A statin lowers cholesterol and lowers CoQ10 at the same time, through the same enzyme.
A statin lowers cholesterol and lowers CoQ10 at the same time, through the same enzyme. Only one of those gets mentioned at the appointment.
Statins block HMG-CoA reductase, the rate limiting enzyme of the mevalonate pathway. That pathway builds cholesterol and CoQ10 out of the same sequence, so suppressing the enzyme brings both down. Vitamin K2 and magnesium fall alongside.
What comes down
Nutrient
What it runs
How the shortfall shows up
CoQ10
Carries electrons between complex I and complex III of the mitochondrial chain. Heart and skeletal muscle hold the highest demand in the body.
Heavy legs, muscle aching after ordinary work, exercise intolerance, fog that coffee does not clear.
Magnesium
Cofactor in over 300 enzyme reactions, including every step that uses ATP.
Cramping, restless legs, palpitations, sleep that does not consolidate.
Vitamin K2
Activates the proteins that move calcium into bone and keep it out of arterial wall.
Silent. Shows up years later on imaging rather than as a symptom.
The markers to ask for
Marker
Functional target
Why you are asking
CoQ10, serum
Upper half of the assay range
Rarely run. Worth asking for by name if fatigue or muscle pain is present.
Magnesium, RBC
6.0 to 6.5 mg/dL
Serum magnesium stays normal while tissue stores fall, so the red cell measure is the useful one.
Vitamin D, 25-OH
50 to 80 ng/mL
Fat soluble absorption sits alongside K2 and the two are dosed together.
hs-CRP
Under 1.0 mg/L
Establishes whether the picture is inflammatory as well as lipid driven.
Rebuilding it
Ubiquinol 200 to 300 mg daily across two meals containing fat, in an amber bottle since CoQ10 oxidises in clear glass. The reduced form matters, because conversion drops after 40 and drops further on a statin. Magnesium glycinate 400 mg evening. Vitamin K2 as MK-7 150 to 200 mcg. Retest: Twelve weeks, then repeat the panel. Muscle symptoms usually move first, often inside eight weeks.
Worth knowing
Cholesterol is the raw material for pregnenolone, upstream of DHEA, testosterone and progesterone. On long-term statin panels those four often sit low together, which is worth raising with your physician.
02 of 10
Metformin
Glucophage, Glucophage XR, Fortamet, Riomet
Between 10 and 30 percent of long-term metformin users become B12 deficient, and the symptom it produces is routinely charted as something else.
Between 10 and 30 percent of long-term metformin users become B12 deficient, and the symptom it produces is routinely charted as something else.
Metformin interferes with calcium-dependent B12 absorption in the terminal ileum. The depletion is gradual, predictable and almost entirely preventable, and it accumulates across years rather than months, which is part of why it escapes attention.
What comes down
Nutrient
What it runs
How the shortfall shows up
Vitamin B12
Myelin maintenance, red cell formation, homocysteine clearance, neurological function.
Numbness and tingling in the feet and hands, cognitive slowing, low mood, fatigue that sleep does not touch.
Folate
Methylation, DNA synthesis, works alongside B12 to clear homocysteine.
Fatigue, mood changes, rising homocysteine on a panel.
CoQ10
Mitochondrial electron transport at complex I, which metformin inhibits directly.
Exercise intolerance and muscle fatigue on top of the diabetes itself.
The markers to ask for
Marker
Functional target
Why you are asking
Vitamin B12, serum
Above 500 pg/mL, ideally 700 to 900
Anything under 400 warrants action even though most labs flag deficiency far lower.
Methylmalonic acid
Low end of range
Rises before serum B12 falls, so it catches the depletion earlier.
Homocysteine
Under 8 umol/L
Reads B12 and folate status together and carries cardiovascular relevance.
Folate, RBC
Upper half of range
Falls alongside B12 and shares the same clearance pathway.
Rebuilding it
Methylcobalamin 1000 mcg sublingual daily. Where serum B12 is under 400 or neuropathy is already present, subcutaneous hydroxocobalamin bypasses the ileal block entirely, which is a physician conversation. L-methylfolate 400 to 800 mcg. Ubiquinol 100 to 200 mg with fat. Retest: B12, MMA and homocysteine at twelve weeks, then every six months while the prescription continues.
Worth knowing
The misattribution is the part that matters. Peripheral neuropathy in a metformin patient gets read as diabetic progression and treated as irreversible, when a share of it is drug-induced B12 depletion that responds to repletion. The distinction is a blood test.
Proton pump inhibitors were approved for four to eight weeks of use.
Proton pump inhibitors were approved for four to eight weeks of use. A great many people have taken them for years without anybody checking what they cost.
Stomach acid does specific work beyond comfort. It cleaves B12 away from food protein, converts dietary iron and calcium into absorbable forms, and holds the low pH that keeps opportunistic bacteria out of the small intestine. Suppress it and all of those slow together.
What comes down
Nutrient
What it runs
How the shortfall shows up
Vitamin B12
Cleaved from food protein by gastric acid before it can be absorbed.
Fatigue, cognitive slowing, tingling in the extremities, macrocytic anemia.
Iron
Requires an acidic environment to convert into the absorbable ferrous form.
Cramping, arrhythmia risk, and bone density loss over years.
The markers to ask for
Marker
Functional target
Why you are asking
Ferritin
70 to 100 ng/mL women, above 100 men
The standard range starts at 15, far below where iron supports thyroid conversion.
Vitamin B12, serum
Above 500 pg/mL
Falls slowly and silently across years of acid suppression.
Magnesium, RBC
6.0 to 6.5 mg/dL
Long-term PPI use carries a recognised magnesium depletion signal.
Full blood count
Normal MCV, RDW under 13
A rising RDW with falling ferritin is an early iron signal months ahead of anemia.
Rebuilding it
Methylcobalamin B12 1000 mcg daily. Magnesium glycinate 400 mg evening. Iron dosed against measured ferritin using a heme form. Saccharomyces boulardii 5 billion CFU. Calcium from food first. Retest: Twelve weeks for B12 and magnesium. Ferritin moves more slowly and is worth repeating at sixteen weeks alongside a full blood count.
Worth knowing
A large share of reflux is driven by low acid rather than high. Food sits, ferments, and the pressure pushes contents upward through a sphincter that never got the pH signal to close. Whether you still need the dose you started years ago is a fair question to bring to your prescriber.
This is the most nutrient-depleting drug class in common use, and the one least likely to be measured before, during or after.
This is the most nutrient-depleting drug class in common use, and the one least likely to be measured before, during or after.
The depletion runs wide rather than deep, touching the B vitamins, several minerals and two amino acids at once. Because the effect is spread across so many systems, the symptoms present as unrelated problems and get distributed across separate specialists who never compare notes.
Cramping, poor sleep, acne, slow healing, low resilience to stress.
Selenium
Runs the deiodinase enzymes that convert T4 into active T3.
Cold intolerance, fatigue, thyroid symptoms on a panel that reads normal.
The markers to ask for
Marker
Functional target
Why you are asking
Ferritin
70 to 100 ng/mL
Reads iron status alongside menstrual blood loss.
Zinc and copper, serum
Zinc upper half, copper mid range
The ratio between them matters more than either value alone.
Homocysteine
Under 8 umol/L
Reads the combined B6, folate and B12 picture in one number.
Full thyroid panel
TSH under 2.0, Free T3 upper third
Contraceptives raise thyroid binding globulin, which lowers the free fraction.
Rebuilding it
An activated B complex with methylfolate, methylcobalamin and P5P. Vitamin C 1000 to 2000 mg. Magnesium glycinate 400 mg evening. Zinc 30 mg morning, leaning zinc-heavy against copper here. Selenium 200 mcg. Ubiquinol 100 mg. Retest: Twelve weeks while continuing. Coming off, the debt takes six to twelve months to repay and the panel is worth repeating at three and nine months.
Worth knowing
Copper moves the other way and climbs. Elevated copper against depleted zinc produces its own picture of mood swings, fog and premenstrual worsening, and it is a common reason symptoms intensify in the months after stopping rather than settling.
These medications deplete magnesium, folate and zinc, which are three of the nutrients most closely tied to the mood they were prescribed to lift.
These medications deplete magnesium, folate and zinc, which are three of the nutrients most closely tied to the mood they were prescribed to lift.
The depletion does not make the medication ineffective and it is not an argument against taking it. It does explain a familiar pattern, where the response is partial, plateaus somewhere short of where it should land, and gets managed with a dose increase rather than a blood test.
Low appetite, poor healing, flat affect, broken sleep on a drug taken partly to improve it.
The markers to ask for
Marker
Functional target
Why you are asking
Magnesium, RBC
6.0 to 6.5 mg/dL
Serum stays normal while tissue stores fall.
Folate, RBC
Upper half of range
The red cell measure reflects months rather than the last meal.
Zinc and copper, serum
Zinc upper half, copper mid range
Read as a ratio rather than in isolation.
Vitamin D, 25-OH
50 to 80 ng/mL
Independently associated with mood and commonly low.
Rebuilding it
Magnesium glycinate 400 mg evening. L-methylfolate 400 mcg. Zinc 30 mg morning with food. Melatonin 0.5 to 1 mg where sleep is broken, since most adults do not need the 5 and 10 mg doses on the shelf. Retest: Twelve weeks. Mood and sleep changes tend to appear before the markers move, often around week six.
Worth knowing
Sodium falls too, which matters in anyone training hard or eating low carbohydrate, because that combination stacks with the medication effect and the resulting symptoms get misread as the underlying condition worsening.
06 of 10
NSAIDs
Ibuprofen, naproxen, diclofenac, aspirin at anti-inflammatory doses
The anti-inflammatory taken daily for years damages the barrier it passes through, and the immune activation that follows is the thing it was taken to reduce.
The anti-inflammatory taken daily for years damages the barrier it passes through, and the immune activation that follows is the thing it was taken to reduce.
There are two separate problems here. The first is straightforward nutrient depletion. The second is structural, because NSAIDs drive intestinal permeability directly and chronic use is a leading cause of small intestinal ulceration.
What comes down
Nutrient
What it runs
How the shortfall shows up
Iron
Oxygen transport, thyroid peroxidase, T4 to T3 conversion.
Falling ferritin from slow blood loss across the small bowel, often with no visible bleeding.
Folate and vitamin C
Methylation, homocysteine clearance, collagen synthesis and tissue repair.
Fatigue, rising homocysteine, slower healing of the tissue being damaged.
Barrier integrity
Tight junction function across the intestinal lining.
Bloating, new food reactivity, and immune activation downstream.
The markers to ask for
Marker
Functional target
Why you are asking
Ferritin
70 to 100 ng/mL women, above 100 men
The single most useful marker in chronic NSAID use.
Full blood count
Normal MCV, RDW under 13
A rising RDW flags the iron problem months before anemia appears.
Faecal occult blood
Negative
Reasonable to request where ferritin is falling with no obvious source.
Homocysteine
Under 8 umol/L
Reads the folate depletion.
Rebuilding it
L-methylfolate 400 mcg. Iron dosed against measured ferritin using a heme form. Vitamin C 1000 to 2000 mg. For the barrier, glutamine 5 to 10 g, zinc carnosine 75 mg twice daily, DGL before meals. Retest: Sixteen weeks for ferritin, which moves slowly. Twelve weeks for folate and homocysteine.
Worth knowing
The iron piece compounds itself. Slow intestinal blood loss pulls ferritin down while somebody supplements iron and cannot work out why the number will not move. The supplement is correct. The loss is faster than the replacement.
Prednisone depletes calcium, vitamin D, vitamin K and magnesium simultaneously, and those four are the inputs bone density depends on.
Prednisone depletes calcium, vitamin D, vitamin K and magnesium simultaneously, and those four are the inputs bone density depends on.
The list runs considerably wider than bone. Potassium, zinc, chromium, B6, vitamin C, folate and selenium all fall, and the microbial picture shifts alongside them. Read those against what people report on long-term steroids and the mapping is close to exact.
What comes down
Nutrient
What it runs
How the shortfall shows up
Calcium, vitamin D and K
Bone mineralisation and the placement of calcium into bone rather than soft tissue.
Bone density loss, which is silent until it is not.
Blood sugar that will not settle, infections arriving more easily, slower healing.
The markers to ask for
Marker
Functional target
Why you are asking
Vitamin D, 25-OH
50 to 80 ng/mL
The foundation marker for the bone conversation.
Magnesium, RBC
6.0 to 6.5 mg/dL
Falls alongside potassium and drives the cardiac symptoms.
HbA1c and fasting insulin
HbA1c under 5.4, insulin 2 to 6 uIU/mL
Insulin rises years before glucose does and is rarely run.
Bone density scan
Baseline
Reasonable to request by name past six months of continuous use.
Rebuilding it
Vitamin D 5000 to 10,000 IU with MK-7 200 mcg, since vitamin D moves calcium and K2 decides where it lands. Calcium from food first. Magnesium glycinate 400 mg. Zinc 30 mg. Chromium picolinate 200 mcg. Activated B complex. Vitamin C 1000 to 2000 mg. Retest: Twelve weeks for the nutrient markers. Bone density on a two year interval unless your physician advises otherwise.
Worth knowing
Chromium and magnesium falling together explains a meaningful share of why glucose control deteriorates on prednisone, and both are correctable while the medication continues.
08 of 10
Cardiovascular medication
Beta blockers, ACE inhibitors, diuretics
Three common cardiovascular drug classes, three different depletion signatures, and one shared consequence in fatigue that gets attributed to the heart condition itself.
Three common cardiovascular drug classes, three different depletion signatures, and one shared consequence in fatigue that gets attributed to the heart condition itself.
These are grouped because a great many people take two of them at once, and the depletions stack rather than overlap. Reading them as one picture is more useful than reading them separately.
What comes down
Nutrient
What it runs
How the shortfall shows up
CoQ10, from beta blockers
Mitochondrial electron transport, highest demand in cardiac muscle.
Fatigue and exercise intolerance, which is a difficult outcome for a cardiac drug.
Zinc, from ACE inhibitors
Immune function, taste perception, wound healing.
Loss of taste and smell, a recognised effect of this class and often zinc driven.
Ask by name where fatigue is the dominant complaint.
Thiamine, whole blood
Mid to upper range
Worth requesting in anyone on a loop diuretic long term.
Rebuilding it
Ubiquinol 100 to 200 mg with fat. Magnesium glycinate 400 mg evening. Zinc 30 mg morning. An activated B complex covering thiamine and B6. Potassium from food, not capsules. Retest: Twelve weeks across the panel, timed to sit alongside whatever cardiovascular review is already scheduled.
Worth knowing
Angiotensin receptor blockers such as losartan and valsartan do not appear to carry the zinc effect seen with ACE inhibitors. Potassium-sparing diuretics deplete folate, calcium and zinc while leaving potassium alone.
09 of 10
Antibiotics
Any broad spectrum course, and the months that follow it
Your gut bacteria manufacture B vitamins, vitamin K and the amino acid precursors your brain uses to build serotonin and dopamine.
Your gut bacteria manufacture B vitamins, vitamin K and the amino acid precursors your brain uses to build serotonin and dopamine. A course takes that production offline alongside the infection.
Palleja and colleagues gave twelve healthy men a four day course of three broad spectrum antibiotics in 2018 and followed their gut bacteria for six months. Diversity largely recovered by around six weeks. Nine species present at baseline were still undetectable at 180 days, and organisms carrying resistance genes appeared during the regrowth window.
What comes down
Nutrient
What it runs
How the shortfall shows up
B vitamins, all
Energy metabolism, methylation, neurotransmitter synthesis.
Fatigue and mood changes in the months after a course, rarely connected back to it.
Vitamin K
Clotting and calcium placement.
Easier bruising, and the bone consequence over longer horizons.
Microbial diversity
Barrier integrity, immune training, bile acid recycling.
Bloating, new food reactivity, histamine problems, changed motility.
The markers to ask for
Marker
Functional target
Why you are asking
Full blood count
Normal MCV, RDW under 13
Reads the B vitamin picture indirectly and cheaply.
Homocysteine
Under 8 umol/L
Rises where B12 and folate production has fallen.
Vitamin D, 25-OH
50 to 80 ng/mL
Immune competence going into and out of an infection.
Ferritin
70 to 100 ng/mL women, above 100 men
Inflammation during infection distorts iron handling for weeks afterward.
Rebuilding it
Saccharomyces boulardii 5 to 10 billion CFU during the course itself, since it is a yeast and the antibiotic does not affect it. An activated B complex and MK-7 100 mcg. Lactobacillus and bifido strains after the course ends, not during. Sodium butyrate 500 to 1000 mg twice daily for 8 to 12 weeks. Retest: Twelve weeks after the course ends. Where symptoms persist past three months, the picture deserves a proper look rather than more time.
Worth knowing
The regrowth comes from whichever species survived, which is why the population you finish with differs from the one you started with. That is the mechanism behind eighteen months of gut symptoms nobody links back to a prescription taken for something unrelated.
10 of 10
Thyroid medication
Levothyroxine, liothyronine, desiccated thyroid
Levothyroxine is not depleting in the way the other classes are.
Levothyroxine is not depleting in the way the other classes are. It is here because the dose you swallow and the dose you absorb drift apart, and the markers that show it are almost never run.
Levothyroxine is T4, which is storage hormone. Your body converts it into T3 before any cell can use it, and that conversion happens outside the thyroid. Roughly a fifth runs through the gut, via intestinal deiodinase enzymes and bacterial sulfatases that free T3 back out of bile for recycling.
What comes down
Nutrient
What it runs
How the shortfall shows up
Selenium
Cofactor for the deiodinase enzymes that perform the conversion.
Conversion that stalls regardless of dose, with Free T3 sitting low.
Iron
Drives thyroid peroxidase and supports conversion directly.
Ferritin under 70 blunts the medication no matter how the dose is adjusted.
Absorption itself
Coffee, calcium, iron and soy all bind the tablet directly.
A TSH that will not settle across repeated dose changes.
The markers to ask for
Marker
Functional target
Why you are asking
Free T3
Above 3.2 pg/mL, upper third
The marker that reads what your cells actually receive.
Reverse T3
Under 15 ng/dL
Reads the receptor level block that Free T3 alone will miss.
Free T3 to reverse T3 ratio
Above 20
The single most useful derived number on a thyroid panel.
TPO and TgAb antibodies
TPO under 9, TgAb under 1
Roughly two thirds of unexplained thyroid pictures turn out to be autoimmune.
Rebuilding it
Selenium 200 mcg as selenomethionine. Zinc 15 to 25 mg with food. Iron dosed against measured ferritin. For absorption, take the tablet on an empty stomach and keep coffee, calcium, iron and soy sixty minutes clear of it. Retest: Six weeks after any change to timing or dose, since that is how long the panel takes to reflect it. Antibodies every six to twelve months.
Worth knowing
Chronic inflammation raises cortisol, cortisol blocks the D1 enzyme, and T4 gets shunted into reverse T3, which occupies the receptor without activating it. No dose increase clears that, which is why the fifth adjustment works no better than the fourth.
If the list does not explain it
Run the panel, correct what is low, and give it twelve weeks. A meaningful share of what people had accepted as permanent turns out to have been a bill nobody was tracking.
If you have done that and the picture still has not moved, the sequencing underneath is usually what needs looking at. That is the work we do.