One of the biggest skincare trends in 2019 wasn’t a miracle food like avocado for once, it was the skincare fridge, the ultimate acne-clearing accessory.
You’ve probably seen them yourself: a compact cube refrigerating all your beloved oils and serums in one handy box. These inventions have snowballed into an unstoppable moneymaker in the last year, beginning life on social media, before finally breaking free into the real world.
You might have noticed skincare minifridges popping up on Instagram feeds, intensifying about a year ago. You might have laughed, dismissing them as a fad, only to realise with horror that one morning, they were popping up in your mind too. Most people have a vague memory of crying “that’s so cute”, before waking up with $50 missing from their wallet.
For some, the artistically arranged social media photographs of pink-coloured skincare fridges, complete with snazzy rose quartz rollers inside, are all too tempting. People are cashing out left right and centre: as a Christmas present for their girlfriend, as an impulse buy, as a strategic decision to enhance the potency of their remedies.
However, putting aside the coolness of having the accessory on your shelf, making you seem like a crafty acne-clearing potion master with all the secrets at your fingertips, is there any real point in buying them? Or is cuteness the main reason?
Do skincare fridges preserve the product’s power?
This is the number one scientific claim behind skincare fridges. In truth, most commercial serums, moisturisers and toners are very stable anyway. They’re packed with preservatives like phthalates, ethyl paraben, methyl paraben, citric acid – you name it.
However, that’s the key point – what about natural topical treatments? The lack of inflammatory, glutathione-depleting preservatives is a very reason we recommend them.
The truth is that neem, rose water, witch hazel, and any fragile plant extracts will particularly benefit from skincare fridges. Aloe vera is a classic example. The precious gel, rich in gibberellin, aloe emodin, and anthraquinones, begins to deteriorate just 6 hours after harvest, and loses all biological potency after 24 (study).
However, one study tested refrigerator temperatures directly, at 4C versus room temperature (22C). Anti-inflammatory compounds called beta-polysaccharides deteriorated significantly after 44 days versus just 12 days.
Similarly, the phytonutrient aloin lasted for 40 days versus 20, when stored in a vacuum. The fresh colour morphed from white to brown, but significantly slower in the refrigerated group.
Then there’s the delicate antioxidants. Like vitamin C, flavonoids, anthocyanins and polyphenols all shatter under intense heat. Strawberries should be refrigerated, broccoli steamed gently, argan oil cold-pressed – antioxidant preservation is the common denominator in these classic strategies. Sometimes, a plant’s main acne player like vitamin E might survive, but more secretive antioxidants like zingerones (found in ginger) might vanish, wiping out half the hidden potential.
With oils meanwhile, almost everyone on skincare chatrooms has opened a bottle and with horror, been blasted with the rancid smell. Skincare fridges have sparked much excitement, and they’re right. We already recommend keeping natural oils in a dark, cool cupboard.
The higher the fragile polyunsaturated fats, the greater the instability, because their short molecular structure is easier to cleave. For example, the formerly noble grapeseed oil, generous in vitamin E and friend of frustrated teenagers, can become a toxic potion swimming with free radicals.
Succumbing to your skincare fridge obsession won’t preserve aloe vera for eternity, as oxygen exposure is also vital. However, the social media hype is undoubtedly justified.
The vitamin C rumours
If there’s a single most common product mentioned alongside skincare fridges, it’s easily vitamin C serums. The logic: vitamin C, or sodium ascorbyl phosphate (commonly found in serums), is particularly fragile, and will vanish within the bottle’s liquid without you ever knowing.
The truth: commercial serums themselves confess to having a short shelf life of only 3 months. Vitamin C depreciation is why, for example, orange juice stored in a warehouse is inferior to a natural orange plucked off a tree. Unopened, they last for years, but the second you unscrew the lid, oxygen flows in and the depreciation process starts. Vitamin C serums start off clear, but slowly morph to a reddy brown, like the surface of Mars, a telltale sign which everyone notices.
That’s where the theorised miracle of skincare fridges steps in. In foods, for example, vitamin C’s temperature is an endlessly researched subject.
At refrigerated temperatures of 4c, broccoli’s vitamin C fell by 0% after 7 days compared to 56% at 20 degrees. For spinach the figures were 75% vs 100%, for carrots, 10% vs 27%, for green peas, 15% vs 60%. Only green beans actually increased, at 77% vs 55% (study). Meanwhile, in a fruit blend containing mango and papaya, it was 58–55% at 28 degrees versus 43–42% at 4 degrees (study).
We could do this all day. As for commercial vitamin C serums? Most contain two shady preservatives: phenoxyethanol and ethyl hexyl glycerine. Phenoxyethanol is a germicide banned in Japan, while EHG can sensitise the skin, but that’s not the point right now. Kill bacteria, they do, but glue together vitamin C’s delicate molecular structure, they do not.
The logic on Instagram is undoubtedly sound. If you’ve ever invented a natural remedy with crashing thunder and blinding lighting, like a strawberry/tamanu oil combination, a skincare fridge could be your friend.
Mind control!
Forgetting antioxidants, one thing people love about skincare fridges is how refreshing they feel on a hot summer’s day.
The cool temperatures are like a luxury spa treatment from the comfort of your own home, even sparking people awake first thing in the morning. Most interestingly, some skincare fridge fanatics claim they became more disciplined with their skincare regimens, enticed by the cool, soothing summer feeling.
In a perfect world, hardcore discipline is all you need. But if you’re constantly distracted, skincare fridges could be excellent for hijacking your brain and getting addicted to aloe vera (adding nicotine might work too).
More mystical benefits have also been proposed: some believe that colder temperatures enhance your skin tone. This is perfectly possible, given cold showers‘ weird glow benefits, which we’ve never fully explained. The theory is that when the initial vasoconstriction reverses, a dose of fresh nutrients floods the skin, or that cold temperatures are like a stress shock that supercharges antioxidant defences. The flaw here though, is that cold water is way simpler.
Some claim that skincare fridges mimic an ice pack, soothing irritated and red skin, but this is way down the inflammation chain. Calming chronic inflammation inside your body is the real secret. So are remedies like aloe vera which sort out specific chemicals like interleukin-8 on a miscrocopic level.
There’s one obvious question: why not use your main fridge?
It comes down to your tastes: some people are appalled at keeping their colourful, green tinged tamanu oil a next to a plate of roast chicken. Others want to feel like James Bond, with a gadget-filled suitcase ready to blast aloe vera in someone’s face.
However, there’s one unavoidable reason not to be sucked into the skincare fridge whirlwind, which is…
Skin permeability
It’s the opposite to the oft hyped mystical benefits: colder temperatures themselves can slow absorption.
Most acne-clearing compounds, whether retinoids or vitamin C, must pass through the skin barrier, which comprises corneocytes in a tightly assembled jigsaw allowing only beneficial molecules through. It’s like the iron gate guarding Mordor, only allowing a couple of orcs through meter by meter.
It is well established in studies that warmer temperatures loosen this barrier. Doctors know it, as the opioid pain killer fentanyl is often applied in slow release patches. Overdoses are fatal, and to prevent extra rapid absorption into the bloodstream, packets often warn against warm rooms and sunlight. The same is true for nicotine patches, diclofenac, lidocaine, isosorbide – dozens of pharmaceutical drugs. Even paraben preservatives absorb faster.
The normal skin temperature is 32C, and at 5 degrees above average, skin absorption of compounds can spike 1.9 fold. At 42 degrees, it can spike 3.4 fold.
Firstly, the tiny little capillaries in your skin expand, opening up blood transportation. It’s the basic biological process, triggered by temperature sensitive nerves, to funnel warmth from the body’s core to fly away through the skin. However, more subtly, the lipid (fat) molecules in your skin barrier change, becoming frizzier and angled, with the space between them increasing.
The fear is therefore that with a skincare fridge, natural compounds like vitamin C and antioxidants will be blocked. You could instinctively grab a frosty witch hazel bottle at 11pm, only for the compounds to rest on the surface all night, waking up 8 hours later to disappointment.
Not all drugs gain power with heat. Oxybuntin (a bladder protecting drug), for example, barely changed; different molecules have different shapes. However, it’s confirmed that natural compounds are affected too, including caffeine (study).
For skincare fridges, the only question is whether decreasing temperatures works oppositely.
Imagine if your favourite regimen is applying grapeseed oil first, followed by witch hazel thirty minutes later. The cool temperatures will easily have enough time to alter capillaries, corneocytes, keratinocytes, lipids, the whole cast of characters.
Decreased absorption is the number one hidden reason to resist the skincare fridge temptation, if functionality not style is your main goal.
The verdict: your strategy
At the end of the day, it’s really personal taste that tips this trend over the edge.
Unless you’re the maddest scientist in all of Transylvania, with dozens of oil bottles littering your shelf, skincare fridges are pointless. They’re great at preserving vitamin C, squeezing every last drop of acne-clearing power out, but you can easily designate a compartment of your main fridge. Another flaw with skincare fridges is that you’ll be trapped on Instagram 24/7 taking photos of them.
However, if you’re completely obsessed? If an elbow sharply nudges you in the ribs whenever the adverts appear on TV? If your dreams always end in a golden skincare fridge falling from the sky and bashing you on the head, no matter how they started? There’s no reason not to get one.
If you do give in, then preservative-free natural remedies should be given priority access. To minimise the absorption decrease, always take them out a full hour before application. Preservation is where the magic happens; there are no benefits of cold temperatures themselves which cannot be obtained with a refreshing splash of cold water each evening.
Skincare fridges are pointless, yet harmless.
BONUS – five topical treatments that last for years
However, what if your fridge is bursting with beer and pizza? Sometimes, it’s cool to have a topical treatment you know is impervious to gradual deterioration, maintaining its acne-clearing powers to the bitter end.
The following remedies are totally stable in the face of light, heat and oxygen:
Raw honey – the king of long-lasting topical treatments. One time, archaeologists excavating tombs in an Egyptian pyramid discovered fine terracotta jars. Inside was raw honey, placed there approximately 3000 years ago as a sweet treat for the afterlife, or a gift for the gods. It was crystallised, but perfectly edible.
It’s all down to raw honey’s abundant natural compounds, like bee defensin 1, methylgyloxal, and antioxidants. For acne, raw honey is immensely antibacterial, and this carries through to self preservation. In 1000 years, when all our cities are reduced to rubble, alien travellers will probably stumble across a lone jar of honey as the sole proof that we ever existed.
Argan oil – one of the most vitamin E-packed oils is also long-lasting. Argan oil has an average shelf life of 2 years plus when stored properly.
The vitamin E itself wards off free radicals, but the fat profile is also important. Stable oleic acid is plentiful (46% of fatty acids), while linoleic acid is lower (33%). The acne-friendly yet unstable grapeseed oil contains 70% linoleic acid, which is great for your skin barrier, strengthening moisture-holding ceramides, but fragile in heat.
Jojoba oil – it comes from a spiky desert shrub in the scorching sands of northern Mexico, so it can probably withstand the sun on your kitchen window ledge. Jojoba oil has a massive shelf life of approximately 5 years. It’s technically a wax, not an oil, making it particularly stable. For acne, jojoba oil is an unstoppable natural moisturiser, kicking sand in the face of chemical-laden creams.
Lavender oil – one of the sturdiest essential oils. Its shelf life of 4 years easily beats tea tree oil at 1 year. Ironically, when it does oxidise, lavender oil becomes a supervillain, as its linalool and limonene compounds morph into irritating mutants.
However, lavender oil is rich in monoterpenols, including linalool, which are much stabler than monoterpenes like myrcene. Also enhancing the stability is lavender oil’s phenolic antioxidants. Role in acne: lowers inflammatory neutrophils and may increase collagen.
Castor oil – another carrier oil with a 5 year life. It’s probably down to castor oil’s unique fatty acid – ricinoleic acid, named after the politician-poisoning toxin ricin (don’t worry, it’s only in the beans).
90% of the total fats are ricinoleic acid. It’s a monounsaturated fat, midway between stable saturated and unstable polyunsaturated, but it could be even stabler than usual, unresearched as it is. For acne, castor oil is mysterious, but promising.
Thanks for reading!