Your guide to the ingredients commonly found in skincare.

Understanding skincare ingredients doesn't have to be complicated. Whether you're choosing your first cleanser or comparing advanced serums, knowing what an ingredient does can help you make more informed skincare decisions.

This guide explains the purpose of many of the ingredients you'll commonly find in skincare products, who they may be suitable for, and what to consider before adding them to your routine.

Please note: Not every ingredient is suitable for every skin type. If you're introducing a new active ingredient, patch test first and avoid combining multiple strong actives (such as exfoliating acids and retinoids) unless advised by a skincare professional.

A

Alpha Arbutin

What is it?
A brightening ingredient that helps reduce the appearance of dark spots and uneven skin tone.

Best for

Pigmentation
Post-acne marks
Uneven skin tone

Things to know
Results develop gradually. Daily SPF is essential to help prevent pigmentation from returning.

Alpha Hydroxy Acids (AHAs)

Examples: Glycolic Acid, Lactic Acid, Mandelic Acid

What are they?
Water-soluble exfoliating acids that remove dead skin cells from the skin's surface to reveal smoother, brighter-looking skin.

Best for

Dull skin
Uneven texture
Fine lines
Pigmentation

Things to know
AHAs can make skin more sensitive to sunlight, so daily SPF is recommended.

Ascorbic Acid (Vitamin C)

What is it?
The pure form of Vitamin C and a powerful antioxidant that helps brighten the complexion and protect against environmental stress.

Best for

Dull skin
Uneven skin tone
Fine lines

Things to know
Store away from heat and direct sunlight, as Vitamin C becomes less stable when exposed to air and light.

Azelaic Acid

What is it?
A multi-purpose ingredient that helps reduce redness, improve uneven skin tone and support blemish-prone skin.

Best for

Acne
Pigmentation
Redness
Rosacea-prone skin

Things to know
Generally well tolerated by many skin types, including sensitive skin.

B

Benzoyl Peroxide

What is it?
An antibacterial ingredient commonly used to help manage acne breakouts.

Best for

Acne
Inflamed blemishes

Things to know
Can cause dryness and may bleach towels, clothing and pillowcases.

Beta Hydroxy Acid (BHA)

Example: Salicylic Acid

What is it?
An oil-soluble exfoliating acid that works inside pores to remove excess oil and dead skin cells.

Best for

Oily skin
Blackheads
Congested pores
Breakouts

Things to know
Introduce gradually if you're new to exfoliating acids.

Biotin

What is it?
A B-vitamin commonly found in haircare products and supplements.

Best for

Haircare

Things to know
Topical biotin has limited evidence for improving hair growth, but it remains a popular ingredient in many formulations.

C

Caffeine

What is it?
A plant-derived ingredient commonly used in eye care products to reduce the appearance of puffiness.

Best for

Puffy eyes
Tired-looking eyes

Things to know
May temporarily improve the appearance of puffiness but is unlikely to treat the underlying cause of dark circles.

Centella Asiatica (Cica)

What is it?
A botanical extract known for its soothing and calming properties.

Best for

Sensitive skin
Redness
Skin barrier support

Things to know
Often recommended after professional skin treatments or during barrier recovery.

Ceramides

What are they?
Natural lipids that help strengthen the skin barrier and reduce moisture loss.

Best for

Dry skin
Sensitive skin
Barrier repair

Things to know
Suitable for almost every skin type and one of the most effective ingredients for maintaining healthy skin.

Collagen

What is it?
A structural protein that helps keep skin firm and resilient.

Best for

Hydration
Dry skin

Things to know
Topical collagen mainly hydrates the skin rather than replacing collagen naturally lost with age.

D

Dimethicone

What is it?
A lightweight silicone that smooths the skin's surface and helps lock in moisture.

Best for

Dry skin
Rough texture
Barrier support

Things to know
Despite common myths, dimethicone is generally considered non-comedogenic for most people.

E

Ectoin

What is it?
A protective ingredient that helps defend skin against environmental stress while supporting hydration.

Best for

Sensitive skin
Dry skin
Skin barrier support

Things to know
Often found in products designed to protect against pollution and environmental damage.

F

Fatty Acids

What are they?
Natural lipids that support the skin barrier and help reduce moisture loss.

Best for

Dry skin
Barrier repair

Things to know
Often combined with ceramides and cholesterol in barrier-supporting moisturisers.

Ferulic Acid

What is it?
A powerful antioxidant frequently combined with Vitamins C and E.

Best for

Environmental protection
Fine lines
Uneven skin tone

Things to know
Helps improve the stability and effectiveness of Vitamin C.

G

Glycerin

What is it?
A humectant that attracts water into the skin, helping maintain hydration.

Best for

Dry skin
Dehydration
Sensitive skin

Things to know
One of the most widely used and effective moisturising ingredients.

Glycolic Acid

What is it?
An AHA derived from sugar cane that exfoliates the skin's surface.

Best for

Dull skin
Pigmentation
Fine lines
Rough texture

Things to know
Because of its smaller molecular size, it penetrates more deeply than some other AHAs.

Green Tea Extract

What is it?
A botanical antioxidant with calming and protective properties.

Best for

Sensitive skin
Redness
Environmental protection

Things to know
Often included in products designed to soothe irritated skin.

H

Hyaluronic Acid

What is it?
A hydrating ingredient that attracts and holds water within the skin.

Best for

Dry skin
Dehydration
Fine lines

Things to know
Works best when followed by a moisturiser to help lock in hydration.

Hydroquinone

What is it?
A prescription-strength skin-brightening ingredient used to treat stubborn pigmentation.

Best for

Melasma
Hyperpigmentation

Things to know
Should only be used under the guidance of a healthcare professional.

I

Isopropyl Myristate

What is it?
A lightweight emollient that improves product texture and spreadability.

Best for

Dry skin

Things to know
May not suit very oily or acne-prone skin, as it can clog pores for some people.

J

Jojoba Oil

What is it?
A lightweight plant oil similar to the skin's natural sebum.

Best for

Dry skin
Combination skin
Sensitive skin

Things to know
Generally well tolerated and helps soften the skin without feeling heavy.

K

Ketoconazole

What is it?
An anti-fungal ingredient commonly found in medicated anti-dandruff shampoos.

Best for

Dandruff
Flaky scalp

Things to know
Available in certain over-the-counter shampoos and stronger prescription treatments.

Kojic Acid

What is it?
A brightening ingredient naturally derived from fungi.

Best for

Pigmentation
Uneven skin tone

Things to know
Often combined with other brightening ingredients for enhanced results.

L

Lactic Acid

What is it?
A gentle AHA that exfoliates while helping to maintain hydration.

Best for

Dry skin
Dull skin
Sensitive skin

Things to know
Often considered gentler than Glycolic Acid.

Linoleic Acid

What is it?
An essential fatty acid that supports the skin barrier.

Best for

Oily skin
Acne-prone skin
Barrier support

Things to know
Helps maintain healthy skin without feeling greasy.

M

Mandelic Acid

What is it?
A gentle AHA with a larger molecular size, meaning it exfoliates more slowly.

Best for

Sensitive skin
Acne
Pigmentation

Things to know
Often a good introduction to exfoliating acids.

Minoxidil

What is it?
A medicine used to help treat certain types of hair thinning.

Best for

Hair thinning

Things to know
Available over the counter in UK pharmacies. Results require consistent, long-term use.

N

Niacinamide (Vitamin B3)

What is it?
A multi-benefit ingredient that supports the skin barrier and improves overall skin health.

Best for

Redness
Oily skin
Pigmentation
Barrier support

Things to know
Suitable for most skin types and works well alongside many other skincare ingredients.

O

Oat Extract

What is it?
A soothing botanical ingredient commonly used in sensitive skin products.

Best for

Sensitive skin
Dry skin
Itchy skin

Things to know
Helps calm irritation and support the skin barrier.

Octocrylene

What is it?
A UV filter used in some chemical sunscreens.

Best for

Daily sun protection

Things to know
Used alongside other UV filters to provide broad-spectrum sun protection.

P

Panthenol (Pro-Vitamin B5)

What is it?
A moisturising ingredient that helps soothe and support the skin barrier.

Best for

Dry skin
Sensitive skin
Barrier repair

Things to know
Often included in products designed for compromised skin.

Peptides

What are they?
Short chains of amino acids that help support the skin's natural collagen-building processes.

Best for

Fine lines
Loss of firmness
Skin longevity

Things to know
Best results are achieved with consistent long-term use.

Phytic Acid

What is it?
A gentle exfoliating acid often used in products for sensitive skin.

Best for

Dull skin
Uneven skin tone

Things to know
Generally milder than many other exfoliating acids.

Q

Quercetin

What is it?
A plant-derived antioxidant with soothing properties.

Best for

Sensitive skin
Environmental protection

Things to know
Often included in anti-ageing and calming skincare formulations.

R

Resveratrol

What is it?
A powerful antioxidant commonly derived from grapes.

Best for

Skin longevity
Fine lines
Environmental protection

Things to know
Often paired with other antioxidants to enhance overall skin protection.

Retinoids (including Retinol)

What are they?
Vitamin A derivatives that support skin renewal and collagen production.

Best for

Fine lines
Acne
Pigmentation
Skin texture

Things to know
Introduce gradually and always wear SPF during the day.

Rosehip Oil

What is it?
A nourishing plant oil naturally rich in fatty acids.

Best for

Dry skin
Dull skin
Barrier support

Things to know
Lightweight and suitable for many skin types.

S

Salicylic Acid

What is it?
A BHA that exfoliates inside the pores to help reduce congestion.

Best for

Oily skin
Acne
Blackheads

Things to know
One of the most effective ingredients for blemish-prone skin.

Shea Butter

What is it?
A rich plant butter that deeply moisturises and softens the skin.

Best for

Dry skin
Very dry skin

Things to know
Ideal for nourishing dry or compromised skin barriers.

Squalane

What is it?
A lightweight oil that helps reduce moisture loss without feeling greasy.

Best for

Dry skin
Sensitive skin
Barrier repair

Things to know
Suitable for almost every skin type, including oily skin.

Sulphur

What is it?
A mineral traditionally used to help reduce excess oil and blemishes.

Best for

Oily skin
Acne

Things to know
May have a noticeable scent and can be drying for some people.

SPF (Sun Protection Factor)

What is it?
A measure of a sunscreen's protection against UVB rays. Broad-spectrum sunscreens also help protect against UVA rays.

Best for

Everyone

Things to know
Daily SPF is one of the most effective ways to help protect your skin from premature ageing and sun damage.

T

Tea Tree Oil

What is it?
A plant oil traditionally used for blemish-prone skin.

Best for

Occasional breakouts

Things to know
Can be irritating if used undiluted or in high concentrations.

Tranexamic Acid

What is it?
A brightening ingredient commonly used to target stubborn pigmentation.

Best for

Melasma
Pigmentation
Post-acne marks

Things to know
Often used alongside other brightening ingredients for best results.

U

Urea

What is it?
A hydrating ingredient that helps soften rough, dry skin.

Best for

Dry skin
Rough skin

Things to know
Higher-strength formulas are commonly used on rough areas such as elbows, knees and feet.

V

Vitamin C

What is it?
A powerful antioxidant that brightens the complexion and helps protect against environmental damage.

Best for

Dull skin
Pigmentation
Fine lines

Things to know
Works particularly well when paired with daily sunscreen.

Vitamin E

What is it?
An antioxidant that helps protect the skin while supporting hydration.

Best for

Dry skin
Environmental protection

Things to know
Often combined with Vitamin C to improve stability and antioxidant protection.

W

Witch Hazel

What is it?
A botanical extract with mild astringent properties.

Best for

Oily skin

Things to know
May feel drying for some people, particularly those with sensitive or dry skin.

X

Xanthan Gum

What is it?
A plant-derived ingredient used to thicken and stabilise skincare products.

Best for

Product texture

Things to know
It has no active skincare benefits but helps create a pleasant product consistency.

Y

Yeast Extract

What is it?
A naturally derived ingredient used for its hydrating and soothing properties.

Best for

Dry skin
Sensitive skin

Things to know
Often included in products designed to support overall skin health.

Z

Zinc Oxide

What is it?
A mineral UV filter used in many sunscreens.

Best for

Sensitive skin
Daily sun protection

Things to know
Provides broad-spectrum protection against both UVA and UVB rays.

Zinc PCA

What is it?
A mineral-based ingredient that helps regulate excess oil while supporting clearer-looking skin.

Best for

Oily skin
Acne-prone skin

Things to know
Frequently combined with Niacinamide in products designed for oily or blemish-prone skin.

Building an Effective Skincare Routine

Understanding ingredients is only one part of achieving healthy skin. The best skincare routine is one that suits your skin type, addresses your skin concerns, and supports your skin barrier.

Before introducing a new active ingredient:

Introduce one new product at a time.
Always patch test before full application.
Wear SPF daily when using retinoids or exfoliating acids.
Be patient—many ingredients take several weeks of consistent use before visible improvements are seen.