Understanding Skin Barrier, Hydration and Repair: A Formulator's Guide
Craft 360
8 minute read
Picture this: You're standing in front of a house under construction. The builders have just finished laying the foundation, and now they're working on the walls. But this isn't just any house – it's the most sophisticated, self-repairing structure you've ever seen. Welcome to your skin.
The Continuous Renewal Process
Your skin operates like a factory that never sleeps. Deep in the basal layer, new skin cells begin their journey with a single mission: travel upward and become part of the protective barrier. As they migrate through the different layers of the epidermis, these cells undergo a remarkable transformation.
During this journey, cells pack themselves with keratin – a protective protein that strengthens them. By the time they reach the surface, these cells have completed their life cycle, becoming the flattened, hardened corneocytes that form your skin barrier.
This cellular journey takes approximately 28 days in healthy skin. Through a process called desquamation, the oldest surface cells naturally shed, making room for fresh ones. It's a continuous cycle of renewal that keeps your barrier functioning optimally.
The Architecture of Skin Protection
Your skin barrier can be visualized as a brick-and-mortar structure. The "bricks" are dead skin cells (corneocytes) held together by a sophisticated "cement" – a precise blend of lipids including ceramides, cholesterol, and fatty acids. This creates what scientists call intercellular lamellae.
This barrier is engineered for protection. The slightly acidic surface (around pH 5.5) creates an inhospitable environment for harmful bacteria. The lipid-rich cement between cells forms a water-resistant seal that prevents moisture loss.
Here's the key insight: you have water-loving cells surrounded by oil-loving lipids. Since oil and water don't mix, your precious hydration stays exactly where it needs to be – inside your skin.
Natural Moisturizing Factors: Your Built-in Hydration System
Within your skin cells live some unsung heroes called Natural Moisturizing Factors (NMFs). These aren't synthetic ingredients – they're your skin's own hydration management system.
NMFs function like moisture magnets throughout your skin cells. This team includes amino acids, urea, lactic acid, and other hygroscopic compounds that attract water molecules and hold them in place. They create a personal humidity control system built into your skin.
What makes NMFs remarkable is their intelligence: they don't just grab any water – they attract moisture from the air and from deeper skin layers, then bind it directly to skin proteins. It's an automatic irrigation system that adjusts based on your skin's needs.
In healthy skin, NMFs comprise about 10% of your skin's dry weight. However, when the barrier becomes compromised, these precious moisture magnets leak out, leaving skin feeling tight and looking dull.
When Barriers Break Down
When your protective barrier develops damage – whether from harsh cleansers, environmental stressors, or over-exfoliation – the consequences are immediate and noticeable.
The water-resistant seal develops gaps. Precious hydration that was safely contained begins to escape through transepidermal water loss (TEWL). Your NMFs start leaking out through these compromised areas.
The result is skin that feels tight, appears rough, and lacks that healthy radiance. Your barrier has lost its two primary functions: keeping harmful elements out and keeping beneficial moisture in.
A Formulator's Strategic Approach
Understanding this barrier science helps you choose ingredients that work synergistically with skin's natural processes.
Humectants: Moisture Recruitment Humectants like glycerin, hyaluronic acid, and sodium PCA act as reinforcements for your skin's NMF system. They function in a similar way to natural NMFs – attracting water from the environment and binding it to the skin. Including humectants in formulas essentially provides backup moisture magnets to support compromised natural hydration systems.
Emollients: Barrier Restoration Carrier oils, butters, ceramides, and squalane function as barrier repair agents. They fill gaps between skin cells, smooth rough patches, and help restore the crucial lipid barrier that prevents water loss.
Here's the critical formulation principle: you can't simply add water to compromised skin and expect it to stay put. The barrier must be repaired first.
Occlusive Agents: Protective Coverage Sometimes barriers need extra protection during the repair process. Occlusive agents like plant waxes and shea butter provide temporary protective coverage while restoration occurs underneath.
The Complete Repair System
Creams excel at barrier repair because they deliver comprehensive support:
The water phase carries humectant reinforcements
The oil phase provides emollient repair materials
Heavier oils and butters offer occlusive protection
Emulsifiers ensure all components work harmoniously
Preservatives, actives, and botanical extracts provide additional benefits
This creates a complete maintenance and repair system that aligns with how skin naturally functions.
The Interconnected Process
The beauty of this system lies in its interconnectedness. Strong barrier function retains natural NMFs and maintains hydration levels. Proper hydration provides cells with the optimal environment for function. Optimal cellular function supports the natural renewal process that maintains barrier strength.
When you formulate with this understanding, you're not randomly combining ingredients – you're supporting a sophisticated biological process. You're helping skin's natural mechanisms work more effectively.
Formulation Strategy
Every ingredient choice either supports or hinders skin's delicate balance. Choose humectants to reinforce moisture management. Select appropriate emollients to provide quality repair materials. Use suitable occlusives to offer protection during restoration.
As formulators, we become partners in skin health. By understanding how skin builds its protective barrier, maintains hydration, and supports ongoing renewal, you can create products that truly work with skin's natural intelligence.
When developing your next formula, ask yourself: Am I supporting skin's natural processes, or creating additional challenges? Your skin – and your customers – will benefit from choices that honor skin's sophisticated biology.
Ready to explore barrier-supporting ingredients for your next formulation? Browse our range of carrier oils, butters, and active ingredients designed to help you create products that truly support skin's natural processes.
20 minute read
This is Part One of our Three Part series on Essential Oils.
Comming up in the next few weeks:
Part Two: Essential Oil Safety and Dermal Limits - A Beginner's Guide for Skincare Formulators
Part Three: Flash Points of Essential Oils: The Science Behind Protecting Your Aroma
When you blend essential oils for skincare or soapmaking, have you noticed how some fragrances disappear within hours while others linger for days? Understanding essential oil notes is the key to creating balanced, long-lasting aromatic blends that don't fade too quickly.
This guide explores what essential oil notes are, why they matter in formulation, and how to use them to craft beautiful, enduring fragrances in your products.
Here’s What You’ll Learn
What Are Essential Oil Notes?
Why Volatility Matters
Why Notes Matter in Skincare and Soapmaking
The Three Notes Explained
Note Classification Can Overlap
Classic Note Ratios for Balanced Blends
How to Blend by Notes: Step-by-Step
Popular Blend Recipes by Note
Special Considerations for Soapmaking
Advanced Blending Techniques
Troubleshooting Common Problems
Storage and Stability
Documentation and Record-Keeping
Wrap-up
What Are Essential Oil Notes?
Essential oil notes refer to the classification of oils based on their volatility—how quickly they evaporate and how long their aroma lasts. This concept comes from traditional perfumery, where fragrances are carefully layered to create complex, evolving scents that develop over time.
Essential oils are categorised into three main notes:
Top Notes (Head Notes): Light, fresh, uplifting aromas that evaporate quickly—typically within 30 minutes to 2 hours.
Middle Notes (Heart Notes): Warm, soft, balancing aromas that form the body of your blend—lasting 2 to 4 hours.
Base Notes: Deep, rich, grounding aromas that evaporate slowly—lingering for 4 to 8 hours or even days.
Think of essential oil notes like musical notes in a symphony. Top notes provide the bright, initial impression; middle notes carry the melody; and base notes offer depth and foundation. Together, they create a harmonious, well-rounded fragrance experience.
Why Volatility Matters
The concept of notes is directly tied to molecular weight and volatility. Essential oils contain dozens or even hundreds of individual chemical compounds, each with different evaporation rates.
Light molecules (like those in citrus oils) evaporate quickly, giving us top notes. Heavy molecules (like those in wood and resin oils) evaporate slowly, creating base notes. Middle notes contain medium-weight molecules that bridge the two.
Understanding this chemistry helps you predict how your blends will behave over time and how to compensate for rapid evaporation.
Why Notes Matter in Skincare and Soapmaking
Fragrance Longevity
One of the most common complaints about natural products is that the scent fades too quickly. This happens because many formulators rely heavily on top-note essential oils, particularly citrus without balancing them with middle and base notes.
When you understand notes, you can anchor your fast-evaporating oils with slower-evaporating base notes, extending the life of your fragrance from hours to days. This creates a more satisfying sensory experience for your customers.
Scent Evolution
A well-balanced blend doesn't smell the same from first application to final dry-down. It evolves, revealing different aromatic layers as the hours pass.
Initial application highlights the bright top notes perhaps fresh bergamot and lemon. After 30 minutes, the top notes fade and middle notes emerge maybe soft lavender and geranium. Several hours later, the base notes dominate warm sandalwood and patchouli. This aromatic journey creates depth and interest, making your products memorable.
Product Type Considerations
Different product formats interact with essential oil notes in unique ways:
Soap: The saponification process and high pH can alter or diminish certain essential oils. Citrus top notes often fade during cure time or within weeks of use. Using more base notes ensures your soap retains scent throughout its life.
Leave-on skincare (creams, lotions, body oils): All three notes can shine because the product remains on skin for hours. Balancing notes creates a pleasant, evolving experience.
Rinse-off products (cleansers, shampoos): Top and middle notes have more impact because the product is washed away quickly. Heavy base notes may be less noticeable.
Cost Efficiency
Base-note essential oils tend to be more expensive than top notes. However, because they're more concentrated and longer-lasting, you often need less of them. Understanding notes helps you create cost-effective blends that deliver maximum aromatic impact.
Therapeutic Balance
Beyond fragrance, notes also relate to aromatherapeutic properties. Top notes are often energising and uplifting; middle notes are balancing and harmonising; base notes are grounding and calming. Blending across all three notes creates products that support both physical and emotional wellbeing.
The Three Notes Explained
Top Notes (Head Notes)
Characteristics:
Light, fresh, bright, sharp, or citrusy aromas
Evaporate within 30 minutes to 2 hours
Create the first impression
Often energising, uplifting, or clarifying
Lower molecular weight
Common Top-Note Essential Oils:
Citrus family: Lemon, lime, bergamot, grapefruit, sweet orange, mandarin, tangerine
Mints: Peppermint, spearmint
Herbs: Basil, eucalyptus, tea tree
Others: Lemongrass, lemon myrtle, citronella
Usage Tips:
Use top notes at 20–40% of your blend for balanced formulations
Increase to 50–60% if you want a bright, fresh-dominant scent
In soap, consider using top notes at lower percentages as they fade fastest
Pair with base notes to extend longevity
Top-Note Challenge in Soap:Citrus oils are notoriously difficult to retain in cold-process soap. The alkaline environment and curing process can strip away these delicate aromas within weeks. Using litsea cubeba (may chang) or lemongrass alongside expressed citrus oils helps anchor the scent. Always increase citrus oil percentages slightly to compensate for loss.
Middle Notes (Heart Notes)
Characteristics:
Soft, warm, floral, herbaceous, or spicy aromas
Evaporate within 2 to 4 hours
Form the main body and character of your blend
Often balancing, harmonising, or soothing
Medium molecular weight
Common Middle-Note Essential Oils:
Florals: Lavender, geranium, chamomile, ylang-ylang, neroli
Spices: Black pepper, cardamom, coriander, ginger
Herbs: Clary sage, rosemary, marjoram, fennel
Others: Pine, cypress, juniper berry, tea tree (overlaps with top)
Usage Tips:
Use middle notes at 30–50% of your blend as the foundation
They act as bridges between volatile top notes and heavy base notes
Excellent for creating well-rounded, balanced blends
Most middle notes hold up well in both soap and skincare
Why Middle Notes Matter:Middle notes are the "heart" of your fragrance. They emerge once top notes fade and work harmoniously with base notes to create a smooth transition. Without middle notes, your blend can feel disjointed—jumping abruptly from bright citrus to heavy wood.
Base Notes
Characteristics:
Deep, rich, earthy, woody, or resinous aromas
Evaporate slowly, lasting 4 to 8 hours or longer
Provide depth, grounding, and staying power
Often calming, centering, or sensual
High molecular weight
Common Base-Note Essential Oils:
Woods: Sandalwood, cedarwood, rosewood
Resins: Frankincense, myrrh, benzoin
Roots: Vetiver, ginger (can overlap with middle)
Others: Patchouli, ylang-ylang (overlaps with middle), vanilla absolute
Usage Tips:
Use base notes at 10–25% of your blend
A little goes a long way, base notes are potent
Essential for soap to maintain scent through cure and use
Act as fixatives, slowing the evaporation of lighter notes
Base Notes as Fixatives:Base notes don't just add their own aroma, they also slow down the evaporation of top and middle notes. This "fixative effect" extends the entire blend's longevity. Patchouli, vetiver, and sandalwood are particularly effective fixatives.
Note Classification Can Overlap
Some essential oils straddle categories, exhibiting characteristics of two notes:
Ylang-ylang: Middle to base (sweet floral with lasting depth)
Clary sage: Top to middle (bright opening, herbaceous body)
Tea tree: Top to middle (fresh camphoraceous opening, medicinal body)
Ginger: Middle to base (spicy warmth with earthy depth)
These "bridge oils" are valuable for creating smooth transitions between note categories.
Classic Note Ratios for Balanced Blends
While there's no single "correct" ratio, these traditional perfumery guidelines create well-balanced blends:
Balanced Blend (Classic Pyramid)
Top notes: 30%
Middle notes: 50%
Base notes: 20%
This ratio produces a harmonious fragrance that evolves gracefully, with each note getting time to shine.
Fresh & Uplifting Blend
Top notes: 50%
Middle notes: 30%
Base notes: 20%
Great for morning skincare products, energising body washes, or citrus-forward blends.
Deep & Grounding Blend
Top notes: 20%
Middle notes: 30%
Base notes: 50%
Perfect for evening skincare, massage oils, or earthy, calming products.
Soap-Specific Ratio
Top notes: 20%
Middle notes: 40%
Base notes: 40%
Compensates for the loss of volatile top notes during saponification and cure.
How to Blend by Notes: Step-by-Step
Step 1: Choose Your Direction
Decide on the overall aromatic character you want:
Fresh and citrusy?
Floral and soft?
Earthy and grounding?
Spicy and warm?
This guides your note selection.
Step 2: Select Oils from Each Category
Choose 1–2 oils from each note category that complement your chosen direction:
Example: Fresh Garden Blend
Top: Lemon (bright, clean)
Middle: Lavender (soft, floral)
Base: Cedarwood (woody, grounding)
Step 3: Calculate Your Ratios
Decide on your note ratio based on product type and desired effect. For a balanced blend, use 30% top, 50% middle, 20% base.
If your total essential oil load is 1% of your formula (typical for facial products), and you're making 100g:
Total essential oils: 1g
Top notes (30%): 0.3g lemon
Middle notes (50%): 0.5g lavender
Base notes (20%): 0.2g cedarwood
Step 4: Create a Test Blend
Use drops in a small vial or bottle
Apply the same ratios (e.g., 3 drops lemon, 5 drops lavender, 2 drops cedarwood)
Let it sit (covered) for 24–48 hours to allow notes to marry
Step 5: Evaluate and Adjust
Smell your test blend at different intervals:
Immediately: Are the top notes too sharp or just right?
After 1 hour: Do the middle notes come through beautifully?
After 4–8 hours: Are the base notes pleasant and lasting?
Adjust ratios as needed. If top notes dominate too much, reduce them. If the blend fades too quickly, increase base notes.
Step 6: Test in Product
Essential oils behave differently in different bases. Test your blend in your actual product formulation:
In soap, scent may fade or morph during cure
In oil-based products, scent disperses differently than in water-based products
pH and other ingredients can affect aroma
Always make a small test batch before committing to full production.
Popular Blend Recipes by Note
Energising Morning Blend
Top (40%): 30% sweet orange, 10% peppermint
Middle (40%): 30% rosemary, 10% eucalyptus
Base (20%): 20% cedarwood
Perfect for shower gels, morning moisturisers, or wake-up body oils.
Calming Evening Blend
Top (25%): 25% bergamot
Middle (50%): 40% lavender, 10% chamomile
Base (25%): 15% sandalwood, 10% frankincense
Ideal for night creams, pillow mists, or relaxing bath products.
Fresh & Floral Blend
Top (35%): 25% lemon, 10% grapefruit
Middle (45%): 35% geranium, 10% lavender
Base (20%): 15% patchouli, 5% vetiver
Beautiful for body lotions, hand creams, or facial mists.
Earthy & Grounding Blend
Top (20%): 20% juniper berry
Middle (30%): 20% clary sage, 10% black pepper
Base (50%): 30% sandalwood, 20% vetiver
Excellent for massage oils, grounding balms, or meditative products.
Citrus Grove Soap Blend
Top (25%): 15% sweet orange, 10% litsea cubeba
Middle (40%): 30% lavender, 10% palmarosa
Base (35%): 25% patchouli, 10% benzoin
Formulated to retain citrus brightness through cold-process saponification.
Special Considerations for Soapmaking
Why Soap Is Different
Cold-process soapmaking involves high temperatures (during saponification), high pH (alkaline environment), and a long cure time (4-6 weeks). All of these factors can alter or diminish essential oil aromas.
What happens to notes in soap:
Top notes: Often fade significantly or disappear entirely
Middle notes: Usually hold well but may soften
Base notes: Remain strong and stable
Soap Blending Strategies
Strategy 1: Increase Base NotesUse 40–50% base notes instead of the typical 20%. This ensures lasting fragrance throughout the bar's life.
Strategy 2: Overpour Top NotesIf you want citrus in your soap, use 30–50% more than you would in skincare. Expect some loss, but enough will remain to provide initial brightness.
Strategy 3: Use Anchoring OilsCertain essential oils act as "anchors" in soap, helping other oils stick around:
Litsea cubeba (may chang) anchors citrus oils
Patchouli and vetiver anchor floral and herbaceous oils
Clays and oat flour can also help "hold" scent
Strategy 4: Add Oils at TraceAdd your essential oil blend when your soap reaches light to medium trace (not at the beginning with other oils). This minimises exposure to heat and alkali.
Strategy 5: Test and WaitAlways test soap blends in small batches and wait through the full cure time before judging scent retention. What smells strong at unmoulding may fade, or what seems faint may strengthen.
Advanced Blending Techniques
Synergy Blending
Some essential oils enhance each other when combined, creating a scent that's more than the sum of its parts. Look for oils within the same aromatic family (e.g., citrus + citrus) or complementary families (e.g., floral + woody).
Natural pairs:
Lavender + rosemary (herbaceous harmony)
Bergamot + geranium (bright floral)
Sandalwood + rose (soft, sensual)
Peppermint + eucalyptus (cooling clarity)
Accord Building
An accord is a small blend of 2–3 oils that smell like a single note. Create accords first, then combine them into your final blend.
Example: Green Accord
Clary sage + pine + juniper berry = fresh forest scent
Use this "Green Accord" as your middle note, then add citrus top notes and cedarwood base notes.
The Rule of Three
Start simple: use just three essential oils, one from each note category. Master three-oil blends before expanding to complex five- or seven-oil formulations. Three oils can create stunning, sophisticated fragrances without overwhelming complexity.
Troubleshooting Common Problems
"My blend smells great in the bottle but disappears on skin"Solution: Increase base notes. Your blend is likely top-note heavy. Add 5–10% more base-note oils to anchor the fragrance.
"My soap loses all scent after curing"Solution: Use soap-specific ratios with higher base notes (40–50%). Consider clays to hold scent and add oils at light trace.
"All my blends smell the same"Solution: Experiment outside your comfort zone. If you always use lavender, try geranium or ylang-ylang instead. Swap cedarwood for vetiver. Small changes create big differences.
"My blend smells too heavy or cloying"Solution: Increase top notes for brightness and lift. Add 10–15% of total % of citrus or mint to lighten deep, resinous blends.
"My citrus soaps fade within a month"Solution: Replace expressed citrus oils with distilled versions where possible (they have less furanocoumarins but better staying power). Use litsea cubeba as an anchor. Increase usage rates by 30–50%.
Storage and Stability
Essential oil blends evolve over time, especially when exposed to heat, light, and oxygen. To maintain aromatic integrity:
Store blends in dark glass bottles (amber or cobalt blue)
Keep in cool, dark places (not bathroom cabinets or sunny shelves)
Fill bottles fully to minimise oxygen exposure
Label with date and replace oxidation-prone oils (citrus, tea tree, pine) after 12 months
Base-note-dominant blends improve with age as notes marry and mellow. Top-note-heavy blends should be used within 6 months for maximum freshness.
Documentation and Record-Keeping
Keep detailed records of every blend you create:
Date created
Note ratios (e.g., 30/50/20)
Exact oil percentages and weights
Product type (soap, lotion, balm)
Scent impressions at initial blending, after 24 hours, after one week
Customer feedback
This documentation helps you replicate successful blends and refine unsuccessful ones. Over time, you'll develop your signature blending style.
Understanding essential oil notes transforms your formulation work from guesswork to intentional artistry. By balancing top, middle, and base notes, you create products with lasting, evolving fragrances that delight your customers and set your brand apart.
Start with simple three-oil blends using the classic 30/50/20 ratio. Smell your blends at different intervals to understand how they develop. Adjust for product type especially soap, where base notes are your best friend.
With practice, you'll develop an intuitive sense for how notes work together, creating sophisticated, long-lasting blends that showcase the full aromatic beauty of essential oils. Whether you're crafting a bright morning face wash or a grounding evening body oil, notes are your roadmap to fragrance success.
Ready to start blending? Choose one oil from each note category, create a small test blend, and observe how it evolves over the next 8 hours. That hands-on experience will teach you more than any theory alone. Happy crafting!
Top notes (bright, volatile, fastest to fade)
Basil (Ocimum basilicum)
Bergamot (Citrus bergamia)
Bergamot Mint (Mentha citrata)
Camphor (Cinnamomum camphora)
Clementine (Citrus clementina)
Eucalyptus globulus (Eucalyptus globulus)
Eucalyptus radiata (Eucalyptus radiata)
Eucalyptus lemon/citriodora (Corymbia/Eucalyptus citriodora)
Fir Needle (fresh fractions; Abies spp.)
Galbanum (fresh green lift; Ferula galbaniflua)
Grapefruit (Citrus paradisi)
Juniper Berry (Juniperus communis)
Lemon (Citrus limon)
Lemongrass (Cymbopogon citratus)
Lime (Citrus aurantifolia)
Mandarin (Citrus reticulata)
Neroli (Citrus aurantium flower)
Orange, Bitter (Citrus aurantium)
Orange, Sweet (Citrus sinensis)
Peppermint (Mentha × piperita)
Petitgrain (Citrus aurantium leaf/twig)
Pine (Pinus spp.)
Ravensara (Ravensara aromatica)
Rosemary (Rosmarinus officinalis; fresher CTs)
Sage, Dalmatian (Salvia officinalis; can bridge)
Spearmint (Mentha spicata)
Tagetes (Tagetes minuta)
Tangerine (Citrus reticulata)
Tea Tree (Melaleuca alternifolia; can bridge)
Verbena, Lemon (Aloysia citriodora)
Yuzu (Citrus junos)
Top–Middle (bridge between sparkle and heart)
Basil (light chemotypes)
Bergamot Mint (Mentha citrata)
Camphor (fresh camphoraceous)
Eucalyptus globulus / radiata
Eucalyptus lemon (citriodora)
Fir Needle (many lots)
Galbanum (green terpene into earthy heart)
Juniper Berry
Lavender (Lavandula angustifolia)
Lavandin (Lavandula × intermedia)
Lemongrass (citral-rich)
Litsea cubeba / May Chang (Litsea cubeba)
Melissa / Lemon Balm (Melissa officinalis)
Neroli (Citrus aurantium flower)
Petitgrain
Pine (brighter fractions)
Rosemary (many chemotypes)
Sage, Dalmatian
Tea Tree (Melaleuca alternifolia)
Middle notes (heart of the blend; florals, herbs, soft spice)
Angelica (Angelica archangelica; seed/root—often shades deeper)
Anise / Aniseed (Illicium verum / Pimpinella anisum)
Bay, West Indian (Pimenta racemosa)
Black Pepper (Piper nigrum)
Cardamom (Elettaria cardamomum)
Carrot Seed (Daucus carota)
Chamomile, German (Matricaria recutita)
Chamomile, Roman (Chamaemelum nobile)
Cinnamon Leaf (Cinnamomum verum; bark leans deeper)
Citronella (Cymbopogon nardus)
Clary Sage (Salvia sclarea)
Clove (Syzygium aromaticum; bud/leaf—deeper edges)
Coriander seed (Coriandrum sativum)
Cumin (Cuminum cyminum)
Cypress (Cupressus sempervirens)
Dill (Anethum graveolens)
Elemi (Canarium luzonicum; lemony resin)
Fennel, sweet (Foeniculum vulgare)
Geranium / Rose Geranium / Bourbon (Pelargonium spp.)
Ginger (Zingiber officinale)
Helichrysum / Immortelle (Helichrysum italicum)
Ho Wood (Cinnamomum camphora linalool CT)
Honeysuckle (absolute/extract)
Hyssop (Hyssopus officinalis)
Jasmine absolute (Jasminum officinale / grandiflorum)
Kanuka (Kunzea ericoides)
Lavender (core heart presence)
Lavandin (heartier lavender hybrid)
Linden Blossom (Tilia spp. absolute)
Manuka (Leptospermum scoparium)
Marjoram, sweet (Origanum majorana)
May Chang / Litsea (Litsea cubeba)
Melissa / Lemon Balm (Melissa officinalis)
Myrtle (Myrtus communis)
Neroli (headspace lifts; heart persists)
Niaouli (Melaleuca quinquenervia)
Nutmeg (Myristica fragrans)
Palmarosa (Cymbopogon martinii)
Parsley (leaf/seed; Petroselinum crispum)
Roman Chamomile (Chamaemelum nobile)
Rose (Rosa damascena / R. centifolia)
Rosewood (Aniba rosaeodora)
Rosemary (many CTs sit here)
Sage (Spanish—Salvia lavandulifolia)
Spruce (Picea spp.)
Tuberose absolute (Polianthes tuberosa)
Turmeric (Curcuma longa)
Violet Leaf (Viola odorata)
Yarrow (Achillea millefolium)
Middle–Base (hearty with persistence; soft fixatives)
Angelica (root/seed; Angelica archangelica)
Cajeput (Melaleuca cajuputi)
Cinnamon (bark/leaf; spicy heart with depth)
Clove (bud/leaf)
Elemi (resin bridge that lingers)
Frankincense Serrata / Frankincense Olibanum
Ginger (Zingiber officinale)
Helichrysum / Immortelle (Helichrysum italicum)
Myrrh (Commiphora myrrha)
Oakmoss absolute (Evernia prunastri)
Palmarosa (Cymbopogon martinii)
Patchouli (Pogostemon cablin)
Rose (particularly heavier absolutes)
Rosewood (Aniba rosaeodora)
Sandalwood (Santalum album / spp.)
Spikenard (Nardostachys jatamansi)
Vetiver (Chrysopogon/Vetiveria zizanoides)
Ylang Ylang (Cananga odorata, complete or heavier fractions)
Base notes (slowest to evaporate; deep fixatives)
Agarwood / Oud (Aquilaria spp.; often sold as absolute/CO2)
Amyris (Amyris balsamifera)
Angelica Root (Angelica archangelica)
Balsam, Peru (Myroxylon balsamum; absolute)
Benzoin resinoid (Styrax benzoin)
Cedarwood (Atlas, Virginian, Himalayan)
Frankincense Serrata / Frankincense Olibanum
Labdanum / Cistus (Cistus ladanifer)
Myrrh (Commiphora myrrha)
Oakmoss absolute (Evernia prunastri)
Patchouli (Pogostemon cablin)
Sandalwood (Santalum album / spp.)
Spikenard (Nardostachys jatamansi)
Tobacco absolute (Nicotiana tabacum)
Vanilla (Vanilla planifolia; absolute/extract)
Vetiver (Chrysopogon/Vetiveria zizanoides)
5 minute read
Starting your skincare formulation journey? One of the most crucial ingredients you'll need to understand is preservatives. While they might not be the most glamorous part of your formulation, they're absolutely essential for creating safe, stable products that your customers can trust.
Let's break down everything you need to know about preservatives – from what they are to how to use them effectively in your formulations.
What Are Preservatives?
Think of preservatives as the guardians of your skincare formulations. They're ingredients specifically designed to prevent the growth of harmful microorganisms like bacteria, fungi, yeast, and mould that can contaminate your products.
Natural and herbal cosmetics are particularly vulnerable because they're made with biodegradable ingredients – the very things that make them gentle on skin also make them appealing to microbes. Without proper preservation, these unwanted guests can multiply rapidly, causing your products to spoil, lose effectiveness, or even become dangerous to use.
Why Do We Use Preservatives in Skincare?
The simple answer? Safety and stability. Here's what preservatives do for your formulations:
Protect Against Contamination: Microorganisms are everywhere – in the air, on surfaces, and even on our skin. When they find their way into unpreserved products, they can multiply rapidly, potentially causing skin irritation, allergic reactions, or even serious infections.
Extend Shelf Life: Without preservatives, your water-based formulations would last only a few days to two weeks (even when refrigerated). Proper preservation can extend shelf life to 12 months or more.
Maintain Product Integrity: Microbial growth doesn't just make products unsafe – it can also change their colour, texture, smell, and performance. Preservatives help maintain the quality you worked hard to achieve.
When Do You Need Preservatives?
Understanding when to use preservatives is crucial for formulator success. The golden rule is simple: If your product contains water or might come into contact with water, it needs a preservative.
Water-Based Products (Always Need Preservatives)
Lotions and creams
Serums and essences
Cleansers and toners
Hydrating mists
Any emulsion (oil-in-water or water-in-oil)
Products That Might Contact Water (Usually Need Preservatives)
Scrubs and exfoliants
Cleansing balms
Bath products
Anything used in the shower or bathroom
Anhydrous Products (Generally Don't Need Preservatives)
Anhydrous = formulations that don’t contain water
Pure oils and oil blends
Balms and salves
Lip balms
Powder products
Note: Anhydrous products may need antioxidants to prevent rancidity, but that's a different concern from microbial contamination.
What Happens When You Don't Use Preservatives?
Visible Changes: Your product might develop an odd smell, change colour, or develop a slimy texture
Invisible Dangers: Harmful bacteria can multiply without obvious signs, creating potential health risks
Product Failure: Your carefully crafted formulation loses its effectiveness as microbes break down active ingredients
Customer Safety: Users may experience skin irritation, infections, or allergic reactions
The Microbial Threats Your Products Face
Understanding your enemy helps you choose the right defence. Here are the main culprits that can attack your formulations:
Bacteria: These single-celled organisms prefer neutral to slightly alkaline pH levels and warm temperatures (30-37°C). Particularly concerning is Pseudomonas, a gram-negative bacteria that's:
Resistant to many antimicrobials
Found in tap water and on skin
Capable of causing serious infections
Yeast: Preferring acidic conditions and room temperature, yeast doesn't typically cause health problems but can alter your product's appearance and texture. Candida albicans is a common culprit.
Mould: These fungi reproduce through spores that can survive for long periods in harsh conditions. They prefer acidic pH and room temperature. Aspergillus niger is particularly notorious for product spoilage.
Types of Preservatives: Understanding Your Options
Now that you understand why preservatives are essential, let's explore the different types available to formulators. Preservatives can be categorised in several ways, but the most important distinction for beginners is understanding the difference between single-action and broad-spectrum preservatives.
Single-Action Preservatives
Traditional preservatives often target specific types of microorganisms:
Some excel against bacteria but struggle with fungi
Others effectively combat mould but miss yeast
Many work well against one type but leave gaps in protection
Examples include pure sodium benzoate (primarily antifungal) or individual organic acids that target specific microbe families.
Broad-Spectrum Preservatives: Your Best Defence
This is where modern preservation gets exciting. Broad-spectrum preservatives effectively target multiple types of microorganisms in one ingredient:
Gram-positive bacteria (like Staphylococcus)
Gram-negative bacteria (like Pseudomonas)
Fungi (including yeast and mould)
Why Choose Broad-Spectrum?
In the past, formulators often used multiple preservatives to cover all bases – one for bacteria, another for fungi, and so on. Today's broad-spectrum preservatives simplify this process by combining multiple antimicrobial agents into one ingredient.
For example, Euxyl K 712 combines sodium benzoate and potassium sorbate, giving you protection against various microorganisms in a single ingredient.
How to Spot a Broad-Spectrum Preservative
Here's a simple trick: Check the INCI name. If it contains two or more ingredients, that's usually a sign you're looking at a broad-spectrum preservative.
This happens because broad-spectrum preservatives are typically mixtures of different preservative agents, each targeting specific types of microorganisms. When you see multiple ingredients listed, it means the manufacturer has combined various antimicrobial agents to create comprehensive protection.
Examples:
Euxyl K 712: INCI - Potassium Sorbate, Sodium Benzoate, Water
Euxyl K 903: INCI - Benzyl Alcohol, Benzoic Acid, Dehydroacetic Acid
Geogard Ultra: INCI - Gluconolactone, Sodium Benzoate, Calcium Gluconate
Geogard 221: INCI - Dehydroacetic Acid, Benzyl Alcohol
Single-ingredient preservatives like pure sodium benzoate or potassium sorbate typically have narrower antimicrobial spectrums, which is why they're often used in combination with other preservatives.
How to Use Preservatives Effectively
Concentration Matters:
Too little: Ineffective protection
Too much: Potential skin irritation and unnecessary expense
Just right: Follow supplier recommendations (typically 0.2-2% depending on the preservative)
pH is CriticalMost preservatives work within specific pH ranges.
Sodium benzoate is most effective at pH 3-4
Many broad-spectrum preservatives work best at pH 3-6
Always check your preservative's optimal pH range and adjust your formulation accordingly.
Temperature Considerations: Add preservatives during the cool-down phase (typically below 40-60°C) to prevent degradation. Heat can reduce their effectiveness or cause them to break down entirely.
Contact Time: Preservatives need time to work. The longer the contact time, the more effective they are at eliminating microorganisms.
Popular Preservative Options for Natural Formulations
Sodium Benzoate
Strengths: Food-grade, GRAS (Generally Regarded As Safe)
Limitations: pH-dependent (works best at pH 3-4), not broad-spectrum
Usage: 0.5-1%, works well combined with potassium sorbate
Best for: Acidic formulations
Potassium Sorbate
Strengths: Naturally occurring, effective against mould
Limitations: Poor against bacteria, pH-sensitive
Usage: 0.3-1.5%, combine with sodium benzoate for broad-spectrum protection
Best for: Mould-prone formulations
Euxyl K 712
Strengths: Combines sodium benzoate and potassium sorbate
Usage: Follow supplier guidelines
Best for: Simplified broad-spectrum preservation
Nat Preserve (Geogard Ultra)
Strengths: ECOCERT/COSMOS compliant, broad-spectrum
Usage: 1-2%, pH range 3-6
Best for: Natural and organic formulations
Supporting Your Preservative System
Chelating Agents: These ingredients bind metal ions that can interfere with preservative effectiveness. Natural options include citric acid, while synthetic options include EDTA.
Preservative Boosters: Ingredients like glycerine can help preservatives penetrate microbial cell walls more effectively.
Good Manufacturing Practices:
Sanitise all equipment and surfaces
Use distilled or deionised water
Work in clean environments
Store ingredients properly
Addressing the Preservative Stigma
Preservatives Are Essential for Safety: The risks of using unpreserved water-based products far outweigh any concerns about properly formulated preservatives.
Natural Doesn't Always Mean Preservative-Free: Many "natural" preservatives are actually combinations of naturally-derived and synthetic ingredients that work together effectively.
Dose Makes the Difference: When used at appropriate concentrations, preservatives are safe and effective. The key is using them correctly, not avoiding them entirely.
Key Takeaways for Beginner Formulators
Water = Preservative: Any water-containing product needs preservation
Broad-spectrum is best: Choose preservatives that protect against multiple microorganisms
Check the INCI: Multiple ingredients usually indicate broad-spectrum protection
pH matters: Match your preservative to your formulation's pH
Follow guidelines: Use preservatives within recommended concentration ranges
Cool-down phase: Add preservatives when your formulation has cooled
Test your products: Consider microbial testing to verify preservation effectiveness
Moving Forward with Confidence
Understanding preservatives might seem overwhelming at first, but they're simply another tool in your formulation toolkit. Like any ingredient, they work best when you understand their properties and use them correctly.
Remember, your goal isn't just to create beautiful, effective products – it's to create safe ones that your customers can use with confidence. Proper preservation is an essential part of that promise.
Ready to start formulating with preservatives? Begin with simple, well-tested combinations like sodium benzoate and potassium sorbate, or explore broad-spectrum options like Geogard Ultra for streamlined preservation.
Your customers' safety and your product's success depend on getting this right – and with the knowledge you've gained here, you're well on your way to creating formulations that are both effective and safe.
Have questions about preservatives or need help choosing the right option for your formulation? Share your thoughts in the comments below!
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