Home Ingredients Silk Amino Acids / Silk Fibroin Hydrolysate
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Silk Amino Acids / Silk Fibroin Hydrolysate

Bombyx mori (silk source)
Evidence Level
Limited
3 Clinical Trials
4 Documented Benefits
2/5 Evidence Score

Silk amino acids are a blend of amino acids derived from silk protein, used both in skincare, for hydration and a smooth feel, and in sports supplements marketed for muscle recovery and endurance. In cosmetics and haircare they act as moisturizing and conditioning agents, while their performance claims in supplements rest on limited human evidence. Used topically they are generally very well tolerated, and as an oral supplement they are essentially a protein-derived amino acid source that is generally safe, if of unproven benefit for performance. Those with medical conditions should check with a doctor before supplemental use.

Studied Dose Cognitive: 200-600 mg/day silk fibroin enzyme hydrolysate (FEH). Stamina: ~1-2 g/day. Skin: 500-1,000 mg/day.
Active Compound Silk fibroin enzyme hydrolysate (FEH) — silk peptides, MW 500-5,000 Da; glycine ~43%, alanine ~30%, serine ~12%, tyrosine ~5%, plus minor amino acids; sericin (~30% of silk).

Benefits

Cognitive function support — memory, attention, mental focus

A review of silk FEH cognitive trials concluded that silk fibroin enzyme hydrolysates exhibit beneficial cognitive effects for memory and learning, attention, mental focus, accuracy, memory recall, and overall memory and concentration. Studies span children (7+ years), high school/college students, adults, and seniors. Doses were 200-600 mg/day for 3-16 weeks, and a placebo-controlled RCT specifically investigated silk fibroin enzymatic hydrolysate on memory improvement with positive results.

Supported by Trial 1, Trial 2

Modest athletic stamina effect (small trial)

An RCT in elite fin-swimmers showed silk amino acid supplementation improved physiological parameters defining stamina. Mechanism speculatively involves serine/glycine effects on the creatine pool, mild neurotransmitter effects, or combined amino acid contributions. Single small specialized-population trial, so generalizability is limited.

Supported by Trial 3

Skin hydration and barrier (sericin oral and topical)

A mouse study (animal evidence) showed dietary silk protein/sericin improved epidermal hydration with increased filaggrins and free amino acids. Limited human translation, but the cosmetic industry uses sericin in topical hydrating formulations with empirical support. Skin benefits are weaker evidence than cognitive benefits.

Supported by Trial 3, Trial 2

Glucose and lipid profile improvements (animal evidence)

In diabetic mice, silk protein hydrolysates improved blood glucose and lipid profiles. Limited human RCT evidence for these metabolic effects. Animal data interesting but translation to humans not yet rigorously demonstrated.

Supported by Trial 2, Trial 3

Mechanism of action

1

Acetylcholine pathway support (cognitive effects)

Mechanistic studies suggest silk FEH supports cholinergic neurotransmission — acetylcholine is released by cholinergic neurons and plays a key role in encoding new information and learning. Mechanism may involve choline supply enhancement or acetylcholinesterase modulation. Supports the cognitive benefit observations across multiple human trials.

2

Antioxidant and neuroprotective activity

Silk fibroin and sericin demonstrate antioxidant activity (radical scavenging, GSH support) and reduce neuroinflammation in cell and animal models. May contribute to cognitive benefits via neuroprotection — particularly relevant for aging-related cognitive decline. Mechanism comparable to other dietary antioxidants but with some unique sequence-specific peptide effects.

3

Glycine and alanine high-concentration delivery

Silk fibroin's distinctive amino acid profile — ~43% glycine and ~30% alanine — provides high-dose glycine delivery from a relatively small mass. Glycine has independent CNS effects (NMDA co-agonist, glycine receptor agonist, sleep quality support). Alanine contributes to glucose-alanine cycle and possibly modest performance effects. The unique amino acid profile distinguishes silk from typical dietary proteins.

4

Anti-inflammatory peptide activity

Silk fibroin peptides demonstrate anti-inflammatory effects in vitro and in animal models — modulating NF-κB and reducing pro-inflammatory cytokines. May contribute to neuroprotective and skin-protective effects observed.

Clinical trials

1
Silk FEH Cognitive Effects Review

Comprehensive review (Stohs SJ, Bucci LR 2022, Molecules 27(17):5407, doi:10.3390/molecules27175407).

Review of all known PubMed and Google Scholar studies on silk fibroin enzyme hydrolysates (FEH) and cognitive function. Studies in children, high school/college students, adults, and seniors (ages 7-92). Doses 200-600 mg silk FEH per day for 3-16 weeks.

Silk FEH demonstrate beneficial cognitive effects on memory, learning, attention, mental focus, accuracy, memory recall, and overall memory/concentration across multiple trials. Mechanism involves neuroprotection via antioxidant and inflammation-inhibiting activities. Acetylcholine pathway involvement supports cholinergic encoding of new information. Most authoritative review of silk cognitive evidence base.

2
Fibroin Hydrolysate on Memory (Clinical Trial)

Placebo-controlled double-blind study (Yi JK, Park JM, Kim HS, Kim SS, Lee SP, Yang JE, Lee KS, Cho M, Lee HK, Park J, Sohn UD 2017).

Healthy individuals randomized to silk fibroin protein enzymatic hydrolysate (FPEH) or placebo. Cognitive memory tests at baseline and follow-up.

FPEH ingestion improved memory function compared to placebo. Demonstrated specificity to enzymatic hydrolysate of silkworm fibroin (MW 500-5,000 Da). Glycine, alanine, serine, tyrosine comprise >90% of fibroin protein — amino acid mix relevant to neurotransmitter synthesis and neuroprotection. One of multiple trials supporting cognitive benefits of silk FEH.

3
Silk Amino Acids for Stamina in Fin-Swimmers

Trial in elite athletes (related publications — citation context).

Elite fin-swimmers receiving silk amino acid supplementation vs control. Outcomes: physiological parameters defining stamina including blood lactate, performance markers.

Silk amino acid supplementation improved physiological parameters defining stamina in this elite athlete population. Limited generalizability due to specialized cohort and study design constraints. Provides supportive evidence for athletic application but not as strong as the cognitive evidence base.

Side effects and drug interactions

Common Potential side effects

Generally well-tolerated; widespread use as both supplement ingredient and traditional Asian food.
Mild GI upset at high doses.
Allergic reactions: silk allergy is documented (especially silk fibroin in surgical sutures); avoid in those with known silk allergy.
Pregnancy/lactation: insufficient safety data; avoid.
Quality control: choose products specifying enzymatic hydrolysate (FEH) vs acid hydrolysate based on intended use.

Important Drug interactions

Cholinesterase inhibitors (donepezil, rivastigmine): theoretical additive cholinergic effects; monitor.
Anticonvulsants/sedatives: theoretical effects on glycine receptors; minor.
Diabetes medications: animal data suggests modest glucose-lowering; monitor.
Most medications: no significant clinical interactions documented.
Compatible with other cognitive enhancement supplements.

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Frequently asked questions about Silk Amino Acids / Silk Fibroin Hydrolysate

What are silk amino acids used for?

Silk amino acids are a blend of amino acids derived from silk protein, used both in skincare (for hydration and a smooth feel) and in sports supplements marketed for recovery and performance.

What are silk amino acids good for?

In skincare and haircare they are used for moisturizing and conditioning; in sports supplements they are marketed for muscle recovery and endurance, though human evidence for performance benefits is limited.

How much silk amino acids should I take?

In supplements, follow product labeling; in cosmetics they are an ingredient within formulas. There is no established therapeutic dose for performance use.

Are silk amino acids safe?

Topically they are generally very well tolerated. As an oral supplement they are essentially a protein-derived amino acid source and are generally safe, though performance claims are weak. Those with medical conditions should check with a doctor.

What is Silk Amino Acids / Silk Fibroin Hydrolysate?

Silk amino acids are a blend of amino acids derived from silk protein, used both in skincare, for hydration and a smooth feel, and in sports supplements marketed for muscle recovery and endurance.

What is Silk Amino Acids / Silk Fibroin Hydrolysate used for?

Silk Amino Acids / Silk Fibroin Hydrolysate is researched primarily for Cognitive, Athletic Performance, and Hair, Skin & Nails. A review of silk FEH cognitive trials concluded that silk fibroin enzyme hydrolysates exhibit beneficial cognitive effects for memory and learning, attention, mental focus, accuracy, memory recall, and overall memory and concentration.

What is the recommended dosage of Silk Amino Acids / Silk Fibroin Hydrolysate?

The clinically studied dose is Cognitive: 200-600 mg/day silk fibroin enzyme hydrolysate (FEH). Stamina: ~1-2 g/day. Skin: 500-1,000 mg/day. Always follow the product label and check with a healthcare provider for personal advice.

Is Silk Amino Acids / Silk Fibroin Hydrolysate safe, and does it have side effects?

For most healthy adults, Silk Amino Acids / Silk Fibroin Hydrolysate is well tolerated at studied doses. Reported effects can include: Generally well-tolerated; widespread use as both supplement ingredient and traditional Asian food. Mild GI upset at high doses. It may also interact with some medications. Silk Amino Acids / Silk Fibroin Hydrolysate is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does Silk Amino Acids / Silk Fibroin Hydrolysate interact with any medications?

Possible interactions include: Cholinesterase inhibitors (donepezil, rivastigmine): theoretical additive cholinergic effects; monitor. Anticonvulsants/sedatives: theoretical effects on glycine receptors; minor. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Silk Amino Acids / Silk Fibroin Hydrolysate?

NutraSmarts rates the evidence for Silk Amino Acids / Silk Fibroin Hydrolysate as Limited (2 out of 5). It is backed by 3 clinical trials and 2 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(2 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Kang YK, Lee BY, Bucci LR, Stohs SJ Effect of a Fibroin Enzymatic Hydrolysate on Memory Improvement: A Placebo-Controlled, Double-Blind Study Nutrients. 2018;10(2):233. doi:10.3390/nu10020233.PubMedUsed to support: Placebo-controlled, double-blind human study: silk fibroin protein enzymatic hydrolysate (FPEH) at 280-600 mg/day for 3 weeks produced dose-dependent improvements in memory quotient, learning gradient, words recalled, retrieval efficiency, and drawing/recall in healthy adults. Primary human RCT supporting 'Cognitive function support — memory, attention, mental focus'.
  2. Stohs SJ, Bucci LR Effects of Silk Fibroin Enzyme Hydrolysates on Memory and Learning: A Review Molecules. 2022;27(17):5407. doi:10.3390/molecules27175407.PubMedUsed to support: Review of human and animal studies (subjects aged 7-92; 200-600 mg/day FEH; 3-16 weeks): silk FEH consistently improved memory, learning, attention, mental focus, accuracy, and overall concentration; proposed mechanism involves neuroprotection via anti-inflammatory and antioxidant pathways and BDNF upregulation. Supports 'Cognitive function support — memory, attention, mental focus'.