The microbiome, community of microorganisms living on and in the body, has been a significant area of research in medicine and dermatology over the past decade. Most coverage focuses on the gut microbiome, but the skin, including the scalp, hosts its own distinct microbial community with real influence on scalp health and hair growth conditions.
What the Scalp Microbiome Is
The scalp microbiome refers to the community of bacteria, fungi, and other microorganisms that live on the scalp surface and within the hair follicle environment. Like the rest of the skin microbiome, it is highly individual, fluenced by genetics, age, diet, hygiene habits, and the products used on the scalp.
The dominant organisms on a healthy scalp include:
- Malassezia, lipid-dependent yeast species (primarily M. restricta and M. globosa) that are the most abundant fungal organisms on the scalp. They are part of the normal scalp flora but can proliferate under certain conditions.
- Cutibacterium acnes (formerly Propionibacterium acnes), bacteria found in sebaceous follicles across the skin, including the scalp.
- Staphylococcus species, S. epidermidis, a common skin commensal that plays a role in barrier protection.
These organisms exist in balance. The scalp provides them with sebum (primarily for Malassezia, which requires fatty acids to survive) and a warm, slightly acidic environment. In return, healthy scalp flora help maintain barrier integrity and inhibit colonisation by more harmful pathogens.
When Balance Is Disrupted
Dandruff and seborrhoeic dermatitis, conditions affecting an estimated 50% and 3-5% of the population respectively, re associated with disruption of this microbial balance, specifically with overgrowth of Malassezia species. When Malassezia metabolises scalp sebum, it produces oleic acid as a byproduct. In susceptible individuals, oleic acid penetrates the skin barrier, triggering an inflammatory response that causes the accelerated skin cell turnover associated with dandruff.
The factors that tip Malassezia from commensal to problematic include: increased sebum production, changes in scalp pH, disruption of the skin barrier, and use of products that alter the scalp environment.
How Hair Care Products Affect the Scalp Microbiome
The surfactants, preservatives, fragrances, and pH of hair care products all interact with the scalp microbiome.
- Harsh surfactants can disrupt the skin barrier and shift scalp pH from its natural acidic range (4.-.5) toward alkaline, creating conditions less favourable to healthy flora balance.
- Synthetic fragrances can be sensitising and in some individuals trigger inflammatory responses that affect barrier integrity.
- Buildup from silicones and waxes around follicle openings alters the local environment and can create conditions that favour Malassezia overgrowth.
- Regular scalp exfoliation helps remove this buildup and normalise the scalp environment.
The Practical Implications
A microbiome-friendly approach to scalp care means choosing products that maintain rather than disrupt scalp pH, use mild surfactants that clean without stripping, and do not leave buildup that alters the follicle environment. Regular exfoliation, weekly or fortnightly, is a practical tool for resetting the scalp surface.
Our DEEP MINT Scalp Scrub uses salicylic acid and physical exfoliation to clear follicle buildup. The VIVID Serum supports the scalp between washes with plant-based oils that do not create occlusive buildup. Full Scalp and Strength collection here.
Related reading
- Scalp Exfoliation: The Complete Guide
- Scalp Health 101: Why Healthy Hair Starts at the Root
- What Does Salicylic Acid Do on the Scalp?
- How Often Should You Use a Scalp Scrub?
- How to Use Rosemary Oil for Hair (and What to Realistically Expect)
Frequently Asked Questions
Is the scalp microbiome the same as the gut microbiome?
No. The scalp and gut each have distinct microbial communities suited to their different environments. The scalp is a skin site with high sebum production and hair follicles; the gut is a mucosal environment with very different conditions. The organisms, diversity, and functions differ substantially. Research on the gut microbiome is more extensive, but the scalp microbiome is an active area of dermatological study.
Can diet affect the scalp microbiome?
Diet influences sebum composition, which is a primary food source for Malassezia. Diets high in certain fats may affect sebum fatty acid profiles and thereby influence Malassezia activity. Research on specific dietary interventions for scalp microbiome health is still developing. General dietary patterns that support skin health, dequate essential fatty acids, zinc, and B vitamins, re relevant to scalp health.
Does washing hair more often help or hurt the scalp microbiome?
It depends on the product and individual. Over-washing with harsh surfactants can strip the skin barrier and disrupt microbial balance. Under-washing allows sebum to accumulate, which can favour Malassezia overgrowth in susceptible individuals. The appropriate frequency varies by sebum production rate, product formulation, and individual scalp type.
What is "scalp skinification"?
Scalp skinification refers to applying skincare principles, pH awareness, barrier support, microbiome consideration, and active ingredients, in scalp care. The term reflects growing recognition that the scalp is skin with specific biological needs, not just a base for hair. It has become a significant trend in professional hair care from 2024 onwards, driven in part by microbiome research.
Are probiotic or prebiotic scalp products backed by research?
Research in this area is growing but still developing. Some studies suggest that certain probiotic ingredients can support skin barrier function and modulate inflammatory responses relevant to scalp conditions. Prebiotic ingredients aim to support the growth of beneficial microorganisms. The evidence base is more established for skin applications than specifically for scalp, and results vary by product formulation and individual condition.