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When it comes to skincare advice, the internet will tell you a lot of things.

Use more actives, try stronger treatments, buy the newest serum promising miraculous collagen-boosting results. The list goes on.

But instead of getting caught up in the endless sea of information, sometimes it's best to go straight to a trusted expert.

Exhibit A: Sydney facialist Carina Gross.

WATCH: Sydney's top-secret facialist Carina Gross, explains what's better — skin products or skin treatments. Post continues below.

If you're deep into the beauty world, you'll probably already know the name. Gross is one of those 'if you know, you know' facialists with more than 30 years of experience and a cult following at her Belaméres Skin Clinic in Sydney.

Her philosophy centres around long-term skin health rather than aggressive quick fixes, and her clients include beauty insiders who swear by her treatments, including our very own Lifestyle Editor and beauty guru Amy Clark.

So when Amy recently had Gross on the You Beauty podcast, she asked her all our burning questions.

The number one thing for plumper, firmer-looking skin.

Her answer was simple: hyaluronic acid.

"The most underrated thing is hyaluronic acid," Gross explained.

"Once we lose hydration in the skin, there's not much we can do to actually increase it."

According to Gross, many people don't realise that dull or tired-looking skin is often simply dehydrated.

"A lot of clients don't understand that when the skin looks dull and tired, they don't actually know it's linked to dehydration," she said.

And it starts earlier than you might think.

From our mid-twenties, the amount of water in our skin begins to decline. By the time we reach 40, we've lost around half of that hydration.

Skincare vs serums: what works better?

Gross says the solution to boosting hydration isn't just by layering on more serums.

"You don't need more products — you need consistency."

What she wants you to know is the best results come from combining a solid skincare routine with professional treatments.

To explain it, she uses a simple analogy.

"Good skincare products are like your bedsheets — you can feel the difference," she said.

"But if you want real change, deep change, structural change, it's the mattress. And the mattress is professional treatments."

In other words, skincare and treatments work best when they support each other.

"There's something that professional treatments do that no product in the world can do," Gross explained.

One example is Gross' signature 'Fairy Dust' treatment, which is also a favourite of You Beauty host Leigh Campbell.

The treatment uses light therapy to activate the skin while delivering a specialised form of hyaluronic acid. Because the molecules are small enough to penetrate deeper into the skin, the treatment helps boost hydration levels where they're needed most.

"There's no product in the world that can do what the treatment does," Gross said.

A new treatment like skin-needling (without the downtime).

If you've thought about skin needling but haven't quite worked up the courage to try it, Gross says there's a newer alternative gaining attention: bioneedling.

In fact, she believes it could be the "future of skin needling".

But before jumping into any collagen-stimulating treatment, Gross says the condition of the skin matters more than most people realise.

"What most people don't know is when your skin is not in a healthy condition, when your skin quality is not at its best… when the barrier, when the hydration levels are not great, skin is actually not ready to go into more trauma, into more stress."

That's why her clinic always assesses the skin first.

"I would say from ten new clients that come and ten want to do needling, maybe two have the right skin condition."

Now back to bioneedling…

This treatment works differently from traditional microneedling, because instead of metallic needles puncturing the skin, it uses microscopic marine-derived spicules.

"Imagine it like this: skin needling works with little metallic needles, and it causes controlled injury to the skin," Gross explained.

"With bioneedling, we massage those spicules into the skin… they are active for about 72 hours, and they stimulate the skin to repair itself."

Because the treatment encourages the skin's natural repair process, it can help improve concerns like texture, pores and pigmentation, all without the visible downtime typically associated with traditional needling.

You can listen to the full You Beauty podcast below or watch You Beauty on YouTube.

Feature image: Supplied.