Hydration Boosting Actives Beyond HA: Polyglutamic Acid, Betaine & Tremella Extract

Overview #

Most brands come to us asking for “the best hydration serum” and lead with hyaluronic acid. That’s fine — HA is a workhorse and we use it constantly. But the honest answer is that HA alone rarely delivers the kind of moisture retention results that justify premium positioning anymore. The market has moved. Polyglutamic acid, betaine, and Tremella fuciformis extract are no longer niche — they’re the actives we’re reaching for when a brand needs a real differentiation story, not just a label claim.

Why HA Is No Longer the Whole Answer #

Hyaluronic acid still earns its place in almost every hydration formula we build. At 0.1–2.0% depending on molecular weight blend, it delivers reliable short-term surface hydration and has decades of safety data behind it. We’re not arguing against it.

The problem is positioning. When every serum on Sephora’s shelf says “HA + Niacinamide,” the ingredient story stops being a differentiator. Brand partners come to us wanting something they can actually talk about — and increasingly, something that performs better in the long-term moisture retention data we run internally.

That’s where the alternatives earn their keep. Polyglutamic acid (PGA) has a water-retention capacity roughly 4–5× that of high-molecular-weight HA by some supplier benchmarks — though we’re still not fully convinced all those numbers hold up under real-world formulation conditions. Betaine is a different mechanism entirely: an osmolyte that works intracellularly, not just at the surface. Tremella extract is the one that surprises most brand partners when they first see the particle size data.

Drop below 0.5% on any of these and you’re essentially paying for label presence, not performance. That’s a conversation we have on almost every brief.

Ingredient Profiles: Concentration, Stability, and What We Actually See in the Lab #

Polyglutamic Acid (PGA)

PGA is a fermentation-derived biopolymer — typically from Bacillus subtilis — and it behaves very differently from HA in formulation. It’s a film-former as much as a humectant. At 0.5–3.0%, it creates a visible occlusive-adjacent layer that slows transepidermal water loss without the greasy feel you’d get from petrolatum or silicone.

Stability is where it gets interesting. PGA is reasonably stable at pH 4.5–6.5, but we’ve seen viscosity drift in formulas that push below pH 4.0 — particularly when combined with AHA systems. One batch we ran at pH 3.8 with 5% glycolic acid showed a 30% viscosity drop by week 6 at 40°C. The formula looked fine at lab scale. At 150kg production, the drift was worse and faster. We now keep PGA out of low-pH exfoliant formulas unless the brand specifically wants to accept that trade-off.

Encapsulation is an option for pH-sensitive systems, but it roughly doubles the raw material cost. Most indie brands at MOQ 3,000 units can’t absorb that without repricing the product.

Betaine

Betaine is underrated. It’s cheap, it’s stable across a wide pH range (3.0–9.0 without issue), and it functions as both a humectant and a skin-conditioning agent. We use it at 1.0–5.0% in most hydration-focused formulas — often as a supporting humectant rather than the hero, but it earns its place.

The osmolyte mechanism is genuinely different from film-forming humectants. Betaine helps cells maintain hydration under osmotic stress, which is why it shows up in barrier repair formulas as well as pure hydration products. For sensitive skin positioning, it’s one of our first reaches.

Cost-wise, betaine is one of the most cost-effective actives in this category. At 3% inclusion, the raw material cost contribution is typically under $0.15 per unit at standard production volumes. That matters when you’re building a formula with three or four actives and watching COGS.

Tremella Fuciformis (Snow Fungus) Extract

This is the one that gets the most questions at trade shows. Tremella polysaccharides have a particle size in the range of 100–400nm depending on extraction method — significantly smaller than high-MW HA — which theoretically allows better skin penetration. We say “theoretically” because the in-vivo penetration data is still limited and supplier claims vary widely.

What we do see consistently in our own stability and sensory testing: Tremella extract at 0.5–2.0% gives a noticeably different skin feel than HA at equivalent concentrations. Lighter, less tacky, with what our sensory panel describes as a “water-burst” effect. For gel-serum formats targeting Asian markets, this is a strong positioning story.

Stability is generally good at pH 4.5–7.0. The main formulation challenge is microbial — Tremella extract is a rich carbon source and we’ve had contamination issues with suppliers who don’t control water activity tightly enough in their raw material. We now require a certificate of analysis with total plate count ≤100 CFU/g before we accept any Tremella shipment. One pilot batch failed because a supplier switched extraction batches mid-project without notifying us. That cost three weeks and a full reformulation cycle.

Comparing the Options: What to Reach For and When #

The cost column is where most brand partners get surprised. PGA sounds like a premium upgrade until you price it at 2% inclusion across a 10,000-unit run. At that point, the COGS delta versus HA is real and it needs to be reflected in retail pricing or absorbed in margin. We almost always push back on briefs that want PGA as the hero active without that conversation happening first.

For a deeper look at how we approach encapsulation for moisture-sensitive actives, see our encapsulation technology formulation guide.

The Clinical Picture — What the Data Actually Shows #

The head-to-head hydration data for PGA versus HA is more interesting than most supplier decks let on. One double-blind, randomized controlled trial (n=44, 8 weeks, twice-daily application) compared a 2% PGA serum against a 2% HMW-HA serum using corneometer measurements. At week 4, both groups showed comparable surface hydration increases (~18–22% above baseline). By week 8, the PGA group maintained a 27% improvement versus 19% in the HA group. The difference in TEWL reduction was more pronounced: PGA showed a 14% reduction versus 8% for HA.

What that study doesn’t capture — and what we’ve learned from our own batches — is the formulation context dependency. Those results were in a simple aqueous serum at pH 5.5. Put PGA into a more complex emulsion with emulsifiers, fragrance, and a preservative system, and the film-forming behavior changes. We’ve seen the TEWL benefit drop significantly in oil-in-water emulsions with high emulsifier loads. The mechanism is sensitive to the surrounding matrix in a way that HA simply isn’t.

For brands targeting EU markets, ingredient safety substantiation for novel actives like Tremella extract falls under EU Cosmetics Regulation 1223/2009, which requires a full cosmetic product safety report (CPSR) including ingredient-level safety data. For US market, the FDA Cosmetics Guidelines framework applies — less prescriptive, but brands selling into both markets need to plan documentation from day one. For China registration, NMPA Cosmetic Regulation has specific requirements for novel botanical and fermentation-derived ingredients that can add 6–12 months to registration timelines if not anticipated early.

Where Most Brands Get This Wrong #

The brief usually says: “We want a hydration serum with PGA, Tremella, and HA — all three.” That’s not inherently wrong. We’ve built that formula. But the failure mode is treating all three as equivalent hero actives at full concentration, then watching the formula cost spiral and the stability profile get complicated.

In most projects we’ve run, the better approach is a tiered system: HA as the base humectant at 0.5–1.0%, betaine as the supporting osmolyte at 2–3%, and then one premium active — either PGA or Tremella — at a meaningful concentration with a clear on-pack story. Trying to hero all three simultaneously usually means none of them are at a concentration that moves the needle on performance data.

The other thing brands consistently underestimate is preservative system interaction. Betaine at high concentrations (above 4%) can affect the activity of some preservative systems — particularly phenoxyethanol-based systems — by altering water activity in the formula. We’ve seen challenge test failures at 5% betaine inclusion that passed at 3%. This is usually where projects go sideways, because it happens late in development when the formula is otherwise finalized.

Honestly, the brands that come to us with a clear primary claim — “this is a TEWL-reduction serum” or “this is an osmotic stress protection formula” — end up with better products than the ones chasing a maximum ingredient list. The ingredient list is a marketing tool. The formula is an engineering problem. Those two things need to be aligned from brief intake, not reconciled at the end.

For brands developing barrier-focused hydration products, our barrier repair and sensitive skin formulation notes cover the preservative and pH system interactions in more detail.

Stability testing protocols for these actives should follow ICH Stability Guidelines as a baseline — particularly for brands targeting regulated markets where shelf-life claims need substantiation.

Formulation Notes for Brand Partners #

What market? What are you expecting on-pack? Those are the first two questions we ask on every hydration brief, because the answers change almost everything about how we build the formula.

A “2% PGA + Tremella Hydra-Serum” for a Korean beauty brand launching on Tmall has completely different formulation priorities than the same concept for a clean beauty brand launching on US Amazon. The first needs a specific skin feel — lightweight, fast-absorbing, no residue — and the NMPA registration timeline needs to be built into the project plan from week one. The second needs a preservative system that reads clean on the label and a stability package that satisfies a US retailer’s vendor requirements.

On concentration: we won’t formulate PGA below 0.5% if it’s going on the label as a hero active. Same for Tremella. If the budget doesn’t support meaningful inclusion levels, we’ll have that conversation directly and suggest repositioning the formula around betaine and sodium PCA, which deliver real performance at a fraction of the cost.

Packaging matters more than most brands expect with these actives. PGA in particular is sensitive to repeated air exposure — we recommend airless pump or nitrogen-flushed tube formats for any formula where PGA is above 1.5%. Airless pump adds roughly $0.50–$0.90 per unit at MOQ 5,000. That needs to be in the budget conversation before formulation starts, not after.

Timeline expectation: from brief sign-off to stability-confirmed formula, budget 14–18 weeks for a novel active combination. Not 8 weeks. We’ve seen too many launch timelines built around 8-week assumptions that don’t account for challenge testing iteration.

Frequently Asked Questions #

Q: Can we put “2% Polyglutamic Acid” on the front of pack — is that concentration actually stable?

At 2% in a well-buffered aqueous serum at pH 5.0–5.5, yes, PGA is stable and that’s a defensible on-pack claim. The caveat is packaging: in a standard open-pump bottle, we see oxidative drift by month 4 at ambient conditions. Airless format extends that to 18+ months in our accelerated stability data. So the claim is stable — the packaging decision determines whether the product actually delivers it at end of shelf life.

Q: We’ve seen Tremella marketed as “better than HA” — is that actually true?

Depends entirely on what you mean by “better.” For surface hydration at 24 hours post-application, the data is roughly comparable at equivalent concentrations. Where Tremella has a genuine edge is skin feel — lighter, less tacky — and potentially longer-term moisture retention in some skin types. We’re still not convinced the penetration depth claims hold up across all skin types. “Different from HA” is more accurate than “better than HA,” and it’s a more honest story to tell consumers.

Q: What’s the minimum order quantity to run a PGA-based serum with you?

Our standard MOQ for a custom formula with PGA as a hero active is 3,000 units. Below that, the raw material cost per unit makes the retail price uncompetitive unless you’re in a very premium positioning. At 3,000 units, expect a COGS roughly 35–50% higher than a comparable HA-only formula, depending on PGA inclusion level and packaging format.

Q: How do we handle the China NMPA registration for Tremella extract — is it a standard ingredient?

Tremella fuciformis extract is listed in the INCI dictionary and has been used in Chinese cosmetics for years, so it’s not a novel ingredient requiring special NMPA pre-approval in most formats. The complexity comes when you’re making specific efficacy claims — “repairs barrier” or “reduces TEWL by X%” — which can trigger a functional claim substantiation requirement under current NMPA rules. Budget an additional 3–4 months if you’re planning claim-substantiated registration.

Q: Can betaine replace HA entirely in a formula to reduce cost?

Mechanistically, no — they work differently and betaine doesn’t replicate the surface film-forming effect of HA. But in a formula where HA is at 0.1% (essentially label presence), replacing it with 3% betaine will almost certainly give you better real-world hydration performance at lower cost. We’ve done this substitution on several projects where the brand needed to hit a price point. The sensory profile is different — less “plump” feel immediately post-application — but the 8-hour moisture retention data is comparable or better in our internal testing.

Have a product concept in mind? Contact our formulation team to request a complimentary brief review.