The plain-English series
What does this
actually mean?
Familiar words. Better questions. Clearer answers.
The terms on a label or in a headline can leave a lot unexplained. Start with what the words mean, see familiar examples, and find out what the evidence can tell you.
100 explanations Connected to the full Atlas guides
No matching explanations. Try a broader term or clear the filters. You can also search the full Atlas.
Each explanation starts with the meaning, then covers examples, limits, evidence, and what to check. References and review status stay visible. How we use sources.
Sleep & recovery
Make sense of sleep, timing, and recovery.
- Sleep & recovery
Melatonin: a sleeping pill or a body-clock signal?
Why can timing matter as much as the dose?
13 references Read explanation - Sleep & recovery
Sleep apnea: when is snoring more than a noise?
What stops and restarts during sleep apnea, and does everyone who snores have it?
12 references Read explanation - Sleep & recovery
Insomnia: why being tired does not always mean you can sleep
How is insomnia different from simply not leaving enough time for sleep?
12 references Read explanation - Sleep & recovery
Circadian rhythm: what does your body clock actually do?
Why can a night owl feel tired but still struggle to sleep early?
10 references Read explanation
Food & nutrition
From familiar foods to unfamiliar ingredients.
- Food & nutrition
Ultra-processed food: does bread, yogurt or cereal count?
Start with the four processing groups, then look at familiar foods.
26 references Read explanation - Food & nutrition
Natural vs. artificial flavors: what is actually different?
Read the flavor terms on a package with more context.
10 references Read explanation - Food & nutrition
Sugar-free, no added sugar, unsweetened: what do the labels mean?
Compare three statements that can sound interchangeable.
16 references Read explanation - Food & nutrition
Lab-grown food: what is it, and how is its safety assessed?
Distinguish cell-cultured meat from other new ways of making food.
11 references Read explanation - Food & nutrition
Processed meat: does deli turkey count?
Look at how a meat was made, as well as which animal it came from.
11 references Read explanation - Food & nutrition
Protein needs and high-protein labels: how much is enough?
Does a high-protein label mean I need more protein, or that it is a better food?
18 references Read explanation - Food & nutrition
Soluble, insoluble, added fiber: what do the different types do?
Does fiber in a bar count like fiber in beans, and why can more cause bloating?
11 references Read explanation - Food & nutrition
Seed oils and omega-6: what does the argument actually mean?
Are people discussing the oil itself, repeated frying, or the food cooked in it?
11 references Read explanation - Food & nutrition
Probiotic, prebiotic, postbiotic: what is actually in the product?
Are live cultures, fermented food and a probiotic the same thing?
11 references Read explanation - Food & nutrition
Best before, use by, sell by: does the date mean food is unsafe?
Which dates concern quality, and what changes after opening?
9 references Read explanation - Food & nutrition
Serving size, portion size and % Daily Value: how do you read the numbers?
Is one serving a recommendation, and does 20% mean I should eat five servings?
11 references Read explanation - Food & nutrition
Food allergy, intolerance and sensitivity: what is the difference?
Can symptoms after eating show which kind of reaction I have?
10 references Read explanation - Food & nutrition
Your gut microbiome: what are good bacteria, diversity and dysbiosis?
Can a stool-test score tell me whether my gut is healthy?
12 references Read explanation - Food & nutrition
Whole grain, whole wheat, multigrain: what should I actually look for?
Does brown or multigrain bread necessarily contain more whole grain?
10 references Read explanation - Food & nutrition
Aspartame, stevia, erythritol: are all sugar substitutes the same?
How do high-intensity sweeteners differ from sugar alcohols?
9 references Read explanation - Food & nutrition
Organic, non-GMO and natural: what does each label actually promise?
Which label concerns farming methods, which concerns genetic engineering, and which tells me about nutrition?
10 references Read explanation - Food & nutrition
Pasteurized, homogenized, UHT and raw milk: which difference matters?
Which process changes microbes, which changes texture, and why does storage differ?
12 references Read explanation - Food & nutrition
Gluten-free: who needs it, and what does the label actually guarantee?
How are celiac disease, wheat allergy and gluten sensitivity different?
10 references Read explanation - Food & nutrition
Lactose-free, dairy-free, nondairy: can these mean different things?
Can lactose-free milk still cause a milk-allergy reaction?
9 references Read explanation - Food & nutrition
Food additive, GRAS, E number: how do ingredients get assessed?
Does GRAS mean the FDA individually approved this ingredient?
8 references Read explanation - Food & nutrition
Emulsifiers and gums: why are they in food, and what do gut studies show?
Are lecithin, xanthan gum and carboxymethylcellulose interchangeable?
11 references Read explanation - Food & nutrition
Carbs, starch, sugar and net carbs: what are you actually counting?
Why do oats, fruit and sweets all count as carbohydrates?
16 references Read explanation - Food & nutrition
Saturated, unsaturated and trans fats: what changes when you swap one for another?
Does low fat automatically mean a better choice?
10 references Read explanation
Movement & fitness
Understand training terms and the numbers on your watch.
- Movement & fitness
Electrolytes: when is a sports drink different from water?
Do you need electrolyte powder for a normal day, and is it the same as rehydration treatment?
11 references Read explanation - Movement & fitness
HRV: why does your watch call you stressed when you feel fine?
What is heart-rate variability, and can you compare your number with someone else?
9 references Read explanation - Movement & fitness
VO2 max: what does your watch know about your fitness?
Is a cardio-fitness estimate the same as a lab test or a prediction of your lifespan?
8 references Read explanation - Movement & fitness
Zone 2 and the fat-burning zone: are they the same thing?
Does an easy heart-rate zone burn more body fat over time?
11 references Read explanation - Movement & fitness
DOMS and lactic acid: what does being sore actually tell you?
Do sore muscles mean a workout worked, and is lactate still trapped there?
10 references Read explanation - Movement & fitness
Weighted vests and rucking: what does adding weight actually change?
Is walking with extra weight the same as strength training, and does it build bone?
9 references Read explanation
Supplements
Read the ingredient, dose, and claim with more context.
- Supplements
Third-party tested, certified, FDA registered: what do these claims tell you?
Find out who checked what, and which questions remain.
13 references Read explanation - Supplements
Magnesium glycinate, citrate, oxide: what changes, and what does elemental mean?
Do different forms do different jobs, and what dose is actually on the label?
15 references Read explanation - Supplements
Creatine: muscle fuel, a steroid, or something else?
What is creatine, and does a loading phase or a different form matter?
21 references Read explanation - Supplements
Whey, isolate, concentrate, complete protein: what is in your scoop?
Is isolate automatically better, and does plant protein count the same way?
13 references Read explanation - Supplements
Collagen peptides: how is this different from ordinary protein?
Does swallowed collagen go straight to skin or joints?
8 references Read explanation - Supplements
Fish oil, omega-3, EPA, DHA: which number matters?
Is 1,000 mg fish oil the same as 1,000 mg omega-3?
15 references Read explanation - Supplements
Vitamin D2, D3, K2 and IU: what does the bottle actually mean?
What is the difference between low vitamin D, a daily requirement and an optimal level?
15 references Read explanation - Supplements
Turmeric and curcumin: is the spice the same as a supplement?
How different is a concentrated extract from turmeric in dinner?
8 references Read explanation - Supplements
Multivitamins and megadoses: does more on the label mean more benefit?
Does 1,000% of a daily value mean a supplement is ten times better?
10 references Read explanation - Supplements
B12, methylated B vitamins and energy: what does the claim mean?
Does more B12 provide more energy when you are not deficient?
8 references Read explanation - Supplements
Adaptogens: a scientific category or a promise on a bottle?
What does stress support tell you about an ashwagandha or adaptogen blend?
9 references Read explanation - Supplements
Pre-workout: what is supposed to do the work?
Is the tingle evidence that a pre-workout is effective?
8 references Read explanation - Supplements
Bioavailable, liposomal, chelated: does better absorption mean better health?
What would prove that an expensive formulation is worth it?
14 references Read explanation
Mental wellbeing
Understand the words we use for mental wellbeing.
- Mental wellbeing
Cortisol: is the stress hormone really the problem?
What do high cortisol, cortisol face and adrenal fatigue actually mean?
11 references Read explanation - Mental wellbeing
Stress, anxiety and panic: how are they different?
When is worry an ordinary stress response, and what does an anxiety disorder mean?
16 references Read explanation - Mental wellbeing
ADHD: how is it different from being distracted?
What do attention deficit, hyperactivity and executive function actually describe?
12 references Read explanation - Mental wellbeing
Burnout: is it the same as depression or exhaustion?
What does burnout describe, and what can the label miss?
9 references Read explanation
Prevention & care
Translate tests, medicines, and the language of evidence.
- Prevention & care
“Abnormal” blood test: does outside the normal range mean something is wrong?
What does a red flag in my patient portal actually mean?
8 references Read explanation - Prevention & care
GLP-1 medicines: what are they, and are Ozempic and Mounjaro the same?
How do these drugs work, and why do names and uses differ?
14 references Read explanation - Prevention & care
Perimenopause and menopause: when does each actually begin?
Can you be in perimenopause while still having periods?
10 references Read explanation - Prevention & care
LDL, HDL, ApoB and Lp(a): what is a cholesterol test counting?
Why can one cholesterol number look fine while another is high?
12 references Read explanation - Prevention & care
Glucose spikes: does every rise after eating need fixing?
What does a glucose monitor measure, and when does a spike matter?
10 references Read explanation - Prevention & care
Blood pressure: what do the top and bottom numbers mean?
Is one high reading the same as hypertension?
14 references Read explanation - Prevention & care
HRT, MHT and bioidentical hormones: what is actually different?
Are all menopause hormones the same, and what does bioidentical tell you?
12 references Read explanation - Prevention & care
Positive, negative, unremarkable: how to read test-report language
Why can a negative test be good news, and what does unremarkable mean?
9 references Read explanation - Prevention & care
HbA1c versus blood sugar: why can the numbers tell different stories?
What is the difference between an average over months and a glucose reading today?
8 references Read explanation - Prevention & care
Insulin resistance and prediabetes: are they the same thing?
Does either term mean diabetes is inevitable?
11 references Read explanation - Prevention & care
Compounded, generic, brand-name: what is the medicine difference?
What should you check before buying a custom-made or online medicine?
11 references Read explanation - Prevention & care
Iron, ferritin and anemia: why are they not interchangeable?
Can iron stores be low before a blood count shows anemia?
8 references Read explanation - Prevention & care
TSH, T4 and thyroid tests: what is the lab actually measuring?
Why does a high TSH sometimes mean an underactive thyroid?
8 references Read explanation - Prevention & care
“Raises risk by 20%”: 20% of what?
How different are relative risk, absolute risk and percentage points?
8 references Read explanation - Prevention & care
Creatinine and eGFR: is a kidney score a percentage?
Does one low eGFR result mean chronic kidney disease?
11 references Read explanation - Prevention & care
“Liver function” tests: do high enzymes mean the liver is failing?
What do ALT, AST, bilirubin and albumin actually tell you?
11 references Read explanation - Prevention & care
Tolerance, dependence, withdrawal and addiction: are they the same?
Does withdrawal automatically mean a person is addicted?
10 references Read explanation - Prevention & care
Antibiotic resistance: does your body become resistant to antibiotics?
What becomes resistant, and why do antibiotics not treat a cold?
10 references Read explanation - Prevention & care
Screening versus diagnosis: why can finding more disease be complicated?
Can a real finding still lead to unnecessary treatment?
13 references Read explanation - Prevention & care
“Linked to” versus “causes”: what can a health study actually establish?
Why do observational studies and trials sometimes seem to disagree?
16 references Read explanation - Prevention & care
Statistically significant, clinically meaningful, proven: are they the same?
Can a tiny effect be significant, or a useful effect be uncertain?
12 references Read explanation - Prevention & care
PCOS: does polycystic mean you have ovarian cysts?
What makes PCOS a syndrome rather than just an ovary finding?
12 references Read explanation - Prevention & care
Endometriosis: what grows where, and is it just a painful period?
What does endometriosis mean, and why is the name not the whole story?
11 references Read explanation - Prevention & care
IBS and IBD: similar letters, different bowel problems
Is irritable bowel syndrome the same as inflammatory bowel disease?
12 references Read explanation - Prevention & care
Heartburn, acid reflux and GERD: are they the same thing?
What is a symptom, what is reflux, and when is it called a disease?
11 references Read explanation - Prevention & care
UTI, bladder infection and kidney infection: what is the difference?
Does burning when you pee always mean a urinary tract infection?
11 references Read explanation - Prevention & care
Stomach flu: why norovirus is not influenza
Are stomach flu, food poisoning and norovirus interchangeable names?
10 references Read explanation - Prevention & care
Inflammation: when is it useful, and when is it a problem?
Does inflammation always mean something is wrong?
8 references Read explanation - Prevention & care
Allergy, autoimmunity and low immunity: what is the immune system doing?
Why does a stronger immune system not always mean a healthier one?
13 references Read explanation
Healthy aging
Look closely at what a health or longevity measure can show.
Products & safety
Understand the product, exposure, and limits of what we know.
- Products & safety
Water filters: what do they actually remove?
Follow a claim from the package to the exact filter and its certification.
14 references Read explanation - Products & safety
Fragrance-free vs. unscented: are they the same?
Look beyond the scent and read the label in context.
9 references Read explanation - Products & safety
Glyphosate and Roundup: what does the cancer evidence tell us?
Separate the ingredient, the product and the way exposure happens.
15 references Read explanation - Products & safety
EMFs: what about your car and the router beside your bed?
Understand the different fields around everyday devices.
13 references Read explanation - Products & safety
Skin absorption: does everything you apply reach your bloodstream?
Follow an ingredient from the skin surface through the questions that matter.
8 references Read explanation - Products & safety
Microplastics and nanoplastics: do more particles mean more risk?
Read particle measurements with their methods and limits in view.
17 references Read explanation - Products & safety
BPA and receipts: what does touching one mean for your health?
Separate contact, absorbed exposure and evidence about health outcomes.
12 references Read explanation - Products & safety
SPF 30, broad spectrum, mineral, water-resistant: what matters on sunscreen?
SPF 30, broad spectrum, mineral, water-resistant: what matters on sunscreen?
13 references Read explanation - Products & safety
Forever chemicals: are PFAS, PFOA and non-stick coatings the same thing?
Forever chemicals: are PFAS, PFOA and non-stick coatings the same thing?
11 references Read explanation - Products & safety
Clean, natural and chemical-free skincare: what do those words actually promise?
Clean, natural and chemical-free skincare: what do those words actually promise?
9 references Read explanation - Products & safety
Hypoallergenic and dermatologist-tested: will this product agree with your skin?
Hypoallergenic and dermatologist-tested: will this product agree with your skin?
12 references Read explanation - Products & safety
HEPA, CADR and ionizers: what does an air purifier actually remove?
HEPA, CADR and ionizers: what does an air purifier actually remove?
12 references Read explanation - Products & safety
AQI and PM2.5: what does that air-quality number mean for your day?
AQI and PM2.5: what does that air-quality number mean for your day?
9 references Read explanation - Products & safety
Black mold, mycotoxins and mold tests: what do the terms actually tell you?
Black mold, mycotoxins and mold tests: what do the terms actually tell you?
9 references Read explanation - Products & safety
Plastic numbers, BPA-free and microwave-safe: what can you infer from the label?
Plastic numbers, BPA-free and microwave-safe: what can you infer from the label?
11 references Read explanation - Products & safety
Red-light therapy: what can a mask or panel actually claim?
Is a home LED mask the same treatment that was tested in a clinic?
8 references Read explanation - Products & safety
Retinol, retinal, retinoids and tretinoin: why are the names so similar?
Retinol, retinal, retinoids and tretinoin: why are the names so similar?
8 references Read explanation - Products & safety
Clean, sanitize and disinfect: which job do you actually need?
Clean, sanitize and disinfect: which job do you actually need?
11 references Read explanation - Products & safety
Radon: why can a gas you cannot smell still require a home test?
Radon: why can a gas you cannot smell still require a home test?
9 references Read explanation - Products & safety
CO, CO₂ and smoke alarms: why are these not interchangeable?
CO, CO₂ and smoke alarms: why are these not interchangeable?
8 references Read explanation