Zinc oxide is a versatile mineral compound with a long-established role in dermatological care across the UK. Recognised in the British National Formulary (BNF) and recommended by NICE for various skin conditions, zinc oxide offers multiple therapeutic benefits including barrier protection, UV defence, and anti-inflammatory properties. From treating nappy rash in infants to providing broad-spectrum sun protection for all ages, this well-tolerated ingredient remains a cornerstone of both preventive and therapeutic skincare. Understanding how zinc oxide works and its evidence-based applications can help you make informed decisions about incorporating it into your skin health routine.

What Is Zinc Oxide and How Does It Work on Skin?

Zinc oxide (ZnO) is an inorganic compound that has been used in dermatological preparations for over a century. It appears as a white, powdery substance and is classified as a physical (mineral) barrier agent with multiple therapeutic properties. In the UK, zinc oxide is available in various over-the-counter preparations and is listed in the British National Formulary (BNF) for several dermatological indications.

Mechanism of Action

Zinc oxide works through several complementary mechanisms on the skin:

• Physical barrier formation: Creates a protective layer that shields skin from moisture, friction, and irritants

• UV protection: Absorbs, scatters and reflects both UVA and UVB radiation, providing broad-spectrum protection when properly formulated

• Mild antimicrobial activity: Exhibits limited antibacterial and antifungal properties, though not a substitute for treatment of infection

• Anti-inflammatory effects: May help reduce inflammatory mediators and soothe irritated skin

• Astringent properties: Mildly dries weeping or oozing lesions

The compound is considered chemically inert and non-sensitising in most formulations, which contributes to its excellent safety profile. When applied topically, zinc oxide remains primarily on the skin surface with minimal systemic absorption through intact skin, reducing the risk of systemic adverse effects. This makes it particularly suitable for use on compromised skin barriers, including nappy rash, minor wounds, and sensitive skin conditions.

Zinc oxide is available in various concentrations and formulations, including creams, ointments, pastes, and suspensions. Medicinal barrier products containing zinc oxide may be licensed by the MHRA, while zinc oxide in sunscreens is regulated as a cosmetic ingredient under UK Cosmetics Regulation (with a maximum permitted concentration of 25% as a UV filter).

Skin Benefits of Zinc Oxide: Evidence and Uses

Clinical evidence supports multiple dermatological applications of zinc oxide, making it a versatile ingredient in both therapeutic and preventive skincare.

Nappy Rash and Barrier Protection

Zinc oxide paste or cream is a first-line treatment for nappy rash (irritant contact dermatitis) in infants. NICE Clinical Knowledge Summaries recommend barrier preparations containing zinc oxide for prevention and management of nappy dermatitis. The compound creates a protective barrier that helps shield skin from prolonged contact with urine and faeces whilst allowing the skin to heal.

Sun Protection

As a mineral UV filter, zinc oxide provides protection against both UVA (320–400 nm) and UVB (290–320 nm) radiation. Unlike some chemical sunscreens, it works immediately upon application and is generally photostable. The NHS recommends using sunscreens with SPF 30 or higher and at least 4-star UVA protection. Mineral sunscreens containing zinc oxide may be suitable alternatives for individuals with sensitive skin who experience reactions to chemical UV filters.

Wound Healing and Minor Skin Conditions

Zinc oxide may provide supportive care in minor skin conditions through its barrier protection, mild antimicrobial and anti-inflammatory properties. It is commonly used for:

• Minor cuts, grazes, and abrasions (as a protective barrier)

• Moisture-associated skin damage (as part of barrier preparations)

• Mild eczema and dermatitis (as an adjunct to standard treatments)

• Post-procedural skin care

Acne and Seborrhoeic Conditions

Whilst not a primary acne treatment according to NICE guidelines, zinc oxide's mild astringent properties may provide adjunctive benefits in managing oily or acne-prone skin. Some formulations combine zinc oxide with other active ingredients for enhanced efficacy, but it should not replace evidence-based acne treatments.

Anti-ageing and Skin Protection

By helping to prevent UV-induced photodamage when used in sunscreens, zinc oxide indirectly supports skin health and may help reduce premature ageing signs, though it should not be considered a treatment for existing photoageing.

How to Use Zinc Oxide Products Safely

Proper application technique and product selection are essential to maximise the benefits of zinc oxide whilst ensuring safety and tolerability.

Application Guidelines

For barrier protection (nappy rash, incontinence-associated dermatitis):

• Cleanse and thoroughly dry the affected area before application

• Apply a thin, even layer to create an effective barrier

• Reapply at each nappy change or after washing

• Avoid rubbing vigorously; gentle patting is sufficient

For sun protection:

• Apply liberally to all exposed skin 15–30 minutes before sun exposure

• Use adequate amounts (approximately half a teaspoon for the face, or follow the two-finger rule)

• Choose at least SPF 30 with 4- or 5-star UVA protection

• Reapply every two hours and immediately after swimming, sweating, or towel drying

• Ensure even coverage, paying particular attention to commonly missed areas (ears, neck, hands)

For wound care or minor skin conditions:

• Clean the area gently with water or saline

• Pat dry and apply a thin layer

• Cover with appropriate dressing if recommended

• Reapply once or twice daily, or as directed

Product Selection Considerations

• Concentration: Higher concentrations for intensive barrier protection; lower concentrations for daily use or sunscreen

• Formulation: Ointments and pastes provide more occlusive protection; creams and lotions are easier to spread and more cosmetically acceptable

• Particle size: Micronised or nano-particle formulations reduce the white cast typical of traditional zinc oxide sunscreens (products containing nano zinc oxide will be labelled with [nano])

• Additional ingredients: Check for potential allergens or irritants, particularly fragrances and preservatives

Storage and Shelf Life

Store zinc oxide products at room temperature, away from direct sunlight. Check expiry dates, particularly for sunscreen products, as efficacy may diminish over time. Most preparations remain stable for 2–3 years when stored correctly. For sunscreens, note the period-after-opening symbol (open jar icon) and consider replacing opened products after 12 months.

Potential Side Effects and Precautions

Zinc oxide is generally well-tolerated with an excellent safety profile; however, awareness of potential adverse effects and appropriate precautions is important for safe use.

Common Adverse Effects

Zinc oxide rarely causes significant side effects when used topically. Potential minor reactions include:

• Skin dryness or tightness: Particularly with frequent application or high-concentration formulations

• Temporary white discolouration: Traditional formulations may leave a visible white cast on the skin

• Mild stinging: Occasionally reported on broken or highly inflamed skin, usually transient

Rare Adverse Reactions

• Allergic contact dermatitis: Extremely uncommon but documented in medical literature. Symptoms include redness, itching, swelling, or rash at application sites

• Folliculitis: Occlusive formulations may occasionally block hair follicles, particularly in individuals prone to this condition

Important Precautions and Contraindications

Avoid use:

• In or near eyes (if accidental contact occurs, rinse thoroughly with water)

• On deep or puncture wounds without medical advice

• Avoid using sprays or powders containing zinc oxide that may be inhaled, particularly in infants and children

Use with caution:

• In individuals with known zinc sensitivity (extremely rare)

• On large areas of broken skin in neonates (seek clinical advice)

When to Seek Medical Advice

Contact your GP or healthcare provider if:

• Skin condition worsens or fails to improve within 7 days of treatment

• Signs of infection develop (spreading redness, warmth, pus, fever)

• Nappy rash shows bright red areas with satellite pustules (possible Candida infection)

• Honey-coloured crusts appear (possible impetigo)

• Severe irritation, blistering, or allergic reaction occurs

• Nappy rash persists despite appropriate barrier cream use

• You are uncertain about product suitability for your specific condition

Drug Interactions

Topical zinc oxide has no known significant drug interactions due to minimal systemic absorption. However, inform healthcare professionals of all topical preparations you are using, particularly if applying multiple products to the same area.

Special Populations

Zinc oxide is considered safe for use in pregnancy, breastfeeding, infants, and elderly patients. It is often the preferred option for vulnerable populations due to its non-toxic nature and minimal absorption. However, always follow product-specific guidance and consult a healthcare professional if you have concerns about use in these groups.

If you experience any unexpected side effects, report them through the MHRA Yellow Card Scheme (yellowcard.mhra.gov.uk).

Frequently Asked Questions