La Roche-Posay Hyalu B5 Pure Hyaluronic Acid Serum: My Plump, Dewy Skin Secret

For years my skincare staples have been retinol + vitamin c. Don’t get me wrong, this is a fantastic duo, but having a dedicated hydrating serum has always been an afterthought.

I’ve had the La Roche-Posay Hyalu B5 Serum in my stash for a while, and goodness do I regret not trying it sooner. Let’s just say using this has changed my mind, and has earned it a permanent spot in my routine. Read on to see why.

Overview

What is it
This face and neck serum leaves skin feeling plump to the touch and helps repair skin by replenishing the natural moisture barrier. Combines concentrated pure hyaluronic acid, madecassoside and vitamin B5 for optimal effectiveness while also being suitable for sensitive skin.

Best suited for
All skin types, but especially those with dry, dehydrated skin that lacks bounce and glow.

Things to note
Does contain alcohol and fragrance, but is far from drying or sensitizing.

Packaging
A tinted blue glass bottle with a dropper cap.

Scent
A fresh scent, reminds me a little of laundry detergent? Noticeable, but not too strong, and does dissipate once applied.

Texture
What you’d expect of a hydrating serum. Viscous, a little thick, but surprisingly not sticky and absorbs quickly into the skin.

Finish
Slightly dewy finish with minimal tackiness. The glow is not an oily or shiny glow, but more like a subtle I-just-sheet-masked! kind of glow.

Price & Size
$39.99 for 50ml on Skinstore (15% off with JENNY), Dermstore (10% with JENNY), CultBeauty, Target, and Ulta

Product Demo

La Roche-Posay Hyalu B5 Serum Ingredients

Obviously the star here is hyaluronic acid, and we see 2 forms used here:

• Sodium Hyaluronate *is* hyaluronic acid, and it’s one of the most effective humectants, an ingredient that draws and holds moisture on the skin, up to 1000 times its weight! According to cosmetic chemist Amanda Foxon-Hill, it can also act as a penetration enhancer for other water-based ingredients!
• Hydrolyzed Hyaluronic Acid is the smaller, or lower molecular weight version, of Sodium Hyaluronate, and depending on its actual molecular weight, it can provide different benefits:
  • 100-300 kDA – can help with skin repair and speed up the wound healing process.¹
  • ~50 kDA – can be absorbed into the skin (as opposed to just sitting on the surface) and actually plump up fine lines and wrinkles by increasing collagen production!^2,3
  • < 50 kDA – can potentially increase inflammation in the skin, so it’s best to avoid⁴

Other ingredients we love to see include: glycerin, panthenol, madecassoside, and vitamin e.

And since this serum does include alcohol, I need to stress again that alcohol in a well-formulated product is a non-issue for most people! If anything, alcohol is probably why this serum has all the benefits of a thick hyaluronic acid serum yet absorbs like a dream and isn’t sticky. But obviously if your skin is reactive towards alcohol, you should still avoid this.

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I know the ingredients can seem almost basic compared to some of the really fancy serums I’ve reviewed before, but these are all well-researched, proven ingredients, so don’t underestimate what the basics can do! 

How I Use Hyaluronic Acid Serums

As with all serums, this should be used on clean skin, after your exfoliant, first essence, and/or toners. A pea sized amount will suffice for your face, but double to include the neck!

• If you’re using multiple serums, use the light to heavy rule and layer your serums according to their texture. Chances are the La Roche-Posay Hyalu B5 will go close to last. 
• If your serums have similar textures, then layer your other (anti-aging, brightening, antioxidant, etc) serums first.

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To maximize the water retaining benefits of your hyaluronic acid serum, make sure to mist your skin lightly before applying! You want to make sure your skin is just slightly damp, not dripping wet, to get best results.

Follow up with the rest of your routine, including your moisturizer and sunscreen. Hyaluronic acid serums can be used morning and night, everyday, just listen to your skin and see what it needs!

My Usage Experience & Results

The hydration results were immediately noticeable. Once absorbed, it made my dry skin feel so plump and juicy, similar to a sheet masking experience. I’m so tempted to apply a second layer (that’s how good it is), but the serum texture is quick viscous and it’d definitely feel too sticky if you used too much. But with just one application it works beautifully to lock in moisture without any uncomfortable side effects.

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I also love how well it absorbed into my skin despite the thicker texture, especially when I’ve misted first. This allows the serum to act like a sponge to absorb all the moisture from the mist and hold that hydration on your skin, instead of it just evaporating. Hence the just-sheet-masked glow.

Whenever I use the Hyalu B5 Hyaluronic Acid Serum the night before, I always wake up to a nice glow the next morning. To keep the dewiness going all day, I make sure to layer it after my vitamin c serum in the morning, sometimes even skipping moisturizer since the serum alone works so well.

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But if you’re expecting this one serum to magically erase your wrinkles and fine lines, you’re in for a disappointment. It’s very good at addressing fine lines due to dryness by adding hydration back to your skin, but you’ll definitely get better anti-aging results by using ingredients like retinol or peptides.

Also if I had to nitpick, I don’t love the dropper with this serum, and it seems to be an issue with La Roche-Posay serums in general. Something about the fit of the dropper with the opening, combined with the serum texture, just leads to product spilling out and creating a bit of a mess around the rims. Or maybe I’m just sloppy.

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Overall though this one is still a winner for me, one of the best hydrating serums I’ve tried yet for the price!

What Others Say

From beauty editors to scientists, let’s hear what other skincare enthusiasts have to say:

This serum blesses my skin with a super-moisturized base — perfect for layering on my favorite moisturizers and oils — and a dewy and plump look.

Jihan Forbes, Allure.com editor

This product is so hydrating and soothing for my skin. It’s my go-to when traveling. It’s like a tall glass of water for your skin and gives a natural, beautiful glow. 

Danielle James, Elle.com beauty director

You can smell and feel the ethanol. Ethanol is a poison to cells… If your skin barrier is damaged there is still a chance that ethanol reached the deeper layers of your skin.

Cyrille Laurent, cell biology researcher

Similar Products

💦 Medik8 Hydra8 B5 Intense
Feels very similar to the LRP and also contains panthenol, but also a bunch of other natural moisturizing factors like sodium pca, amino acids, urea, and low % lactic acid for a super gentle exfoliation. Also alcohol and fragrance free. For me the LRP moisturizes and plumps better though, but both are lovely.

💦 Filorga Hydra-Hyal Serum
The most effective HA serum I tried before the LRP, this one feels just a touch lighter but still incredibly hydrating and plumping, with 5 kinds of hyaluronic acid plus their proprietary NCEF complex. It’s a lot pricier though.

💦 SkinCeuticals Hyaluronic Acid Intensifier
Another great, but pricey, HA serum that delivered noticeable results. This one is unique in that it contains 10% Proxylane, an ingredient L’oreal claims to increase the production of natural moisturizing factors in our own skin, which can improve overall firmness and hydration. I personally don’t think it’s worth the high price tag though.

💦 The Inkey List Hyaluronic Acid
Doesn’t feel like your typical HA serum, in that it’s actually very light and not sticky at all. For me it was great for mixing with their 30% vitamin c, but as a standalone hydrating serum it’s definitely not as effective as the LRP.

💦 The Ordinary Hyaluronic Acid 2% + B5
I personally haven’t tried this one, but the ingredients are promising and many people rave about its efficacy. On the other hand, I’ve also heard not so great things about its stickier texture and finish.

Final Verdict

Jenny Wu

Passionate about science-based skincare. Tested hundreds if not thousands of products since my 20's. Working regularly with brands like iHerb, Ulta, CurrentBody, and MedStar Health to share my knowledge and experience in all things beauty. Learn more.

Skin profile: 35+, dry/combination, focused on well-aging, hydration, and a healthy glow ✨