Application · Hydration & barrier repair
Moisturisers, serums and body care that hydrate, lock in moisture and support a healthy skin barrier. Developed by CSL formulation scientists.
Guires Cosmetic Science Lab
At Guires Cosmetic Science Lab, CSL formulation chemists develop moisturiser formulations and barrier-repair products with glycerin, hyaluronic acid and ceramides, with claims such as 24-hour hydration proven by Corneometer and TEWL studies. With more than 10 years of experience, the team develops formulas that measurably improve skin hydration and barrier function using an evidence-based approach. TEWL measures the water lost through the stratum corneum, the outer layer of the skin barrier, so a fall in TEWL shows the barrier recovering.
Start your project with Guires CSLWhat shoppers look for now
Hydration is still the most requested skin care benefit, and people expect it to last through the day.
Shoppers now talk about their skin barrier and look for ceramides and barrier-repair claims.
A single moisturiser that hydrates, repairs and soothes is replacing multi-step routines.
The science
Hydration depends on water-binding humectants inside the skin and a lipid barrier that stops it escaping. We formulate for both.
Humectants
Glycerin and hyaluronic acid bind water in the outer skin layer. Randomised trials show glycerin raises hydration within a week, and that lower-weight hyaluronic acid also improves elasticity.
Barrier lipids
Ceramides, cholesterol and fatty acids rebuild the lipid layers between skin cells. Controlled trials show ceramide creams lower water loss and keep working after use stops.
Key actives
Chosen for each market’s ingredient rules and your target cost. Tap an ingredient marked → to read the published evidence.
Claims & evidence
The claims brands ask for most, the study that supports each one, and how strong that evidence is.
| Claim brands ask for | Typical evidence | Evidence tier |
|---|---|---|
| “Hydrates for 24 hours” | Corneometer at 1, 8 and 24 hours | Tier 3 |
| “Strengthens the skin barrier” | TEWL over 2–4 weeks | Tier 3 |
| “Soothes dry skin” | Expert grading and self-assessment | Tier 2 |
Clinical evidence
Peer-reviewed human studies behind the actives and approaches on this page. Each links to its record.
Double-blind, placebo-controlled, randomised · 24 adults with atopic dermatitis · 4 weeks
Skin hydration rose vs vehicle from week 1 (p<0.0001) and barrier function (TEWL) improved by week 4.
Breternitz M et al. Skin Pharmacol Physiol 2008;21(1):39–45 · PMID 18025807
Randomised, controlled, intra-individual · 76 women · 60 days
All molecular weights improved hydration and elasticity vs vehicle; the low weights (50 and 130 kDa) also reduced wrinkle depth.
Pavicic T et al. J Drugs Dermatol 2011;10(9):990–1000 · PMID 22052267
Randomised, double-blind · 197 adults with atopic dermatitis · 30 days
Both relieved dryness equally; the glycerin cream caused less stinging (10% vs 24% moderate–severe).
Lodén M et al. Acta Derm Venereol 2002;82(1):45–47 · PMID 12013198
Double-blind, randomised · 24 adults with dry skin · 28 days + 7-day follow-up
Better hydration, lower TEWL and improved skin pH at every time point, maintained 7 days after stopping.
Lueangarun S et al. Dermatol Ther 2019;32(6):e13090 · PMID 31585489
Double-blind, vehicle-controlled studies · 169 adults · 2 weeks
Hydration rose and TEWL fell significantly vs vehicle and untreated skin; the richer lotion still moisturised 6 days after stopping.
Weber TM et al. J Clin Aesthet Dermatol 2012;5(8):29–39 · PMID 22916312
Randomised, double-blind, intra-individual, multicentre · 65 adults · 28 days
Efficacy and tolerability equivalent to the active comparator on eczema score, global assessment and itch.
Marini A et al. Skin Pharmacol Physiol 2014;27(2):57–65 · PMID 23949258
These are published studies on ingredients, methods and routines, not on products we have made. A finished product needs its own testing before a claim goes on pack, and we design that study with you. See the full evidence library
Hydration and barrier claims are cosmetic in all major markets. Treatment claims for eczema or dermatitis are not.
Concept spotlight
Example concepts to show the range. Every project starts from your own brief, and the finished formula belongs to you.
A ceramide and glycerin cream with kinetic hydration data to 72 hours.
A lightweight serum layering three hyaluronic acid weights.
A fast-absorbing lotion for rough, very dry skin, tested for stinging.
Sectors
Stay ahead in hydration & barrier repair with regulation updates, the latest research, ingredient spotlights, recalls and market trends, written by the Guires CSL formulation, testing, clinical and regulatory teams.
Explore market insights
FAQ
Hydrating ingredients add water to skin; moisturising also includes lipids that seal it in. Most products need both.
With TEWL measurements, often after a controlled barrier challenge, on panels over two to four weeks.
Yes, with the same Corneometer methods, usually on the lower leg or forearm.
You do. We sign an NDA before you share your brief, and the formula and technical file are handed over at the end of the project.
Every hydration & barrier repair project at Guires CSL runs inside an ISO 9001 certified quality system, with documented methods, calibrated instruments, traceable raw materials and reviewed reports, so the results behind your product can be checked and defended.
Guires CSL quality & accreditations
In their words
“A balanced humectant system in a light emulsion delivers lasting hydration with no heavy after-feel.”
“Corneometer-based testing, run to a clear and well-documented protocol, gave us instrumental evidence for our long-lasting hydration claim.”
“Their barrier-mimetic lipid system was confirmed through TEWL measurements, giving us measured proof of barrier support.”
“Occlusives, humectants and emollients were balanced to meet our hydration, barrier and sensory targets at the same time.”
Insights
Guidance from our formulation, testing and regulatory teams on the topics this page covers.
The ingredient themes shaping US skin-care briefs, and what each one means for formulation and claims.
Read articleLactic acid exfoliates like glycolic acid but penetrates more slowly and helps the skin make its own barrier lipids. Here is the evidence, and why it suits dry and…
Read articleCeramides are the main lipids of the skin barrier. Here is what trials show for dry and eczema-prone skin, how strong the evidence is, and how CSL formulation scientists…
Read articleFrom the CSL bioscience lab
Start a project
Our formulation chemists, testing scientists and regulatory specialists work alongside your team, from the first brief to a market-ready product. Bring a brief, a benchmark or just an idea: a scientist will reply within one working day with next steps and an indicative scope.
