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Cosmetic Ingredients Glossary
A guide to the ingredients you'll find in your everyday cosmetic products.
Understanding Your Skincare: A Consumer's Guide
Ingredient lists can feel overwhelming. This glossary breaks down the most common ingredients found in everyday cosmetics — what they do, how to use them safely, and what to watch out for.
Hydrators
Ingredients that attract and retain moisture in the skin.
Actives
Powerful ingredients that visibly improve skin concerns.
Barrier Builders
Ingredients that protect and strengthen the skin's natural defence.
Exfoliants
Acids that resurface and refine skin texture and tone.
Mamuka
Mamaku (New Zealand Black Fern) is a native New Zealand plant treasured for its healing, soothing, and hydrating properties. Rich in natural polysaccharides and antioxidants, Mamaku helps to tighten the appearance of pores, calm irritation, and support a healthy skin barrier. Its natural astringent qualities make it ideal for balancing oil production and targeting acne-prone skin, helping to reduce breakouts while keeping the skin clear, calm, and nourished.
In skincare, polysaccharides are valued for their ability to retain moisture, form protective barriers, and soothe the skin.
Products that use this: Triple Molecular Hydration Serum
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Aqua (Water)
The foundation of nearly every cosmetic formulation — simple, essential, and universal.
What It Does
Acts as a solvent, dissolving other ingredients and forming the base of water-based formulations. Essential for delivering hydration to the skin.
Important Info
The most common ingredient in skincare globally. Its presence indicates the product is water-based, which affects texture, absorption, and formulation stability.
Warnings
No specific concerns. However, water-based products require preservatives to prevent microbial growth — check for these on the label.
Commonly Found In
Lotions, creams, serums, cleansers, toners, and most leave-on and rinse-off formulations.
Glycerin
A skincare staple and one of the most effective — and gentle — moisturising agents available.
What It Does
A powerful humectant that draws moisture from the air into the skin, keeping it hydrated and supple throughout the day.
Commonly Found In
Moisturisers, cleansers, serums, and toners.
Important Info
Glycerin is a common, effective, and well-tolerated moisturising agent suitable for virtually all skin types — including sensitive skin.
⚠️ Warnings
Can feel slightly sticky in high concentrations. This is usually balanced out by other formulation ingredients and rarely noticeable in finished products.
Hyaluronic Acid
Hero Hydrator
All Skin Types
One of the most celebrated skincare ingredients — a moisture-binding superstar that plumps, smooths, and replenishes.
What It Does
Holds up to 1,000 times its weight in water, visibly plumping the skin and reducing the appearance of fine lines and dehydration.
Important Info
Naturally found in the skin. Excellent for all skin types, particularly dry or dehydrated. Works well layered with other actives.
Warnings
In very dry environments, HA can draw moisture from deeper skin layers. Always follow with an occlusive or moisturiser to seal hydration in.
Commonly Found In
Serums, moisturisers, eye creams, hydrating masks, and plumping treatments.
Ceramides
Barrier Support
Sensitive Skin Friendly
Your skin's natural defence system, in a bottle. Ceramides are the building blocks of a strong, healthy skin barrier.
What They Do
Lipids naturally found in the skin barrier that retain moisture and shield against environmental aggressors like pollution and harsh weather.
Important Info
Replenishing ceramides strengthens the skin barrier, significantly reducing sensitivity, dryness, and transepidermal water loss (TEWL).
Warnings
Generally very safe and beneficial for all skin types. One of the few ingredients with virtually no known contraindications.
Commonly Found In
Moisturisers, barrier repair creams, anti-ageing products, and sensitive skin formulations.
Vitamin C (Ascorbic Acid)
Antioxidant
Brightening
Your morning shield against the world. Vitamin C is a powerhouse antioxidant that brightens, protects, and restores radiance.
What It Does
Brightens the complexion, fades dark spots, protects against free radical damage, and supports collagen synthesis for firmer skin.
Best Practice
Apply in the morning to enhance your sunscreen's protective effect. Look for stable forms: L-Ascorbic Acid, Sodium Ascorbyl Phosphate, or Ascorbyl Glucoside.
⚠️ Warnings
May cause mild tingling at higher concentrations. Some forms degrade quickly when exposed to light and air — store in opaque, airtight packaging.
Commonly Found In
Brightening serums, moisturisers, and morning treatment products.
Salicylic Acid (BHA)
Exfoliant
Oily & Acne-Prone
The go-to acid for blemish-prone skin. Salicylic acid works where others can't — deep inside the pore.
What It Does
A beta-hydroxy acid that exfoliates inside the pores, unclogging them, reducing breakouts, and improving overall skin texture and clarity.
Why It Works
Unlike AHAs, salicylic acid is oil-soluble. This allows it to cut through sebum and penetrate deep into pores — making it uniquely effective for oily and acne-prone skin.
⚠️ Warnings
  • Can cause dryness and peeling — start with low frequency
  • Increases sun sensitivity — use SPF daily
  • Avoid if you have a salicylate allergy
  • Not recommended for young children
Commonly Found In
Cleansers, toners, spot treatments, exfoliating masks, and acne-focused formulations.
Matilda Jane | Ingredient Glossary
Nature Refined | Function-First Skincare

Antioxidants
Antioxidants protect skin from environmental damage by neutralizing harmful free radicals. These protective compounds help prevent premature aging while supporting skin's natural defense systems for healthier, more resilient skin.

Emollients
Emollients soften and smooth the skin's surface by filling in gaps between skin cells. These conditioning agents create a protective barrier that locks in moisture while giving skin a silky, refined texture.
Peptides
Peptides are short chains of amino acids that signal skin cells to produce more collagen and elastin. These powerful molecules help firm and smooth skin while supporting natural repair processes for a more youthful appearance.
Soothing & Hydrating
Sensitive Skin Friendly
Aloe Vera Powder 200×
A concentrated, ultra-potent form of aloe — 200 times stronger than standard aloe leaf juice.
What It Does
Calms redness, irritation and inflammation while delivering deep hydration. The 200× concentration means a tiny amount goes a long way — it's aloe, but supercharged.
Important Info
Plant-based and derived from the inner leaf of Aloe barbadensis. Vegan, palm-free. The powder form is more stable and shelf-stable than liquid aloe, making it ideal for concentrated formulations. Suitable for all skin types, especially reactive or compromised skin.
⚠️ Things to Know
Generally extremely well tolerated. Rare sensitivity reactions are possible — as with any botanical, patch test if you have known plant allergies. The 200× concentration means formulations use very small amounts, so actual exposure is low.
Commonly Found In
Serums, soothing creams, post-procedure products, eye gels, and sensitive skin formulations.
Multi-Tasker
All Skin Types
Niacinamide (Vitamin B3)
Few ingredients do as much as niacinamide. A true multi-tasker that addresses a wide range of skin concerns simultaneously.
What It Does
Improves skin texture, reduces redness, minimises pores, regulates oil production, and strengthens the skin barrier — all in one ingredient. Also helps fade dark spots and even skin tone over time.
Important Info
Origin: Synthetically produced in its cosmetic form — not derived from animals or plants. Vegan and palm-free. Water-soluble and very stable, making it easy to formulate. Works well alongside retinol, vitamin C, and acids.
⚠️ Things to Know
Some people experience mild flushing or redness when starting use, especially at concentrations above 10%. This is usually temporary. Start with a lower concentration (2–5%) and build up. Rare cases of sensitivity have been reported.
Commonly Found In
Serums, moisturisers, toners, and acne treatments.
De-Puffing
Eye Area Favourite
Caffeine
Your morning coffee, but for your skin. Caffeine is a natural stimulant that wakes up tired, puffy skin.
What It Does
Constricts blood vessels to reduce puffiness and dark circles, especially around the eyes. Improves micro-circulation, making skin look more awake and energised. Also a potent antioxidant that helps protect against UV-related damage.
Important Info
Origin — naturally derived from coffee beans, tea leaves, and other plants. Vegan and palm-free. The caffeine used in skincare is typically extracted from green coffee or tea, or produced synthetically. Both forms are effective.
⚠️ Things to Know
Very well tolerated by most skin types. Effects on puffiness are temporary — it works best with consistent use. Not a permanent fix for dark circles caused by pigmentation (it works better on those caused by fluid retention or poor circulation).
Commonly Found In
Eye creams, serums, under-eye patches, and energising face masks.
What-it-does: solvent, moisturizer/humectant, emulsion stabilizer, antimicrobial.
Derived from sources like sugarcane or corn, this ingredient can be synthetic or plant-based. Modern, bio-based versions are a popular, sustainable choice for eco-conscious skincare.
This multi-tasking ingredient helps keep your products stable and well-preserved while giving them a silky, pleasant feel. As a moisturiser, it keeps your skin hydrated, improves texture, and even helps your favourite sunscreen stay put.
Key Attributes:
  • Vegan: Yes
  • Palm-free: Yes
  • Can be plant-based: Yes; both traditional synthetic and 100% bio-based versions are available.

⚠️ Things to Know
Pentylene Glycol is widely considered safe for leave-on products by the Cosmetic Ingredient Review (CIR) and is generally well-tolerated. However, those with very reactive or compromised skin may occasionally experience mild irritation. While rare, it has been flagged in some research as an emerging allergen, and its ability to enhance the absorption of other ingredients might amplify the effects of strong actives. If you have highly sensitive skin, it is always a good idea to patch test new products first.
Also-called: Water | What-it-does: solvent
Good old water, aka H2O. The most common skincare ingredient of all. You can usually find it right in the very first spot of the ingredient list, meaning it’s the biggest thing out of all the stuff that makes up the product. 
It’s mainly a solvent for ingredients that do not like to dissolve in oils but rather in water. 
Once inside the skin, it hydrates, but not from the outside - putting pure water on the skin (hello long baths!) is drying. 
One more thing: the water used in cosmetics is purified and deionized (it means that almost all of the mineral ions inside it is removed). Like this, the products can stay more stable over time. 
A mildly viscous, amber-colored liquid with fatty odor, made from Castor Oil and polyethylene glycol (PEG).
If it were a person, we’d say, it’s agile, diligent & multifunctional. It’s mostly used as an emulsifier and surfactant but most often it is used to solubilize fragrances into water-based formulas.
What-it-does: buffering
Citric acid comes from citrus fruits and is an AHA. If these magic three letters don’t tell you anything, click here and read our detailed description on glycolic acid, the most famous AHA. 
So citric acid is an exfoliant, that can - just like other AHAs - gently lift off the dead skin cells of your skin and make it more smooth and fresh. 
There is also some research showing that citric acid with regular use (think three months and 20% concentration) can help sun-damaged skin, increase skin thickness and some nice hydrating things called glycosaminoglycans in the skin. 
But according to a comparative study done in 1995, citric acid has less skin improving magic properties than glycolic or lactic acid. Probably that’s why citric acid is usually not used as an exfoliant but more as a helper ingredient in small amounts to adjust the pH of a formulation. 
Glycerin - superstar
Also-called: Glycerol | What-it-does: skin-identical ingredient, moisturizer/humectant | Irritancy: 0 | Comedogenicity: 0
  • A natural moisturizer that’s also in our skin
  • A super common, safe, effective and cheap molecule used for more than 50 years
  • Not only a simple moisturizer but knows much more: keeps the skin lipids between our skin cells in a healthy (liquid crystal) state, protects against irritation, helps to restore barrier
  • Effective from as low as 3% with even more benefits for dry skin at higher concentrations up to 20-40%
  • High-glycerin moisturizers are awesome for treating severely dry skin
Lactic Acid - superstar
  • It’s the second most researched AHA after glycolic acid
  • It gently lifts off dead skin cells to reveal newer, fresher, smoother skin
  • It also has amazing skin hydrating properties
  • In higher concentration (10% and up) it improves skin firmness, thickness and wrinkles
  • Choose a product where you know the concentration and pH value because these two greatly influence effectiveness
  • Don’t forget to use your sunscreen (in any case but especially so next to an AHA product)
Antioxidant
All Skin Types
Your skin's built-in antioxidant — and one of the most trusted protective ingredients in skincare.
What It Does
Neutralises free radicals caused by UV exposure and pollution, helping to prevent premature ageing. Also acts as an emollient, softening and conditioning the skin. Works especially well paired with Vitamin C — together they provide significantly better photoprotection than either alone.
Important Info
Origin — naturally derived from plant oils (sunflower, soybean, wheat germ). The natural form (d-alpha tocopherol) is more bioavailable than the synthetic version (dl-alpha tocopherol). Can be vegan, but check the source — some forms are derived from animal products. Palm-free versions are available and increasingly common.
⚠️ Things to Know
Can be comedogenic (pore-clogging) for some people, particularly in high concentrations or in heavy formulations — rated 0–3 on the comedogenicity scale. Those with acne-prone skin should patch test. Also acts as an antioxidant preservative in formulations, helping extend product shelf life.
Commonly Found In
Moisturisers, serums, sunscreens, lip balms, and body oils.
Anti-Ageing
Collagen Booster
GHK-Cu (Copper Peptide)
One of skincare's most exciting peptides — a naturally occurring compound that tells your skin to repair and rebuild itself.
What It Does
Stimulates collagen and elastin production, supports wound healing, and acts as a powerful antioxidant. Clinically shown to improve skin thickness, elasticity, and fine lines after 8–12 weeks of consistent use. Also helps remodel and renew skin tissue.
Important Info
Origin: GHK-Cu is a tripeptide (three amino acids) naturally found in human plasma, saliva, and urine — levels decline significantly with age. In skincare, it's produced synthetically to replicate this naturally occurring compound. Vegan. Palm-free.
⚠️ Things to Know
Don't combine with strong acids (vitamin C as ascorbic acid, AHAs, BHAs) at the same time — copper peptides degrade at low pH, reducing effectiveness. Use in separate routines (e.g. morning vs evening). Generally very well tolerated, including by sensitive skin.
Commonly Found In
Anti-ageing serums, eye creams, repair treatments, and post-procedure skincare.
Stress Defence
Neurocosmetic
Neurophroline®
Skincare meets neuroscience. Neurophroline is a plant-based ingredient that helps your skin cope with stress — literally.
What It Does
Blocks cortisol (the stress hormone) production in skin cells and triggers the release of natural calming neuropeptides (endorphins). The result: reduced redness, improved skin tone, and a more radiant complexion. Visible results in as little as two weeks.
Important Info
Origin: Extracted from the seeds of Tephrosia purpurea (wild indigo), a plant native to India with a long history in Ayurvedic tradition. ECOCERT/COSMOS approved, NATRUE certified, and vegan suitable. Palm-free. Water-soluble.
⚠️ Things to Know
A relatively newer ingredient with a growing (but still limited) body of clinical evidence. Well tolerated in studies. Often used in post-procedure skincare to calm redness after peels, laser, or injectables. No known significant contraindications.
Commonly Found In
Anti-stress serums, day and night creams, eye care products, and post-procedure formulations.
Natural Retinol Alternative
Pregnancy-Friendly
Bakuchiol
The plant-based answer to retinol — all the anti-ageing benefits, without the irritation.
What It Does
Stimulates collagen and elastin production, reduces fine lines, evens skin tone, and has antioxidant and anti-inflammatory properties. Clinically shown to deliver comparable results to retinol, but with significantly less irritation, dryness, or sensitivity.
Important Info
Origin: Extracted from the seeds and leaves of Psoralea corylifolia (babchi plant), native to Asia and used for centuries in traditional Chinese and Ayurvedic medicine. 100% plant-based, vegan, and palm-free. Unlike retinol, it's considered safe to use during pregnancy (though always check with your doctor).
⚠️ Things to Know
Generally very well tolerated, even by sensitive skin. Rare cases of sensitivity have been reported — patch test if you have reactive skin. Note: the babchi plant faces some sustainability concerns due to low germination rates, so look for responsibly sourced versions. Not the same chemical structure as retinol, but activates similar skin pathways.
Commonly Found In
Anti-ageing serums, facial oils, night creams, and pregnancy-safe skincare ranges.
Barrier Repair
Soothing
Gotu Kola (Centella Asiatica)
An ancient healing herb that's become a modern skincare hero — trusted for centuries, now backed by science.
What It Does
Promotes collagen synthesis and wound healing, reduces inflammation, and strengthens the skin barrier. Its active compounds (asiaticoside, madecassoside, asiatic acid) support skin repair and help calm redness, making it brilliant for sensitive, damaged, or post-procedure skin.
Important Info
Origin: A medicinal plant (Centella asiatica) native to tropical regions of South and Southeast Asia — India, Sri Lanka, Indonesia, Malaysia. Used for centuries in Ayurvedic and Traditional Chinese Medicine. 100% plant-based, vegan, and palm-free.
⚠️ Things to Know
Very well tolerated by most skin types, including sensitive and reactive skin. Rare allergic reactions are possible — as with any botanical, patch test if you have known plant allergies. Quality and potency can vary significantly between products depending on the extract concentration used.
Commonly Found In
Soothing serums, barrier repair creams, sensitive skin moisturisers, and post-procedure products.
Antioxidant
Anti-Inflammatory
Green Tea Extract
One of the most studied plant antioxidants in skincare — your skin's daily shield against the world.
What It Does
Neutralises free radicals from UV exposure and pollution, helping prevent premature ageing. Its key active compound, EGCG (epigallocatechin gallate), also reduces inflammation, supports skin hydration, and has shown promise in reducing acne and evening skin tone.
Important Info
Origin: Derived from the leaves of Camellia sinensis (the tea plant), cultivated in China, Japan, and across Asia for over 4,000 years. 100% plant-based, vegan, and palm-free. The unfermented (green) leaves retain the highest levels of antioxidant catechins.
⚠️ Things to Know
Very well tolerated. Needs to be formulated at an acidic pH to remain stable and effective — poorly formulated products may lose potency. Works best combined with other antioxidants (like Vitamin C or E). Caffeine is a natural component of green tea extract, so those sensitive to caffeine should be aware.
Commonly Found In
Antioxidant serums, moisturisers, sunscreens, toners, and eye creams.
Antioxidant
Brightening
Green Coffee Extract
Coffee before it's roasted — and packed with more antioxidant power than your morning cup.
What It Does
Rich in chlorogenic acid (a potent antioxidant) and natural caffeine. Protects skin from free radical damage, helps reduce the appearance of dark spots and uneven tone, improves micro-circulation, and reduces puffiness. The unroasted beans retain significantly more antioxidant activity than roasted coffee.
Important Info
Origin: Derived from the raw, unroasted beans of Coffea arabica or Coffea canephora (robusta). 100% plant-based, vegan, and palm-free. The green (unroasted) state preserves the highest concentration of chlorogenic acids and other beneficial polyphenols.
⚠️ Things to Know
Generally well tolerated. Contains natural caffeine, which may cause mild sensitivity in very reactive skin types — patch test if unsure. Effectiveness can vary depending on the concentration and formulation. Emerging ingredient with a growing body of evidence, but less extensively studied than green tea extract.
Commonly Found In
Eye creams, brightening serums, anti-fatigue moisturisers, and body firming products.