Updated: November 2025
Why New Zealand sheep wool keratin is the most bioavailable, effective keratin source available for hair, skin, and nails
Sheep wool, the soft and cosy material we associate with warmth and comfort, holds within it a remarkable substance: keratin.
Keratin is the protein that makes sheep wool unique, resilient, and functional.
But here's what most people don't realise: not all keratin is the same.
The keratin from New Zealand sheep wool is structurally superior because of the conditions in which it develops, how it's extracted, and its inherent bioavailability.
Understanding the science behind sheep wool keratin unlocks why Kiri10 chose this source specifically, and why our Functional Keratin™ products deliver results other supplements simply can't match.
Let's explore the molecular architecture, chemical properties, and practical applications that make sheep wool keratin exceptional.
The Structure of Sheep Wool Keratin: Molecular Architecture
What Is Keratin?
Keratin is a fibrous structural protein, and it's the fundamental building block of hair, skin, and nails in all mammals.
In humans, keratin comprises 95% of hair structure and 75% of skin's outer layer.
Sheep wool keratin is identical in structure to human keratin.
This bio-identity is critical.
When you ingest keratin that's structurally identical to your own, your body recognises it and utilises it efficiently.
The Amino Acid Foundation
Keratin is composed of amino acids, specifically arranged in precise sequences.
Key amino acids in keratin:
Cysteine (forms disulfide bonds, creates strength)
Methionine (contains sulphur, essential for structure)
Glycine (provides flexibility)
Arginine (supports collagen production)
Leucine (supports protein synthesis)
These amino acids arrange into incredibly complex three-dimensional structures.
The Complex Structure: Alpha-Helices and Beta-Sheets
This is where it gets fascinating:
Alpha-helices are spiral formations of amino acids
Beta-sheets are flat, parallel arrangements
These structures intertwine, creating a robust, flexible matrix
The balance of these structural elements gives keratin its unique properties
Why this matters for you:
When keratin is broken down (hydrolysed) excessively, these structures collapse
This renders the keratin less effective
Functional Keratin™ maintains these structures, preserving bioactivity
This is why Functional Keratin™ achieves 91% bio-identity to human keratin.
Disulfide Bonds: The Secret to Strength
Perhaps the most critical aspect of keratin structure is disulfide bonding.
Here's how it works:
Cysteine amino acids form disulfide bonds (S-S connections)
These bonds cross-link the protein chains
This creates incredible tensile strength
These bonds are what make hair flexible yet strong
Why hydrolysed keratin fails:
When keratin is heavily processed, disulfide bonds break
This destroys the structural integrity
The resulting product is weak and ineffective
Functional Keratin™ preserves these critical bonds.
Physical Properties of Sheep Wool Keratin: Why It Performs
Strength and Durability
Despite its appearance as soft, delicate fibres, sheep wool keratin is remarkably strong.
The science:
The interlocking structure of keratin fibres provides exceptional tensile strength
Wool can withstand significant stretching without breaking
It maintains its structure through repeated stress
This durability translates to hair that resists breakage.
Elasticity and Flexibility
Sheep wool exhibits remarkable elasticity.
What this means:
Hair (made of keratin) can stretch and return to original shape
This allows hair to move naturally without brittleness
Flexibility prevents snapping and permanent damage
When keratin is deficient, hair loses this flexibility
Supplementing with Functional Keratin™ restores it.
Water Absorption and Moisture Regulation
One of keratin's most remarkable properties is moisture management.
The mechanism:
Keratin's structure contains hygroscopic properties
It can absorb up to 30% of its weight in moisture
Critically, it does this without feeling wet
This moisture is distributed evenly throughout the structure
For your hair:
Hair with adequate keratin retains hydration
Hair with keratin deficiency loses moisture rapidly
This is why dry hair is usually a keratin problem, not a moisture problem
Functional Keratin™ supplementation restores moisture retention.
Thermal Insulation Properties
Wool's exceptional insulation comes from keratin structure.
How it works:
Keratin fibres are crimped, creating tiny air pockets
These pockets trap body heat
They create a buffer against cold temperatures
This same principle applies to scalp health
Chemical Properties of Sheep Wool Keratin: The Molecular Detail
Hydrophobic and Hydrophilic Balance
Keratin has a unique chemical balance.
The property:
Certain regions of keratin repel water (hydrophobic)
Other regions attract water (hydrophilic)
This balance allows keratin to manage moisture without becoming waterlogged
It also protects against excessive water loss
Disulfide Bonding Chemistry
The chemistry of disulfide bonds is critical.
How they work:
Two cysteine molecules bond through their sulphur atoms
This creates S-S (disulfide) linkages
These bonds are extremely strong and flexible
When these bonds are intact, keratin is strong
When damaged, keratin becomes weak
Heat, UV exposure, and harsh chemicals break these bonds.
Antimicrobial Properties
Keratin possesses natural antimicrobial activity.
The mechanism:
Amino acids like cysteine have antimicrobial properties
Keratin naturally resists bacterial and fungal growth
This is why wool products naturally resist odours
Your scalp benefits from keratin's antimicrobial action.
pH Balance and Scalp Health
Keratin exists optimally at a specific pH.
Why this matters:
Your scalp naturally maintains pH 4.5-5.5
Keratin is most stable and effective in this range
When pH is disrupted, keratin degrades
This is why using harsh, high-pH shampoos damages hair
Using pH-balanced products preserves keratin.
New Zealand Sheep Wool Keratin: Why It's Superior
The Environment Advantage
New Zealand sheep graze on pristine, mineral-rich pastures.
How this matters:
Sheep fed on nutrient-rich grass produce superior wool
The keratin in their wool reflects their dietary nutrition
This results in naturally superior keratin quality
Regenerative farming practices enhance this further.
Extraction and Preservation
How keratin is extracted matters enormously.
The difference:
Poor extraction methods break disulfide bonds
They destroy the complex structure
This results in ineffective hydrolysed keratin
Functional Keratin™ uses a proprietary extraction process
This preserves the keratin's structure and bioactivity.
Bio-Identity
Keratin from New Zealand sheep wool achieves 91% bio-identity to human keratin.
What this means:
Your body recognises it as compatible
It absorbs and utilises it efficiently
Results appear faster
Effects are more dramatic and lasting.
From Wool to Your Body: The Journey of Functional Keratin™
The Extraction Process
The journey from sheep wool to usable keratin supplement is precise.
Steps involved:
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High-quality wool is sourced from regenerative farms
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The wool undergoes careful purification
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Proprietary extraction methods preserve structure
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Multiple filtration stages remove impurities
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The result is highly bioavailable Functional Keratin™
Bioavailability: Why It Matters
Not all ingested keratin becomes usable by your body.
Bioavailability measures:
How much of what you consume your body actually uses
Hydrolysed keratin: typically 30-40% bioavailable
Functional Keratin™: 91% bioavailable
This explains why results differ so dramatically.
How Your Body Uses Keratin
When you supplement with Functional Keratin™:
Your digestive system recognises it as compatible protein
It's absorbed into your bloodstream
Your body distributes it to hair, skin, and nails
These tissues immediately incorporate it into structure
Results become visible within 2-4 weeks.
Applications of Sheep Wool Keratin: Beyond Textiles
Hair Health and Beauty
The primary application is hair health.
How keratin supports hair:
Strengthens the hair shaft structure
Fills gaps in damaged hair
Restores moisture retention
Reduces frizz and improves shine
Promotes faster, stronger growth
Skin Health and Renewal
Keratin is increasingly used in skincare.
Benefits for skin:
Supports collagen production
Maintains skin elasticity
Promotes cell turnover
Reduces fine lines and wrinkles
Improves skin barrier function.
Nail Health and Strength
Nails are 95% keratin.
Keratin's role in nails:
Directly strengthens nail structure
Prevents brittleness and breakage
Promotes faster growth
Improves appearance and health.
Joint and Connective Tissue Support
Research is exploring keratin's role in joint health.
Emerging applications:
Keratin supports cartilage structure
Supports collagen synthesis in connective tissue
May help with exercise recovery
Future supplements may target joint health.
Kiri10's Commitment: Science Into Products
Our Product Philosophy
At Kiri10, we don't just use keratin.
We use Functional Keratin™ from New Zealand sheep wool.
Why we chose this source:
Highest bioavailability available
Superior structural integrity
Ethical, regenerative sourcing
Proven clinical results
KiriGlow: The Complete Formula
Our KiriGlow supplement contains more than just keratin.
The formula includes:
Functional Keratin™ (91% bioavailable)
OptiMSM™ (provides sulphur for keratin production)
Additional nutrients supporting absorption
This combination creates synergistic results.
Our Future Vision
We're expanding keratin applications beyond oral supplements.
Coming developments:
Triple-Keratin Complex™ haircare system
Advanced skincare with Functional Keratin™
Targeted nail care products
Joint and muscle support formulations
All using New Zealand sheep wool keratin.
References and Further Reading
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Keratin Structure and Properties - PMC - Scientific overview of keratin molecular structure
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Disulfide Bonds in Keratin - Journal of Protein Chemistry - Research on disulfide bond chemistry
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Moisture Retention in Hair - International Journal of Cosmetic Science - Studies on keratin and hydration
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Effect of keraGEN IV Keratin Oral Supplementation - Lincoln Agritech - Clinical study on Functional Keratin™ bioavailability
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New Zealand Regenerative Farming - Beef + Lamb Genetics - Information on NZ farming practices
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Wool and Antimicrobial Properties - Textile Research Journal - Research on keratin's natural antimicrobial activity
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Hair Structure and Keratin - Dermatology Research and Practice - Scientific overview of hair structure
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KiriGlow Keratin Supplement - Kiri10 - Functional Keratin™ supplement from NZ sheep wool
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