HYDRATION HERO

ST.SAJ Hyaluronic Acid Serum bottle labeled Hyaluronic Smoothing Complex, 50ml, with clear dropper and sleek packaging.

ST.SAJ Hyaluronic Smoothing Complex - 98% say it gave them plumper, dewier skin

ST.SAJ Hyaluronic Smoothing Complex two-step how to use - massage onto face neck and décolletage after cleansing and toning, then layer serums on top

ST.SAJ Emmylou recommending Hyaluronic Smoothing Complex - quench thirsty skin as four multi-weighted Hyaluronic Acids work their magic

ST.SAJ Hyaluronic Smoothing Complex customer review - Susan, Perth WA, 64

ST.SAJ Emmylou holding Hyaluronic Smoothing Complex, smiling

HYALURONIC SMOOTHING COMPLEX

Name: HYALURONIC SMOOTHING COMPLEX
Brand: ST.SAJ
SKU: SJ1003
Price: 54.95 AUD
Availability: InStock

$54.95~~$54.95~~ Save 0%

4.9

Rated 4.9 out of 5 stars

Plumping

Hydrating

Smoothing

Revitalising

Free AU Shipping On Orders Over $150

Four molecular weights of Hyaluronic Acid target hydration at every layer of the skin
Betaine and Panthenol help skin retain moisture longer and support natural regeneration
Glycerin draws and locks in moisture for long-lasting hydration
Lightweight, fast-absorbing texture with zero stickiness or residue
Oil-free, non-comedogenic, suitable for all skin types, including sensitive skin

Four molecular weights of Hyaluronic Acid - each one hydrating at a different depth of the skin.

The result is hydration that actually holds, not just surface moisture that disappears by midday. Glycerin draws moisture into the skin and locks it there. Betaine and Panthenol strengthen the skin barrier so moisture stays locked in and supports natural regeneration.

Lightweight formula absorbs on contact and layers seamlessly under serums, oils or moisturiser.

Apply after cleansing and essence, before your treatment serums.

Pairs with PEPTIDE POWER ESSENCE and seal with SUPREME SKIN 7 for the complete layering routine.

50ml / 1.7fl oz

50ml / 1.70 fl oz

Gently massage onto face, neck and décolletage after cleansing and essence.
Follow with your treatment serums and seal with SUPREME SKIN 7.

Aqua, Glycerin, Propanediol, Butylene Glycol, Betaine, Hamamelis Virginiana (Witch Hazel) Water, Sodium Hyaluronate Crosspolymer, Sodium Hyaluronate, Sodium Acetylated Hyaluronate, Hydrolyzed Sodium Hyaluronate, Panthenol, Polyacrylate Crosspolymer-6, Xanthan Gum, Pentylene Glycol, Allantoin, Sodium Phytate, Phenoxyethanol, Ethylhexylglycerin, Citric Acid.

No artificial colours, parabens, silicones, phthalates, chemical UV filters.

Complete the Routine

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BUILD WITH

$135.00 ~~$174.85~~

ESSENTIALS ROUTINE

How to Use

Gently massage onto face, neck and décolletage after cleansing and essence.
Follow with your treatment serums and seal with SUPREME SKIN 7.

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4.9

Rated 4.9 out of 5 stars

Based on 78 reviews

100%would recommend this product

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78 reviews

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H
Helen
I recommend this product
Rated 5 out of 5 stars
2 hours ago
5 Stars
Hydrating, my skin loves it
Was this helpful?
DV
Dana V.
Verified Buyer
I recommend this product
Rated 5 out of 5 stars
4 hours ago
Hydration Plus!
I’m really loving the ST. SAJ Hyaluronic Serum! It feels lightweight on the skin, absorbs beautifully and leaves my skin feeling hydrated, soft and plump without feeling sticky or greasy. It’s easy to layer with my other skincare products and leaves my skin feeling fresh and looking more radiant. A great addition to my skincare routine and one I’d happily recommend! ✨
Was this helpful?
LB
Lisa B.
Verified Buyer
I recommend this product
Rated 4 out of 5 stars
4 days ago
Hydrating!!
Love this hyaluronic serum. Feels so hydrating and not sticky.
Was this helpful?
MM
Michala M.
Verified Buyer
I recommend this product
Rated 5 out of 5 stars
1 week ago
Amazing!
I have been using St Saj since it first started and I couldn’t be happier, my skin looks and feels the best it has ever felt! ✨
I also really love how I have my products on a subscription, so I don’t have to worry about them running out. 🤍
Was this helpful?
JP
Judy P.
Verified Buyer
I recommend this product
Rated 4 out of 5 stars
1 week ago
Hydrated
I’m hydrated to hell now, hell yeah! Awesome product and I just love applying it daily, such a skincare theatrical experience 💜
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Australian Made

VEGAN & CRUELTY FREE

Because it's the difference between skin that looks plump and dewy versus dull and tired. Hyaluronic acid is a humectant, which means it pulls water into your skin and holds it there. More hydration = plumper skin, fewer visible fine lines, better texture, and a healthier barrier.
Most people strip their skin with harsh actives and then wonder why it's irritated and reactive. Hyaluronic acid fixes that. It's the foundation everything else builds on.
At ST.SAJ, we use multiple molecular weights of HA in Hyaluronic Smoothing Complex so it penetrates at different skin depths. You're not just hydrating the surface, you're hydrating all the way down. That's the obsession.
Yes. It absorbs cleanly and leaves skin hydrated without grease, so it sits perfectly under makeup. Let it dry for a minute after application, then apply your other serums, moisturisers or foundation as usual. Your makeup will go on smoother and last longer because your skin barrier is hydrated.
No. Hyaluronic Smoothing Complex is formulated to hydrate without the grease. It absorbs cleanly and leaves skin looking dewy and hydrated, not shiny or oily. You get that healthy glow without the sticky or heavy feeling.
It's designed to hydrate your skin throughout your routine, so it plays well with everything layered on top.
Yes, all ST.SAJ formulations are proudly Australian made, produced right here in Melbourne.

We are officially licensed to carry the Australian Made logo, reflecting our commitment to local manufacturing, quality control, and supporting Australian industry.

From formulation to filling and packing, our products are developed with care and precision to meet the highest standards.
Yes, ST.SAJ products are formulated to be suitable for use during pregnancy and while breastfeeding.

However, we always recommend reviewing each individual product page and consulting your healthcare professional before introducing any new skincare during this time.

If breastfeeding, avoid applying products directly to the chest area or anywhere the baby may come into contact during feeding.

If you have specific ingredient questions, our team is always here to help guide you.

Overnight, your skin naturally forms an acid mantle, a protective layer made up of sebum and beneficial lipids that help maintain barrier function and microbiome balance.

In the morning, this protective layer does not require active cleansing. For most skin types, simply rinsing with water is enough before applying your treatment products.

We recommend the following morning approach:

Rinse → Essence → Serums → Moisturiser → SPF

Night-time is when active cleansing is essential to properly remove SPF, makeup, pollution, and daily buildup.

This philosophy supports long-term barrier health rather than over-stripping the skin.
We proudly offer Free Shipping on all Australian orders over $150.
Shipping on Australian orders under $150 is a flat rate of $10.00. We also offer express shipping for those that need their skincare in a hurry!
Yes, we do. See our shipping rates at checkout if you are one of our amazing friends abroad.
Please check our Returns Policy for information on returns.
If you believe you’ve had an allergic reaction to a ST.SAJ product, please email glow@stsaj.com straight away. Stop using the product for now, but don’t throw it away. If you’ve used less than 20% off the product we can discuss a refund after our team assesses the images of your reaction.
Selected Ultra Beauty stores. Use our store locator and pop in your postcode to find your nearest store.

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