Supplements
Evidence-based supplement guidance from clinical practice. What works, what does not, proper dosing, interactions, and the difference between hospital-grade and consumer products.
By topic.
Vitamin D
Beyond bone health — immune modulation, mood, and the optimal range debate.
Magnesium
Forms, dosing, and the widespread deficiency most physicians overlook.
Omega-3 Fatty Acids
EPA/DHA dosing, sources, and the anti-inflammatory evidence.
- 04NAC (N-Acetyl Cysteine)Glutathione precursor with evidence across respiratory, psychiatric, and liver health.Moderate Evidence
- 05CoQ10Mitochondrial electron carrier — critical for statin users and energy metabolism.Moderate Evidence
- 06CurcuminAnti-inflammatory bioavailability challenge and the formulations that actually work.Moderate Evidence
- 07ProbioticsStrain-specific evidence, when they help, when they do not, and what to look for.Moderate Evidence
- 08QuercetinSenolytic, antihistamine, and zinc ionophore properties — what the evidence shows.Emerging Research
- 09BerberineAMPK activator with metformin-comparable glucose-lowering effects.Moderate Evidence
The Evidence-Based Supplement Guide
Download the complete physician's guide. Evidence-based, no hype.
All Articles
117 articles
Supplements Berberine for PCOS: Clinical Evidence, Dosage Protocol, and Integrative Management
How berberine addresses insulin resistance, androgen excess, and anovulation in PCOS — clinical evidence, dosing, and what to combine it with.
Supplements Bacopa Monnieri: A Physician's Evidence-Based Guide to Cognitive Enhancement and Stress Resilience
Bacopa monnieri improves memory, reduces anxiety, and protects neurons. Discover the clinical evidence, optimal dosing, forms, and who benefits most from this Ayurvedic nootropic.
Supplements Magnesium Forms Explained: Glycinate, Threonate, Malate, Citrate — Which Is Right for You?
A physician-reviewed guide to the eight major magnesium forms — bioavailability, clinical targets, dosing, and who should avoid which type.
Immunology Probiotics for Allergic Disease: From Adjunct Supplement to Immune-Modifying Strategy
How specific probiotic strains shift Th2-dominant immune responses in allergic rhinitis, eczema, food allergy, and asthma — a clinical guide to strain selection and protocol design.
Supplements Vitamin D as a Neuroimmune Signal: Mental Health Applications Beyond Bone
How vitamin D acts as a lifespan neuroimmune signal in psychiatry — from depression and schizophrenia to autism and cognitive decline. Clinical dosing and evidence.
Supplements Creatine for Brain Health: The Cognitive Benefits Your Longevity Stack Is Missing
Clinical evidence shows creatine monohydrate boosts cognitive performance under sleep deprivation, in vegetarians, and after TBI—far beyond its muscle reputation.
Longevity Dasatinib + Quercetin Senolytic Protocol: Dosing, Cycling, and Clinical Evidence
A physician's guide to the D+Q senolytic combination — clinical evidence, dosing schedule, cycling intervals, patient selection, and lab monitoring for longevity practice.
Supplements CDP-Choline (Citicoline): The Physician's Guide to Dosing, Evidence, and Clinical Use
A clinical review of CDP-choline (citicoline) for cognitive function, brain fog, and neuroprotection — with dosing protocols, mechanisms, and comparison to alpha-GPC.
Supplements L-Citrulline vs L-Arginine: Nitric Oxide, Cardiovascular Health, and Performance
A physician's clinical guide to nitric oxide precursors — how L-citrulline outperforms L-arginine for blood pressure, endothelial function, erectile health, and exercise recovery.
Supplements Lactoferrin: Clinical Evidence, Dosing, and Immune Benefits
A physician's guide to lactoferrin—how this iron-binding glycoprotein modulates immunity, supports gut barrier integrity, and may benefit chronic illness patients.
Longevity Methylene Blue Dosage Guide: Clinical Protocols, Forms, and Safety
Evidence-based methylene blue dosage guide covering cognitive, mitochondrial, and antimicrobial applications with safety protocols and contraindications.
Longevity Urolithin A Dosage: Physician's Guide to Timing, Protocol, and the Clinical Evidence
Physician-reviewed urolithin A dosage guide: optimal dose from 500mg to 2g, timing, cycling, and stacking protocols backed by clinical evidence.
Longevity Pterostilbene vs Resveratrol: Which Stilbene Is Better for Longevity?
Pterostilbene offers 4× greater bioavailability than resveratrol with longer half-life. Compare clinical evidence, dosing, and Dr. Douwes's protocol for stilbene supplementation.
Supplements 5-HTP and Tryptophan: A Physician's Guide to Serotonin Precursors for Sleep, Mood, and Brain Fog
Dr. Julian Douwes explains 5-HTP vs tryptophan for serotonin support — dosing, safety, interactions, and clinical use in Lyme disease and post-COVID patients.
Supplements CoQ10 for Fertility: What the Research Says About Egg Quality and Sperm Health
CoQ10 supplementation may improve egg quality, embryo viability, and sperm parameters. A physician's evidence review covering dosage, form, and who benefits most.
Supplements Benfotiamine for Peripheral Neuropathy: A Physician's Evidence Review
Fat-soluble thiamine that crosses cell membranes conventional B1 cannot. How benfotiamine repairs peripheral nerves, reduces oxidative stress, and supports recovery in Lyme, diabetes, and post-COVID neuropathy.
Supplements Lumbrokinase vs Nattokinase: Which Fibrinolytic Enzyme Is Right for You?
Comparing lumbrokinase and nattokinase for fibrin clearance, biofilm disruption, post-COVID microclots, and cardiovascular health — with clinical dosing guidance.
Supplements Collagen Peptides: A Physician's Guide to Types, Benefits, and Evidence
Dr. Douwes reviews the clinical evidence on collagen peptides—types I, II, and III, joint cartilage data, gut healing, skin aging, and how to dose effectively.
Immunology Hashimoto's Thyroiditis: A Functional Medicine Approach to Root-Cause Treatment
Discover how functional medicine addresses Hashimoto's thyroiditis beyond TSH levels—root causes, advanced testing, and evidence-based protocols to reduce antibodies and symptoms.
Supplements D-Ribose for Chronic Fatigue: Restoring Cellular Energy from the Ground Up
D-ribose is a five-carbon sugar that drives ATP synthesis. Learn how it helps chronic fatigue, fibromyalgia, Lyme fatigue, and post-COVID exhaustion.
Supplements Carnosine: The Anti-Glycation Dipeptide That Declines With Age
Carnosine declines 63% by old age. A physician's guide to why this dipeptide matters for anti-glycation, brain health, and how to supplement effectively.
Supplements Ashwagandha vs Rhodiola Rosea: Which Adaptogen Is Right for You?
A physician's evidence-based comparison of ashwagandha and rhodiola rosea — mechanisms, dosing, clinical use cases, and how to choose the right adaptogen for your goals.
Supplements Ergothioneine: The Longevity Amino Acid Your Cells Actually Store
L-ergothioneine is a unique cytoprotective amino acid found in mushrooms and aged cheeses. Learn how it protects mitochondria, slows aging, and why your cells hold onto it so tightly.
Protocols Mitochondrial Dysfunction: Root Causes, Testing, and Evidence-Based Treatment
How mitochondrial dysfunction drives fatigue, brain fog, and chronic illness — plus clinical testing and protocols to restore cellular energy production.
Supplements Berberine vs Semaglutide: What the Evidence Actually Shows
A physician's evidence-based comparison of berberine and semaglutide for blood sugar control and weight loss — mechanisms, efficacy, safety, and who benefits most.
Longevity Klotho Protein: The Anti-Aging Hormone That Controls How Fast You Age
Klotho protein declines with age and predicts cognitive decline, kidney disease, and cardiovascular risk. Here's what the science says about boosting it.
Supplements Butyrate Supplement Guide: Gut Permeability, Immunity, and SCFA Therapy
A physician's clinical guide to butyrate supplements: mechanisms, evidence for gut permeability and immunity, dosage protocols, and which patients benefit most.
Supplements Pregnenolone: The Neurosteroid That Powers Memory, Mood, and Stress Resilience
Pregnenolone is the master precursor to all steroid hormones. Learn how declining levels affect cognition, stress response, and how to supplement safely under clinical guidance.
Longevity Homocysteine: What Your Levels Mean and How to Lower Them
High homocysteine quietly damages blood vessels and the brain. A physician explains optimal ranges, root causes like MTHFR, and evidence-based ways to lower it.
Supplements Methylcobalamin vs. Cyanocobalamin: A Physician's Guide to B12 Supplementation
Dr. Douwes breaks down every B12 form — methylcobalamin, adenosylcobalamin, hydroxocobalamin — covering dosing, testing, and who truly benefits from active B12.
Supplements PQQ Supplement: Mitochondrial Biogenesis, Brain Health & Clinical Dosing Guide
Pyrroloquinoline quinone (PQQ) promotes mitochondrial biogenesis, neuroprotection, and cellular energy. Dr. Douwes reviews the evidence and clinical dosing protocols.
Supplements Serrapeptase vs Nattokinase: Which Fibrinolytic Enzyme Is Right for You?
A physician-led comparison of serrapeptase and nattokinase: mechanisms, clinical evidence, dosing, and which fibrinolytic enzyme fits your health goals.
Supplements Myo-Inositol & D-Chiro-Inositol: A Physician's Evidence-Based Guide
Dr. Douwes reviews myo-inositol and D-chiro-inositol for PCOS, insulin resistance, egg quality, and anxiety — with dosing, ratios, and clinical evidence.
Supplements L-Theanine: Evidence-Based Guide to Dosage, Benefits, and Synergistic Stacks
Clinical review of L-theanine: mechanisms, optimal dosing for anxiety, sleep, and cognitive performance, plus evidence-based stacking protocols for adult patients.
Supplements Glycine: The Amino Acid Behind Better Sleep, Collagen, and Longevity
Glycine at 3 g before bed improves sleep quality in RCTs. As a longevity molecule it drives collagen synthesis, glutathione via GlyNAC, and mTOR modulation.
Supplements Selenium: Thyroid Protection, Antioxidant Defense & Heavy Metal Detox
A physician's guide to selenium dosing, forms, and clinical uses for thyroid health, glutathione recycling, mercury detox, and immune support.
Supplements Serrapeptase Anti-Inflammatory Enzyme: Clinical Evidence and Dosing Guide
A physician's guide to serrapeptase: how this proteolytic enzyme reduces inflammation, breaks down biofilm, and compares to NSAIDs — with evidence-based dosing.
Supplements Astaxanthin: The Most Potent Antioxidant for Mitochondrial and Cardiovascular Health
A physician's guide to astaxanthin—6,000× more potent than vitamin C—with clinical evidence for heart health, neuroprotection, eye health, and longevity.
Supplements Lumbrokinase: The Fibrinolytic Enzyme Your Doctor Probably Hasn't Mentioned
Lumbrokinase is a potent fibrinolytic enzyme with emerging evidence for post-COVID microclots, Lyme biofilms, and chronic inflammation. A physician's clinical overview.
Supplements Melatonin: Complete Dosing and Benefits Guide
A physician's evidence-based guide to melatonin dosing, timing, forms, and benefits beyond sleep — including longevity, immunity, and cancer biology.
Supplements Phosphatidylcholine: The Essential Phospholipid for Liver, Brain, and Cellular Health
Dr. Douwes explains how phosphatidylcholine supports liver detoxification, cognitive function, and cellular membrane integrity — and who needs it most.
Supplements Alpha-GPC: The Physician's Guide to Choline for Cognitive Performance and Neuroprotection
Dr. Julian Douwes reviews Alpha-GPC dosing, mechanisms, clinical evidence for brain performance, acetylcholine synthesis, and how it compares to other choline sources.
Supplements L-Glutamine for Gut Health: Leaky Gut, Mucosal Repair, and Clinical Dosing
L-glutamine is the intestinal lining's primary fuel source. Explore the clinical evidence for leaky gut, Lyme dysbiosis, post-COVID recovery, and optimal dosing protocols.
Supplements Medicinal Mushrooms: Clinical Evidence for Reishi, Cordyceps, Turkey Tail, and Chaga
A physician's review of the four most-studied medicinal mushrooms — what the clinical evidence actually shows and how I use them in integrative practice.
Supplements Tongkat Ali: A Physician's Evidence-Based Guide to Dosage, Benefits, and Safety
Dr. Douwes reviews tongkat ali (Eurycoma longifolia) for testosterone, cortisol, and fatigue—covering clinical evidence, optimal dosing, and who actually benefits.
Supplements Apigenin Supplement Benefits: NAD+ Booster, Senolytic & Sleep Aid
Apigenin inhibits CD38 to raise NAD+ levels, clears senescent cells, and deepens sleep. A physician's evidence-based guide to dosing, stacking, and safety.
Supplements Bovine Colostrum: Clinical Evidence for Immune Modulation and Gut Healing
A physician's review of bovine colostrum supplements — immune IgA, growth factors, leaky gut, and how to use it clinically. Evidence-graded and protocol-ready.
Supplements NMN Supplement: A Physician's Evidence-Based Dosing Guide
Clinical review of NMN supplementation: mechanisms, human trial data, optimal dosing (250–1,000 mg/day), forms ranked by bioavailability, and candidacy criteria.
Supplements Akkermansia muciniphila: The Gut Barrier Strain Your Longevity Protocol Is Missing
Akkermansia muciniphila strengthens gut barrier integrity, improves metabolic markers, and predicts immunotherapy response. A clinical review of supplementation evidence.
Supplements MTHFR Gene Mutation: Symptoms, Testing, and a Physician's Methylation Protocol
Dr. Douwes explains MTHFR gene variants, how they disrupt methylation and detox, which labs to run, and the evidence-based supplement protocol he uses clinically.
Supplements Zinc Supplement Guide: Immune Function, Testosterone & Wound Healing
A physician's evidence-based guide to zinc supplementation — covering dosing, forms, immune support, testosterone, wound healing, and who actually needs it.
Supplements Acetyl-L-Carnitine (ALCAR): Brain Health, Fatigue, and Neuropathy — A Physician's Review
Acetyl-L-Carnitine (ALCAR) supports mitochondrial energy, acetylcholine synthesis, and nerve repair. Dr. Douwes reviews the clinical evidence, dosing, and stacking strategies.
Supplements Lithium Orotate: Neuroprotection, Mood Stability & Longevity
A physician's guide to lithium orotate microdosing — mechanisms of neuroprotection, evidence for mood stability, Alzheimer's prevention research, and safe dosing protocols.
Supplements Vitamin K2: The Missing Nutrient for Cardiovascular Health, Bone Density, and Calcium Metabolism
Physician guide to vitamin K2 (MK-4 vs MK-7): how it directs calcium away from arteries into bones, optimal dosing, and why most people are deficient.
Supplements GlyNAC: Glycine + NAC Protocol That Reverses Aging Markers
GlyNAC supplementation restores glutathione, reverses mitochondrial dysfunction, and improves multiple hallmarks of aging. Clinical evidence and physician dosing guide.
Supplements DHEA Supplementation: Evidence-Based Guide to Anti-Aging and Hormone Health
DHEA declines 80% by age 70. Physician-reviewed guide covering dosing, benefits for cognition, immunity, and bone density, and who should consider it.
Supplements Boron: The Overlooked Mineral for Testosterone, Bone Density, and Inflammation
Dr. Julian Douwes reviews why boron belongs in a serious longevity stack — from free testosterone elevation and bone protection to vitamin D activation and CRP reduction.
Supplements Creatine for Longevity and Brain Health: What the Evidence Actually Shows
Creatine does far more than build muscle. This physician-reviewed guide covers creatine supplementation for longevity, cognitive health, and sarcopenia prevention.
Supplements Shilajit: Fulvic Acid, Mitochondrial Energy, and Testosterone Support
A physician's clinical guide to shilajit — how fulvic acid drives mitochondrial energy, supports testosterone, and offers neuroprotective effects. Dosing, forms, and safety.
Supplements Sulforaphane and NRF2: The Clinical Case for Broccoli's Most Powerful Compound
Sulforaphane activates the NRF2 pathway to upregulate cellular defenses. A physician's review of clinical evidence, bioavailability, and dosing strategies.
Protocols Myers Cocktail IV Therapy: A Physician's Guide to Nutrients, Benefits & Who It's For
A physician's clinical guide to Myers Cocktail IV therapy—ingredients, evidence-based benefits, who benefits most, what to expect, and how it compares to other IV protocols.
Protocols High-Dose IV Vitamin C: Evidence, Protocol, and Clinical Applications
Dr. Julian Douwes reviews high-dose IV vitamin C: mechanisms, dosing protocols, cancer adjunct use, immune support, and safety considerations from clinical practice.
Supplements Palmitoylethanolamide (PEA): A Physician's Guide to Natural Anti-Inflammatory Therapy
Dr. Julian Douwes reviews PEA (palmitoylethanolamide) for chronic inflammation, neuropathic pain, and immune modulation — dosing, evidence, and clinical use.
Supplements Phosphatidylserine: Memory, Cortisol & Cognitive Aging
A physician's clinical guide to phosphatidylserine — how it supports memory, blunts cortisol, and slows cognitive aging. Evidence-based dosage and protocols.
Supplements Rhodiola Rosea: Clinical Evidence for Fatigue, Cortisol, and Cognitive Performance
A physician's guide to Rhodiola rosea — how it modulates the HPA axis, reduces stress-related fatigue, and improves cognitive performance in clinical practice.
Supplements TUDCA: Liver Protection, Mitochondrial Support, and Neuroprotection Explained
A physician's evidence-based guide to TUDCA — how this bile acid supports liver health, stabilizes mitochondria, reduces ER stress, and protects neurons.
Longevity Alpha-Ketoglutarate (AKG): A Physician's Guide to the Longevity Molecule
Dr. Julian Douwes reviews the evidence on alpha-ketoglutarate (AKG) supplementation — from TCA cycle biochemistry to epigenetic aging and clinical dosing.
Protocols IV Glutathione Therapy: Clinical Uses, Dosing Protocols, and What to Expect
A physician's guide to IV glutathione therapy — indications, dosing protocols, clinical evidence, and how it compares to oral and liposomal forms.
Longevity Taurine and Longevity: A Physician's Evidence Review
Dr. Julian Douwes examines taurine's role in aging, the landmark 2023 Science study, clinical dosing protocols, and who stands to benefit most.
Longevity Resveratrol and Longevity: What the Clinical Evidence Actually Shows
A physician's review of resveratrol's SIRT1 activation, cardiovascular and neuroprotective data, bioavailability limits, and practical dosing for longevity.
Supplements Alpha-Lipoic Acid: Neuropathy, Heavy Metal Detox, and Mitochondrial Repair
Dr. Douwes reviews alpha-lipoic acid dosing, R-ALA vs racemic forms, clinical uses for neuropathy, heavy metal chelation support, and mitochondrial longevity.
Longevity NAD Supplement Guide: NMN, NR, NADH and Oral NAD+ Precursors Compared
A physician's comparison of every oral NAD+ precursor — NMN, NR, NADH, and NAD3 — covering mechanisms, dosing, cofactors, and when to upgrade to IV therapy.
Supplements Ashwagandha and Cortisol: What the Clinical Evidence Actually Shows
How ashwagandha (KSM-66, Sensoril) lowers cortisol, calms the HPA axis, and reduces chronic stress — with dosing, timing, and safety from a physician's perspective.
Supplements Berberine and Blood Sugar: Mechanisms, Evidence, and Clinical Protocols
Dr. Douwes breaks down how berberine lowers blood sugar, what the clinical trials actually show, and the dosing protocol he uses in practice.
Longevity Urolithin A: Activating Mitophagy for Muscle Health and Longevity
Dr. Douwes reviews urolithin A — the gut-derived metabolite that activates mitophagy, preserves muscle function, and extends healthspan in clinical trials.
Longevity Spermidine and Longevity: The Autophagy Activator Your Cells Are Waiting For
Spermidine triggers cellular autophagy, protects cardiovascular and cognitive health, and extends lifespan in animal models. What the human evidence actually shows.
Supplements CoQ10 for Heart Health: What the Clinical Evidence Actually Shows
Cardiologist-reviewed guide to CoQ10 for heart failure, hypertension, and statin-related symptoms. Dosing, forms, and who benefits most.
Supplements Magnesium for Sleep: Which Form Works Best and Why
Dr. Julian Douwes reviews the clinical evidence on magnesium for sleep — comparing glycinate, threonate, and oxide, with dosing protocols used in integrative practice.
Supplements Ubiquinol vs Ubiquinone: Which Form of CoQ10 Actually Works Better?
Ubiquinol vs ubiquinone: understand the biochemical difference, absorption data, and when each form is clinically appropriate for your patients.
Longevity Anti-Aging Supplements: A Physician's Actual Stack for Longevity
A practicing physician's evidence-based anti-aging supplement stack. NAD+, resveratrol, CoQ10, omega-3, vitamin D — what works, what's overhyped, and what I actually take.
Longevity NAD+ Injections vs Oral Supplements: Which Delivery Method Works?
NAD+ IV injections vs oral NMN vs sublingual NAD+ compared. Bioavailability data, clinical outcomes, cost analysis, and what I recommend in practice.
Longevity Fisetin vs Quercetin: Which Senolytic Flavonoid Is Better?
A physician's comparison of fisetin and quercetin as senolytic agents — mechanisms, evidence, dosing protocols, and which patients benefit from each flavonoid.
Supplements Best Probiotic Strains by Condition: IBS, Bloating, Immunity, and Mood
Physician guide to evidence-based probiotic strain selection. Which specific strains work for IBS, bloating, immunity, mood, and vaginal health, with dosing and evidence grades.
Supplements NAC vs. Glutathione: Which Antioxidant Should You Take?
Physician comparison of NAC vs glutathione supplements. Oral bioavailability, mechanisms, when to use each, liposomal glutathione, and evidence-based recommendations.
Supplements Berberine vs Metformin: AMPK Activation Compared
Head-to-head comparison of berberine and metformin for glucose control, lipids, and longevity. Both activate AMPK — but how do they really compare?
Longevity NAD+ IV vs NMN vs NR: Which NAD Precursor Is Best?
NAD+ IV, NMN, and NR compared by a physician. Bioavailability, evidence, cost, and who benefits from which approach based on clinical experience.
Peptides Epithalon vs NMN: Anti-Aging Mechanisms Compared
Epithalon vs NMN comparison by Dr. Julian Douwes. Telomere lengthening vs NAD+ replenishment — different aging hallmarks, different evidence, and when to use each.
Supplements CoQ10 for Statin Users: Why Your Cholesterol Medication Depletes CoQ10
Physician guide to CoQ10 depletion from statins. Why it happens, symptoms of statin-induced CoQ10 deficiency, optimal dosing with ubiquinol, and what the evidence shows.
Supplements How to Choose a Probiotic: CFU Count, Strains, and What Actually Matters
Physician guide to choosing a probiotic supplement. CFU count myths, strain identification, delivery mechanisms, third-party testing, and what the label should tell you.
Peptides LL-37 and Vitamin D: The Immune Connection
How vitamin D regulates LL-37 production and why this matters for immunity. The cathelicidin pathway, optimal levels, and clinical implications.
Supplements CoQ10 Dosage by Condition: Heart, Fertility, Migraines, and Energy
Physician guide to CoQ10 dosing by condition. Ubiquinol vs ubiquinone, heart health, male fertility, migraine prevention, energy, and statin users. Evidence-based protocols.
Supplements When to Take Supplements: The Complete Timing Guide
Evidence-based supplement timing guide. Fat-soluble vitamins with meals, magnesium at night, iron on an empty stomach, and how to build morning and evening stacks based on pharmacokinetics.
Supplements Probiotics vs. Prebiotics vs. Postbiotics: What the Difference Means for Your Gut
Physician guide to probiotics, prebiotics, postbiotics, and synbiotics. Definitions, mechanisms, when to use each, and how they work together for gut health.
Supplements Best Curcumin Supplements for Absorption: Meriva, BCM-95, Theracurmin, and Piperine Compared
Physician comparison of curcumin formulations for absorption. Meriva, BCM-95, Theracurmin, NovaSOL, and piperine ranked by bioavailability data, clinical evidence, and cost.
Supplements Berberine Dosage for Blood Sugar: Evidence-Based Protocol
Physician guide to berberine dosing for blood sugar, insulin sensitivity, and metabolic health. Optimal doses, timing, GI management, and comparison to metformin.
Supplements Omega-3 Dosage for Inflammation: EPA and DHA for Joints, Brain, and Heart
Evidence-based omega-3 dosing for inflammation. How much EPA and DHA for joint pain, cardiovascular inflammation, neuroinflammation, and autoimmune conditions. Physician protocols.
Longevity Metformin vs. Berberine: AMPK Activators Compared
Head-to-head comparison of metformin and berberine for longevity, AMPK activation, blood sugar, and exercise compatibility. Evidence, dosing, and which to choose.
Supplements Magnesium Deficiency Symptoms: The Warning Signs Most People Miss
Physician guide to magnesium deficiency symptoms including muscle cramps, insomnia, anxiety, heart palpitations, and fatigue. Testing, causes, and how to correct it.
Supplements NAC for Fertility: How N-Acetyl Cysteine Supports Reproductive Health
Evidence-based guide to NAC for fertility in men and women. PCOS, ovulation, sperm quality, oxidative stress, and dosing protocols from clinical trials.
Supplements Magnesium Glycinate vs. L-Threonate: Which Form for Sleep, Anxiety, and Brain Health?
Physician comparison of magnesium glycinate vs magnesium L-threonate. Which form for sleep, which for cognition, absorption differences, dosing, and evidence quality.
Supplements Quercetin as a Senolytic: Protocol, Dosage, and What the Research Shows
Physician guide to quercetin senolytic protocols. Quercetin + dasatinib evidence, quercetin + fisetin alternatives, dosing schedules, and the science of clearing senescent cells.
Infectiology Nattokinase and Serrapeptase for Biofilm Disruption
How proteolytic enzymes nattokinase and serrapeptase degrade biofilm matrix components — mechanism, dosing, evidence, and clinical considerations.
Supplements Fish Oil vs. Krill Oil vs. Algae Oil: Which Omega-3 Source Is Best?
Physician comparison of fish oil, krill oil, and algae oil for omega-3 supplementation. EPA and DHA content, absorption, sustainability, cost, and evidence-based recommendations.
Supplements Curcumin vs. Turmeric Supplements: Why the Spice Alone Is Not Enough
Physician guide to curcumin vs turmeric supplements. Why turmeric spice has poor bioavailability, how curcumin extracts differ, and what to look for in a supplement.
Supplements Curcumin for Joint Pain and Arthritis: Dosage, Timeline, and What the Meta-Analyses Show
Evidence-based curcumin dosing for joint pain and arthritis. Meta-analysis results, comparison to NSAIDs, best formulations, timeline to improvement, and physician protocols.
Supplements When to Take Magnesium: Morning vs. Night, With or Without Food
Physician guide to magnesium supplement timing. When to take glycinate, threonate, citrate, and other forms for maximum absorption and effect. Morning vs night, food interactions.
Supplements NAC Dosage Guide: How Much to Take for Liver, Lungs, and Immune Support
Evidence-based NAC dosing by condition. Liver support, respiratory health, immune function, mental health, and general antioxidant use. Physician-guided protocols.
Supplements Nattokinase: The Fibrinolytic Enzyme for Microclots
Evidence-based guide to nattokinase for fibrinolysis and microclots. Mechanism, dosing, post-COVID relevance, combination with serrapeptase, and safety with blood thinners.
Supplements Probiotics: Matching the Right Strain to the Right Condition
Evidence-based guide to probiotic strain selection. Which strains work for which conditions, when to avoid probiotics, CFU counts, spore-based vs traditional, and what I use in clinical practice.
Supplements Lion's Mane: Nerve Growth Factor and Cognitive Benefits
Evidence-based guide to lion's mane mushroom for brain health. NGF stimulation, cognitive benefits, dosing, extract types, and what the clinical data supports.
Supplements Curcumin: Why Most Supplements Don't Work and Which Ones Do
The bioavailability problem with curcumin explained. Comparing Meriva, Longvida, BCM-95, Theracurmin, liposomal, and piperine forms. Dosing by condition.
Supplements Ashwagandha: Cortisol, Thyroid, and Evidence-Based Dosing
Evidence-based guide to ashwagandha. Cortisol reduction, thyroid effects, dosing, extract types, safety, and what the clinical data actually shows.
Immunology Mistletoe Therapy (Iscador): Evidence in Integrative Oncology
Mistletoe extract (Iscador, Helixor) for cancer: mechanism, NK cell activation, quality of life evidence, injection protocols, and the German clinical tradition.
Supplements NAC (N-Acetyl Cysteine): The Most Underrated Supplement in Medicine
NAC N-acetyl cysteine benefits reviewed by a physician. Glutathione precursor, psychiatric uses, liver protection, COVID research, and dosing from 600-1800mg.
Supplements CoQ10: Ubiquinol vs Ubiquinone — What Actually Matters
Evidence-based guide to CoQ10 supplementation. Ubiquinol vs ubiquinone, absorption differences, statin interactions, mitochondrial function, and what I recommend in clinical practice.
Longevity Best Supplements for Deep Sleep: Evidence Ranked
Physician-ranked guide to sleep supplements. Magnesium glycinate, glycine, apigenin, L-theanine, and ashwagandha compared by evidence quality for deep sleep enhancement.
Immunology Integrative Oncology: What It Is and What It Is Not
A clinician's guide to integrative oncology. What complementary therapies have evidence, how they work alongside conventional treatment, and what 35 years of clinical experience at Klinik St. Georg have shown.
The Physician's Guide to Supplements
In-depth reference by Dr. Julian Douwes
Why a Physician Writes About Supplements
Most supplement information falls into two camps: uncritical marketing (“this will change your life”) or blanket dismissal (“supplements are expensive urine”). Neither serves patients well.
I prescribe supplements daily — in a hospital setting, monitored with laboratory testing, adjusted based on response. I also see the damage from unguided supplementation: patients spending hundreds monthly on products that interact with their medications, contain contaminants, or simply do not work.
This guide bridges that gap. Evidence-graded. Honest about limitations. Written by someone who uses these tools clinically.
Evidence Grading System
Every supplement recommendation on this platform uses a five-tier system:
| Level | Meaning | Example |
|---|---|---|
| Strong | Multiple RCTs, meta-analyses | Vitamin D for immune function, omega-3 for inflammation |
| Moderate | Limited RCTs, consistent observational data | CoQ10 for statin users, NAC for glutathione support |
| Emerging | Preclinical evidence strong, human trials early | NMN for NAD+ restoration, fisetin as senolytic |
| Traditional | Historical clinical use, limited modern trials | Andrographis for infection, milk thistle for liver |
| Insufficient | Marketed but unproven | Most “detox” supplements, many nootropic stacks |
Quality: The First Question
Before asking “what should I take?” ask “what am I actually taking?”
The Quality Problem
The supplement industry operates under far less regulatory scrutiny than pharmaceuticals. The FDA does not pre-approve supplements for safety or efficacy. Third-party testing consistently finds products that contain less active ingredient than labeled, contain contaminants, or contain entirely the wrong compound.
What to Look For
- Third-party testing: USP Verified, NSF Certified for Sport, or ConsumerLab approved
- GMP certification: Not just compliance (legally required) but actual third-party audit
- Form matters: Magnesium oxide (poorly absorbed) vs. magnesium glycinate (well absorbed). Ubiquinone vs. ubiquinol. Folic acid vs. methylfolate.
- Practitioner-grade lines: Thorne, Pure Encapsulations, Designs for Health, Klaire Labs maintain higher standards than mass-market brands
The German Advantage
In Germany, products like mistletoe extract (Iscador, Helixor) and systemic enzyme therapy (Wobenzym) are approved pharmaceuticals — not “alternative supplements.” They undergo drug-level manufacturing oversight and clinical testing. This regulatory distinction matters.
Core Categories
Vitamins
Vitamin D3 + K2 — The most commonly deficient nutrient in chronically ill patients. We target serum 25(OH)D of 40-60 ng/mL. K2 (MK-7) directs calcium to bones, preventing vascular calcification. A 2025 DKFZ meta-analysis found 20% mortality reduction in deficient cancer cohorts. Always test before dosing. Evidence: Strong.
B-Complex (methylated) — Methylcobalamin, methylfolate, P-5-P, riboflavin-5-phosphate. Essential for energy metabolism, methylation, and neurotransmitter synthesis. Critical for MTHFR variant carriers. Evidence: Strong for deficiency.
High-Dose IV Vitamin C — At pharmacologic levels (achievable only via IV), vitamin C acts as a pro-oxidant selectively cytotoxic to cancer cells. A Phase 2 RCT showed doubling of overall survival in metastatic pancreatic cancer. Requires G6PD screening. Fundamentally different from oral supplementation. Evidence: Moderate-Strong for oncology.
Minerals
Magnesium — Cofactor in 300+ enzymatic reactions. A 2026 RCT showed magnesium L-threonate supplementation associated with 7.5-year cognitive age reduction. Six forms for six purposes: glycinate (sleep), L-threonate (cognition), malate (energy), taurate (cardiovascular), citrate (bowel motility), oxide (avoid — low bioavailability). Evidence: Strong.
Zinc — Essential for T-cell maturation and immune function. 15-30 mg/day. Long-term use requires copper co-supplementation. Evidence: Moderate.
Selenium — Required for glutathione peroxidase and thyroid hormone conversion. 200 mcg/day selenomethionine. Narrow therapeutic window — excess is toxic. Evidence: Moderate.
Antioxidants and Mitochondrial Support
NAC (N-Acetylcysteine) — Glutathione precursor (4-fold synthesis increase). Mucolytic. Biofilm disruptor. Used in our Lyme protocols for both detoxification support and biofilm disruption. 600-1,800 mg/day. Evidence: Moderate-Strong.
Glutathione — The master antioxidant. IV delivery bypasses poor oral absorption. Liposomal and S-acetyl forms improve oral bioavailability. Lyme patients frequently exhibit depleted glutathione. Evidence: Moderate.
CoQ10 — Mitochondrial electron transport chain cofactor. Ubiquinol form better absorbed. Combined with alpha-lipoic acid, a prospective study showed substantially reduced fatigue in chronic COVID patients. Essential for statin users. Evidence: Moderate.
Fatty Acids
Omega-3 (EPA/DHA) — Anti-inflammatory through resolvin and protectin synthesis. Decreased omega-3 levels documented in CFS patients. Triglyceride form outperforms ethyl ester for bioavailability. Test with omega-3 index (target 8-12%). Quality varies enormously — check TOTOX values and heavy metal testing. Evidence: Strong.
Herbal and Botanical
Curcumin — NF-kB inhibition, anti-inflammatory, anti-proliferative. Bioavailability is the challenge — requires piperine, liposomal, or phytosome formulation. Evidence: Moderate.
Berberine — AMPK activator (same pathway as metformin), antimicrobial, glucose regulation. Emerging evidence as PD-L1 checkpoint inhibitor with immunomodulatory actions. Evidence: Moderate.
Mistletoe Extract — Immunostimulation through lectins activating NK cells and T-cells. Approved as cancer therapy in Germany. 62% of oncology patients in German studies received mistletoe. Phase I trial at Johns Hopkins established safety. Evidence: Moderate (European standard of care for integrative oncology).
Ashwagandha — HPA axis regulation. A 2025 meta-analysis confirmed statistically significant cortisol reduction (15-30%) and anxiety improvement. Evidence: Strong for stress/cortisol.
Enzymes and Fibrinolytics
Nattokinase — Fibrinolytic enzyme. A 2024 study showed 84% microclot reduction in vitro. Directly relevant to Dr. Beate Jaeger’s microclot research in Post-COVID. RCT found enzyme + probiotic combination achieved 91% fatigue-free status in Post-COVID at 14 days. Evidence: Emerging.
Wobenzym — German pharmaceutical. Combination of bromelain, trypsin, papain, and rutin. Meta-analysis confirmed non-inferiority to diclofenac for knee osteoarthritis with better safety profile. Evidence: Moderate.
Longevity Compounds
NMN/NR — NAD+ precursors. January 2026 RCT showed both double circulating NAD+ levels. NMN reduced inflammatory signals post-exercise (February 2026 RCT). FDA confirmed NMN remains available as dietary supplement (September 2025). Important caveat: lifespan extension NOT proven in humans. Evidence: Emerging.
Quercetin — Senolytic (clears senescent “zombie cells”), anti-inflammatory, mast cell stabilizer. Quercetin + dasatinib is the most studied senolytic combination. Evidence: Moderate for anti-inflammatory, Emerging for senolytic.
Drug-Supplement Interactions
This is the section most supplement guides skip. Critical interactions:
- Omega-3 + anticoagulants — Additive bleeding risk at high doses (>3g/day)
- Curcumin + chemotherapy — May interfere with certain agents; timing matters
- St. John’s Wort + practically everything — Potent CYP450 inducer
- NAC + nitroglycerin — Potentiates hypotension
- Vitamin K2 + warfarin — Alters INR (consistent intake is key, not avoidance)
- Berberine + metformin — Additive glucose lowering (monitor closely)
- Ashwagandha + thyroid medication — May increase thyroid hormone levels
- Quercetin + cyclosporine — Increases drug levels
Always disclose your full supplement list to every prescribing physician.
Supplements to Stop Before Treatment
If you are coming to St. George Hospital for treatment, we will provide specific guidance. General principles:
- 7-14 days before surgery: Stop omega-3, vitamin E, ginkgo, garlic supplements (bleeding risk)
- Before apheresis: Stop nattokinase/serrapeptase (fibrinolytic overlap)
- Before immunotherapy: Discuss antioxidants (theoretical concern about reducing treatment efficacy)
- Before hormone-sensitive procedures: Pause DIM, I3C, maca, DHEA
Building Your Stack
The most common mistake is starting with advanced compounds before establishing foundations. Our approach:
Foundation (everyone): Vitamin D3+K2, magnesium, omega-3, B-complex, probiotics. Test, dose, and verify.
Condition-specific (guided by labs): NAC for glutathione support, CoQ10 for mitochondrial function, zinc for immune support, curcumin for inflammation. Add based on diagnostic findings, not marketing.
Advanced (physician-supervised): NMN/NR for NAD+ restoration, senolytic protocols, peptides, IV formulations. These require monitoring and medical oversight.
Start with fewer, higher-quality supplements rather than more, cheaper ones. Test before and after. If a supplement isn’t moving your biomarkers in the right direction within 90 days, stop it.