
What's That Rash?
Get answers to the health questions everyone's asking. Our experts give you the information you need to feel good and make the best decisions for your brain and body.
Latest episodes

Jul 15, 2025 • 20min
Methylene blue: why are people drinking blue dye?
In a video that went viral, Robert F. Kennedy Jr was seen on a plane dropping a cobalt blue liquid into his drink.People quickly started to assume it was methylene blue, a substance that in some corners is being heralded for apparent anti-ageing properties.Norman and Tegan look at the research that has been done so far … and some of the risks of dosing yourself with unproven medications.References:Efficacy and safety of methylene blue in the treatment of malaria: a systematic reviewMethylene blue as antidote for cyanide poisoning - JAMACellular and Molecular Actions of Methylene Blue in the Nervous SystemMethylene Blue: The Little-Known DisinfectantThe Potentials of Methylene Blue as an Anti-Aging Drug - PMCIs methylene blue really a brain booster? A pharmacologist explains the scienceFrom Mitochondrial Function to Neuroprotection—an Emerging Role for Methylene Blue | Molecular NeurobiologyAnti-Aging Potentials of Methylene Blue for Human Skin Longevity | Scientific ReportsWhat to know about methylene blue - Harvard Health Toxicology and carcinogenesis studies of methylene blue trihydrate (Cas No. 7220-79-3) in F344/N rats and B6C3F1 miceChromoendoscopy with methylene blue and associated DNA damage in Barrett's oesophagus - The LancetGeneration of oxidant stress in cultured endothelial cells by methylene blue: protective effects of glucose and ascorbic acid - ScienceDirectThe photodynamic and direct actions of methylene blue on mitochondrial energy metabolism: A balance of the useful and harmful effects of this photosensitizerIf you enjoyed this episode, check these out!How worried should you be about microplastics?Is NAD+ a miracle anti-ageing supplement?

Jul 8, 2025 • 21min
Do healthy people need lymphatic treatments?
You might've been advertised lymphatic massage treatments promising to boost your energy and leave you looking snatched.The lymphatic system is great at clearing out gunk and checking our bodies for potential nasties like bacteria and viruses.Norman and Tegan discuss whether it's possible to have a 'sluggish' lymphatic system in need of help, without having a diagnosable condition.References: Manual lymphatic drainage treatment for lymphedema: a systematic review of the literatureComparative Effects of Facial Roller and Gua Sha Massage on Facial Contour, Muscle Tone, and Skin Elasticity: Randomized Controlled TrialComparison of the Immediate Effect of Petrissage Massage and Manual Lymph Drainage Following Exercise on Biomechanical and Viscoelastic Properties of the Rectus Femoris Muscle in WomenThe Effects of Kinect-Enhanced Lymphatic Exercise Intervention on Lymphatic Pain, Swelling, and Lymph Fluid LevelExercise and the lymphatic system | MD Anderson Cancer Center If you enjoyed this episode, check these out!Can collagen supplements keep your skin supple?Which hair loss treatments actually work?

Jul 1, 2025 • 19min
Is whitening your teeth bad for you?
Some people might be naturally blessed with pearly whites, but many people aren’t happy with the shade of their teeth.There’s nothing inherently unhealthy about yellower teeth, and staining happens throughout our lives.Norman and Tegan unpack the long history of teeth whitening (with everything from urine to nitric acid) and discuss where there’s potential for harm.References: From Gunpowder to Teeth Whitener: The Science Behind Historic Uses of UrineShades of white: what you should know about teeth whitening - The University of SydneyWhite wine can stain teeth - NatureDo different bleaching protocols affect the enamel microhardness? - PMC Assessment of cytotoxic and genotoxic effects of conventional and whitening kinds of toothpaste on oral mucosa cells: Acta Odontologica ScandinavicaAccidental ingestion of 35% hydrogen peroxide - PMCIf you enjoyed this episode, check these out!How risky is sharing a toothbrush?Why are people taping their mouths?

Jun 24, 2025 • 19min
What are the health benefits of coffee?
Coffee has been an important part of human cultures for centuries, and it has a long history of being both heralded and demonised.But the more we learn about coffee – even independent from caffeine – the more that comes to light about its potential benefits.Norman and Tegan drink in the evidence so far, which gets down to the nitty gritty of brewing techniques and milk additions. References:Coffee - The Nutrition Source - Harvard School of Public HealthCoffee consumption and risk of endometrial cancer: Findings from a large up-to-date meta-analysisCaffeinated and Decaffeinated Coffee Consumption and Risk of Type 2 Diabetes: A Systematic Review and a Dose-Response Meta-analysisCoffee consumption and risk of stroke in womenCaffeine, Mental Health, and Psychiatric DisordersAssociation of Coffee Drinking With Mortality by Genetic Variation in Caffeine Metabolism: Findings From the UK BiobankPhysical characteristics of the paper filter and low cafestol content filter coffee brews - ScienceDirect Coffee consumption and mortality from cardiovascular diseases and total mortality: Does the brewing method matter? | European Journal of Preventive CardiologyPhenolic Acid–Amino Acid Adducts Exert Distinct Immunomodulatory Effects in Macrophages Compared to Parent Phenolic Acids | Journal of Agricultural and Food Chemistry The deep, rich and problematic history of coffee in Australia and worldwide - ABC NewsIf you enjoyed this episode, check these out!Am I addicted to caffeine?Can consuming dairy really give you acne?A single glass of red wine for your health, yeah or nah?

Jun 17, 2025 • 21min
You'll catch your death! Does cold weather cause colds?
There tend to be more bugs around in winter making everyone snotty and uncomfortable.But does this mean that cold weather causes colds? Well no, viruses cause the common cold.But, as Norman and Tegan explain, winter does set the stage for those viruses to have more moments in the spotlight.References:Understanding the symptoms of the common cold and influenza - PMCCold temperature and low humidity are associated with increased occurrence of respiratory tract infections - ScienceDirect Immune system of cold-exposed and cold-adapted humans | European Journal of Applied PhysiologyImmune changes in humans during cold exposure: effects of prior heating and exerciseCold exposure impairs extracellular vesicle swarm–mediated nasal antiviral immunity - Journal of Allergy and Clinical Immunology Airborne transmission efficiency of SARS-CoV-2 in Syrian hamsters is not influenced by environmental conditions | npj VirusesIf you enjoyed this episode, check these out!Norman tried an ice bath so you don't have toIs NAD+ a miracle anti-ageing supplement?

Jun 10, 2025 • 19min
Should you go organic if you're worried about pesticides?
Organic fruits and vegetables are one thing, but the label is popping up on packaged foods too.Are they healthier for us because they’re certified organic? How much harm are pesticides doing to our health?Norman and Tegan dig into organic farming to find out whether they’re worth the extra price. References:Organic Certification ExplainedPesticides | Food Standards Australia New Zealand Pesticides impacts on human health and the environment with their mechanisms of action and possible countermeasures - ScienceDirectGlobal analysis shows how pesticides leach into the environment - The University of SydneyEcological impacts and management strategies of pesticide pollution on aquatic life and human beings - ScienceDirectA Systematic Review of Organic Versus Conventional Food Consumption: Is There a Measurable Benefit on Human Health?Cellulose Surface Nanoengineering for Visualizing Food SafetyComparison of Different Home/Commercial Washing Strategies for Ten Typical Pesticide Residue Removal Effects in Kumquat, Spinach and CucumberIf you enjoyed this episode, check these out!Should we all be vegetarian?Can you adapt to allergies or does the dog have to go?

Jun 3, 2025 • 21min
What we do (and don't) know about tinnitus
Explore the elusive nature of tinnitus, where silence can seem unattainable. Discover its many causes, from underlying neurological links to psychological effects. The hosts discuss a variety of current and emerging treatments aimed at providing relief. Dive into historical perspectives on tinnitus and even hear about distraction therapy from ancient times. Plus, insights from listeners on integrating cardio and strength training round out this informative conversation, shedding light on the complex interplay of sound, silence, and our bodies.

May 27, 2025 • 18min
Should you train cardio and strength on the same day?
Dive into the debate on mixing cardio and strength training in your routine! Discover the benefits and drawbacks of concurrent training, along with personal anecdotes from the hosts. Learn how aerobic exercise boosts heart health and endurance while strength training plays a pivotal role in overall fitness. The importance of training order and enjoyment in workouts is also highlighted. Plus, listen to a unique personal story about the connection between acne and fitness, adding a humorous twist to the discussion!

May 20, 2025 • 20min
Why do some people run hot, while others run cold?
Are you constantly getting scolded for pressing your cold feet against your partner in bed? Or told your hands are icy cold?It’s well known that some people run cold and others run hot. But why does this happen, and does it say anything about your health?Norman and Tegan unpack the physiology and get into some of the reasons we experience temperature differently.References:Individual differences in normal body temperature: longitudinal big data analysis of patient records | The BMJGender Matters! Thermal Comfort and Individual Perception of Indoor Environmental Quality: A Literature Review | SpringerLinkSex differences and aging: Is there a role of brown adipose tissue? - ScienceDirectCool Temperature Alters Human Fat and Metabolism | National Institutes of Health (NIH) A Review of Cultural Background and Thermal Perceptions in Urban EnvironmentsOutdoor thermal perception and adaptation of immigrants from cold climates to hot arid climate - ScienceDirectDrivers of diversity in human thermal perception – A review for holistic comfort models - PMC

May 13, 2025 • 20min
Can consuming dairy really give you acne?
You might've heard a friend complaining about their latest break-out and swearing off dairy products as a result. Or that friend might be you.It’s a common complaint, but does it have any scientific merit?Norman and Tegan explore whether consuming dairy can cause acne, and if so, how a glass of milk might lead to pimples.References:The Influence of Genetics and Environmental Factors in the Pathogenesis of Acne: A Twin Study of Acne in WomenPatient Perceptions About Acne, Nutrition, and a Dietary Information Gap Diet and acne: A systematic reviewCan the right diet get rid of acne? - American Academy of Dermatology Association High school dietary dairy intake and teenage acneEffect of Chocolate on Acne Vulgaris - 1969Double-blind, Placebo-controlled Study Assessing the Effect of Chocolate Consumption in Subjects with a History of Acne Vulgaris