Why sunscreen is the most important step in any skincare routine.

There is a hierarchy in skincare, and sunscreen sits at the top of it. The evidence is not close. UV radiation — primarily UVA and UVB — is responsible for an estimated 80–90% of visible skin ageing: the fine lines, the texture changes, the uneven pigmentation, the loss of elasticity that most skincare products claim to address. Preventing that damage from occurring is categorically more effective than treating it after the fact.

More visible skin ageing is prevented by consistent daily SPF than by any other single skincare product or practice. This is not a marketing position. It is the most replicated finding in photodermatology.

Why UV radiation ages skin

UVA — long-wave ultraviolet, constituting roughly 95% of the UV that reaches the earth's surface — penetrates deeply into the dermis. It generates reactive oxygen species (free radicals) that break down collagen and elastin, disrupts cellular DNA, and causes cumulative oxidative damage that leads to premature ageing. UVA intensity is broadly consistent year-round, across seasons, and — critically — through window glass. The tan a person develops from sitting near a window is UVA-induced. The ageing that accompanies it is also UVA-induced.

UVB — short-wave ultraviolet, blocked partially by glass and more variable with season and latitude — causes sunburn and is the primary driver of skin cancer. It also stimulates melanin production, causing pigmentation changes. SPF ratings measure UVB protection specifically.

Both contribute to visible ageing. A sunscreen that only addresses one — an old-formula SPF without broad-spectrum UVA protection — is meaningfully incomplete.

What SPF numbers mean

SPF (Sun Protection Factor) measures how much UVB radiation a sunscreen filters out relative to unprotected skin. SPF 30 blocks approximately 97% of UVB. SPF 50 blocks approximately 98%. SPF 100 approaches 99%.

The difference between SPF 30 and SPF 50 is real but marginal — less than two percentage points of additional UVB blocked. The more significant variable is consistent application rather than a higher SPF number. Sunscreen applied inconsistently, in too-thin a layer, or not reapplied after several hours of direct sun provides less protection than a reliable SPF 30 worn every day without fail.

For UVA protection, look for "broad-spectrum" labelling (mandatory in Australia and the US on any product making a sun protection claim) or the PA+++ rating system used on many Asian formulations. The PA system measures persistent pigment darkening — a proxy for UVA protection. PA+++ and PA++++ indicate meaningful broad-spectrum coverage.

Chemical vs mineral sunscreens

Chemical filters — avobenzone, tinosorb S, tinosorb M, octinoxate, oxybenzone — absorb UV energy and convert it to heat, which dissipates. Modern formulations using photostabilised avobenzone or tinosorb are cosmetically elegant: they go on clear, layer well under makeup, and do not leave a white cast.

Mineral filters — zinc oxide and titanium dioxide — physically scatter and reflect UV radiation. They are photostable by nature, very well-tolerated (zero to minimal sensitisation), and are the recommended choice for reactive or sensitised skin. The trade-off is a white cast, though modern micronised and encapsulated mineral filters have reduced this substantially.

Both systems provide effective protection when well-formulated and properly applied. The best sunscreen is the one a person will actually use daily.

How to use it

Last step in the morning routine. After cleanser, any serums, and moisturiser. SPF is not layered under other products — it is the final step before UV exposure.

Adequate quantity. Most people apply less than half the amount required to achieve the stated SPF. The recommendation for face and neck is approximately half a teaspoon — more than most people use. Applying a too-thin layer reduces the effective SPF significantly.

Reapplication in direct sun. Filters degrade with UV exposure and sweat. Reapplication every two hours in direct sunlight is the standard recommendation. In an office environment, a single morning application is typically sufficient.

The Lux & Glo position

The ritual — cleanser, serum, moisturiser — is a treatment and barrier-support routine. Sunscreen is not part of it. It is a separate, non-negotiable product worn every morning regardless of what treatment routine a person follows.

The single most effective thing a person can do for the long-term appearance of their skin is to wear broad-spectrum SPF 30 or higher every day, starting as early as possible. Everything else is secondary.