Acne Vulgaris and Functional Medicine Approaches to Treatment

Acne vulgaris is one of the most prevalent dermatological conditions worldwide, affecting approximately 85% of adolescents and a significant number of adults. This inflammatory disorder of the pilosebaceous unit manifests as comedones, papules, pustules, nodules, and cysts, often leading to physical discomfort, scarring, and psychosocial distress. While conventional treatments focus on symptom management, functional medicine offers a holistic, root-cause approach to addressing acne. This article explores the pathophysiology of acne vulgaris, its traditional management, and the functional medicine strategies that aim to resolve underlying triggers and restore systemic balance.

Pathophysiology of Acne Vulgaris

Acne vulgaris arises from a multifaceted interplay of factors, including excessive sebum production, follicular hyperkeratinization, colonization by Cutibacterium acnes (formerly Propionibacterium acnes), and inflammation.

1. Sebum Overproduction: Androgens play a critical role in stimulating sebaceous gland activity. Elevated levels of dihydrotestosterone (DHT) or heightened sensitivity of sebaceous glands to androgens can lead to excessive sebum secretion, creating an environment conducive to bacterial overgrowth.
2. Follicular Hyperkeratinization: This process involves the abnormal shedding of keratinocytes within the hair follicle, leading to clogged pores and the formation of comedones. Factors like hormonal fluctuations, oxidative stress, and vitamin A deficiency contribute to this dysfunction.
3. Microbial Colonization: C. acnes is a commensal bacterium that thrives in sebum-rich environments. Its proliferation within clogged follicles triggers the release of pro-inflammatory mediators, perpetuating inflammation.
4. Inflammation: Both innate and adaptive immune responses are activated in acne. Pro-inflammatory cytokines, oxidative stress, and disruptions in the skin barrier amplify the inflammatory cascade.

The Root Causes of Acne Vulgaris from a Functional Medicine Perspective

Acne vulgaris is a multifactorial disorder influenced by genetic, hormonal, environmental, and lifestyle factors. While conventional medicine primarily targets symptoms through topical and systemic therapies, functional medicine emphasizes identifying and addressing the root causes of acne. This systems-based approach considers the interplay of hormonal imbalances, gut health, inflammation, and environmental exposures in the development and persistence of acne. Functional medicine provides a holistic and sustainable healing roadmap by understanding these underlying factors.

Hormones play a central role in the pathogenesis of acne. Functional medicine examines hormonal dysregulation that contributes to excessive sebum production and inflammation.

1. Androgens and Sebum Production: Elevated androgens, such as testosterone and its more potent derivative, dihydrotestosterone (DHT), stimulate sebaceous glands to produce excess oil. This creates an environment conducive to clogged pores and bacterial overgrowth. Functional medicine evaluates androgen levels and considers factors like polycystic ovary syndrome (PCOS), adrenal dysfunction, or heightened sensitivity of sebaceous glands to androgens.
2. Estrogen Dominance: An imbalance between estrogen and progesterone can exacerbate acne. Functional practitioners assess liver function and detoxification pathways, as the liver is critical in metabolizing and clearing excess estrogens from the body.
3. Cortisol Dysregulation: Chronic stress elevates cortisol levels, which can increase androgen production, impair immune function, and worsen inflammation. Functional medicine strategies focus on stress reduction and adrenal support to restore hormonal balance.

The gut-skin axis underscores the connection between gastrointestinal health and skin conditions. Dysbiosis, or an imbalance in the gut microbiota, significantly contributes to acne.

1. Intestinal Permeability (“Leaky Gut”): A compromised intestinal barrier allows endotoxins and antigens to enter systemic circulation, triggering inflammation that manifests in the skin.
2. Small Intestinal Bacterial Overgrowth (SIBO): SIBO is linked to systemic inflammation and exacerbation of acne. Functional medicine addresses SIBO through targeted antimicrobial therapies, probiotics, and dietary interventions.
3. Gut-Brain-Skin Connection: Stress-induced changes in gut motility and microbiota composition can influence skin health. Functional medicine emphasizes the role of a healthy microbiome in modulating inflammation and promoting skin healing.

Chronic inflammation is a key driver of acne pathogenesis. Functional medicine identifies sources of systemic inflammation and implements anti-inflammatory interventions.

1. Dietary Triggers: High-glycemic index foods and dairy products are known to exacerbate acne by increasing insulin-like growth factor-1 (IGF-1) and androgen activity. Functional medicine promotes an anti-inflammatory diet rich in whole foods, omega-3 fatty acids, and antioxidants.
2. Oxidative Stress: Acne lesions are associated with elevated oxidative stress. Functional practitioners recommend antioxidants like vitamins C and E, selenium, and polyphenols to counteract free radical damage.
3. Immune Dysregulation: Overactivation of the innate immune system leads to the release of pro-inflammatory cytokines. Functional medicine modulates immune responses through gut health optimization and nutrient therapy.

Exposure to environmental toxins and impaired detoxification pathways contribute to acne. Functional medicine assesses these factors and supports the body's natural detoxification mechanisms.

1. Endocrine Disruptors: Chemicals in plastics, personal care products, and pesticides can mimic or interfere with hormone function, exacerbating acne—functional medicine advocates for reducing toxin exposure by choosing clean, non-toxic products.
2. Liver Function: The liver is essential for metabolizing hormones and detoxifying harmful substances. Functional practitioners use nutrients like glutathione, N-acetylcysteine (NAC), and methylation cofactors to enhance liver function.
3. Heavy Metals: Accumulation of heavy metals like lead, mercury, or cadmium can impair cellular function and increase oxidative stress. Functional medicine may include chelation or dietary strategies to reduce the metal burden.

Nutritional imbalances and deficiencies can impair skin health and exacerbate acne.

1. Zinc: Zinc deficiency impairs immune function, promotes inflammation, and increases susceptibility to Cutibacterium acnes. Supplementation can reduce acne severity and support skin healing.
2. Vitamin A: A key keratinization regulator, vitamin A deficiency contributes to clogged pores and inflammation. Functional medicine ensures adequate intake through diet or supplementation.
3. Omega-3 Fatty Acids: Low omega-3 levels can increase inflammatory mediators. Functional medicine emphasizes including fatty fish, flaxseeds, and walnuts in the diet.
4. Vitamin D: Vitamin D modulates immune responses and has anti-inflammatory properties. Deficiency is common in acne patients, and supplementation can improve outcomes.

Stress is both a trigger and a perpetrator of acne. Functional medicine addresses the impact of chronic stress on hormonal regulation, gut health, and immune function.

1. Cortisol and Inflammation: Prolonged stress elevates cortisol, which can worsen androgen-mediated sebum production and inflammation.
2. Mind-Body Interventions: Techniques such as mindfulness, yoga, and deep breathing are integral to functional medicine’s approach to reducing stress and promoting skin healing.

Laboratory Tests Utilized in Functional Medicine for Acne Vulgaris

Functional medicine, which focuses on identifying and addressing the root causes of disease, employs a variety of laboratory tests to uncover the underlying contributors to acne. By using these tests, practitioners can develop personalized treatment plans that address imbalances and optimize overall health.

Hormonal imbalances are a central factor in the development of acne. Functional medicine employs comprehensive hormonal testing to evaluate androgen levels, estrogen-progesterone balance, and adrenal function.

• Salivary Hormone Testing: Measures free (bioavailable) hormones, including testosterone, dihydrotestosterone (DHT), estrogen, progesterone, and cortisol. It helps detect elevated androgens, stimulating sebum production and contributing to acne. Assesses cortisol patterns throughout the day to identify chronic stress and its impact on hormonal regulation.
• Serum Hormone Testing: Measures total levels of hormones like testosterone, dehydroepiandrosterone sulfate (DHEA-S), and insulin-like growth factor-1 (IGF-1). It helps diagnose conditions like polycystic ovary syndrome (PCOS), a common cause of hormonal acne in women.

The gut-skin axis highlights the significant role of gastrointestinal health in acne pathogenesis. Functional medicine tests gut health to identify dysbiosis, infections, and intestinal permeability.

• Comprehensive Stool Analysis (EnteroScan®): Evaluates the balance of beneficial and pathogenic bacteria, fungi, and parasites in the gut. Identifies dysbiosis, which can increase systemic inflammation and contribute to acne. Measures markers of digestive function, such as pancreatic elastase and fat absorption, and intestinal inflammation markers like calprotectin.
• Small Intestinal Bacterial Overgrowth (SIBO) Breath Test: Detects an overgrowth of bacteria in the small intestine, a condition linked to acne via systemic inflammation and increased intestinal permeability. Identifies hydrogen and methane gas production, which helps guide targeted treatments.
• Intestinal Permeability Testing: Measures zonulin levels, a protein regulating tight junctions in the intestinal lining. Elevated zonulin indicates increased intestinal permeability (“leaky gut”), which allows inflammatory molecules to enter circulation and trigger skin inflammation. It also measures fatty acid binding protein 2 (FABP2). If the intestinal epithelium is damaged, FABP2 is released into the circulation and can be measured in serum.

Chronic inflammation and immune dysregulation are critical contributors to acne. Functional medicine evaluates inflammatory markers and immune function through laboratory testing.

• High-Sensitivity C-Reactive Protein (hs-CRP): A systemic marker of inflammation, often elevated in individuals with chronic inflammatory conditions, including acne.
• Cytokine Panels: Measures levels of pro-inflammatory cytokines such as interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and interleukin-1β (IL-1β). Helps identify systemic inflammatory patterns contributing to acne.
• Food Sensitivity Testing (TrophoScan®): Identifies immune-mediated reactions to specific foods that may exacerbate systemic inflammation and acne. Tests for IgG antibodies against common food triggers like dairy, gluten, and eggs.

Optimal nutrient levels are essential for skin health. Functional medicine uses nutritional testing to identify deficiencies that may impair skin function and contribute to acne.

• Micronutrient Testing: Evaluates levels of vitamins, minerals, and antioxidants such as zinc, vitamin A, vitamin D, and selenium. Deficiencies in these nutrients are associated with impaired skin barrier function and increased inflammation.
• Omega-3 and Omega-6 Fatty Acid Testing (ΩmegaScan®): Assesses the balance of anti-inflammatory omega-3 and pro-inflammatory omega-6 fatty acids. Imbalances can contribute to systemic inflammation and acne.

The liver plays a crucial role in hormone metabolism and detoxification. Functional medicine evaluates detoxification capacity to address acne triggers.

• Liver Function Tests: Measure enzymes such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST) to assess liver health. Identifies potential impairments in detoxification pathways that could exacerbate hormonal imbalances.
• Organic Acids Testing (MetaBolomiX™): Assesses metabolic byproducts of detoxification, mitochondrial function, and microbial overgrowth. Identifies impairments in detoxification pathways or nutrient deficiencies that affect skin health.
• Heavy metals: Tests for exposure to heavy metals (e.g., lead, mercury) and environmental toxins that can disrupt hormonal balance and increase oxidative stress.

Oxidative stress damages skin cells and contributes to inflammation in acne. Functional medicine uses tests to evaluate oxidative damage and antioxidant capacity.

• Glutathione: Measures glutathione levels, the body’s master antioxidant, which protects against oxidative stress and supports detoxification.
• Lipid Peroxidation Markers (Malondialdehyde, MDA-TBARS): Assesses oxidative damage to lipids, a common feature in acne lesions.

Conventional Management of Acne Vulgaris

Conventional acne treatments target these primary pathogenic mechanisms. These include topical and systemic therapies such as:

• Topical Retinoids: Promote normalization of follicular keratinization and prevent comedone formation.
• Benzoyl Peroxide: Reduces C. acnes colonization and exhibits anti-inflammatory properties.
• Antibiotics: Topical and systemic antibiotics reduce bacterial load and inflammation but carry risks of antimicrobial resistance.
• Hormonal Therapies: Oral contraceptives and anti-androgens like spironolactone regulate androgen levels.
• Isotretinoin: A potent retinoid used for severe cases, it reduces sebaceous gland size and sebum production.

While effective, these treatments often come with side effects, such as skin irritation, systemic toxicity, or dysbiosis, prompting interest in alternative approaches like functional medicine.

Management of Acne Vulgaris according to Functional Medicine

Functional medicine adopts a systems-based approach to uncover the root causes of acne, focusing on diet, gut health, hormonal balance, inflammation, and detoxification pathways. By addressing these factors, functional medicine seeks to create an environment where the skin can heal naturally.

Nutrition significantly influences the pathogenesis of acne. Functional medicine practitioners assess dietary habits and recommend changes tailored to the individual.

• High Glycemic Load Foods: Diets rich in refined carbohydrates and sugars spike insulin levels and insulin-like growth factor-1 (IGF-1), exacerbating sebaceous gland activity and inflammation. A low-glycemic index diet can mitigate these effects.
• Dairy: Dairy consumption, particularly skim milk, has been linked to acne due to the presence of hormones and bioactive molecules that stimulate androgen production.
• Omega-3 Fatty Acids: These have anti-inflammatory properties that counteract the pro-inflammatory effects of arachidonic acid found in omega-6-rich diets.
• Micronutrients: Deficiencies in zinc, vitamin A, vitamin E, and selenium impair skin health. Supplementation or dietary inclusion of these nutrients supports barrier function and reduces inflammation.

The gut microbiota profoundly impacts systemic inflammation, hormonal balance, and skin health. Disruptions in gut microbial balance—gut dysbiosis—have been implicated in acne.

• Small Intestinal Bacterial Overgrowth (SIBO): SIBO and other dysbiotic conditions increase intestinal permeability (“leaky gut”), allowing endotoxins to enter circulation and trigger inflammation. Probiotics, prebiotics, and targeted antimicrobial therapies can restore gut health.
• Dietary Fiber: High-fiber diets support a diverse microbiome and regulate blood sugar, mitigating acne triggers.
• Fermented Foods: Incorporating foods like yogurt, kimchi, and sauerkraut introduces beneficial bacteria and enhances gut integrity.

Hormonal imbalances—notably elevated androgens and estrogen dominance—are significant contributors to acne. Functional medicine employs several strategies to restore hormonal balance:

• Adaptogens: Herbs like ashwagandha, Rhodiola, and holy basil modulate stress responses and regulate cortisol levels, indirectly influencing androgen activity.
• Liver Support: The liver plays a critical role in hormone metabolism. Nutrients like N-acetylcysteine (NAC), milk thistle, and methylation cofactors (e.g., B vitamins) enhance detoxification.
• Phytoestrogens: Compounds in flaxseeds and legumes help balance estrogen levels by modulating estrogen receptors.

Chronic systemic inflammation exacerbates acne. Functional medicine emphasizes anti-inflammatory strategies:

• Antioxidants: Vitamins C and E, polyphenols, and glutathione combat oxidative stress.
• Anti-Inflammatory Diet: Emphasizing whole foods, fatty fish, colorful vegetables, and spices like turmeric and ginger reduces inflammatory markers.
• Lifestyle Interventions: Stress reduction techniques such as mindfulness, yoga, and adequate sleep lower systemic inflammation.

Exposure to toxins and impaired detoxification pathways can contribute to acne. Functional medicine supports detoxification through:

• Sweat Therapy: Regular exercise and sauna use promote the excretion of toxins through sweat.
• Nutrient Support: Cruciferous vegetables, sulfur-containing foods (like garlic and onions), and methyl donors enhance liver detoxification phases.
• Environmental Assessment: Reducing exposure to endocrine disruptors in personal care products and plastics minimizes hormonal disturbances.

Several herbs and plant extracts possess properties that can target acne effectively:

• Tea Tree Oil: Extracted from the Melaleuca alternifolia plant, tea tree oil has potent antimicrobial and anti-inflammatory properties. Topical application of diluted tea tree oil can help reduce acne lesions by targeting the bacteria Cutibacterium acnes (formerly Propionibacterium acnes).
• Aloe Vera: Aloe vera gel, rich in polysaccharides and antioxidants, soothes irritated skin and accelerates wound healing. Its anti-inflammatory properties make it a popular remedy for acne-prone skin.
• Green Tea Extract: Green tea contains epigallocatechin gallate (EGCG), which has anti-inflammatory and antimicrobial effects. Topical and oral consumption of green tea may reduce sebum production and improve acne severity.
• Neem: Known for its antibacterial and antifungal properties, neem leaves, or oil can be used in face masks or cleansers to help control acne-causing bacteria.

Natural substances with antimicrobial and soothing properties are widely used in acne management:

• Honey: Raw or Manuka honey has antibacterial properties and can be applied as a mask to reduce inflammation and promote healing.
• Apple Cider Vinegar: Diluted apple cider vinegar may help balance skin pH and reduce acne-causing bacteria.
• Turmeric: A paste made with turmeric and honey can be applied to acne-prone areas for its anti-inflammatory and antimicrobial effects.

• Zinc: Zinc is one of the most studied supplements for acne treatment. It is known for its anti-inflammatory and antibacterial properties, which can reduce the severity of acne lesions. Zinc helps regulate sebum production and supports the immune system in combating Propionibacterium acnes, the bacteria associated with acne. Studies have shown that oral and topical zinc can improve acne symptoms with fewer side effects than antibiotics.
• Omega-3 Fatty Acids: Omega-3 fatty acids, found in fish oil, possess anti-inflammatory properties that can help mitigate the inflammation associated with acne. These fatty acids balance pro-inflammatory and anti-inflammatory eicosanoids, potentially reducing redness and swelling. Moreover, omega-3s can improve overall skin barrier function, often compromised in individuals with acne.
• Vitamin A: Vitamin A is essential for maintaining healthy skin, as it regulates cell turnover and reduces the risk of clogged pores. Retinoids, derivatives of vitamin A, are a cornerstone of acne treatment, but high doses of oral vitamin A can also benefit some individuals. However, supplementation should be approached cautiously and under medical supervision to avoid toxicity.
• Vitamin D: Vitamin D plays a critical role in immune modulation and may help reduce the inflammatory responses associated with acne. Deficiency in vitamin D is common among individuals with acne, and supplementation can help improve skin health and enhance the body’s ability to combat acne-related bacteria.
• Probiotics: Gut health is closely linked to skin health, and probiotics can be beneficial for addressing acne by improving gut microbiota balance. Probiotics help reduce systemic inflammation, modulate immune responses, and decrease intestinal permeability, possibly contributing to acne flare-ups. Strains like Lactobacillus and Bifidobacterium are particularly effective in supporting gut and skin health.
• N-Acetylcysteine (NAC): N-Acetylcysteine is a precursor to glutathione, a potent antioxidant that helps neutralize free radicals and reduce oxidative stress. NAC has anti-inflammatory properties and may help regulate the immune system. Some studies suggest that NAC supplementation can improve the severity of acne, particularly in individuals with hormonal imbalances.
• Evening Primrose Oil: Evening primrose oil is rich in gamma-linolenic acid (GLA), an omega-6 fatty acid with anti-inflammatory properties. It is thought to help regulate hormones and reduce the severity of acne lesions. This supplement may be beneficial for individuals whose acne is linked to hormonal fluctuations, such as those seen in polycystic ovary syndrome (PCOS).
• Selenium: Selenium is a trace mineral with antioxidant properties that protects skin from oxidative stress. It also supports the immune system and enhances the efficacy of other antioxidants like vitamin E. Low selenium levels have been associated with increased acne severity, making supplementation a valuable strategy for some individuals.
• Green Tea Extract: Green tea extract is rich in polyphenols, particularly epigallocatechin gallate (EGCG), which has anti-inflammatory and antimicrobial effects. Topical and oral green tea supplements have shown efficacy in reducing sebum production and the size of acne lesions. Additionally, green tea’s antioxidant properties help protect the skin from environmental damage.
• Vitamin E: Vitamin E is a fat-soluble antioxidant that helps protect the skin from oxidative damage and supports overall skin repair. Combined with other antioxidants like vitamin C or selenium, it can enhance the skin’s ability to heal and reduce acne-related inflammation.