What is sunscreen made from?

What are the active ingredients?

The active ingredients are the sunscreen's UV filters. Mineral filters are zinc oxide and titanium dioxide. Chemical filters include avobenzone, octinoxate, octocrylene, homosalate, octisalate, oxybenzone and bemotrizinol. A sunscreen can contain several filters because different ingredients cover different parts of the UV spectrum. Some combinations also help the formula stay stable in sunlight. Avobenzone provides UVA protection, for example, while octinoxate provides UVB protection. Bemotrizinol covers both. Ingredient availability differs between countries; bemotrizinol became a permitted sunscreen active ingredient in the US in June 2026.123

Both mineral and chemical sunscreens protect mainly by absorbing UV radiation. Mineral sunscreens also reflect some light. The idea that mineral sunscreen only reflects rays while chemical sunscreen absorbs them is too simple. Both form a protective layer on the skin. Smaller mineral particles help reduce white residue and improve spreading, so two mineral sunscreens can look and feel quite different.23

What else goes into sunscreen?

The ingredients surrounding the filters make up the vehicle, meaning the base that carries them. In topical products, bases commonly contain water, oil, alcohol or propylene glycol, with ingredients such as emulsifiers, preservatives and fragrances. Not every sunscreen contains every ingredient in that list. A cream is usually an emulsion, a mixture of oil and water, and often feels moisturising. A lotion is generally thinner. A gel can have a water or alcohol base. Preservatives help extend a cream's shelf life. These are general formulation patterns, not a recipe shared by every sunscreen.5

Manufacturers use texture names differently, so a lotion and a cream can be close relatives with separate stationery. The full formula matters: changes in a topical product's base can change its performance, not just how pleasant it feels. Sunscreens also come as sticks, oils, pastes and sprays. A different format can have different application directions, so use the instructions for the product you actually bought.15

How do you read the ingredient label?

On US sunscreen labels, look for the "Active Ingredients" section to identify the filters. Then check the protection claims: broad spectrum, SPF 30 or higher, and water resistance. SPF measures protection against sunburn, primarily from UVB; broad spectrum means protection against both UVA and UVB. The finished product's protection rating matters more than recognising one filter name. In the UK, choose SPF 30 or higher with at least four stars for UVA protection. A UVA symbol inside a circle indicates that the product meets the EU standard.36

Regular sunscreen use helps reduce the risk of skin cancer and sun related skin ageing, as well as protecting against sunburn. The benefit comes from using the sunscreen, not merely choosing an impressive ingredient list. No sunscreen filters out all UV radiation, so clothing and shade remain part of sun protection. A higher SPF is not permission to spend longer in the sun.267

What makes tinted sunscreen different?

Tinted sunscreens contain iron oxide, which helps protect against visible light as well as adding colour. Visible light can contribute to dark spots and melasma, a condition that causes patches of darker skin. This additional protection is especially useful for darker skin tones. A tint can also help disguise the white residue some sunscreens leave. Still choose broad spectrum protection and SPF 30 or higher; colour is an extra feature, not a substitute for UV protection.3

Which ingredients suit sensitive skin?

For sensitive skin, choose a mineral sunscreen containing zinc oxide, titanium dioxide, or both. Mineral sunscreens are generally less likely to cause irritation or allergic reactions than chemical sunscreens. Chemical formulas can cause irritation in some people and burning if they get into the eyes. If a sunscreen causes a reaction, discuss the ingredients with a healthcare provider or dermatologist. For babies younger than six months, prioritise shade and protective clothing, and ask a doctor before using sunscreen.134

Some sunscreen filters are absorbed through the skin and enter the body. Whether exposure to particular filters carries safety risks remains under investigation. That uncertainty does not change the established public health benefit of sunscreen used with other sun protection measures.1

How do you use the finished formula?

1. 1Apply sunscreen before sun exposure, following the label. General US directions say 15 minutes before going outside. Never spray sunscreen directly onto your face.
2. 2Cover all exposed skin, including your ears, neck, hands and feet. For an adult's whole body, aim for around six to eight teaspoons. Applying too little reduces protection.
3. 3Reapply every two hours outdoors, and after swimming, sweating or towel drying. Water resistant sunscreen has a tested limit of 40 or 80 minutes in water; it is not waterproof.
4. 4Use sunscreen daily when the forecast UV index reaches three or higher, alongside shade and clothing. Seek medical help for sunburn if you feel unwell or the skin swells badly or blisters.

Do extra ingredients and "reef safe" claims matter?

Some sunscreens include extra ingredients intended to support protection by changing the skin's response to sunlight. Evidence for most of these additions is weak. Choose by the sunscreen's tested protection rather than treating added skincare ingredients as replacement filters.2

The words "reef safe" have no FDA definition, so the front of the bottle is not a marine biology qualification. The effects of sunscreen ingredients on reefs remain uncertain. Some destinations restrict particular filters; check current local rules before travelling.23

Can the ingredients lose their effectiveness?

Keep sunscreen away from excessive heat and direct sunlight. While outdoors, store the container in shade or wrap it in a towel. Discard sunscreen past its expiry date. For US products without an expiry date, discard them three years after purchase; discard them sooner if you cannot tell how old they are. On UK products, also check the open jar symbol: the number followed by M shows how many months the product lasts after opening.16