As anyone who's dutifully followed a diet of avocado, salmon, chia seeds and nuts in the quest for a glowing complexion knows, what's on the inside shows on the outside - aka, you are what you eat. It's a message that truly hits home after one too many big nights followed by regrettable 3am Maccas meals - sadly, nothing shows on the face more than not looking after yourself.

Enter beauty supplements: probiotic-rich superfoods in potent powder or liquid form that you take with your morning smoothie or glass of water, sprinkle over yoghurt or - for the truly #fitspo among us - mix into bliss balls. With advocates ranging from Elle Macpherson (she has her own range - The Super Elixir) to perennially radiant Sara Donaldson of Harper and Harley (she, like many Aussie influencers, swears by The Beauty Chef's Glow powder), beauty supplements are generating just as much buzz as traditional glow-getters like highlighter and tried and true treatments like Omnilux.

A quick skim of the comments section on The Beauty Chef is enough to compel anyone to buy up in bulk - legions of customers credit the wonder powders for everything from clearing up their acne to cutting sugar cravings - and everyone mentions the lit-from-within glow. Carla Oates, the Sydney-based naturalist behind The Beauty Chef (mantra: 'beauty begins in the belly'), puts it down to the way gut health manifests itself on the skin. "Our guts are where 70% of our immune system lies, where we metabolise hormones, neutralise pathogens, make detoxifying enzymes and where we make nutrients," she says. "So much of what goes on in our digestive system can impact our skin... by healing your gut, you feel more energised [and] you will notice your skin looking better, more radiant, and hair and nails, stronger and more lustrous."

Bottled beauty: the next-gen supplements everyone is secretly taking

How does it work? In the case of the Elle Macpherson's Super Elixir, the finely ground, lurid green powder contains 45 alkalising and antioxidant-rich ingredients - including Shiitake mushrooms, prebiotics, Chinese herbs and natural digestive enzymes - to restore the body's pH balance and deliver a potent nutrient hit. The only catch? The taste is not for the faint-hearted, and no amount of coconut water (which The Body recommends you mix it with) can disguise it.

Pre- and probiotics are the key to The Beauty Chef's Inner Beauty Powders and liquid-form Beauty Boosts, which contain fermented fruits and vegetables like chickpeas and macqui berries to boost their nutritional value. "I discovered the art of fermentation about 20 years ago when I made kombucha tea with a friend," says Oates. "Around 15 years ago, I started to lacto-ferment vegetables with the aim of healing my gut health and I noticed a big difference in my skin." And thus, the broad-spectrum probiotic Beauty Chef range was born.

Bottled beauty: the next-gen supplements everyone is secretly taking

Oates isn't the only Australian experimenting with ingestible beauty supplements - Chanelle Louise is the founder of CILK Inner Beauty Rose Extract, a pretty pink elixir that can be added to mineral water and even - wait for it - champagne. Louise was inspired to formulate the luxe skin-loving liquid after a brain injury prevented her husband from drinking alcohol and she followed suit. "I struggled to find sugar-free, non-boring, beautiful drinks that emulated the experience that I loved about red wine," she says. "I was drinking rose tea at the time [and] I have always used rose water on my skin too for its hydrating effect, however I could feel it was only sinking into the surface. I wanted to gain the full benefit of this ancient and powerfully healing ingredient from the inside out."

What exactly are the benefits of rosewater? According to Louise, Rose Damascena (they get theirs from a certified organic farm in Rose Valley, Bulgaria) is a source of anti-inflammatory phytochemicals that aid detoxification and digestion. "Just as rosewater cleanses the skin, when drinking the therapeutic elements of antioxidants and phytochemicals including vitamins, glycosides and flavonoids aid acne prevention, anti-ageing, dermal regeneration activity and an overall balancing and harmonising of the skin and mind," she says. "The addition of locally grown hibiscus and vanilla further provide a potent phenolic and flavonoid combination, extending the free radical protection against the metabolic damage of everyday life." Plus, it makes for a very pretty Instagram post.

Bottled beauty: the next-gen supplements everyone is secretly taking