By Barbara Marengo, Founder, PHILOGENI · Medically-referenced · Updated July 2026
You bought the serum everyone recommended. You layered it under your moisturizer like you were told to. And somehow, your skin tightened over the next few hours instead of softening. If that's happened to you — especially on a plane, in winter, or in an air-conditioned office — you didn't imagine it, and you didn't use too little.
Quick answer: Hyaluronic acid is a humectant — it pulls water toward itself. In a humid environment, it pulls that water from the air into your skin. In a low-humidity environment (winter homes, airplane cabins, air-conditioned offices), there's no water in the air to pull from, so it pulls from the deeper layers of your own skin instead — leaving your skin drier than before you applied it. The fix isn't more HA. It's the right molecular weight, layered under a lipid seal.
What hyaluronic acid actually does — and doesn't
Hyaluronic acid is a polysaccharide that occurs naturally in skin, produced by dermal fibroblasts under estrogen's influence. Its defining property is water-binding: a single molecule can hold up to a thousand times its own weight in water. [1] As estrogen declines through perimenopause, fibroblast production of hyaluronic acid drops, and the deeper layers of skin hold less water — which is exactly why topical HA looked, on paper, like such an obvious fix.
In practice, whether it works depends almost entirely on three variables most labels don't disclose: molecular weight, ambient humidity, and what it's formulated alongside.
The molecular weight problem
Hyaluronic acid in skincare comes in a few rough size bands, and they behave very differently:
| Molecular weight | Where it works | What it actually does |
|---|---|---|
| High (>1,000,000 Daltons) — most common on the high street | Surface only | Pulls water from the air to the surface; doesn't reach the deeper layers where your own HA is depleting |
| Medium (100,000-500,000 Daltons) | Upper stratum corneum | Penetrates slightly further, rarely reaches the dermis |
| Low / fragmented (<50,000 Daltons) | Deepest penetration | Reaches furthest, but poorly-formulated versions can be pro-inflammatory if oversized fragments accumulate |
Most products that list "hyaluronic acid" don't disclose which of these you're getting — which means you're shopping blind. A well-formulated product layers two or three molecular weights together (sometimes labeled "multi-weight" hyaluronic acid) to address different depths at once. These are a minority of what's actually on shelves.
The low-humidity paradox
This is the part that explains the "my skin got drier" experience directly. Hyaluronic acid is a humectant — it pulls water toward itself, full stop. In a humid environment, it pulls that water from the surrounding air into your skin, which is the intended effect. In a low-humidity environment — most North American homes in autumn and winter, airplane cabins, air-conditioned offices, ski weeks — there simply isn't enough water in the air for it to draw on.
The molecule still does its chemistry. With no external water available, it pulls from the deeper layers of your own skin toward the surface instead, and the deeper layers dehydrate faster than they would have without it. [2] Many women have applied an HA serum on a long flight, watched their skin tighten within a couple of hours, and assumed they simply hadn't used enough — when the real issue was using it in the wrong environment, without anything above it to seal the moisture in.
The fix isn't less HA or more HA — it's a lipid layer above it. Hyaluronic acid applied under a lipid-rich moisturizer or facial oil that seals the surface is a meaningfully different, and much more reliable, proposition than HA applied alone.
Tremella: what the mushroom kingdom has quietly offered for centuries
Worth knowing about, whichever brand you choose: Tremella fuciformis, the "snow mushroom," has been used in traditional Chinese skincare for over a thousand years, historically described as a substance for retaining moisture in the skin. Modern chemistry has since characterized why.
Tremella polysaccharides are structurally similar to hyaluronic acid — long sugar chains with substantial water-binding capacity — but their average molecular size tends to be smaller than high-molecular-weight HA, meaning better penetration into the stratum corneum. [3] Their water-binding capacity is broadly comparable to hyaluronic acid in lab measurements. What they carry that hyaluronic acid doesn't is additional bioactive signaling in the same family as the medicinal mushrooms — hydration plus a soothing, antioxidant-supportive character, rather than hydration alone.
What to look for on a label
- Is the molecular weight disclosed? If not, assume the common high-molecular-weight form — useful for surface hydration, not for the deeper layers where your own HA is declining.
- Is there a lipid nearby? Squalane, ceramides, or a botanical oil sitting close to the HA on the ingredient list functions as the seal that makes the HA actually work, rather than backfire.
- If you see Tremella fuciformis (sometimes listed as sporocarp extract), you're looking at a botanical alternative most of the industry hasn't caught up to yet.
How PHILOGENI approaches this
The M-Veil Bio-Lipid Concentrate and Resilience Balm aren't hyaluronic acid serums — they're built as the lipid layer this article is actually about: a squalane- and hemisqualane-led formula designed to help replenish and condition dry, depleted-looking skin and seal in whatever hydration step you use underneath. If your routine includes a hyaluronic acid serum, applying it before either M-Veil product — rather than instead of a lipid layer — is exactly the pairing the science above supports.
Frequently asked questions
Why did my skin get drier after using hyaluronic acid serum?
Most likely a low-humidity environment: hyaluronic acid pulls water toward itself, and without moisture in the air to draw on, it pulls from your skin's deeper layers instead. Applying it under a lipid-rich product, rather than alone, generally resolves this.
What molecular weight of hyaluronic acid is best?
It depends what you're targeting — high molecular weight for surface plumping, low molecular weight for deeper penetration. Most brands don't disclose this, but a formula combining multiple weights covers more ground than a single-weight product.
Should I use hyaluronic acid on a flight?
Only if you're layering it under an oil or lipid-rich cream that can seal the moisture in — cabin air is extremely low-humidity, and HA alone in that environment tends to backfire.
Is Tremella fuciformis better than hyaluronic acid?
They're broadly comparable on hydration alone, with lab studies suggesting rough parity or a slight edge either way depending on the measure. Tremella's advantage is the additional soothing, antioxidant-family activity it carries beyond hydration.
Do I need a separate hydrating serum if I use a facial oil?
Not always — it depends on your skin's needs. Many women in the hormonal transition find a lipid-forward product does more of the structural work, with a humectant layered in only during particularly dry stretches or seasons.
The takeaway
Hyaluronic acid isn't a bad ingredient — it's an incomplete one on its own, especially in a low-humidity environment or without the right molecular weight for what you're targeting. If it's ever made your skin feel drier rather than softer, that's not a sign you need more of it. It's a sign you're missing the lipid layer that makes it work in the first place.
This article is intended for educational purposes and is not medical advice.
Sources
1. Papakonstantinou E, Roth M, Karakiulakis G. Hyaluronic acid: A key molecule in skin aging. Dermato-Endocrinology. 2012;4(3):253-258.
2. Verdier-Sévrain S, Bonté F, Gilchrest B. Biology of estrogens in skin: implications for skin aging. Experimental Dermatology. 2006;15(2):83-94. PubMed
3. Ma X, Yang M, He Y, Zhai C, Li C. A review on the production, structure, bioactivities and applications of Tremella polysaccharides. International Journal of Biological Macromolecules. 2021;188:431-447.
About the author: Barbara "Barbi" Marengo is the founder of PHILOGENI and author of The Resilience Guide. Read more from Barbi →