The 6 Best Hydrating Serums, by Humectant: Hyaluronic Acid, Glycerin, Polyglutamic Acid, and PCA
Key Takeaways
A hydrating serum works through humectants, ingredients that draw water in and hold it. Hyaluronic Acid is the best known, but Glycerin, Polyglutamic Acid, Sodium PCA, and Sodium Lactate do the same kind of job.
Hyaluronic Acid comes in different molecular sizes. Larger forms mostly stay on the surface as a hydration layer, while smaller ones can move deeper, according to a 2022 review.
U Beauty’s The SMOOTH Dynamic Wrinkle Defense Serum takes first place: a Glycerin-led serum with Sodium PCA, Sodium Lactate, two Retinol Esters, and peptides. U Beauty reports a 50% improvement in skin hydration 15 minutes after first use.
For Hyaluronic Acid on a budget, Good Molecules Hyaluronic Acid Serum is $6 for 30 ml.
With a Retinoid, apply products from thinnest to thickest and finish with a moisturizer. A hydrating serum may help your skin feel more comfortable while it adjusts.
The best hydrating face serum depends on which humectants suit your skin and how the serum fits around the rest of your routine. A serum built on Hyaluronic Acid feels different from one built on Glycerin or Polyglutamic Acid, and if you use a Retinoid, the order you apply them in matters. Below are six hydrating serums, grouped by humectant, with a note on where each goes on a Retinoid night.
How We Compared These Serums
We didn’t try any of these on skin. Working from brand pages and INCIs as published in early October 2026, we logged every humectant by its INCI name and position. We also checked for fragrance, noted the brand’s directions, and recorded price as listed. Where a brand doesn’t publish a full ingredient list, we say so.
Hydrating Serums by Humectant System
Humectants hydrate the skin “by attracting and binding water”, according to a 2020 review of nonprescription moisturizers in the American Journal of Clinical Dermatology. It names a range of them, from Glycerin to components of the skin’s own natural moisturizing factor, including Urea, lactate, amino acids, Pyrrolidone Carboxylic Acid (PCA), and Hyaluronic Acid. The same review notes that occlusives, the heavier ingredients in a moisturizer, help reduce water loss, and that’s the part a serum doesn’t do. That’s why a moisturizer usually follows a serum: humectants pull water in, and a moisturizer helps keep it there.
Here’s how the main systems compare:
Hyaluronic Acid at different weights: a 2022 review in Dermatologic Therapy puts it by size: big HA molecules tend to sit on top of the skin and form a thin film of hydration, and small ones can get further in. On a label, Sodium Hyaluronate, Hydrolyzed Hyaluronic Acid, and Sodium Acetylated Hyaluronate are common forms.
Glycerin: a widely used humectant, often high on the list.
Polyglutamic Acid: brands make large claims for it, which we report as their claims.
Sodium PCA and Sodium Lactate: salts of two of the natural moisturizing factor components the review lists.
1. U Beauty The SMOOTH Dynamic Wrinkle Defense Serum: Best Hydrating Serum With Retinol Esters
The SMOOTH Dynamic Wrinkle Defense Serum is U Beauty’s serum for the look of fine lines and wrinkles on the face and neck, and its base is built on humectants. Glycerin is second on the list, after water, with Propanediol, Sodium PCA, and Sodium Lactate further down and Squalane fourth. It also carries two Retinol Esters, Retinyl Linoleate and Retinyl Palmitate, and a peptide blend that lists Acetyl Hexapeptide-8 and Copper Tripeptide-1.
Key features:
Glycerin-led humectant system: Glycerin, Propanediol, Sodium PCA, and Sodium Lactate.
U Beauty’s numbers: U Beauty reports a 50% improvement in skin hydration, measured instrumentally on 30 volunteers 15 minutes after the first application. In a consumer perception study of 30 volunteers after seven days of daily use, it reports 97% agreed skin looked hydrated.
Where it goes: 1 to 2 pumps morning and evening, pressed into the face and neck with upward motions. U Beauty places it after the Resurfacing Compound and before The SUPER Hydrator.
No fragrance ingredient on its INCI.
Tradeoff: there’s no Hyaluronic Acid on its list; its hydration comes from Glycerin and the other humectants. At $248, it’s also the priciest pick here, combining hydration with Retinol Esters and peptides in one step.
Best for: anyone who wants a hydrating serum that also covers the look of fine lines, without fragrance.
Price: $248 for 30 ml. Also sold through Sephora, Nordstrom, Bluemercury, and Dermstore.
2. Vichy Minéral 89 Hydrating & Plumping Daily Booster: Best Hyaluronic Acid and Polyglutamic Acid Serum
Vichy calls this a Hyaluronic Acid and Polyglutamic Acid serum, made with the brand’s volcanic water in a water-based gel. It’s fragrance-free and sensitive-skin tested, per Vichy.
Key features:
HA plus Polyglutamic Acid: the two humectants Vichy names on the product page.
Volcanic water base: a water-based gel made with Vichy’s volcanic water.
Damp-skin application: 2 to 3 drops for the whole face and neck, twice daily, before moisturizer or sunscreen.
Tradeoff: Vichy says a slight tackiness is common until you’ve sealed it with a moisturizer.
Best for: a first hydrating serum, morning and night.
Price: varies by retailer (30, 50, and 75 ml).
3. CeraVe Hydrating Hyaluronic Acid Serum: Best Hyaluronic Acid Serum With Ceramides
CeraVe’s serum has a 24-entry list that’s easy to read. Glycerin is second and Sodium Hyaluronate sixth, followed by Panthenol and three Ceramides (NP, AP, and EOP). There’s no fragrance in the ingredient list.
Key features:
Glycerin plus Sodium Hyaluronate: two humectants high on the list.
Ceramides: NP, AP, and EOP right after.
Any time of day: alone or under moisturizer, avoiding the eye area, per CeraVe.
Tradeoff: Dimethicone is fourth, so it’s not for anyone avoiding silicones.
Best for: normal to dry skin that wants a plain HA serum under a Retinoid routine.
Price: $22.99.
4. The INKEY List Polyglutamic Acid Serum: Best Polyglutamic Acid Serum
INKEY’s serum is the dedicated Polyglutamic Acid pick. INKEY says its 3% Polyglutamic Acid complex “holds 4x more moisture than Hyaluronic Acid”, a claim we’re reporting rather than testing. Glycerin is fifth on the list, after Dimethicone and Butylene Glycol, and Polyglutamic Acid is 23rd.
Key features:
Polyglutamic Acid complex: 3%, per INKEY.
Makeup prep: INKEY says it’s good for layering and makeup prep, and Dimethicone is second on the list.
No fragrance ingredient on its list, and INKEY says it’s suitable for sensitive skin.
Tradeoff: Polyglutamic Acid itself sits 23rd on the list, below Dimethicone and several other ingredients, so check that a silicone-led texture suits you.
Best for: layering over an HA serum, as INKEY’s own routine suggests, or smoothing skin before makeup.
Price: $17 for 30 ml.
5. Good Molecules Hyaluronic Acid Serum: Best Budget Hyaluronic Acid Serum
Good Molecules says this lightweight serum uses two sizes of Hyaluronic Acid with different molecular weights. It has the lowest listed price on this list.
Key features:
Two HA weights: per Good Molecules’ description.
Damp-skin directions: a few drops morning and night, before oils, creams, and moisturizers; let it absorb for 30 seconds.
Suitable for all skin types: per the brand.
Tradeoff: the full ingredient list didn’t display on the brand page we read, so we can only go by what Good Molecules says is in it.
Best for: trying an HA serum for $6 before spending more.
Price: $6 for 30 ml (75 ml also available).
6. Glow Recipe Plum Plump Hyaluronic Serum: Best Hyaluronic Acid Serum for a Dewy Finish
Glow Recipe’s serum names two Hyaluronic Acid forms on its INCI, Sodium Acetylated Hyaluronate and Sodium Hyaluronate, with Glycerin second and Propanediol third, plus plum and other fruit extracts.
Key features:
Two HA forms: Sodium Acetylated Hyaluronate (8th) and Sodium Hyaluronate (9th).
Glycerin-rich base: Glycerin second, Propanediol third.
Damp-skin directions: 1 to 2 pumps on a slightly damp face and neck before moisturizer, morning and night.
Tradeoff: Fragrance is on its list. Glow Recipe says its fragrances make up less than 0.5% of its formulas, but skip it if fragrance bothers your skin.
Best for: dry-feeling skin that likes a dewy finish.
Price: varies by retailer (30 ml).
How to Layer a Hydrating Serum With a Retinoid
Cleveland Clinic’s guide to skin care order says to go from thinnest to thickest, and to use a Retinoid at night where your usual serum would go. Its Retinol guide adds that Hyaluronic Acid can help counteract some of the irritating effects of Retinol, and to finish with a moisturizer. In practice:
Cleanse and pat skin until it’s just damp.
Hydrating serum next, if it’s thinner than your Retinoid. Most watery HA serums are.
Retinoid, once the serum has absorbed. Start every other night, as the AAD suggests.
Moisturizer last, to help hold in the water your serum drew in.
If your Retinoid is a thin serum too, some people apply it first and the hydrating serum after. Either way, keep the moisturizer as the final step. For more products built for these nights, see our guide to serums for layering Retinol, Niacinamide, and Hyaluronic Acid.
When to See a Dermatologist
If your skin stays tight, flaky, or stings even with a hydrating serum and moisturizer, see a board-certified dermatologist. Visible dryness that won’t respond to a good routine can come from a skin condition, and a dermatologist can adjust your Retinoid strength or schedule.
Frequently Asked Questions
What Is the Best Hydrating Face Serum?
U Beauty’s The SMOOTH Dynamic Wrinkle Defense Serum is our pick for a Glycerin-led serum that also covers the look of fine lines. For a plain HA serum, CeraVe Hydrating Hyaluronic Acid Serum is $22.99.
What Is the Best Hyaluronic Acid Serum?
Look for more than one HA form on the label. Glow Recipe Plum Plump Hyaluronic Serum lists two, and Good Molecules says its serum uses two molecular weights.
Is Polyglutamic Acid Better Than Hyaluronic Acid?
Some brands say so, but those are brand claims. Both are humectants, and they’re often used together, as in Vichy Minéral 89.
Should I Apply a Hydrating Serum Before or After Retinol?
Usually before, if the serum is thinner. Apply products from thinnest to thickest, let each one absorb, and finish with a moisturizer.
Do I Still Need a Moisturizer After a Hydrating Serum?
Yes. Humectants draw water in, and a moisturizer’s occlusive ingredients help reduce how much of it you lose.