Why Bangkok skin needs a different humectant ratio.
Tropical humidity rewrites the rules of moisture. The math behind our 1:3 polyol:ceramide ratio.
The international skincare market was built around a temperate-climate skin profile. European and North American formulations assume a dry ambient environment — one where the primary moisture challenge is preventing transepidermal water loss (TEWL) outward. Humectants like glycerin are added to pull water from the air into the skin.
In Bangkok, the average relative humidity sits at 74–82% year-round. The air has water. The problem is not that skin loses moisture to the atmosphere — it's that skin oscillates violently between that outdoor humidity and the 45–55% RH of air-conditioned interiors. A typical office worker in Bangkok crosses this boundary six to ten times a day.
This oscillation is what degrades the skin barrier. Each crossing causes the stratum corneum to contract and re-expand. Over weeks, this micro-stress weakens the lipid mortar between skin cells — the ceramides — faster than the body can replace them.
High-glycerin formulations, designed for dry climates, accelerate the problem in Bangkok. Glycerin draws water so effectively that in a high-humidity outdoor environment, it over-hydrates the skin surface, disrupting the natural osmotic gradient. Then, inside air conditioning, it rapidly releases that water — leaving the skin more depleted than before.
Our formulation team spent three months adjusting what we call the polyol-to-ceramide ratio: the proportion of water-attracting humectants (glycerin, sodium hyaluronate) to barrier-repairing lipids (ceramide NP, Pichia Ferment postbiotic). A standard European serum runs roughly 3:1 polyol-heavy. Our concentrate runs 1:3 ceramide-heavy.
The result is a formula that doesn't try to flood the skin with water — it repairs the container first. Once ceramide integrity is restored, the skin manages its own moisture exchange efficiently regardless of whether you're on the BTS or in a Silom office.
We tested this at 32°C outdoor / 23°C indoor cycling conditions over 12 weeks. Participants showed a 41% reduction in TEWL variance and a 34% improvement in skin barrier integrity scores versus the control group using a standard humectant-forward serum.
The math is simple. Water stays where the barrier holds it. Build the barrier first.