Skin has a few key jobs: staying hydrated, staying firm, bouncing back. This week we look at how those jobs get harder or easier depending on the season — and what's actually happening at a structural level.
Did you know your skin can weigh anywhere from 3.5 to 10kg depending on body size, and covers up to 2m² of surface area? That's a lot of real estate holding us together, sealing in moisture, warding off invaders, regulating temperature, and — last but not least — forming the visible front of our identity.
But skin isn't constant. Not across our bodies, not across time. As the seasons shift, so does the rhythm of our skin. As we travel across climates, our skin has to adapt in real time. It's worth "listening" to your skin as it moves through these transitions, rather than assuming one routine fits all year.
What actually happens to skin, season to season
As winter approaches in the southern hemisphere, humidity drops and skin becomes more vulnerable to dryness and dehydration. Moisture maintenance matters from both directions — replenishing from the inside with water, and retaining from the outside with an intact, functional skin barrier.
Our seaweed gel — a botanical alternative to hyaluronic acid — is a strong plumping molecule that, alongside natural lipids like shea butter in NOURISH, helps lock in that hydration.
Going the other way — winter into summer — is where it gets genuinely interesting, because this shift has actually been measured. A 2022 study tracking skin through one winter-to-summer transition (in vivo, 14 volunteers) found some striking structural changes:
- a 25% rise in epidermal hydration,
- a 34% drop in surface roughness,
- a 23% increase in skin thickness,
- a 22% rise in firmness, and
- a 23% jump in elasticity.
Melanin and redness both rose sharply too, which tracks with more sun exposure and blood flow at the skin's surface.
Worth being honest about the study itself: 14 people, measured at the arm, in one climate. It's a real, peer-reviewed data point — not a universal law of skin. But it's a genuinely good illustration of just how physically responsive skin is to its environment, season to season.
That's not an argument for moving to the equator, though — because summer brings its own, much less forgiving stressor.
The one constant: UV
UV exposure doesn't take a season off. Even on cooler, cloudier days, lower ambient warmth doesn't mean lower UV — and that gap between "feels mild" and "is still doing damage" is exactly where sun protection tends to get skipped. Our natural zinc-based SHIELD (SPF15) is built for that ongoing, unglamorous, every-day layer of protection — the kind that matters more than any single event.
Good protection still needs a solid routine underneath it. Cleansing is foundational, but it has to work with skin function, not against it — our CLEANSE and PURIFY face mask lift impurities while preserving the skin's natural oils and barrier. Regular exfoliation, meanwhile, keeps cell turnover moving — our SeaScrub calcium carbonate (oyster shell) powder buffs gently without abrasion.
Skin doesn't just have a seasonal clock — it has a daily one too
Here's a fact that rarely makes it into skincare content: skin has its own circadian rhythm, separate from your sleep-wake cycle. Barrier repair, water loss, and permeability all shift measurably across the 24-hour cycle — skin is genuinely doing different jobs at different times of day, not just different times of year. It's a good reminder that "listening to your skin" isn't just a seasonal exercise; it's closer to a daily one.
The hidden ecosystems living on your skin
At PhycoHealth, our clinical research into seaweed extracts started with gut microbiome effects — which, as is now fairly well established, has knock-on benefits for skin health. But skin has its own microbiome too, and it isn't one system — it's many. The skin under your arms, on your forearms, on your face, and in high-sweat versus low-sweat areas each host their own distinct microbial communities.
When that balance is disrupted, it's associated with a range of skin conditions, including psoriasis. Our ongoing research is exploring whether our seaweed extracts can act as a pre-biotic skin ingredient — supporting the species that maintain skin surface integrity, while resisting infection-causing microorganisms. It's early-stage work, but it's a genuine extension of the science behind the PhycoHealth range we launched in 2019.
Where this is heading
Beyond skincare, our seaweed ingredient has shown real potential in more clinical settings — with peer-reviewed publications behind it, and work underway with surgeons on wound-healing and reconstructive applications. That's a longer story for another week — but it's the same underlying science showing up in a very different context.