Sunscreen has to be up there with one of the most potent sensory triggers of long summer days; slathered across your face and limbs, the scent of coconut or zinc drifting through the air. But nostalgia aside, sunscreen isn’t seasonal. SPF is a daily essential for guarding your skin against wrinkles, fine lines, pigmentation and, most importantly, skin cancer.

Sunscreen is typically categorised as either chemical or physical (or mineral), with much debate among experts and enthusiasts as to which is “better”.

The subject gets a little confusing, so we spoke to some dermatologists to clarify the contrasts between the two.

What’s the difference between chemical and physical sunscreen?

Chemical sunscreen tends to be lightweight, easily massaged into the skin and is arguably the most common form of SPF on the market.

Dr Shyamalar Gunatheesan, a dermatologist and the founder of Melbourne’s ODE Dermatology, says chemical sunscreens are “composed of organic filters … that absorb the UV radiation and then disperse the energy as a release of heat (from the body)”.

Common ingredients in chemical suncreams include avobenzone (which absorbs harmful UVA rays, octinoxate (which absorbs harmful UVB rays) and octocrylene (which absorbs both UVA and UVB rays).

Meanwhile, physical sunscreen tends to be thicker in texture, although Dr Gunatheesan notes that their texture has vastly improved in recent years. Physical sunscreens as those “made out of inert, inorganic filters which have the ability to reflect and scatter UV rays, thereby preventing the absorption of UV light into the skin,” she says.

Examples of physical sunscreens include zinc oxide and titanium dioxide.

Sounds complex, right? But “chemical” and “physical” (or “mineral”) filters actually have far more in common than we’ve been led to believe, according to Dr Michele Squire, a scientist and the founder of prescription skincare service Qr8 Mediskin.

“These are terms coined by the cosmetic industry that don’t really tell the whole story – minerals are ‘chemicals’ too!” she says. “The truth is that mineral and chemical UV filters work in exactly the same way – they both absorb UV light and transform it into harmless heat energy, which dissipates from the skin. Some filters, both mineral and some chemical, also reflect a small amount of UV away from the skin.” Where each filter differs is the time required for the protection to take effect. “Chemical sunscreens need at least 15 minutes of application time to penetrate the stratum corneum (outer layer of skin or epidermis) before exposure to the UVB and UVA,” says Dr Gunatheesan. “Physical sunscreens sit on the skin surface, hence do not need to penetrate the skin for efficacy.” Is physical sunscreen a “natural” SPF option?

Perhaps the biggest point of contention when it comes to sunscreen is the assertion that physical formulas are somehow more natural or “safe” for the skin than chemical filters. But as Dr Squire explains, this claim is little more than a myth.

“The minerals used in sunscreen are first processed with chemicals to purify them and allow them to disperse in sunscreen formulations,” she says.

“Given there have been many rigorous scientific reviews, there is now very strong evidence that the list of commonly used active ingredients used in sunscreen do not pose a concern for human health,” the Cancer Council says on its website. “The Therapeutic Goods Administration (TGA) regulates sunscreens in Australia, ensuring that only approved ingredients, including chemicals, which have been assessed for quality and safety, are used in each product.”

(It’s worth pointing out that UV-blocking chemicals oxybenzone and octinoxate have been found to be harmful to coral and other marine life.) Rather than purchasing according to marketing rhetoric or unsubstantiated and non-scientific opinions on the internet, Dr Squire recommends choosing a sunscreen formula based solely on personal preference. “The best sunscreen is one that is properly regulated – look for the AUSTL number on the product to indicate it has been tested and listed with our TGA – that you will wear, and wear enough of, and at a price you can afford.” [Are some SPF formulas preferrable for certain skin types?

“People with sensitive skin, eczema, or rosacea or those prone to hyperpigmentation, such as melasma, will benefit from a physical sunscreen,” says Dr Gunatheesan. “Those with acne-prone skin might prefer a lightweight chemical sunscreen.”

If you’re still unsure, Dr Squire recommends trying different formulas – both chemical and physical – until you find the one you love to wear. “The best sunscreen is the one you will actually use. Choosing a sunscreen that works for your skin really is a process of trial and error, and there is no one-size-fits-all answer.”

How do I know which sunscreen formula is right for me?

To help you find the best sunscreen for you, Dr Squire has a few tips.

Opt for a sunscreen with the highest possible SPF
“At least SPF30+, but preferably SPF50+ in a texture that works with your skincare or makeup, at a price point that encourages liberal use. This means you will actually apply enough of it and reapply it during the day.”

Experiment with a few different formulations
“There are many cosmetically elegant and wearable high-SPF sunscreens now available, at accessible price points. Experiment with a few different formulations until you find the right one for your skin type. Sunscreens with chemical filters still tend to be more cosmetically elegant and ‘wearable’ than mineral, although these formulations are also improving.”

Look for a broad-spectrum sunscreen that provides maximum protection
“That is, a formula that protects against both UVA and UVB radiation – you’ll see the UVA symbol in a circle on the packaging.”

Make sure your sunscreen actually does what it says it does
“In Australia, this means it is registered by our Therapeutic Goods Association (TGA) on the basis of accurate testing data. These sunscreens will have an ‘AUST L’ number printed on the packaging.”

A simple tip for those with oily skin
“To reduce greasiness, rather than layering sunscreen over moisturiser, you can use sunscreen alone as your daily moisturiser, as most sunscreens are formulated in an emollient base. If your skin feels too dry doing this, try a hydrating serum underneath.”

A few expert-approved formulas to try

Chemical

Ultra Violette Supreme Screen SPF 50+ Hydrating Facial Sunscreen ($49)
“A facial sunscreen that does double duty as a moisturiser,” says Dr Squire.

La Roche-Posay Anthelios Invisible Fluid Sunscreen SPF 50+ ($31.95)
“This formula also comes in a tinted version, for makeup-free days,” says Dr Squire.

Physical

Colorescience Sunforgettable Total Protection Brush-On Shield SPF 50+ ($100)
“This powder [has] skin-tone matching technology, which makes reapplication a pleasure,” says Dr Gunatheesan.

Rationale The Tinted Serum SPF50+ ($172)
“My favourite for a daily face sunscreen,” says Dr Gunatheesan. “It’s a pure zinc sunscreen that is lightweight, perfect on all skin tones and a high SPF.”