its own.
About a third of sericin's building blocks are the amino acid serine, along with aspartic acid, glycine and threonine. that composition is heavy on hydroxyl groups, which is why it dissolves in water and holds onto moisture so strongly.
If you eat it, sericin gets digested just like any other protein, broken into amino acids and small peptides, it doesn't reach your bloodstream in one piece. so the part of oral use that actually makes biochemical sense is its contribution of amino acids.
When it dries, sericin forms a continuous water-loving film. that's why it's used in skin products and gels, it's a physical property, not a biological effect on the body.
Where Sericin comes from.
Sericin is the sticky protein that glues a silkworm cocoon together. Making silk soft means washing it off, so for most of history it went down the drain. It is about a third serine, an amino acid, and it holds water well, which is why it turns up in both drinks and skin products.
Made from an animal material. Species and tissue are the things worth knowing, and both belong on a label.
Silkworm cocoons, including yellow cocoon varieties which carry a different pigment and flavonoid profile from white. Sericin is roughly a quarter to a third of the cocoon by weight.
Cocoons are boiled in water, dilute alkali, soap solution or with proteases. This dissolves the sericin coating and releases the fibroin filaments. Historically the sericin-bearing water was discarded as effluent.
The recovered protein is hydrolysed enzymatically or chemically to reduce molecular weight. Enzymatic routes give a narrower and more reproducible peptide distribution than acid or alkaline routes.
Membrane filtration removes salts, residual detergent and fibroin fragments, and can fractionate by molecular weight.
Material is characterised by molecular weight distribution and protein content. This is the specification that actually distinguishes one sericin from another.
Supplied as a spray-dried powder for oral and dry formats, or as a preserved aqueous solution for topical use.
Cocoon colour and whether the degumming used enzymes, alkali or soap are rarely stated on a label, and both change the finished material.
The forms it comes in.
The essence, in one line each.
- Sericin-derived oligopeptides from yellow silk cocoons were tolerated in the tested dose range and were accompanied by shifts in gut microbiota composition.Open-label trial. Oo-Puthinan S et al., 2026 (Foods). PMID 42450525 ↗
- Adding sericin to freezing and thawing media changed measured sperm quality parameters after cryopreservation.In vitro study. Aghaz F et al., 2020 (The Aging Male). PMID 30453816 ↗
- Sericin added to a semen freezing extender improved post-thaw quality measures and fertility rate in roosters.Animal study. Ratchamak R et al., 2023 (Animal Bioscience). PMID 37170513 ↗
- Sericin in the freezing extender improved post-thaw sperm quality measures in goats, with changes in glutamine metabolism reported alongside.Animal study. Yu Y et al., 2025 (Animals). PMID 41096425 ↗
- Sericin supplementation of freezing media altered heat shock protein 70 expression and redox measures in post-thaw semen.Animal study. Reddy VS et al., 2018 (Cryobiology). PMID 30098997 ↗
- Sericin added before and during in vitro maturation reduced the damage seen when oocytes were exposed to hydrogen peroxide.In vitro study. Yindeetrakul S et al., 2026 (Veterinary Medicine International). PMID 42180161 ↗
- Silk-derived sericin changed how heterotypic cell spheroids formed and how they responded to metformin in culture.In vitro study. Calvo-Chica LE et al., 2026 (Biomaterials Advances). PMID 42335554 ↗
These are the studies our verdict leans on, chosen from the 7 we read for Sericin. The full linked list is below.
The studies, linked.
8 sources behind our Sericin verdict: peer-reviewed studies and registered clinical trials. Every one links straight to PubMed, the journal, or ClinicalTrials.gov. Read them yourself.
- Clinical trialSafety Evaluation of a Film-forming Cream Containing Sericin and Chitosan for Pressure Sore Treatment in Healthy VolunteersClinicalTrials.gov ↗112 participants, Completed
- Clinical trialClinical Efficacy of Wound Dressing Containing Silk Sericin for Split-thickness Skin Graft Donor Site TreatmentClinicalTrials.gov ↗Phase 1, 30 participants, Completed
- Clinical trialSafety of Cream Containing Sericin and Turmeric in Healthy VolunteersClinicalTrials.gov ↗106 participants, Unknown
- Clinical trialClinical Efficacy of the Novel Biocellulose Wound Dressing Containing Silk Sericin and Polyhexamethylene Biguanide for Split-thickness Skin Graft Donor SitesClinicalTrials.gov ↗Phase 2, 32 participants, Unknown
- Clinical trialEfficacy and Safety of Cream Containing Sericin and Turmeric in Psoriasis PatientsClinicalTrials.gov ↗30 participants, Unknown
- Clinical trialClinical Efficacy and Safety of Sericin Hydrogel Sheet Impregnated With Bird's Nest Extract in Prevention of Hypertrophic Scar Development at Split-thickness Skin Graft Donor SiteClinicalTrials.gov ↗30 participants, Unknown
- Clinical trialClinical Efficacy of Silk Sericin Dressing With Collagen for Split-thickness Skin Graft Donor Site TreatmentClinicalTrials.gov ↗30 participants, Unknown
- Clinical trialEfficacy and Safety of Sericin and Chitosan Cream for Preventing and Limiting the Progressive of Pressure SoreClinicalTrials.gov ↗20 participants, Unknown
Evidence surfaced via Semantic Scholar (Allen Institute for AI) and ClinicalTrials.gov. Ranked by study type and citation weight, not cherry-picked.
FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. This information is for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Consult your healthcare provider before starting any supplement regimen.