FactoWiki

Health answers

Health answers and supplement buying guides

Plain-English, evidence-based answers to common questions about health concerns and the supplements marketed for them — what the research supports, what it doesn't, and what to check before you buy.

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Looking for quick answers to specific questions? Browse our 100 Health Answers — short, honest explainers covering nerve, blood sugar, weight, prostate, brain, gut and more, each with the ingredients and products that matter.

Nerve Health

What causes tingling in the feet?

Tingling in the feet has many possible causes, from temporary pressure to nerve-related conditions. Here's a p…

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Nerve Health

Best vitamins and ingredients for nerve health

Which vitamins and supplement ingredients actually have research behind them for nerve health? A look at the o…

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Blood Sugar & Metabolism

What ingredients support healthy blood sugar levels?

From berberine to cinnamon, many ingredients are marketed for blood sugar. Here's which ones have real evidenc…

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Weight & Metabolism

How to compare weight-loss supplements

Weight-loss supplements are the most hype-prone category there is. Here's a practical, honest checklist for co…

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Gut & Digestive Health

Do probiotics really help gut health?

Probiotics are everywhere, but the evidence is more nuanced than the marketing. Here's what the research actua…

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Prostate & Men's Urinary Health

What to check before buying a prostate supplement

Prostate supplements are popular with older men, but the evidence is mixed and the claims can mislead. Here's …

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Men's Vitality & Testosterone

Best ingredients for men's vitality

Men's-vitality supplements promise a lot. Here's which ingredients have at least modest evidence, which don't,…

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Skin & Anti-Aging

Can collagen supplements support skin elasticity?

Collagen supplements are marketed hard for youthful skin. Here's what the research actually suggests about ski…

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Buying Guides

How to read a supplement label before buying

A supplement label tells you more than the marketing does — if you know what to look for. Here's how to read o…

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Buying Guides

Are supplement reviews always reliable?

Many "supplement reviews" online are really sales pages in disguise. Here's how to spot a trustworthy review f…

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prostate

Best ingredients for prostate health

Which prostate-supplement ingredients have real evidence for urinary symptoms — and which are mostly marketing…

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blood-sugar

Do blood sugar supplements really work?

An honest look at whether blood-sugar supplements lower glucose — which ingredients have evidence, and the saf…

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dental

How to compare dental health supplements

How to judge oral-health supplements by ingredients and evidence — and what they can never replace.…

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brain

What causes weak memory after 40?

Why memory can feel weaker after 40 — the everyday causes, the warning signs, and where supplements realistica…

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hearing

Can supplements support hearing health?

The honest evidence on hearing and tinnitus supplements — why it's weak, and what actually helps.…

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vision

Best vitamins and ingredients for eye health

Which eye nutrients have real evidence — the AREDS2 core — and what supplements can't do for your vision.…

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safety

How to check a supplement's side effects before you take it

A practical guide to checking interactions and side effects before starting any supplement.…

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label-literacy

What is a proprietary blend (and why it matters)?

What a proprietary blend is, why companies use them, and how to spot under-dosed ingredients.…

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safety

How to avoid fake and scam supplement websites

The red flags of fake supplement sites and fake reviews — and how to buy safely.…

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gut

Best ingredients for gut health

Which gut-health ingredients have real evidence — probiotics, prebiotics and fibre — and which claims outrun t…

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skin

Best ingredients for skin and anti-aging

Which skin supplements have real evidence — collagen, antioxidants, vitamin C — and the one factor that beats …

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brain

How to compare brain and memory supplements

How to judge nootropic and memory supplements by ingredients, doses and honest evidence.…

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mens-health

How to compare men's vitality supplements safely

How to judge men's vitality and 'testosterone' supplements — and the safety issue that defines the category.…

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womens-health

Can supplements help with UTIs and bladder control?

What the evidence says about cranberry, D-mannose and bladder supplements — and when to see a doctor.…

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gut

Prebiotics vs probiotics: what's the difference?

A clear explainer on prebiotics, probiotics, postbiotics and fibre — and which one you actually need.…

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how-to

How long do supplements take to work?

Realistic timelines for when supplements show effects — and why instant-results claims are a red flag.…

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safety

Are 'natural' supplements safer than prescription drugs?

Why 'natural' doesn't mean safe — interactions, contamination and the regulation gap explained.…

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label-literacy

What does 'clinically proven' mean on a supplement label?

How to decode 'clinically proven', 'studies show' and similar marketing claims on supplement labels.…

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nutrition

Can supplements replace a healthy diet?

Why supplements complement rather than replace food — and the limited cases where they genuinely help.…

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berberine

What does berberine actually do?

What berberine is, the real evidence for blood sugar and cholesterol, and the interactions that make it a doct…

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ashwagandha

Is ashwagandha worth taking?

The evidence for ashwagandha on stress, sleep and testosterone — plus the thyroid and pregnancy cautions.…

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alpha-lipoic-acid

What is alpha-lipoic acid good for?

The real evidence for alpha-lipoic acid in nerve symptoms and blood sugar — forms, doses and safety.…

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saw-palmetto

Does saw palmetto work for the prostate?

The honest evidence on saw palmetto for urinary symptoms — why big trials were negative, and what has better s…

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bacopa

What does bacopa monnieri do for memory?

The evidence behind bacopa, the slow timeline, and the digestive and thyroid cautions worth knowing.…

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tongkat-ali

Is tongkat ali a real testosterone booster?

What tongkat ali actually does, the honest take on testosterone claims, and the sourcing and contamination pro…

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coq10

What is CoQ10 good for?

The evidence for coenzyme Q10 in heart health, statin muscle aches and migraine — plus forms and absorption.…

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omega-3

What is fish oil (omega-3) good for?

The real evidence for omega-3 on triglycerides, heart, dry eye and mood — and how to judge quality.…

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prostate

Beta-sitosterol vs saw palmetto: which is better for the prostate?

A head-to-head on the two big prostate ingredients — which has the evidence, and what neither can do.…

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magnesium

Does magnesium help sleep, and which form is best?

What magnesium does for sleep and relaxation, how the forms differ, and the safety points that matter.…

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lions-mane

What is lion's mane good for?

The early evidence for lion's mane on memory and mood, what's still unproven, and how to judge a product.…

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ginkgo

Does ginkgo biloba improve memory?

What the big trials found about ginkgo and memory, its mixed dementia evidence, and the bleeding risk to know.…

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gymnema

What is gymnema sylvestre good for?

Gymnema's real sweet-taste-blocking effect, its weaker blood-sugar evidence, and the safety catch with diabete…

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creatine

What is creatine good for?

Why creatine is the most-researched sports supplement, its emerging cognitive uses, and the kidney myth explai…

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milk-thistle

What is milk thistle good for?

The honest evidence on milk thistle for the liver, why 'detox' claims overreach, and the safety basics.…

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l-theanine

What does L-theanine do?

How L-theanine creates calm focus, why it pairs with caffeine, and what to realistically expect.…

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curcumin

Is turmeric (curcumin) good for inflammation and joints?

The evidence for curcumin on joint pain, the big absorption problem, and the safety points that matter.…

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sleep

Melatonin vs magnesium for sleep: which should you try?

How melatonin and magnesium differ for sleep, which suits which problem, and why neither fixes chronic insomni…

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safety

What do third-party testing seals mean on supplements?

How USP, NSF and Informed Sport seals work, what they do and don't verify, and how to spot fake 'tested' badge…

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probiotics

How to read CFU counts on probiotic labels

What CFU means, why bigger isn't always better, and the label details that matter more than the number.…

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rhodiola

What is rhodiola good for?

The evidence for rhodiola on stress and fatigue, how to take it, and what to realistically expect.…

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vitamin-d

What does vitamin D do, and who actually needs it?

Vitamin D's real role in bone and immune health, who's likely deficient, and why mega-doses aren't the answer.…

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nac

What is NAC (N-acetylcysteine) good for?

NAC's genuine medical uses, the emerging supplement claims, and where the evidence is still thin.…

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st-johns-wort

Does St John's wort work for depression?

The real evidence for St John's wort in mild depression — and the serious drug interactions that make it risky…

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quercetin

What is quercetin good for?

The evidence for quercetin on allergies, immunity and exercise — and the absorption problem behind it.…

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elderberry

Do elderberry supplements help colds and flu?

What the evidence says about elderberry for colds and flu, the safety of raw berries, and realistic expectatio…

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valerian

Does valerian root help you sleep?

The mixed evidence for valerian on sleep and anxiety, how to take it, and why it's no knockout sedative.…

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citrulline

What are L-citrulline and L-arginine good for?

How these 'nitric oxide' amino acids work for blood flow and exercise — and which one actually absorbs better.…

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garlic

Does garlic lower blood pressure and cholesterol?

The real evidence for garlic supplements on blood pressure and cholesterol, plus the bleeding caution to know.…

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zinc

What is zinc good for, and can you take too much?

Zinc's roles in immunity and healing, when it actually helps, and why its safe range is surprisingly narrow.…

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ginseng

What is panax ginseng good for?

The evidence for panax (Asian) ginseng on energy, cognition and more — plus the cautions that come with it.…

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maca

Does maca boost libido and energy?

What the evidence says about maca for libido, energy and fertility — and why it doesn't raise testosterone.…

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collagen

Collagen types explained: which one is best for you?

The difference between collagen types I, II and III, marine vs bovine, and which suits skin versus joints.…

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joints

Do glucosamine and chondroitin work for joints?

The genuinely contested evidence on glucosamine and chondroitin, the form that matters, and how to trial them.…

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green-tea

Is green tea extract safe, and what is it good for?

Green tea extract's modest metabolism evidence, its real liver-safety signal, and how to use it sensibly.…

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cinnamon

Does cinnamon lower blood sugar?

The honest evidence on cinnamon for blood sugar, and the Cassia-versus-Ceylon distinction that affects safety.…

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ginger

What is ginger good for?

Ginger's genuinely strong evidence for nausea, its digestive and joint uses, and the bleeding caution.…

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vitamin-b12

What is vitamin B12, and who needs a supplement?

Vitamin B12's role in nerves and blood, who's at risk of deficiency, and why it only 'boosts energy' if you're…

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garcinia

Does garcinia cambogia work for weight loss?

The weak weight-loss evidence for garcinia cambogia and the serious liver-safety concerns you should know.…

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beetroot

What is beetroot (beet juice) good for?

How beetroot's nitrates support blood pressure and exercise, the harmless red-urine effect, and who should be …

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vitamin-c

What is vitamin C good for?

Vitamin C's real roles in immunity and collagen, the cold-prevention myth, and why mega-doses aren't better.…

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red-yeast-rice

Does red yeast rice lower cholesterol (and is it safe)?

Why red yeast rice is essentially an unregulated statin — it can lower cholesterol, but with real risks and un…

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chromium

What is chromium good for?

The weak evidence behind chromium for blood sugar and weight, and why deficiency is rare.…

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taurine

What is taurine good for?

Taurine's roles in the heart and exercise, why it isn't a stimulant, and what the evidence really shows.…

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citicoline

What is citicoline good for?

The evidence for citicoline on focus, brain energy and cognition — one of the better-supported nootropic ingre…

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5-htp

Does 5-HTP help mood and sleep?

The evidence for 5-HTP on mood and sleep — and the serious serotonin-syndrome risk with antidepressants.…

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pycnogenol

What is pycnogenol (pine bark extract) good for?

The circulation and skin claims behind pine bark extract, the industry-funded evidence caveat, and safety.…

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hawthorn

What is hawthorn good for, and is it safe with heart medication?

Hawthorn's traditional heart uses, the modest evidence, and the serious interactions that make medical input e…

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selenium

What is selenium good for, and can you take too much?

Selenium's roles in thyroid and antioxidant defence, why deficiency is uncommon, and its surprisingly narrow s…

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phosphatidylserine

What is phosphatidylserine good for?

The evidence for phosphatidylserine on memory and age-related cognition, plus sourcing and safety.…

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benfotiamine

What is benfotiamine good for?

How benfotiamine differs from regular vitamin B1, its use for nerve symptoms, and what the evidence shows.…

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acetyl-l-carnitine

What is acetyl-L-carnitine good for?

The evidence for acetyl-L-carnitine on nerves, brain and energy — and where the claims outrun the research.…

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bilberry

What is bilberry good for?

The truth about bilberry and eyesight, the WWII night-vision myth, and where its antioxidants may help.…

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olive-leaf

What is olive leaf extract good for?

The evidence for olive leaf extract on blood pressure and immunity, and how to read its modest claims.…

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citrus-bergamot

What is citrus bergamot good for?

The emerging evidence for citrus bergamot on cholesterol, how it differs from a statin, and the safety basics.…

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inositol

What is inositol good for?

The evidence for inositol in PCOS, mood and metabolic health, plus forms and safety.…

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fenugreek

Does fenugreek boost testosterone and libido?

What the evidence says about fenugreek for libido and testosterone, blood sugar, and the safety points.…

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pygeum

What is pygeum good for?

The evidence for pygeum on prostate and urinary symptoms, how it compares to other ingredients, and safety.…

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buying

Are supplement discounts and '3-for-1' deals real?

How supplement pricing and bulk discounts actually work, which deals are genuine, and the traps to avoid.…

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safety

When should you stop taking a supplement?

Clear signals it's time to stop a supplement — no benefit, side effects, new medications, or it's simply not n…

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epimedium

What is horny goat weed (epimedium) good for?

The weak evidence behind horny goat weed for libido — and the serious spiking problem in this category.…

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stinging-nettle

What is stinging nettle good for?

The different uses of nettle root and leaf — prostate, allergies and joints — and what the evidence shows.…

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cranberry

Does cranberry prevent UTIs?

What the evidence really says about cranberry for urinary tract infections, juice vs supplements, and the limi…

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huperzine-a

What is huperzine A good for (and why dosing matters so much)?

Huperzine A's drug-like action on memory, the critical microgram dosing, and why it isn't a casual supplement.…

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grape-seed

What is grape seed extract good for?

The antioxidant and circulation evidence for grape seed extract, plus how it relates to pine bark and safety.…

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buying

How to spot and cancel supplement subscription traps

How auto-ship and 'free trial' traps work, the warning signs, and how to cancel and dispute unwanted charges.…

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safety

How to store supplements and read expiry dates

Where to keep supplements, why the bathroom is the worst spot, and what expiry dates actually mean.…

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safety

Do you need to cycle supplements?

What 'cycling' supplements means, which ones might benefit, and why it's unnecessary for most.…

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vitamins

Are gummy vitamins as good as pills?

The real trade-offs of gummy vitamins — fewer nutrients, added sugar, faster degradation — versus capsules and…

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label-literacy

What does 'GMP certified' mean on a supplement?

What Good Manufacturing Practice covers, what it doesn't, and how it differs from third-party testing.…

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safety

How many supplements is too many?

The real risks of taking lots of supplements — interactions, overlapping doses and cost — and how to trim your…

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