Skin Probiotics and Skin Care Products for the Microbiome

There are many skin care products on the market today that claim to "nourish" or "balance" the skin microbiome with ingredients called skin probiotics, but do these products really work to increase good bacteria and beneficial skin flora? The skin microbiome refers to the community of microbes, including bacteria, fungi, and viruses, that live on the surface of our skin. This microbial community has adapted over time to thrive in the relatively harsh environment of human skin. But can probiotic skin care products truly support the balanced functioning of this complex microbial ecosystem? In this blog, I'll take a scientific look at common ingredients in skin probiotic products and evaluate whether they can deliver on their claims to increase healthy skin bacteria and skin flora. You can find a list of probiotic and prebiotic ingredients towards the end of the blog.

The skin microbiome plays a critical role in maintaining skin health and preventing disease. This community of microbes that lives on our skin regulates key functions like immune responses, wound healing, and protection against infections and inflammation. When the microbiome is thrown out of balance, it can lead to common skin disorders. 

An imbalance in skin flora occurs when the healthy microbes on the skin's surface get disrupted. This allows harmful microbes to grow and infections to happen. Healthy skin bacteria can also become harmful when it overgrows and dominates other good skin bacteria. Diversity of good skin bacteria is the healthiest skin microbiome and the goal of microbiome targeted skin care products. 

An unbalanced skin microbiome is known as dysbiosis.  Science is just beginning to unravel repercussions of skin dysbiosis. The development of skin conditions like acne, eczema, seborrheic dermatitis, and chronic wounds have been tied to microbial imbalances in the skin microbiome. Problems with the immune system in the skin are also linked to an unbalanced microbiome. By supporting a diverse and balanced skin microbiome, we may be able to prevent and treat many skin problems.

The problem is- scientists have not completely figured out yet which bacteria are healthiest for the skin and which cause acne, rosacea, and other skin disorders,

There are many different skin probiotics and prebiotics found in skin care products.  You can find a list of skin probiotics at the end of the blog

Cleansing can disrupt the skin microbiome  by stripping away skin  lipids, depositing lipids and temporarily altering skin pH and hydration. However, the disruption is temporary, so cleanser choice is not critical.   

The moisturizer and serum you choose seems to affect the microbiome more than your cleanser choice does unless you wash too often or use an antibacterial cleanser with alcohol or other antimicrobials in it.

 In one clinical trial, researchers analyzed the effects of various liquid body washes used regularly on the forearms. They found small decreases in antimicrobial peptides after washing, but no major shifts in overall bacterial diversity. 

One study (9) found that while cleansing led to microbial compositional changes, the skin microbiota was resilient and able to adapt.  The microbiome rapidly shifted after cleansing but reached equilibrium within a day. 

Overall, research indicates cleansing causes temporary microbial fluctuations, but the resilient skin microbiome is able to rebound while reducing potentially harmful bacteria. Maintaining skin barrier health by using a moisturizer and avoiding excessive washing frequency  minimizes microbiome disruption.

Serums that contain prebiotic and probiotic ingredients can nourish your microbiome.

Acne is a long-term skin condition caused by inflammation. The specific causes of acne are complex and not fully understood; however two microbes - Propionibacterium acnes (P. acnes) and Malassezia - are known to play a role by affecting oil production, clogging pores, and triggering inflammation. 

In a 2017 study, Dréno and colleagues analyzed the skin microbiota of 26 people with mild to moderate acne. (28) At the start, they found higher levels of Proteobacteria and Firmicutes and lower levels of Actinobacteria compared to healthy skin. While Staphylococci were more abundant on acne lesions, P. acnes made up less than 2% of the bacteria. After 28 days of treatment with either an antibiotic or a skincare product, Actinobacteria and Staphylococci decreased, but only Actinobacteria dropped with the antibiotic.

In another 2018 study, Kelhälä and team (29) confirmed that higher levels of the bacteria P. acnes (now called C. acnes) was  linked to more severe acne. Acne patients had different cheek microbiota compared to controls, including more of a certain Streptococcus. The medications isotretinoin and lymecycline reduced acne severity, lowered P. acnes levels, and increased microbial diversity on the cheeks and back.

These studies show that lowering C. acnes bacteria levels and increasing microbiome diversity can help improve acne.

Research shows  aging has a significant impact on the composition and diversity of skin microbes. A 2019 study by Dimitriu et al. analyzed skin microbiome samples from 495 people of different backgrounds. They identified aging as one of the top factors, after lifestyle, physiology, demographics, and skin pigmentation, that alters the skin microbiome. (7)

Aging brings many changes to skin properties, including skin barrier disruption, modified oil gland activity, and differences in protein production. These age-related shifts disrupt the ecological conditions that skin microbes depend on to survive. As the skin environment transforms with age, the altered microbial communities influence immune function, skin barrier integrity, and other functions. Rebalancing the skin microbiome of aged skin is the goal of antiaging skin care products that target the microbiome.

Atopic dermatitis (AD), also called eczema, is characterized by altered skin and gut flora and diminished diversity of the skin microbiome.

Although its precise role is unclear, Staphylococcus aureus selectively colonizes the lesions of AD patients but not healthy skin (14). Reduced microbiome diversity in AD correlates with greater disease severity and overgrowth of harmful bacteria like S. aureus (19). Skin affected by AD has low bacterial diversity, with increased S. aureus and S. epidermidis and decreased Propionibacterium acnes compared to healthy skin (16). S. aureus colonization precedes AD symptom onset, suggesting it may contribute to AD development (20). Excess S. aureus with depleted S. epidermidis levels typifies AD (21).

Eradicating S. aureus alone does not improve AD (24). 

Early studies applying commensal organisms like S. hominis or R. mucosa topically lessened AD symptoms and S. aureus colonization (19). 

Given the microbiome role in eczema, prebiotics, probiotics, and microbiota transplant therapies warrant exploration but it is too soon to know which skin microbiome products really work to treat or cure eczema. 

Cleansers that reduce overall skin bacteria or deposit fatty acids on the skin may help regulate the microbiome or prevent secondary infections in eczema.

The difference between prebiotics and probiotics is that prebiotics feed beneficial bacteria while probiotics are the beneficial bacteria themselves. Both prebiotics and probiotics support skin health when used topically by nourishing beneficial microbiota, fighting pathogens, regulating moisture and inflammation, and promoting overall balance in the skin microbiome. Keep reading for a list of skin probiotics and prebiotics.

Prebiotics nourish beneficial microbes already living on the skin's surface. They provide nutrients that selectively feed and support helpful bacteria like lactobacilli and actinobacteria that make up the skin microbiome.

By providing nourishment, prebiotics help populations of protective bacteria flourish. With adequate sustenance from prebiotics, beneficial microbes grow and thrive. This allows them to better colonize the skin, crowd out harmful microbes, and maintain balance.

A well-nourished microbiome with ample good bacteria helps skin function optimally.

Some common prebiotics include inulin, fructooligosaccharides (FOS), galacto-oligosaccharides (GOS), and resistant starch. When prebiotics reach the colon, they are fermented by gut bacteria like Bifidobacteria and Lactobacilli. This selective stimulation helps these healthy bacteria thrive. A diet rich in prebiotic fibers has been shown to increase the diversity of gut microbiota, enhance immune function, improve digestion, and offer other health benefits. Prebiotics support the beneficial microbial balance in the gut.

Prebiotics can be beneficial for skin health when used topically in skincare products. Prebiotics help nourish and selectively stimulate the growth of good bacteria that reside on the skin’s surface. Some common prebiotics used in topical skincare include:

• Beta-glucan
• Aloe vera
• Honey
• Seaweed extracts
• Pomegranate extract
• Licorice root
   

When applied on the skin, these prebiotic ingredients help strengthen the skin’s protective microbiome layer. This helps inhibit the growth of harmful bacteria that can cause inflammation, acne, dermatitis, etc. Topical prebiotics also help retain moisture in the skin, improve skin barrier function, and exert antioxidant effects. Their ability to optimize the skin microbiome helps reduce irritation, sensitivity, and signs of aging.

Probiotics are live beneficial microbes that reinforce and diversify the skin's microbiome. 

By populating the skin with “good bacteria,  they help increase numbers of protective microbes and promote a balanced, healthy microbial community.

Probiotics are live microorganisms that provide health benefits when consumed or put on the skin. Common probiotic strains come from two groups of bacteria - Lactobacillus and Bifidobacterium. They help populate the gut with beneficial microbiota to optimize digestion and nutrient absorption. Probiotics can help alleviate gastrointestinal issues like diarrhea, constipation, IBS, lactose intolerance, and infections. They also support immune function and produce vitamins. Studies show probiotics may boost mood, heart health, weight loss, and skin conditions too. Supplements and fermented foods like yogurt, kefir, sauerkraut, and kimchi contain probiotics. These "good bacteria" are essential for maintaining intestinal homeostasis and overall health.

Probiotics applied topically in skincare also benefit the skin’s microbiome by introducing good live microorganisms. Some common probiotics used include:

• Bifidobacterium
•  Lactobacillus, Bacillus
• yeast strains. 

Clinical studies show topical probiotic skincare helps reduce skin sensitivity, increase moisture retention, decrease inflammatory cytokines, and regulate sebum production. 

Probiotics applied on the skin can help inhibit pathogens, balance oiliness, hydrate the skin barrier, and calm inflammatory skin conditions like acne, rosacea, eczema. 

Sprays, creams, lotions, cleansers and masks containing probiotics or their byproducts help restore microbial diversity, protect against damage, and promote healthier skin. Like in the gut, balance between good and bad microbes on the skin is vital for optimal skin function.

Below is a list of skin prebiotics and probiotics and how they work.

Alpha-glucan oligosaccharide is a carbohydrate derived from plants that consists of short chains of glucose molecules linked together. It is typically sourced from rice, barley, oats, yeast, algae, and fungi.

In skincare formulations, alpha-glucan oligosaccharide functions as a humectant, skin-conditioning agent, and antioxidant. Some of its key benefits include:

• Boosts hydration - 

The oligosaccharide structure allows alpha-glucan to attract and bind moisture to the skin. This provides immediate and long-lasting hydration benefits.

• Skin barrier repair - 

Alpha-glucan oligosaccharide enhances the skin's barrier function by stimulating ceramide and lipid production. This helps repair damage and lock in moisture.

• Anti-inflammatory effects - 

Studies show alpha-glucan oligosaccharide can suppress inflammatory cytokines and enzymes like elastase that break down collagen. This calms irritation and redness.

• Antioxidant protection - 

The compound exhibits free radical scavenging abilities to protect against oxidative stress caused by UV exposure and pollution.

• Wound healing - 

Research indicates alpha-glucan oligosaccharide can activate immune cells and stimulate collagen production to accelerate wound closure and tissue regeneration.

Overall, alpha-glucan oligosaccharide is a versatile ingredient that provides comprehensive hydrating, soothing, strengthening, and protecting effects for the skin. Its mix of biological activities make it useful in anti-aging, acne-fighting, sensitive skin, and post-procedure skincare products.

Siralice™ is a form of baccillus ferment that is said to increase cell energy based on , computational analysis that identified a
potential activity on the sirtuin-3 gene. (36)

I am looking into getting more data on this ingredient so stay tuned.

Diglucosyl gallic acid is a biotechnologically created molecule that is activated by the skin's microbiome to act as a skin-brightening, anti-inflammatory, and photoprotectant ingredient.

 Once applied on skin, it is partially converted by the skin microbiome into trihydroxy benzoic acid, a natural tyrosinase enzyme inhibitor. Together, these two molecules work synergistically to control skin pigmentation and color. 

Diglucosyl gallic acid is a novel cosmetic ingredient that leverages the skin microbiome to provide synergistic whitening, soothing, and UV protective effects when applied topically, making it a unique addition to skin care and cosmetic products targeting hyperpigmentation and inflammation.

Diglucosyl gallic acid has been shown to reduce free radical generation, inhibit tyrosinase production, prevent melanin transfer to upper skin layers, and control skin inflammation. Research indicates it can protect against UV rays by decreasing UV spot formation over time through non-filter effects. It also modulates skin color by improving skin brightness, reducing redness, yellowness, and brownness. This is attributed to its anti-melanogenesis properties, including decreasing melanin content, and its anti-inflammatory effects. (44)

The EWG rates Diglucosyl gallic acid as a 1 (very safe). There is no known toxicity.

Gluco-oligosaccharides (GOS) are short chain carbohydrates that can be derived from plants or  dairy products. When formulated into skincare products and applied topically, they provide several benefits:

• Humectant properties - GOS attract and bind moisture to the skin. They are excellent humectants that help hydrate and plump the skin.
• Prebiotic effects - Topical GOS selectively feed and stimulate the growth of beneficial bacteria on the skin's surface. This helps strengthen the microbiome.
• Skin barrier enhancement - Research shows GOS can increase ceramide production in skin cells. Ceramides are natural lipids that help reinforce the skin barrier.
• Anti-inflammatory - GOS have been found to suppress inflammatory cytokines and reduce irritation in sensitive skin. This helps calm conditions like eczema.
• Antimicrobial - By promoting beneficial bacteria growth, GOS inhibit colonization by harmful microbes. This provides protection.
• Wound healing - In studies, GOS stimulated fibroblast production of collagen and accelerated wound closure. This aids tissue repair.

Overall, topical use of gluco-oligosaccharides provides hydration, prebiotic nourishment for skin microbes, reinforcement of the protective barrier, soothing of irritation, and faster healing of wounds. GOS are excellent multifunctional ingredients for dry, sensitive, or damaged skin.

A lysate is a solution containing the contents of lysed (broken open) cells. Lysates contain all the complex biological molecules released from inside the cells, including proteins, DNA, RNA, lipids, carbohydrates, and other biomolecules. The cell composition, elasticity, and activation of macrophages differ between bacterial strains, even within the same species [39]. Lysates from probiotic bacteria are used in cosmetic products because they contain a variety of biologically active molecules that may provide benefits to skin health and function. Lysate contains the soluble contents of the bacterial cells but not whole intact cells.

Bifidobacterium longum reuteri : 
A bacterial lysate from the probiotic Bifidobacterium longum reuteri strain was shown to decrease vasodilation, edema, mast cell degranulation, and TNF-alpha release. (37) Studies assessing barrier function through trans-epidermal water loss showed improvement with application of a product containing this lysate.

Lysates of Lacticaseibacillus rhamnosus GG: 
The lactobacilli lysates L. rhamnosus GG and L. reuteri significantly increased the rate of re-epithelialization of wounds (40).
Intriguingly, little has been reported on the chemical composition of the lysates being used in cosmetics. The effects of lysates differ between bacterial strains, and therefore the way they act on skin will differ. Although there is value in using these types of preparations, further studies are still required on a strain-dependent basis before drawing conclusions and making claims.
 

In skincare, Pseudoalteromonas ferment extract has demonstrated the following benefits:

• Antioxidant protection - The extract contains several antioxidant compounds such as carotenoids and amino acids like taurine. These help neutralize free radicals and prevent oxidative damage to skin cells.
• Anti-inflammatory effects - Studies have shown the extract can inhibit inflammatory mediators like nitric oxide and prostaglandins. Reducing inflammation in the skin helps minimize redness, irritation, and sensitivity.
• Antimicrobial properties - Pseudoalteromonas ferment extract exhibits antimicrobial effects against common skin microbes like Propionibacterium acnes and Staphylococcus aureus. This provides protection against pathogens that can cause acne and skin infections.
• Boosts collagen production - Compounds in the extract like sulfated polysaccharides and amino acids can stimulate fibroblast activity and collagen synthesis in the skin. This leads to firmer, more youthful looking skin.
• Skin barrier enhancement - The extract has been shown to increase skin ceramide production and expression of tight junction proteins. This strengthens the skin barrier function, improving moisture retention.
  Overall, Pseudoalteromonas ferment extract is a marine biotechnology ingredient that provides comprehensive skin protection, anti-aging benefits, and a reinforced moisture barrier when included in skincare formulations. Its multifaceted bioactive compounds make it a promising ingredient for sensitive, acne-prone, or dry skin types.

This ferment is a yeast extract with antioxidant effects. (47)

Saccharide isomerase, a class of hygroscopic compounds characterized by their ability to absorb and retain water also possesses the ability to be metabolized by the skin's local microbiota.

In 2020, a scientific investigation (9) evaluated the impact of a soap-based body wash supplemented with saccharide isomerase on the skin’s microbial composition.  The study aimed to identify changes in the abundance of specific microbial taxa in association with the application of this active body wash formulation. Results indicated that saccharide isomerase binds to the skin, providing both short-term and long-term moisturization effects. Despite the perturbations associated with skin cleansing, the skin microbiota demonstrated resilience, with capabilities to re-establish and adjust its composition.

The inclusion of saccharide isomerase in the body wash formulation showed a decrease in the abundance of bacteria such as B.casei and R.mucilaginosa, which have potential implications in skin infections. In contrast, the beneficial bacterium P.marcusii increased in presence. It is noteworthy that saccharide isomerase’s metabolic product, astaxanthin, offers additional skin benefits. Continued research in this area is crucial to further elucidate the relationship between skincare ingredients like saccharide isomerase and the skin's microbiota composition.

Saccharomyces ferment filtrate is a byproduct of fermented yeast that is used in skincare for its protective and soothing properties. It is derived from Saccharomyces cerevisiae, a species of yeast used in winemaking, baking, and brewing. During the fermentation process, the yeast metabolizes sugar into alcohol, carbon dioxide, and other compounds that impart flavor and aroma.

The liquid portion of the fermented yeast is then filtered and processed to extract the desirable components for skincare. These include amino acids, proteins, minerals, vitamins, and other nutrients. Specifically, saccharomyces ferment filtrate is rich in B vitamins like biotin, niacin, and pantothenic acid. It also contains high amounts of glutathione, an antioxidant that helps neutralize free radicals and prevent cellular damage.

When applied topically on the skin, saccharomyces ferment filtrate provides several benefits:

Anti-inflammatory effects - The nutrients in saccharomyces calm inflammation by inhibiting inflammatory pathways involving cytokines, histamines, and prostaglandins. This helps reduce redness, swelling, and irritation.
Antioxidant protection - The glutathione and vitamins in saccharomyces ferment filtrate scavenge free radicals and prevent oxidative damage caused by UV exposure and pollution. This helps fight signs of aging.
Improved skin barrier function - Saccharomyces ferment filtrate enhances the skin's natural barrier by stimulating ceramide production and increasing moisture retention. This helps keep skin hydrated, smooth, and protected.
Skin brightening - The B vitamins and amino acids in saccharomyces ferment filtrate inhibit tyrosinase activity and suppress melanin production. This helps brighten skin tone and reduce hyperpigmentation and dark spots.
Overall, saccharomyces ferment filtrate is a multi-tasking skincare ingredient that provides comprehensive anti-inflammatory, antioxidant, moisturizing, and brightening effects for the skin. Its protective nutrients make it an excellent addition to skincare products aimed at sensitive, dry, dull, or damaged skin.

β-Glucan exhibits many biological activities and functions such as stimulation of the immune system and anti-inflammatory, anti-microbial, anti-oxidant, and wound healing effects. However, due to its dense triple helix structure, it has poor solubility, which makes it difficult to formulate and absorb into the skin.

 To make it easier to work with, β-Glucan is chemically modified into other ingredients such as Sodium carboxymethylated beta-glucan, which is a chemically-modified, water-soluble, beta-1,3-glucan derived from the cell walls of yeast (Saccharomyces cerevisiae). 

Carboxymethylated beta-glucan preparations have historically been used in cosmetic and other topical personal care products as a binding agent and for adding viscosity to products. 

Since it is derived from renewable botanical sources like oats and barley, it is a more sustainable ingredient choice.

Vitreoscilla ferment is derived from a probiotic microorganism called Vitreoscilla filiformis, which is a gram-negative bacterium.. The Vitreoscilla filiformis bacteria is fermented under controlled conditions to produce the active ingredients used in skincare products.  The fermented ingredients are extracted from this specific bacterial strain. Through this proprietary biofermentation process, the bacteria culture generates beneficial enzymes, peptides and other compounds.

The ferment contains amino acids, peptides, glycoproteins, and enzymes produced during the fermentation process. These various nutrients provide skincare benefits when applied topically.

More studies are needed to verify its efficacy and mechanisms.

Benefits:

In skincare, Vitreoscilla ferment is thought to have moisturizing, soothing, and antioxidant effects. The peptides and glycoproteins may help strengthen the skin barrier function. The amino acids can contribute to better hydration in the skin.

The nutrients in Vitreoscilla ferment can help nourish skin cells, stimulate collagen production, and regulate sebum/oil. Its enzymes may also aid in gentle exfoliation of dead skin cells on the surface.

This ingredient is found in many K-beauty skincare products focused on anti-aging, brightening, acne prevention, and moisturizing effects. The properties of Vitreoscilla ferment make it a versatile additive.

Vitreoscilla filiformis is generally considered safe for topical use in skincare. The EWG rates it as a 1. But there is limited research specifically on Vitreoscilla ferment and its long-term safety. 

We still have a lot to learn about which skin flora is healthiest- but- we do have data on which microorganisms are commonly found on the skin.

Recent studies using advanced gene sequencing have revealed the most abundant bacterial species found on healthy human skin. (4)  Skin is normally dominated by gram-positive bacteria like Staphylococcus, Corynebacterium, Enhydrobacter, Micrococcus, Cutibacterium, and Veillonella species. (5)  Common gram-negative skin bacteria include Roseomonas mucosa, Pseudomonas, Acinetobacter, Pantoea septica, and Moraxella osloensis.(6) Additional research has confirmed gram-negative bacteria such as Enterobacteriaceae and anaerobes are part of the transient microbiota on the skin,

In addition to bacteria, the skin microbiome contains populations of fungi and yeasts. Malassezia species are the most abundant fungal residents on human skin. These lipophilic yeasts consume oils on the skin's surface. Though usually harmless, Malassezia can overgrow and cause conditions like tinea versicolor, folliculitis, and seborrheic dermatitis. Other common fungal genera found on skin include Candida, Cryptococcus, Rhodotorula, Aspergillus, and Alternaria species. These fungi are part of the normal skin flora, but may act opportunistically as pathogens in some cases. Research continues to uncover the diversity of fungal communities inhabiting the skin and their complex interactions with bacterial populations and the host immune system. Understanding what constitutes a healthy mycobiome remains an important area of skin microbiome research.

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