Yogurt is one of the staples of homemade acne remedies. Bio-live yogurt is recommended everywhere, in recipes combined with cinnamon, honey, cucumber, ginger and endless natural ingredients.
The reality? Yes, yogurt is an excellent ingredient, to carry other ingredients and to increase their penetration due to its fats. But the potential of applying yogurt to your face goes far beyond what many realise.
In short, yogurt is one of the craziest, most obscure, yet most effective moisturisers you can apply to your face. It has nothing to do with the fats, the nutrients, or its thickness and creaminess. The moisturising properties are entirely down to the bacteria.
Yogurt increases skin hydration and moisture
Recently, the discovery of healthy gut bacteria has opened a whole new realm of opportunity for acne. Bacteria which churn out inflammation-lowering butyrate, mood boosting serotonin, and enhance nutrient absorption have all been discovered. There’s literally millions of these strains and for acne, more juicy facts are being revealed constantly.
But there’s another area colonised by beneficial bacteria which is much less investigated – the skin. We know that p.acnes bacteria causes acne, and we know that malassezia yeasts causes pityrosporum folliculitis. We also know now that p.acnes substrain 1a is much worse for acne, compared to other strains which are beneficial. The skin also has colonies of bifidobacterium which can prevent yeast overgrowth.
With that in mind. topical application of bacteria is a rapidly developing area of acne science. Creams and lotions containing probiotics are becoming increasingly popular. For example, one probiotic spray you can buy contains Ammonia-Oxidizing Bacteria, known as “sweat eating bacteria”.
AOB has the interesting property of consuming ammonia, a component of sweat. During the digestion of ammonia, AOB churns out healthy metabolites which improve skin tone and appearance. Ammonia-oxidising bacteria is found naturally in human skin pores, but in low levels, and can also be crippled by benzoyl peroxide and chlorine. This spray intends to increase its levels and benefits…
…which brings us to yogurt. Yogurt is the most famous biolive food sold widely today. It’s also popular as a topical treatment in Indian Ayuvedic medicine and homemade recipes in the households of many acne-clearing enthusiasts.
The specific strains of bacteria in yogurt are Streptococcus thermophilus and Lactobacillus bulgaricus. These strains are lactic acid producing bacteria; they’re able to consume the lactose sugars in milk and churn out lactic acid in its place. This gives yogurt its signature taste, as using different strains results in a different dairy product such as fermented cheese. Taste aside, the lactose itself gives both bacteria room to thrive, multiplying further as they consume ever more of the sugar.
The greatness of yogurt for your skin lies within the streptococcus thermophilus strain. This strain is a non-mobile fermentative bacteria. It’s a member of the feared streptococcus family, but is completely safe, unlike the disease-causing Streptococcus pneumoniae.
Streptococcus thermophilus is not a normal part of human skin flora, but is an excellent one once it arrives there. In this study from 2007, scientists applied a cream containing high amounts of streptococcus thermophilus to human skin. 20 healthy volunteers were made to apply either the cream or a placebo to the skin of their forearms.
After 14 days, the bacteria group enjoyed a significant increase in skin hydration. In the placebo group nothing changed.
The streptococcus thermophilus led to increases in skin water binding ability, as well as skin barrier function. Trans-epidermal water loss, the quantity of moisture leaving the skin’s outermost layer, fell significantly.
Essentially, this bacteria can be summarised as being an excellent moisturiser, excellent against dry skin, and excellent for skin tone. This is excellent news for yogurt, since the the greater the fermentation, the more bio-live a natural yogurt, and the more streptococcus thermophilus it contains.
The joys of ceramides…
The same study also detected a huge increase in skin ceramide levels, and this was deemed to be responsible.
This study was the follow up to another promising one from 1999, where applying streptococcus thermophilus led to a huge increase in skin ceramide levels after just 7 days, and in a dose-dependant manner. Yet another study found that applying streptococcus thermophilus increased ceramide levels, this time soothing the symptoms of atopic dermatitis such as scaling and irritation.
The bacteria found in yogurt is basically proven to increase ceramides. Ceramides are fat-based structural compounds in skin which form about 43% of the stratum corneum layer. They’re vital for skin barrier function and reductions have been linked to both atopic dermatitis and ageing.
Ceramides have a very important role in retaining moisture, in controlling trans-epidermal water loss, and essentially, keeping water bound in the skin. You could say that while hyaluronic acid stores water and moisture in the skin, layers of ceramides seal the moisture in and prevent its escape.
On top of the confirmed benefits, acne patients were proven in this study to have lower ceramide levels than average. Topical yogurt can increase ceramide levels, if it’s dense in bacteria.
The normal formation of ceramides begins when an enzymes called sphingomyelinase converts sphingomyelin into sphingosines. Ceramide molecules essentially consist of sphingosine and dihydroxysphingosine, and this enzyme is key for creating them. You don’t need to know how sphingosines work, you just need to know that the enzyme sphingomyelinase is vital. Deficiencies in sphingomyelinase lead to low ceramide formation and poorly hydrated skin, and possibly acne.
…and the connection to yogurt
It turns out that streptococcus thermophilus naturally churns out its own form of sphingomyelinase, a form which acts identically to human-produced sphingomyelinase.
In each study, it was found that streptococcus thermophilus increased sphingomyelinase activity on the skin, and that’s how it increased ceramide formation. Ceramide formation is supposed to be a process your body undergoes by itself, but with topical yogurt, you can supercharge the formation of these natural moisturisers, assuming that your choice is rich in bacteria.
Each study was performed on both isolated human cells (in vitro) and living humans (in vivo). Streptococcus thermophilus was able to increase sphingomyelin and the formation of ceramides in both cases. You might expect bacteria to be less active in real human skin, because it has to affect ceramide enzymes which form within the deeper keratinocyte cells. How is a mere bacterial strain supposed to penetrate the depths of human skin, and then gain entry to cells? The likes of p.acnes bacteria only dwell within skin pores.
It turns out that the skin stores sphingomyelin within multiple pools. Some sphingomyelin is stored within keratinocyte cells, but some of this raw material for ceramides exists on the external surface of cells, while small pools also exist in intercellular space.
Streptococcus thermophilus and its enzymes can reach these two stores, and combine them for a strong increase in ceramides. This is why the bacteria increased hydration in the first study, why it increased skin barrier function, and why it improved atopic dermatitis.
Finally, this is why yogurt is a secret moisturising miracle for your skin. Not because of its fats, but its profile of bacteria. It’s about as obscure a moisturiser as you can get, but a rock solid one.
Hyaluronic acid potential
Another factor of interest is that streptococcus thermophilus churns out hyaluronic acid, just like it produces sphingomyelinases. Commercial hyaluronic acid for usage in creams is manufactured using Streptococcus zooepidemicus, and its relative has the power too.
This is why yogurt is such a strong food source of hyaluronic acid. As we discussed here, hyaluronic acid stores water within your skin and increases moisture rapidly. Hyaluronic acid levels decline with age and that’s why older people have dryer, thinner and less elastic skin. Therefore, an interesting qustion which we don’t have the answer to is whether yogurt can increase your hyaluronic acid levels.
The problem is that topically applying hyaluronic acid is ineffective in most cases, as hyaluronates are created and organised deep within your skin’s structure. Unlike vitamin C or antioxidants, applying hyaluronic acid externally usually achieves nothing. However, there’s a chance that bacteria could migrate deeper into your dermis and churn out hyaluounic acid there. It’s also possible that your skin could break down the hyaloruonic acid and recycle its ingredients.
If true, this power would make yogurt even more of a moisturising monstrosity. I’d put the chances at significantly lower than 50%, but it’s something to remember.
There is one confirmed topical probiotic though – soy milk. Properly fermented soy milk, as opposed to cheaper products, contains high amounts of the bacteria Bifidobacterium breve. Scientists in a 2000 study applied bacteria-rich soy milk to mice skin for a grand total of six weeks.
By the end of the study, the skin’s own production of hyaluronic acid significantly increased. The expected benefits also materialised, including more moisturised skin and thicker skin. A team of mice which received unfermented soy milk enjoyed no benefits.
The two compounds believed to explain the increase were genistein and daidzein. Both were present in the fermented milk but not the unfermented batch. These isoflavone compounds are produced by bifidobacterium breve and have been separately confirmed to stimulate hyaluronic acid production. This study found that both increased the density of hyaluronates in skin, so thanks to its bacteria, soy milk contains compounds which indirectly increase hyaluronic acid (the best approach).
Like yogurt, soy milk is another hidden secret for moisturising, and this illustrates the potential of topical probiotics overall.
Other yogurty powers
Yogurt isn’t particularly rich in vitamin A, vitamin E or vitamin C, although full-fat yogurt is more nutritious. However, it contain surprising amounts of antioxidants, believed to be generated by bacterial activity.
Proper yogurt is also drenched in lactic acid. Topically applied lactic acid was shown to improve skin quality massively after 3 months in this study. At 5% concentration it thickened and firmed up the epidermis; at 12% concentration lactic acid thickened and firmed up the dermis and epidermis. The skin also grew smoother, while wrinkles faded away. What’s even better is that lactic acid enhances ceramide formation as well, so essentially, it multiplies yogurt’s main benefit further.
Lactic acid is also a member of the alpha hydroxy acid class along with citric acid, a class which is used in cosmetics for removing dead skin cells on the outer layer of the face. What’s weird is that alpha hyroxy acids have a side effect of making the skin thinner, which I wouldn’t recommend, but the study above happily contradicts this.
Another advantage is that this nutrition comes in a fat base, the natural fats of dairy like lauric acid and palmitic acid, which will enhance the penetration. You normally have to add carrier oils to topical treatments, but yogurt and its compounds come prepacked. This also applies to the bacteria; the great studies on streptococcus thermophilus applied it using a fat-based cream.
How to find the most bio-live yogurt
The success of this acne remedy depends entirely on its bacterial content. The antioxidants, lactic acid, and ceramides depend on it. If your yogurt isn’t properly biolive you might as well not bother, so how do acquire the holy grail of yogurts?
Your first task is to avoid basic grocery store yogurts. Low fat, artificially flavoured, filler-loaded yogurts should be avoided for the simple reason that they’re fun foods, not health foods. They’re not intended to be truly biolive, they’re intended to taste great and appeal to kids while maybe delivering some calcium.
Commercial yogurts contain the correct species of bacteria, streptococcus thermophilus, but far from the right content. Remember that the glorious seal of “Live and Active Cultures” means nothing. Numerous common brands of yogurt bearing this seal have been analysed and found to contain less than the legally required level of 100 million live cultures per gram. The seal is often only true at the time of manufacture, not sale.
A problem with eating yogurt is that many brands are so high in added sugar, which feeds unhealthy gut microorganisms like candida, that the beneficial bacteria is completely outweighed. Luckily, this is no problem topically, but flavour enhancers of commercial yogurt such as aspartame and sucralose actually have antibacterial properties.
The task is to get an organic yogurt brand, but interestingly, many are higher in sugar than conventional counterparts. They obviously think that they can get away with it, so follow this strategy. The only two ingredients should be organic milk, and live cultures. Get an organic brand which specifically boasts of high probiotic counts.
What about the classic yogurt factors? Full fat yogurt is vital, because the streptococcus thermophilus was applied in an oil base in the studies. You also need fats for lactic acid and antioxidant penetration, so the ultimate strategy (though not absolutely necessary) is to buy organic Greek yogurt. Greek yoghurt is strained to remove additional whey, the protein rich liquid. Therefore, gram for gram, what remains is richer in fat. Buying raw milk is unnecessary because the lactose which feeds the bacteria is no more concentrated.
There’s so many different brands coming and going that it’s hard to recommend a specific one. Whole Foods shops sell highly biolive yogurt brands, and because these products market themselves specifically on their high bacterial content, they’re usually reliable, but always check the label for streptococcus thermophilus. Most yogurts contain this strain, but there are exceptions: the popular brand Chobani is an example.
A great hidden sign to stay alert for is tanginess. The sour tang of yoghurt is derived from lactic acid, lactic acid which is pumped out furiously by the bacteria. The more biolive the yogurt, the move lactic acid there should be.
If you ever leave a truly biolive yogurt for two weeks in the fridge while you go on holiday, you might be pleasantly surprised to find that it’s still edible when you return. You might be unpleasantly surprised to feel like your mouth is about to explode when you eat it; the tanginess will have multiplied exponentially thanks to constant bacterial fermentation while you were away. The sugar content should have also decreased.
You can tell if your yoghurt is up to standard for acne by simply eating a small amount of it.
The verdict – analysis
Full-fat, organic biolive yogurt is an excellent hidden moisturiser, operating through one of the most obscure mechanisms imaginable.
The increase in ceramides and skin quality from streptococcus thermophilus is well supported; you just have to track a great brand down. But how useful is yogurt within your overall skin enhancing strategy?
It’s definitely not necessary – far from it. You can acquire glowing and smooth skin from both your diet and by avoiding environmental villains which assault it like air pollution. Streptococcus thermophilus isn’t even a natural part of human skin flora. But it’s a truly great bonus strategy you can use, one which has minimal downsides.
As for acne itself, the opportunities are mostly limited to the moisturising side benefits. But that’s not a bad thing, because strong and healthy skin is very important for preventing microfissures, skin which is weak in the face of irritants, and p.acnes overgrowth. You will also be less reliant on chemical grocery store moisturisers, some of the worst cosmetics for inflammation. Then there’s the fact that low ceramide levels are tentatively linked to acne.
The best thing about topical yogurt is its uniqueness. You can nourish your epidermis with fatty acids with grapeseed oil, high-linoleic sunflower oil, or tamanu oil. Great as those topical treatments are, yogurt has a secret weapon they don’t. The fats of yoghurt will also provide more traditional moisturising properties.
You can surrender to the skin-clearing hive mind and use yogurt in recipes; jumping on the bandwagon would be smart here. Or you can use yogurt as a moisturiser in isolation.
Regardless, if you want to go all out on anti-ageing, skin tone, and skin smoothness, topical yoghurt is a great topical treatment to try.
Thanks for reading!