Care Guide
Moisturizer ingredients: research to help you decide
We have compiled some research studies to help inform decisions about moisturizers. Most moisturizers combine several kinds of ingredients; below is what each kind does, what some studies have found, and what to keep in mind.
Research on an ingredient does not guarantee how a particular product performs.
A product's full formula, strength and texture all matter. Several of the studies below were run or funded by moisturizer makers; we note this in the sources.
Glycerin and other water-binders
Water-binder (humectant)
What it does: Draws water into the skin's outer layer.
On the label: Glycerin (glycerol), hyaluronic acid (sodium hyaluronate)
What some studies found
- A large review found the benefits of glycerin better documented than those of most moisturizer ingredients.
- In a controlled study, glycerin supplied the added hydration while petrolatum reduced water loss, which is why many formulas combine the two.
Keep in mind
- Many glycerin studies were of lower quality.
- Hyaluronic acid is another common water-binder, with less direct evidence in the studies we reviewed.
Sources: Lindh and Bradley, Am J Clin Dermatol, 2015 (review of 48 studies) (opens in a new tab); Vaillant et al., J Cosmet Dermatol, 2020 (industry affiliation) (opens in a new tab).
Urea
Water-binder at low strength; smoother at higher strength
What it does: At lower strengths it binds water. At higher strengths it also loosens rough, scaly buildup.
On the label: Urea, often listed with a percentage such as 5% or 10%
What some studies found
- It is among the best-documented moisturizer ingredients.
- In people with diabetes, urea creams reduced foot dryness more than plain creams after four weeks; the reviewers rated this finding high certainty.
- In a small trial in people with an inherited dry-skin condition, a 7.5% urea cream improved dryness and roughness on the lower legs.
Keep in mind
- Higher strengths can sting cracked or irritated skin.
- Related ingredients such as hydroxyethyl urea are different, and research on urea does not automatically apply to them.
- If you have diabetes, check foot care with your clinician.
Sources: Lindh and Bradley, Am J Clin Dermatol, 2015 (review of 48 studies) (opens in a new tab); Borgström et al., Front Clin Diabetes Healthc, 2026 (review of 12 trials) (opens in a new tab); Dorf et al., Skin Health Dis, 2021 (opens in a new tab).
Other natural moisturizing factors
Water-binders like the skin's own
What it does: Mimic the small water-binding compounds that skin makes itself.
On the label: Sodium PCA, sodium lactate, amino acids such as glycine and serine
What some studies found
- They are usually tested inside whole formulas. Products made with them improved lower-leg hydration in short studies.
Keep in mind
- Because they are tested as part of a mix, their own contribution is not known.
- These studies were run or funded by moisturizer makers.
Sources: Baldwin et al., J Drugs Dermatol, 2024 (industry ties disclosed) (opens in a new tab); Gallinger et al., Skin Res Technol, 2022 (manufacturer research team) (opens in a new tab).
Petrolatum and other sealers
Sealer (occlusive)
What it does: Forms a thin film on the skin that slows water loss.
On the label: Petrolatum (petroleum jelly), mineral oil, dimethicone
What some studies found
- In a controlled study, petrolatum accounted for the reduced water loss in a moisturizer.
- Dermatologists recommend petroleum jelly for very dry hands and heels.
- Some body washes leave a little petrolatum on the skin after rinsing; in a manufacturer study on dry leg skin, such a wash did better than a regular wash.
Keep in mind
- It feels heavy. In a large trial, ointments were the least liked texture, so sealers suit small areas or nighttime.
Sources: Vaillant et al., J Cosmet Dermatol, 2020 (industry affiliation) (opens in a new tab); American Academy of Dermatology: dry hands (opens in a new tab); American Academy of Dermatology: dry, cracked heels (opens in a new tab); Wei et al., Int J Cosmet Sci, 2021 (manufacturer research team) (opens in a new tab); Allen et al., Clin Exp Dermatol, 2024 (opens in a new tab).
Ceramides
Skin fats (barrier lipids)
What it does: Resemble the fats that hold the skin's outer barrier together.
On the label: Ceramides (for example NP, AP, EOP), cholesterol, fatty acids
What some studies found
- Pooling five small studies found a slight improvement in dryness scores and no clear difference in water loss.
Keep in mind
- Fine to have in a moisturizer, but not a reason on its own to pick one product over another.
Sources: Nugroho et al., Indian J Dermatol, 2023 (pooled analysis of 5 studies) (opens in a new tab).
Softeners
Softener (emollient)
What it does: Smooth the skin's surface and set how a product feels.
On the label: Fatty alcohols such as cetyl alcohol, shea butter, squalane, plant oils
What some studies found
- They are rarely studied on their own. Their main job is texture.
Keep in mind
- Texture matters: people keep using the products they like, and steady use is what makes moisturizers work.
Sources: Augustin et al., J Dtsch Dermatol Ges, 2019 (dry-skin position paper) (opens in a new tab).
Lactic acid and higher-strength urea
Smoother (exfoliant)
What it does: Loosen rough, scaly buildup so skin feels smoother.
On the label: Lactic acid or ammonium lactate, urea at higher strengths such as 10%
What some studies found
- Urea is well studied for rough, thickened skin.
- Lactic acid is a common smoothing ingredient, described alongside urea in a dermatology position paper on dry skin.
Keep in mind
- Use only on rough, unbroken patches, separate from your everyday moisturizer.
- They can sting cracked or irritated skin.
- Salicylic acid, found in some smoothing body washes, is another option; the research we compiled did not cover it.
Sources: Borgström et al., Front Clin Diabetes Healthc, 2026 (review of 12 trials) (opens in a new tab); Dorf et al., Skin Health Dis, 2021 (opens in a new tab); Augustin et al., J Dtsch Dermatol Ges, 2019 (dry-skin position paper) (opens in a new tab).
Texture: lotion, cream or ointment
How the product is made to feel
What it does: The base that carries the ingredients, which decides how a product spreads and feels.
On the label: Lotions, creams, gels, ointments; pumps, tubes or tubs
What some studies found
- In a trial of 550 children, lotions, creams, gels and ointments worked about equally well over 16 weeks, and ointments were liked least.
- In an adult lower-leg study, a lotion raised skin hydration more than a cream.
Keep in mind
- Pick the texture, finish and bottle you will reach for every day.
Sources: Ridd et al., Lancet Child Adolesc Health, 2022 (550-child trial) (opens in a new tab); Allen et al., Clin Exp Dermatol, 2024 (opens in a new tab); Baldwin et al., J Drugs Dermatol, 2024 (industry ties disclosed) (opens in a new tab).
Dermidia offers care recommendations, not medical advice. If you have eczema, diabetes, poor circulation, immune suppression, open cracks, bleeding, signs of infection, or persistent itching, follow your clinician's plan and seek medical advice.