Health Reference LibraryNutri Tailor Health Reference Library
Welcome.
When you look for reliable answers to a health topic online, you often run into one of two issues. There's wellness content that's confident but light on evidence. There's also peer reviewed research that's rigorous but locked behind paywalls and written for clinicians.
This library provides best of both worlds. We've gathered the published research and summarised it in plain language: what's been studied, what was found, where the evidence is strong, and where it's still uncertain. Drop by to check one thing, or follow the threads when you want to go deeper.
It's free and every article is fully referenced.
Topics
Iron
103 entries
Magnesium
37 entries
Vitamin D
43 entries
B Vitamins
49 entries
Omega-3
28 entries
Zinc
15 entries
Supplement protocols
3 entries
Adaptogens
0 entries
Blood markers
37 entries
Iron
- Can hair shedding point to low iron, and what should you test?
- Can iron deficiency raise resting heart rate?
- Can restless legs at night point to low iron?
- Can you take iron and magnesium together?
- Can you take zinc and iron together?
- Does iron compete with calcium for absorption?
- Does vitamin C help iron absorption?
- Does vitamin C help iron absorption?
- Ferritin 10: what does a result under 12 mean?
- Ferritin 10: what your result means
- Ferritin 11: what your result means
- Ferritin 12: what your result means
- Ferritin 120: is that normal or getting high?
- Ferritin 13: what your result means
- Ferritin 14: what your result means
- Ferritin 15 to 30: what your result means
- Ferritin 15: is that low, and what should you do?
- Ferritin 15: what your result means
- Ferritin 16: what your result means
- Ferritin 17: what your result means
- Ferritin 18: is that low or normal?
- Ferritin 18: what your result means
- Ferritin 19: what your result means
- Ferritin 200: is that high?
- Ferritin 21: what your result means
- Ferritin 22: what your result means
- Ferritin 23: what your result means
- Ferritin 24: what your result means
- Ferritin 25: is that low or just borderline?
- Ferritin 30 to 50: what your result means
- Ferritin 35: is that OK, or still on the low side?
- Ferritin 4: what your result means
- Ferritin 400: how concerning is a raised result?
- Ferritin 5: what does a result below 8 mean?
- Ferritin 5: what your result means
- Ferritin 6: what your result means
- Ferritin 60: is that a good level?
- Ferritin 7: what your result means
- Ferritin 8: what your result means
- Ferritin 85: what does a result between 71 and 100 mean?
- Ferritin 9: what your result means
- Ferritin between 50 and 300: what a healthy-range result means
- Ferritin blood test results explained: what does your number mean?
- Ferritin: what your level means, low, normal and high (UK)
- Foods for energy: what works
- Foods high in iron: UK portions and how far they get you
- Haemoglobin 100: what your result means
- Haemoglobin 105: what your result means
- Haemoglobin 110: what your result means
- Haemoglobin 115: what your result means
- Haemoglobin 118: what your result means
- Haemoglobin 120: what your result means
- Haemoglobin 125: what your result means
- Haemoglobin 130: what your result means
- How do iron, sleep, and stress create a vicious cycle?
- How do iron, thyroid, and mitochondria determine energy levels?
- How does a vegetarian or vegan diet change iron needs?
- How does inflammation mask iron deficiency on ferritin?
- How does iron deficiency impair thyroid function?
- How does iron status specifically affect female fertility?
- How does low ferritin affect focus before anaemia develops?
- How does low ferritin affect sleep quality independently of fatigue?
- How does low ferritin affect thyroid, energy, and cognition?
- How does nutrition help prevent and manage haemorrhoids?
- How is hereditary haemochromatosis managed nutritionally?
- How long does iron take to correct deficiency, and when to retest?
- How long does iron take to improve energy?
- How long does iron take to resolve symptoms and ferritin?
- How long does it take to fully replete iron stores?
- How much iron should I take, and how much is too much?
- Iron bisglycinate vs ferrous fumarate: which should you take?
- Iron deficiency symptoms: what to check and what to do (UK)
- Iron panel normal but still exhausted: what should I check?
- Iron supplementation timeline: when to expect sleep improvement?
- Is a ferritin of 20 normal?
- Is there a loading protocol for iron supplementation?
- Nootropics and supplements for focus: what the evidence supports
- Period pain: what helps, and when it needs a GP
- Should you take iron with coffee or tea?
- Transferrin saturation above 45 percent: what a high result means
- Transferrin saturation below 20 percent: is that low, and what should you do?
- TSH above 10: what the guideline says happens next
- TSH below 0.4: a low TSH, and what needs checking
- TSH blood test results explained: what your number means in the UK
- TSH of 2.5 to 4: high-normal, and what it does and does not mean
- TSH of 4.5 to 10: subclinical hypothyroidism, and what happens next
- What do iron tests and thresholds mean in pregnancy?
- What does a high ferritin result mean?
- What does iron deficiency mean in men?
- What does low ferritin with normal haemoglobin mean?
- What does the full iron panel tell us beyond ferritin alone?
- What ferritin level is optimal for women?
- What ferritin level warrants iron supplementation?
- What nutritional support helps with heavy periods and iron loss?
- What's the iron-sleep-stress triad and how does it present?
- When is the best time to take iron, and should you take it with food?
- Which form of iron should you buy?
- Which supplements for fatigue and low energy have evidence?
- Which supplements for hair loss have evidence?
- Which symptoms point to low iron, and what should you test?
- Why do endurance runners lose iron, and what should they watch?
- Why do iron, thyroid, and vitamin D deficiencies compound?
- Why does inflammation block iron use even with full stores?
Magnesium
- Can I take calcium and magnesium together?
- Can you take magnesium and zinc together?
- Foods high in magnesium: UK portions and how far they get you
- How do stress and magnesium depletion reinforce each other?
- How do stress, sleep, and magnesium reinforce each other?
- How do vitamin D, K2, and magnesium work together?
- How do you fall asleep faster? What the evidence supports
- How do you improve deep sleep? What influences it
- How do you lower cortisol? What the evidence supports
- How do you reduce anxiety naturally? What the evidence supports
- How do you reset a broken sleep schedule?
- How does magnesium affect HRV (heart rate variability)?
- How long does magnesium take to work for anxiety?
- How long does magnesium take to work for sleep?
- How long does magnesium take to work?
- How much magnesium should I take, and how much is too much?
- Magnesium bisglycinate vs magnesium glycinate: is there a difference?
- Magnesium citrate: what dose, how well absorbed, and when is it the right form?
- Magnesium for muscle cramps: how quickly should it work?
- Magnesium glycinate vs magnesium citrate: which should you take?
- Magnesium glycinate vs magnesium malate: which should you take?
- Should you take magnesium in pregnancy?
- What are the symptoms of low magnesium?
- What are the symptoms of perimenopause, and what helps?
- What does an effective sleep hygiene routine look like?
- What is magnesium bisglycinate and when is it the right form?
- What is magnesium malate good for?
- What is the best time to take magnesium: morning or night?
- What magnesium level is optimal?
- What should a perimenopause diet look like? What the evidence supports
- When does magnesium need therapeutic vs standard dosing?
- Which breathing exercises for anxiety have evidence?
- Which magnesium is best: glycinate, citrate, malate or threonate?
- Which supplements for anxiety have evidence?
- Which supplements for menopause have evidence?
- Which supplements for PMS have evidence?
- Which supplements for sleep have evidence?
Vitamin D
- Can you get enough vitamin D from food?
- D2 vs D3: what's the difference and which should you take?
- Do low B12 and low vitamin D worsen mood together?
- Do vitamin D deficiency and poor sleep compound immune risk?
- Do you need magnesium for vitamin D to work?
- Do you need to take calcium with vitamin D?
- Do you need to take K2 with vitamin D3?
- How do malabsorption, vitamin D, and low protein compound?
- How do sun exposure and UV affect vitamin D and skin?
- How do thyroid, gut, and vitamin D issues compound each other?
- How do you support your immune system? What the evidence supports
- How does vitamin D deficiency affect sleep and circadian rhythm?
- How long does vitamin D take to work?
- How much vitamin D should I take, and at what dose does it become risky?
- Should you take vitamin D in pregnancy?
- Supplements for low mood: what the evidence supports
- Vitamin D 12: what your result means
- Vitamin D 25 to 50: what your result means
- Vitamin D 25: what your result means
- Vitamin D 50 to 125: what your result means
- Vitamin D at 15 nmol/L: what does a deficient result mean?
- Vitamin D at 150 nmol/L: too high, or just high?
- Vitamin D at 250 nmol/L: what should you do now?
- Vitamin D at 30 nmol/L: is that low?
- Vitamin D at 45 nmol/L: nearly there, or still low?
- Vitamin D at 60 nmol/L: is that a good level?
- Vitamin D at 90 nmol/L: comfortably replete, what now?
- Vitamin D blood test results explained: what does your number mean?
- Vitamin D deficiency: symptoms, levels and what to do (UK)
- Vitamin D for mood: how long does it take in winter?
- Vitamin D loading dose: when is it appropriate, and how is it calculated?
- What are the symptoms of vitamin D deficiency?
- What is a normal vitamin D level?
- What nutrition shifts in spring as vitamin D synthesis resumes?
- What pattern suggests B vitamin deficiency even with normal B12?
- What vitamin D level needs supplementation?
- What's the protocol for loading and maintaining vitamin D?
- What's the vitamin D situation for darker-skinned UK adults?
- When and how much vitamin D should UK adults take in autumn?
- When is the best time to take vitamin D?
- Which form of vitamin D should you buy: D3, D2, and does K2 matter?
- Which immune supplements have evidence?
- Who needs to take vitamin D all year round?
B Vitamins
- Adenosylcobalamin B12: what is the mitochondrial form, and when should you choose it?
- B12 180 to 350: what your result means
- B12 above 900: is a high result anything to worry about?
- B12 blood test results explained: what does your number mean?
- B12 deficiency: symptoms, levels and what to do (UK)
- B12 for vegans: what should you test, and what should the numbers show?
- Biotin (vitamin B7): does it help hair and nails, and what is the blood test warning?
- Can you take B12 and folate together?
- Cyanocobalamin B12 drops: what is the standard form, and when does it make sense?
- Folate 3 to 4: is that low, and what should you do?
- Folate 5 to 20: is that normal?
- Folate below 3: is that deficient, and what should you do?
- Folate blood test results explained: what does your number mean?
- Folate deficiency: symptoms, levels and what to do (UK)
- Folate vs folic acid vs methylfolate: which should you take?
- Foods high in vitamin B12: UK portions and the plant diet gap
- Foods high in vitamin B6: UK portions and how far they get you
- How do B vitamins affect homocysteine and brain/CV health?
- How do B12 injections compare to oral supplements?
- How long does B12 repletion take, including neurological recovery?
- How long does B12 take to work?
- How long does biotin take to work?
- How much biotin should I take, and can you take too much?
- How much folate should I take, and how much is too much?
- How much vitamin B12 should I take, and can you take too much?
- How much vitamin B6 should I take, and what are the risks of long term high doses?
- Hydroxocobalamin B12: what is it, and when should you choose it?
- Is a B12 of 250 low?
- Methylcobalamin B12: what is it, and when should you choose it?
- Methylcobalamin vs cyanocobalamin: which B12 should you take?
- Methylfolate (5-MTHF): what is it, and when should you choose it?
- NADH: what is the coenzyme form of B3, and what doses did trials use?
- Niacinamide (nicotinamide): what does the non-flush B3 do at 500mg?
- Riboflavin 5-phosphate (R5P): what is active vitamin B2, and when should you choose it?
- Total vs active B12: what does your test result measure?
- What are the different forms of choline and when does each apply?
- What are the symptoms of folate deficiency?
- What are the symptoms of vitamin B12 deficiency?
- What is the MMA test and what does the result mean?
- What's a complete prenatal nutrition protocol beyond folate?
- What's the optimal folate level vs lab reference ranges?
- When are high-dose B vitamins needed vs a standard B complex?
- When does B12 level warrant supplementation vs injections?
- When is a B12 loading protocol needed vs standard oral?
- When is the best time to take a vitamin B complex, and should you take it with food?
- When is the best time to take vitamin B12, and should you take it with food?
- Which B12 is best: methylcobalamin, adenosylcobalamin or hydroxocobalamin?
- Which form of vitamin B2 should you buy: R5P or riboflavin?
- Which form of vitamin B6 should you buy: P5P or pyridoxine?
Omega-3
- Cholesterol blood test results explained: what your numbers mean in the UK
- Does omega-3 improve HRV, and how quickly?
- Does the omega-3 to omega-6 ratio matter in practice?
- Fish oil, krill oil, or algal oil: which is best for omega-3?
- Foods for skin health: what the evidence supports
- Foods high in omega 3: UK portions, EPA and DHA, and the plant gap
- HDL below 1: what a low HDL means and what raises it
- How do you lower cholesterol naturally? What the evidence supports
- How long does omega-3 EPA+DHA take to reach therapeutic levels?
- How long does omega-3 take to lower CRP?
- How long does omega-3 take to work?
- How much omega 3 should I take, and how much is too much?
- hs-CRP above 3: low-grade inflammation, and what drives it
- hs-CRP blood test results explained: what your number means
- hs-CRP of 1 to 3: average, and what it does and does not mean
- hs-CRP of 10 or more: acute, not baseline, and what to do
- Omega 3 vs fish oil: what is the difference?
- Omega-3 index: what is it, how to test, what to target?
- Supplements for blood pressure: what the evidence supports
- Supplements for heart health: what the evidence supports
- Supplements for muscle recovery: what the evidence supports
- Total cholesterol above 7.5 or LDL above 4.9: the familial hypercholesterolaemia check
- Total cholesterol of 5 to 6.5: borderline, and what it means
- Triglycerides above 1.7: what a raised result means and what moves it
- What does the evidence show about seed oils and omega-6?
- What is an anti-inflammatory diet, and what does the evidence support?
- When is the best time to take omega 3, and should you take it with food?
- Which supplements for joint pain have evidence?
Zinc
- Best zinc supplement for immunity: which form and dose does the evidence support?
- Foods high in zinc: UK portions and how far they get you
- How do you increase testosterone naturally? What the evidence supports
- How does zinc deficiency affect immunity, mood, skin, and hormones?
- How does zinc supplementation affect copper levels?
- How long does zinc take to work?
- How much zinc should I take, and what is the maximum safe dose long term?
- What are the symptoms of zinc deficiency?
- What is zinc picolinate and is it the best absorbed form?
- When is the best time to take zinc, and should you take it with food?
- Which supplements help wounds repair?
- Which zinc form is best: picolinate, citrate, or glycinate?
- Why do zinc, vitamin A, and protein deficiencies impair immunity?
- Why does zinc supplementation deplete copper?
- Why is serum zinc unreliable, and what should I test instead?
Supplement protocols
Blood markers
- Apps that explain blood test results in the UK: how do they compare?
- Blood test results explained, UK: what your numbers mean
- Free blood test result interpreter: what do your blood test results mean?
- Free T4 blood test results explained: what does your number mean?
- Haemoglobin at 110 g/L in a woman: how low is that?
- Haemoglobin at 120 g/L in a man: is that a problem?
- Haemoglobin at 150 g/L and above: normal, or too high?
- Haemoglobin at 90 g/L: how serious is moderate anaemia?
- Haemoglobin blood test results explained: what does your number mean?
- HbA1c of 40: upper-normal, and what it does and does not mean
- HbA1c of 42 to 47: non-diabetic hyperglycaemia, and what to do about it
- HbA1c of 48 to 53: the diagnostic band, and what happens next
- HbA1c of 58 and above: above target, and what the guideline says
- How do you balance your hormones? What the evidence supports
- How do you improve concentration? What the evidence supports
- How do you lower blood sugar? What the evidence supports
- How do you resolve fatigue? A step-by-step order
- How to boost your metabolism: what works and what is marketing
- How to lose weight sustainably: what the evidence supports
- MCV high or low: what does your result mean?
- Nutri Tailor tools: blood test interpreter, dose pages and timing pages
- Nutri365 vs ChatGPT for health questions: how do they compare?
- Nutritionist cost UK: what you are paying for, and the routes that cost nothing
- Thriva, Medichecks or a GP panel: what your nutritional markers mean (UK)
- What are the symptoms of insulin resistance, and how do you check?
- What do HbA1c levels mean? The UK bands explained
- What do your UK blood test results mean, and which app explains them?
- What does a raised or low white blood cell (WBC) differential tell us?
- What does your Oura data mean, and what should you do with it?
- What supplements should I take? A three-tier answer
- Which app combines your Oura data, blood test results and conversations to help you reach your health goals?
- Which apps work with your Oura ring?
- Which supplements for weight loss have evidence?
- Why am I always tired? Working through the causes
- Why are you always tired even after a full night of sleep?
- Why do I have brain fog? The causes worth checking
- Why do I have no energy? Working through the causes
What you’ll find here
Every entry covers a specific clinical question:
- Forms compared (magnesium glycinate vs citrate vs oxide, iron bisglycinate vs sulphate, vitamin D3 vs D2)
- Dose-response evidence
- Timing and interactions
- Specific situations such as pregnancy, perimenopause and athletes
- Testing and lab interpretation
- What guideline bodies (NHS, NICE, SACN, BNF, NIH, Endocrine Society) currently recommend
- Common misconceptions where they exist
What you won’t find
- Personal health advice. The library reports what published research shows; it does not tell you what to do.
- Confident claims that the evidence does not support. Where the research is limited or conflicting, entries say so.
- Hidden commercial bias. Where Nutri Tailor sells a relevant product, there is a soft callout. The clinical content stands on its own.
How entries are reviewed
See how the library is edited and what changes when evidence shifts.