Research · Skin hydration and structure

The plump effect: water, structure, and what studies show.

“Plump” is used for two different things: skin that holds more water in its outer layer, and skin whose structure holds up beneath. This guide reads the clinical studies behind each, from hyaluronic acid weights and humectants to ceramides, retinoids, vitamin C and injectables, and says plainly where the evidence ends. Every claim cites its source.

Smooth skin on a shoulder curve beaded with small water droplets, in soft light

4 weeks
A low-molecular-weight hyaluronic acid lotion reached skin capacitance of 56.37 AU, against 49.01 AU for vehicle, in 36 older adults with dry skin.⁶
30 to 40%
Improvement in photodamage at day 180 in both the tretinoin and the vehicle group of a chest-rejuvenation trial.¹⁴
70%
Higher prostaglandin E2 in the skin of people over 80 than in people aged 21 to 30. It lowers collagen production in cell studies.⁹
90.6% vs 3.7%
Rated as improved on the Global Aesthetic Improvement Scale after intradermal hyaluronic acid gel, against a no-treatment control, in 420 people.¹⁵

The short answer

Two kinds of plump. Water held in the stratum corneum depends on moisturizing compounds and lipids,¹ while collagen production in the dermis declines with age.⁹ Creams are tested on the first far more often than the second.
Hydration is well supported. Hyaluronic acid products improved hydration against placebo or vehicle in two trials, and lower molecular weights did better on some measures.⁵⁶
Structure has fewer topical answers. The collagen evidence sits mostly with topical retinoids,¹¹¹² yet in one trial the vehicle group improved about as much as the active group over six months.¹⁴
The strongest numbers come from procedures. Intradermal hyaluronic acid gel beat a no-treatment control for six months, though the control was not a sham and the authors include the manufacturer’s staff.¹⁵

01 · Two kinds of plump

The surface and what lies beneath.

When a product promises plump skin, it may mean either of two things, and the studies measure them with different tools. We keep them apart throughout this page.

The first is about water. The stratum corneum, the outermost layer of the epidermis, retains water through natural hygroscopic compounds inside its cells and through intercellular lipids arranged to limit water loss.¹ The second is about the dermis. Production of type I collagen declines during aging, which leads to skin thinning and impaired function.⁹

Two clear glass dishes on cream linen, one holding clear serum and the other thick white cream

Water in the outer layer
Measured with skin capacitance and transepidermal water loss (TEWL). Studies of humectants, hyaluronic acid, ceramides and niacinamide report these.⁶⁷⁸
Structure in the dermis
Measured with histology, elasticity and blinded clinical scoring. Studies of retinoids and vitamin C report these, and they run longer.¹²¹³

02 · Holding water

How skin keeps water, and what humectants add.

A rounded dome of clear gel on a pale ivory stone tile

Natural humectants

A 2007 review reports that glycerol exists in the stratum corneum as a natural endogenous humectant, and that hyaluronan, long thought of as a dermal component, is also found in the epidermis.¹

Water channels

Aquaporin-3 in the epidermis is permeable to water and to glycerol. Mice deficient in it show reduced stratum corneum hydration.⁴ That finding is from mice, not from a cream trial.

Humectant plus occlusive

Basic emollients are typically formulated with humectants such as glycerol, urea and lactic acid, and with occludents such as petrolatum or liquid paraffin to restore the epidermal barrier.²

What the clinical review adds. A 2025 review of clinical studies found that most basic emollient formulations are safe and effective at improving dry skin in senile xerosis, psoriasis, ichthyosis and diabetes, and concluded that regular, ongoing use should be the mainstay of basic therapy.³ The conditions reviewed are dry-skin conditions, so this supports hydration, not a change in structure.

03 · Hyaluronic acid weights

Does molecular weight change the result?

Two randomized trials compared hyaluronic acid (HA) of different molecular weights. Both found a benefit for lower weights on at least one measure. Both explain it by better penetration, which neither measured directly.

2011: five weights, around the eye

76 women aged 30 to 60 with periocular wrinkles used 0.1% HA creams of 50, 130, 300, 800 or 2,000 kDa for 60 days, with a vehicle cream around the other eye.⁵
Every HA cream significantly improved hydration and elasticity compared with placebo.⁵
Wrinkle depth improved significantly only in the 130 and 50 kDa groups. The authors say this may be due to better penetration of low-molecular-weight HA.⁵

2024: older adults, dry legs

36 nursing-home residents aged 60 to 80 with dry skin received low-molecular-weight HA, high-molecular-weight HA and vehicle lotions on three sites on the leg.⁶
After four weeks, skin capacitance was 56.37 AU for low-molecular-weight HA, 52.37 AU for high-molecular-weight HA and 49.01 AU for vehicle.⁶
TEWL and symptom scores did not differ between groups, and no side effects were found.⁶

How to read this. The 2024 authors note that the idea that low-molecular-weight HA works better in aging skin had lacked clinical support, and their result is evidence for hydration over four weeks.⁶ Neither trial shows HA reaching or changing the dermis.

For how hyaluronic acid is used in a Vanu Health formula, see our hyaluronic acid ingredient page.

04 · Barrier and lipids

Moisture is not the same as a stronger barrier.

Ceramides and glycerine

58 adults with a history of eczema applied a lipid-and-glycerine emulsion to one forearm and lower leg and a glycerine emulsion to the other, twice a day for 28 days.⁷
With the lipid emulsion, TEWL after 20 tape strips fell from 38.02 to 29.79 g m⁻² h⁻¹. The glycerine-only emulsion had no effect on it, although it reduced dryness.⁷
Two ceramide species in the lipid emulsion rose in the stratum corneum, by 24% and 19%.⁷

Niacinamide, with and without ultrasound

67 women aged 30 to 60 with signs of aged skin were randomized to four groups, two of which also had weekly 5 MHz ultrasound for eight sessions.⁸
The niacinamide formulation improved stratum corneum water content and reduced TEWL and sebum.⁸
Consumers reported better firmness, elasticity and fewer wrinkles, especially in the ultrasound groups. Ultrasound alone showed no instrumental improvement.⁸

What this supports. A humectant can ease dryness without changing barrier function, and a barrier improvement needs the right lipids.⁷ The eczema-prone participants and the consumer ratings in these trials limit how far the findings reach.

05 · Structure

Collagen, elastic fibres, and the long game.

What changes with age

In sun-protected skin, the enzymes behind prostaglandin E2 were higher in people over 80 than in those aged 21 to 30 (3.4-fold and 2.7-fold for mRNA), and prostaglandin E2 itself was up 70%.⁹
Fibroblasts in aged skin spread less because collagen fibrils are fragmented, which in the lab raised prostaglandin E2 and lowered collagen production.⁹
In cultured fibroblasts, collagen fragments suppressed hyaluronan synthesis through lower HAS2 expression, a possible link between collagen damage and falling hyaluronan after UVB.¹⁰

Retinoids

A 2016 review states that retinoids have demonstrated efficacy in treating photoaged skin.¹¹
A 2001 review reports that topical tretinoin has been shown to prevent and repair clinical features of photoaging, by preventing collagen loss from, and stimulating new collagen formation in, the papillary dermis of sun-exposed skin.¹²
Irritation limits use. A 2022 trial notes it usually resolves after about a month.¹⁴

The vehicle lesson

In a double-blind chest trial, 29 people completed six months with either tretinoin 0.05% lotion or its vehicle, a mix of sodium hyaluronate, soluble collagen and glycerin. Both groups showed 30 to 40% improvement at day 180 on the blinded evaluator’s score, and satisfaction was equal.¹⁴ The authors credit the hydrating vehicle for part of the result. A moisturizing base can look like an active.

Vitamin C

In 20 women with photoaged skin, six months of a cream with 5% vitamin C and 0.1% madecassoside improved deep and superficial wrinkle scores, suppleness, firmness, roughness and hydration, and an elastic fibre network with normal structure reappeared in the papillary dermis.¹³ It is a small study of a two-ingredient formula.

06 · Beyond the jar

When hyaluronic acid goes under the skin.

A 2026 multicenter trial in China randomized 420 people two to one to three full-face intradermal injections of a non-cross-linked HA gel, three weeks apart, or no intervention. Blinded evaluators rated 90.63% of the treatment group as improved on the Global Aesthetic Improvement Scale, against 3.65% of controls, with the effect sustained for six months. Skin hydration and elasticity rose from baseline, and adverse events were mild and transient.¹⁵

Two points set it apart from creams. The control group had no treatment at all, so the comparison does not separate the gel from the injection itself. And several authors work for the gel’s manufacturer.¹⁵ It shows what a clinic procedure can do, not what a cream does.

07 · Evidence at a glance

Seven studies, side by side.

Every study here ran from four weeks to six months. The bars show each study’s stated length against the longest.

28 days58 adults predisposed to atopic dermatitis
4 weeks36 nursing-home residents aged 60 to 80 with dry skin
8 weeks67 women aged 30 to 60 with signs of aged skin
60 days76 women aged 30 to 60 with periocular wrinkles
6 months20 women with photoaged skin
180 days29 people aged 37 to 66
6 months420 people

Clinical studies on skin hydration and structure: who took part, how long, what was measured and the result
Who and where	Length	What was measured	Result
58 adults predisposed to atopic dermatitis; forearm and lower leg	28 days	Water loss through the barrier (TEWL20), ceramides, skin moisture	A lipid and glycerine emulsion improved the barrier; a glycerine-only emulsion reduced dryness but had no impact on the barrier.⁷
36 nursing-home residents aged 60 to 80 with dry skin; leg	4 weeks	Skin capacitance, TEWL, symptom score	Low-molecular-weight hyaluronic acid beat high-molecular-weight and vehicle on capacitance. TEWL and symptom scores did not differ.⁶
67 women aged 30 to 60 with signs of aged skin; face	8 weeks	Clinical, instrumental and consumer assessments	The niacinamide formulation improved stratum corneum water content and reduced TEWL and sebum. Ultrasound alone showed no instrumental improvement.⁸
76 women aged 30 to 60 with periocular wrinkles; split-face against vehicle	60 days	Hydration, elasticity, wrinkle depth from skin replicas	All five hyaluronic acid weights improved hydration and elasticity. Wrinkle depth improved significantly only with 50 and 130 kDa.⁵
20 women with photoaged skin	6 months	Clinical scores, elasticity, elastic fibre histology	5% vitamin C with 0.1% madecassoside improved wrinkle, firmness and hydration scores. Two-thirds of subjects improved.¹³
29 people aged 37 to 66; chest, active against vehicle	180 days	Blinded photodamage and wrinkle scores, erythema, satisfaction	Both groups improved 30 to 40%. The active group had more mild erythema at day 90, similar to vehicle by day 180.¹⁴
420 people; intradermal injections against no intervention	6 months	Blinded Global Aesthetic Improvement Scale, dryness and dullness rate, hydration, elasticity	Higher improvement rates than control, sustained for six months. Authors include employees of the gel’s manufacturer.¹⁵

08 · Reading a claim

Five questions to ask of any plumping claim.

Water or structure?
Skin capacitance and TEWL measure hydration and barrier.⁶ Histology of elastic fibres or collagen measures structure.¹³ A hydration result does not show a structural one.
How long did it run?
The hydration trials here lasted 28 days to 8 weeks.⁶⁷⁸ The dermal and wrinkle findings took 6 months.¹³¹⁴
Was there a vehicle control?
The chest trial’s vehicle group showed a similar improvement to the active group on the blinded score.¹⁴ Without a vehicle arm, a base can pass for an active.
Who paid, and who is the author?
The injectable trial lists authors from the gel’s manufacturer.¹⁵ That is disclosed, and still worth weighing.
Is it your skin, and your site?
The trials tested the leg of older adults with dry skin,⁶ the arms and legs of adults prone to eczema,⁷ the chest,¹⁴ and the face.⁸ A result in one site and group does not carry over automatically.

09 · What we could not confirm

The gaps, stated plainly.

A yearly percentage of collagen lost with age. We saw figures on blogs but the research we read states that production declines, with no yearly rate, so we state none.⁹
That hyaluronic acid “holds 1,000 times its weight in water”. We could not trace it to a study we could read.
Whether hyaluronic acid applied to skin reaches the dermis. The trials infer penetration to explain results but did not measure it.⁵⁶
Peptides, growth factors, caffeine, and silicone or soft-focus particles that blur the look of skin. We found no study we could read to cite, so we make no claim about their plumping effect.
How humectants behave in low humidity, and how much sealing with an occlusive adds. The reviews describe the roles but we did not verify a figure.²
A timeline of “3 to 12 months” for structural change from topicals. The studies we read ran 28 days to 6 months.
A comparison with radiofrequency, microneedling and other energy devices. We did not review them.

Vanu Health’s DermaGlass® masks are hydrating skincare. This page makes no plumping, firming or anti-aging claim about them or any other Vanu Health product.

10 · Questions

Frequently asked questions.

What is the difference between hydrated skin and plump skin?

Hydration is about water held in the outer layer of the skin, the stratum corneum, which depends on moisturizing compounds inside its cells and on the lipids between them. Plumpness that lasts depends on the dermis beneath, where type I collagen production declines with age and leads to skin thinning. The studies we read measured these separately: skin capacitance and water loss for hydration, and collagen or elastic fibres for structure. ^{1, 9, 13}

Does low-molecular-weight hyaluronic acid work better?

In two trials it did better on some measures. In a 2011 study of five molecular weights, all 0.1% creams improved hydration and elasticity compared with placebo, and wrinkle depth improved significantly only with the 50 and 130 kDa creams. In a 2024 trial of 36 older adults with dry skin, the low-molecular-weight lotion raised skin capacitance more than the high-molecular-weight lotion or vehicle, and water loss did not differ. Both teams suggest better penetration, but neither study measured where the hyaluronic acid went. ^{5, 6}

Can a moisturizer rebuild collagen?

The moisturizer trials we read measured skin water, water loss, elasticity or appearance, not collagen. The evidence for collagen sits with topical retinoids: a review reports that tretinoin prevents loss of collagen from, and stimulates new collagen formation in, the papillary dermis of sun-exposed skin. ^{6, 7, 8, 12}

Does vitamin C plump skin?

One small study gave 20 women with photoaged skin a cream with 5% vitamin C and 0.1% madecassoside for six months. Wrinkle, firmness, suppleness, roughness and hydration scores improved, and the elastic fibre network in the upper dermis looked more normally structured. Because two ingredients were used together, the study cannot say how much was due to vitamin C. ¹³

How long do results take?

It depends on what is measured. The trials on this page ran from 28 days for hydration measures up to six months for wrinkle, elasticity and dermal findings. We found no source we could read that gives a single timeline for “plumper” skin, so we do not give one. ^{6, 7, 13, 14}

Does Vanu Health make a plumping claim?

No. This page reports what published studies say. It makes no plumping, firming or anti-aging claim about any Vanu Health product.

Keep reading

The Research Desk: every guide and dataset from the same team.
Hyaluronic acid: the humectant behind weightless hydration.
Sunlight and skin health: UV, photoaging and sunscreen amounts.
Blue light and skin: pigmentation, screens and iron-oxide sunscreen.
Ingredients: what is in a Vanu Health formula, and why.

Collagen types: types I, III, IV, VII and XVII in skin.
Seasonal skincare: how skin changes across spring, summer, autumn and winter.
Green seaweed and ulvan: a human hydration study.
Glycation and AGEs: advanced glycation end-products and skin aging.
The Truth About Wrinkles: a book from the Vanu Health library.
The Health of Water: a book from the Vanu Health library.
Research Desk sources: every reference, organised by guide.
The Research Desk: all guides and datasets.

Sources

Where every claim comes from.

Numbers in brackets link to these entries. Each study was read as its PubMed record, with the title, journal, date and abstract, and study details come from PubMed, the US National Library of Medicine. Links open the paper through its DOI. Dates are those shown on the source.

All sources across the Research Desk are collected, by page, in the master source list.

[1] Journal of Cosmetic Dermatology (Verdier-Sévrain and Bonté). Skin hydration: a review on its molecular mechanisms. June 2007.
[2] International Journal of Dermatology (Fluhr and colleagues). Restoring skin hydration and barrier function: mechanistic insights into basic emollients for xerosis cutis. April 2025.
[3] International Journal of Dermatology (Szepietowski and Tadini). Basic emollients for xerosis cutis not associated with atopic dermatitis: a review of clinical studies. June 2025.
[4] International Journal of Cosmetic Science (Brandner). Pores in the epidermis: aquaporins and tight junctions. December 2007.
[5] Journal of Drugs in Dermatology (Pavicic and colleagues). Efficacy of cream-based novel formulations of hyaluronic acid of different molecular weights in anti-wrinkle treatment. September 2011.
[6] Archives of Dermatological Research (Muhammad and colleagues). Effectiveness of topical hyaluronic acid of different molecular weights in xerosis cutis treatment in elderly: a double-blind, randomized controlled trial. June 2024.
[7] British Journal of Dermatology (Andrew and colleagues, University of Sheffield). Topical supplementation with physiological lipids rebalances the stratum corneum ceramide profile and strengthens skin barrier function in adults predisposed to atopic dermatitis. September 2025.
[8] Current Medicinal Chemistry (Vergilio and Leonardi). Topical formulation with niacinamide combined with 5 MHz ultrasound for improving skin ageing: a double-blind, randomised, placebo-controlled clinical study. 2025.
[9] Journal of Investigative Dermatology (Li and colleagues, Fisher group). Age-associated increase in skin fibroblast-derived prostaglandin E2 contributes to reduced collagen levels in elderly human skin. April 2015.
[10] Journal of Biological Chemistry (Röck and colleagues). Collagen fragments inhibit hyaluronan synthesis in skin fibroblasts in response to ultraviolet B (UVB): new insights into mechanisms of matrix remodeling. March 2011.
[11] American Journal of Clinical Dermatology (Riahi, Bush and Cohen). Topical retinoids: therapeutic mechanisms in the treatment of photodamaged skin. June 2016.
[12] Clinical and Experimental Dermatology (Griffiths). The role of retinoids in the prevention and repair of aged and photoaged skin. October 2001.
[13] Experimental Dermatology (Haftek and colleagues). Clinical, biometric and structural evaluation of the long-term effects of a topical treatment with ascorbic acid and madecassoside in photoaged human skin. May 2008.
[14] Journal of Drugs in Dermatology (Wood and colleagues). A prospective, randomized, double-blind, vehicle-controlled study evaluating the efficacy, safety, and patient satisfaction of tretinoin 0.05% lotion for chest rejuvenation. June 2022.
[15] Dermatologic Surgery (Liao and colleagues; some authors are from the gel’s manufacturer). Efficacy and safety of sodium hyaluronate gel for facial skin rejuvenation. February 2026.

This page is general information from the Vanu Health Research Team. It is not medical advice. The images are AI-generated illustrations, not study images. Last updated October 30, 2026.