4 dermatologists told us the most underrated (and overrated) skincare products.

In news that surprises absolutely no one, spending money on skincare products you don't really need sucks. Big time.

And that's part of the reason I'm always annoying innocent dermatologists — so we can suss out exactly what we need in our skincare routines and what we don't.

Watch: Here are seven ways to improve your skin while sleeping. Post continues below.

Because while we all have those non-negotiable staples we swear by (hey, hyaluronic acid!), there are actually a whole load of other ingredients that don't get the same airtime.

And more often than not, these products and ingredients have the same — if not more — benefits than your usual line-up.

That's why we've hit up some of Australia's finest dermatologists and asked them to give us the lowdown on all the most underrated products you need to know about (as well as the ones you might want to pull back on!).

The most underrated skincare products.

Ceramides.

We're calling it: Ceramides are going to be the next big thing in skincare. Not only are they incredible for strengthening your skin barrier and smoothing your skin, but they also have amazing benefits for ageing skin.

"Ceramides are definitely one of the most important and under-rated ingredients found in good quality skincare," said specialist dermatologist and CeraVe ambassador Dr Ryan De Cruz from Southern Dermatology.

View this post on Instagram

A post shared by Dr Ryan De Cruz (@drryandecruz)

"They have the greatest body of scientific research proving their beneficial effects on skin quality, hydration and inflammation," said De Cruz.

Ceramides make up over 50 per cent of your skin's composition, but due to ageing and sun damage, the quality and quantity of ceramides in your skin reduces. So, this is why it becomes important to replenish them.

"They are little-known heroes of the skin barrier, that naturally decline with age, environmental stressors and skin disease. When replenished, ceramides bolster the strength of the skin barrier and aid any anti-ageing technique."

Niacinamide.

Another quiet achiever? Niacinamide. Whether you're dealing with acne, sensitive skin, dryness or dark spots — niacinamide is the heavy-lifting multitasker that doesn't get nearly enough attention.

"Niacinamide (vitamin B3) is gaining momentum as a 'must-have' cosmeceutical ingredient. But, I really think that it remains underutilised," said cosmetic dermatologist Dr Katherine Armour from Bespoke Skin Technology.

View this post on Instagram

A post shared by Dr Katherine Armour (@drkatherinearmour)

"A lot of the ground-breaking research on the benefits of niacinamide came from the University of Sydney. It helps to combat ultraviolet light-induced DNA damage, tackles pigmentation and fine lines, zaps inflammation, supports the skin barrier, and down-regulates oil gland function (thus improving acne)."

What a bloody show-off!

"Niacinamide has proven benefits in acne and atopic dermatitis. Niacinamide is the one cosmeceutical ingredient that should be in the water as far as I’m concerned!"

*Slathers niacinamide on toast.*

SPF.

We know, we know. But it's so true! SPF is hands-down the most important product you can ever put on your face — so of course it needs more hype.

"It probably sounds cliché, but I still think that the most under-used ingredient is SPF. Strict daily sun protection is the most effective anti-ageing ingredient available, and also dramatically reduces the risk of skin cancer," said dermatologist Dr Cara McDonald from Complete Skin Specialists.

View this post on Instagram

"Many people though still think that they only need high SPF, broad-spectrum sun protection if they are expecting to be outdoors for prolonged periods or likely to be sunburnt."

Importantly, Dr McDonald reminds us we should always aim for primary sunscreen and not think that the SPF in moisturiser or makeup will be sufficient. Because it ain't.

Vitamin D.

Vitamin D would have to be the least-talked-about vitamin in skincare land — yet it's so darn crucial for healthy skin.

"Vitamin D is an important protective anti-inflammatory and anti-aging ingredient, known to be essential in the diet. It is now also emerging as a powerful skincare ingredient but is currently under-used," said Dr McDonald.

Not only does it work to calm inflammation and protect the skin from environmental aggressors, but it's also a powerhouse ingredient when it comes to improving cell turnover.

Get on it!

Zinc.

Another seriously underrated superstar ingredient is zinc. Zinc deserves better, you guys!

This guy literally goes above and beyond for your skin — helping to calm inflammation, minimise acne breakouts and promote smooth, even skin. A HUGE bonus? It can also be used as a physical block, minimising harmful UV damage.

"Zinc oxide is always thought to be heavy and gluggy, but with the right technology this is a brilliant sunscreen that's broad spectrum," said medical and aesthetic dermatologist Dr Shyamalar Gunatheesan from Ode Dermatology.

Lactic acid.

While actives like salicylic and glycolic acid are pretty big names on the beauty streets, lactic acid is a little quieter — but seriously delivers *incredible* benefits to the skin. (Psst... it's especially good if you struggle with sensitivity and dryness!).

"Lactic acid is one of the key actives that is going to help with our skin renewal," Dr Shyamalar.

"It turns on our anti-ageing genes. Lactic acid also provides gentle continued exfoliation of our skin, it increases a very hydrating substance in our skin called natural moisturising factor, and it can also help with overall collagen building and skin luminosity."

The most over-used skincare products.

Vitamin C.

Anyone else absolutely addicted to using vitamin C in skincare? Please take a seat. We need to talk. Because apparently it's not all it's cracked up to be.

"By far and away the most over-used ingredient in skincare right now is vitamin C," said Dr Armour. "Seriously!"

"Yes, it's a fabulous collagen stimulator and brightening ingredient. So, it can be a useful fine-line fighting and brightening ingredient. BUT, as a dermatologist, I can tell you that vitamin C is one of the most common causes that I see of perioral dermatitis and skin irritation," said Dr Armour.

Eek! No good. If you're struggling with sensitivity and irritation and vitamin C is one of your non-negotiables, this could be why.

"It is also often unstable in formulation. This means that you may not be applying what you think you are. I think that we have been excited by all things vitamin C for a long time because it was one of the first cosmeceutical ingredients after retinoids and AHAs to get some solid scientific data behind it. But we need to move on! There are so many other cosmeceutical ingredients that do all the same things as vitamin C, without the risk of irritation," said Dr Armour.

"Niacinamide and astaxanthin have solid scientific data to show that they do all the same things as vitamin C without the risk of giving you a rash. They are by far and away my preference over vitamin C."

Retinol.

"It's a great active, vitamin A, and certainly the various skincare companies and cosmeceutical [industry] have utilised the fact that retinol is very important for collagen building, pigment recalibration and overall good skin cellular turnover," said Dr Shyamalar.

The issue? It's not for everybody. And it's waaay too easy to go too hard, too fast.

"If you've got truly sensitive skin, you don't want to jump to a higher percentage of retinol, retinaldehyde and ultimately the retinoic acid component. Using a higher percentage [can] result in inflammation that can be persistent, so it's important to find the right retinol for you — perhaps one that is compounded with other stabilising ingredients, one that is slow release."

Anyone else taking notes?

Dr Shyamalar goes on to say there are other ways to build collagen, aside from just introducing a retinol.

Instead, she suggests looking out for antioxidants such as glutathione and superoxide dismutase (sounds 100 per cent jibberish — but have a squiz at the ingredients list on your product packaging!). Ingredients like these will help prevent collagen breakdown without the risk of irritation, as well as promoting overall skin luminosity. Win.

Fragrance.

If you're a gal with sensitive skin, this one's for you. "In my opinion, the most overused ingredient is fragrance," said Dr McDonald.

"Many people are sensitive or even allergic to fragrances and do not realise that it is the fragrance in the product causing them problems."

Poor lambs.

"Many people still assume that 'natural' ingredients, including natural fragrances from essential oils, are immune from causing problems — but this is far from the truth."

Soap.

Are you using soap on your face? Please... don't.

"Some people still don't realise that soap is designed to remove oils and grease and should not be used on dry, sensitive or irritated skin," said Dr McDonald.

And with so many amazing cleansers out there, why would you wanna use soap?

"It doesn't matter what kind of soap — goat's milk, natural, or moisturising — it should be avoided."

Do you use any of the above products and ingredients? Share your thoughts with us in the comment section below.

Feature image: Instagram/drcara_dermatologist; drshammitheesan.