Diabetic Neuropathy: Why Numbness Is More Dangerous Than Pain, Which Drugs Work and the B12 Check Nobody Does
People come in about the burning. The burning is miserable, it ruins sleep, and it is treatable.
The numbness is what takes the foot.
⚠️ Pain protects you. It reports the stone in your shoe, the too-hot bath, the blister forming on the little toe. When that reporting stops, injuries happen and continue happening, unnoticed, for days.
A stone carried in a shoe for a week becomes an ulcer. An ulcer becomes an infection. Infection in a foot with poor circulation and poor healing is how most non-traumatic lower-limb amputations begin — and almost all of them start as something small that nobody felt.
Which is why the single most useful thing on this page is not a medicine. It is a daily look at your own feet.
🔢 The numbers that make foot care feel urgent
Foot care sounds fussy until the figures are stated plainly.
- 👣 Roughly one in five to one in three people with diabetes will develop a foot ulcer at some point
- 🚨 The great majority of non-traumatic lower-limb amputations are preceded by an ulcer
- 🔄 Around 40 percent of healed ulcers return within a year, and around two thirds within five years — so a healed foot stays a high-risk foot for life
- 👀 Most of this is preventable by catching pressure points and small injuries in the first day or two
That recurrence figure is the one that changes behaviour. The routine is not something you do until the foot heals; it is permanent, like brushing teeth.
🧬 Too much signal, too little signal
Nerve fibres damaged by diabetes fail in two opposite ways, and most people have a mixture. Working out which dominates tells you what to do.
| Too much signal — irritable nerves | Too little signal — lost protection |
|---|---|
| Burning, especially at night | Numbness, a dead or wooden feeling |
| Stabbing or electric-shock jolts | Cannot tell hot water from warm |
| Bedsheets feel painful on the feet | Reduced vibration sense |
| Pins and needles, crawling sensations | Cuts, blisters and burns found by accident |
| Feet feel cold while being warm to touch | Unsteadiness, especially in the dark |
| What it needs: medication, and sleep protection | What it needs: daily inspection, footwear, and vigilance |
Two things follow. The quiet version is the dangerous one, and treating the pain can make the danger worse — because relief removes the last bit of feedback the foot was still giving. Pain treatment and foot protection go together; the second is not optional once the first works.
And the balance problem is real. Loss of position sense from the feet means the body relies on vision to stay upright, which is why these falls happen at night and in the shower.
🔎 The pattern that says this is diabetic neuropathy
Typical diabetic polyneuropathy has a recognisable shape, and knowing it matters because departures from it mean something else is going on.
The usual pattern: symmetrical, both feet equally; starts in the toes and creeps upward over years in a stocking distribution; sensory far more than weakness; slow; hands affected much later if at all.
🚩 These features are not typical and need investigating rather than assuming:
🔹 One side much worse than the other, or one single nerve affected
🔹 Coming on over days or weeks rather than years
🔹 Weakness more prominent than numbness, or foot drop
🔹 Hands affected before or equally with the feet
🔹 Thighs or hips, with wasting and severe pain
🔹 Good glucose control throughout, with short diabetes duration
Up to about one in ten people with diabetes and neuropathy have a different cause, and several of those causes are reversible. Being diabetic does not make every nerve symptom diabetic.
💊 The reversible cause that metformin creates
If you take one thing from this page besides looking at your feet, take this.
Metformin interferes with vitamin B12 absorption, and after years of treatment a substantial minority of people become deficient. B12 deficiency causes a neuropathy that looks almost identical to the diabetic kind — numb feet, pins and needles, poor balance.
The differences matter: B12 deficiency is found with one cheap blood test, it is treated with tablets or injections, and caught early it improves or resolves. Left alone it causes permanent spinal cord damage.
It is missed constantly, because the symptoms are attributed to the diabetes that is sitting right there. Anyone on long-term metformin with neuropathy should have B12 measured — and if the level is borderline, ask whether an additional marker can be checked, because B12 alone can read normal while deficiency is present at tissue level.
Other reversible or distinct causes worth excluding at the same appointment:
- 🩸 Underactive thyroid
- 🍷 Alcohol, which causes its own identical neuropathy and is routinely underreported
- 💊 Too much vitamin B6. Counter-intuitive and genuinely common — high-dose B6 supplements, often taken for nerve symptoms, cause neuropathy themselves
- 🧪 Kidney disease, certain blood protein abnormalities, chemotherapy, HIV, and some medicines
🩺 Screening, and what the tests actually are
Nerve damage starts before symptoms, which is why screening is scheduled rather than symptom-driven. Annually from diagnosis in type 2 diabetes, and from five years after diagnosis in type 1.
| Test | What it shows |
|---|---|
| 10 g monofilament | A calibrated nylon strand pressed on set points until it bends. Not feeling it means protective sensation is lost — the single best predictor of ulcer risk |
| Tuning fork or vibration | Large-fibre function, often the earliest measurable loss |
| Pinprick, temperature, ankle reflexes | Small-fibre function and reflex loss |
| Foot pulses and skin inspection | Circulation, which determines whether anything can heal |
| Nerve conduction studies | Only for atypical or rapidly progressing cases, not routine |
| Lying and standing blood pressure | Autonomic involvement |
Ask for the monofilament result in plain terms: can I feel it or not. A foot that cannot feel the monofilament needs a different level of daily care from one that can, and that single answer should change your routine.
🍬 Glucose control, honestly
This section is more nuanced than most sources admit, and the nuance is useful.
In type 1 diabetes, tight glucose control clearly prevents and slows neuropathy. The evidence is strong and long-standing.
In type 2 diabetes the effect of glucose control alone is much weaker. Large trials of intensive lowering produced only modest effects on neuropathy. That is not an argument against control — it is an argument that in type 2, the whole metabolic picture matters: blood pressure, lipids, weight and smoking all damage the tiny vessels feeding the nerves, and addressing them is not secondary. See our guides to type 2 diabetes, blood pressure and cholesterol.
Smoking deserves its own line. It narrows exactly the microvessels that supply nerves, and it is the most impactful single change available to most people with neuropathy. The methods that work are in our guide to smoking cessation.
💡 One phenomenon worth knowing, because it frightens people away from good control. A rapid improvement in glucose — a fall of two or three HbA1c percentage points within a few months — can trigger an acute, severe, burning neuropathy. It is sometimes called treatment-induced neuropathy.
It is real, it is temporary, and it settles over months. It is not a reason to let control slip back — it is a reason to improve control steadily rather than abruptly, and to mention it if severe pain appears just as your numbers get better.
💊 What actually treats the pain
First, what does not: paracetamol and anti-inflammatories work poorly here. This is not inflammation, it is misfiring nerve signalling, and the drugs that help are ones that alter that signalling. Expect to reduce pain by perhaps a third to a half, not to abolish it — the realistic targets are sleeping through the night and walking comfortably.
| Option | Dosing | Where it fits |
|---|---|---|
| Gabapentin | 300 mg at night, increasing every 3 to 7 days to 900 to 3600 mg daily in three doses | First line. Helps sleep. Needs dose reduction if kidneys are impaired — see below |
| Duloxetine | 30 mg for a week, then 60 mg daily | First line, and specifically licensed for painful diabetic neuropathy. One tablet daily. Also treats coexisting low mood |
| Amitriptyline | 10 mg at night, up to 25 to 75 mg | Effective and cheap. Sedating, which helps sleep. Avoid or use cautiously over 65 — confusion, urinary retention, falls |
| Venlafaxine | 75 to 225 mg | Alternative where duloxetine is unsuitable |
| Capsaicin or lidocaine patches | Applied locally | Useful for a limited painful area with no systemic burden |
| Alpha-lipoic acid | 600 mg daily | Modest evidence, well tolerated. Reasonable as an addition, not a replacement |
Two general rules. Start low and go slow — nearly all the early dropouts are from dizziness and drowsiness that would have settled. And give each drug four to eight weeks at a proper dose before concluding it failed; combinations of two agents at moderate doses often work better and are tolerated better than one at maximum.
Opioids are not the answer here. They work poorly for nerve pain long term, and the risks accumulate. If they are being offered as a first step for this, it is worth asking about the options above instead.
🫀 Gabapentin, properly
Gabatop (Gabapentin) calms overactive nerve signalling by binding a specific channel subunit on nerve endings, reducing the release of the transmitters that carry pain. It is not a painkiller in the ordinary sense and does nothing taken occasionally.
Titration is the whole technique:
- 🌙 Start 300 mg at bedtime — 100 mg in older or frail people. The first doses cause drowsiness, which is why they go at night
- 📈 Increase every three to seven days, usually by 300 mg, moving to twice then three times daily
- 🎯 Effective range 900 to 3600 mg daily in three divided doses. Doses must be spread — absorption falls as the amount per dose rises
- ⏳ Allow four to eight weeks at the target dose
- 📉 Never stop abruptly. Taper over at least a week, longer after prolonged use
⚠️ The kidney point, which matters specifically in diabetes. Gabapentin is removed from the body entirely by the kidneys, unchanged. Diabetic kidney disease is common and often silent.
With reduced kidney function the standard dose accumulates, producing drowsiness, confusion, unsteadiness, visual disturbance, twitching and falls — frequently mistaken for the neuropathy worsening or for ageing. The dose must be set according to kidney function, sometimes a fraction of the usual.
So: make sure your kidney function has been checked recently before starting, and if you feel unexpectedly foggy or unsteady on a modest dose, report it rather than pushing through.
Other things to know:
- 🦵 Ankle swelling is common and easily mistaken for heart failure. Mention it rather than assuming either
- ⚖️ Weight gain and increased appetite occur, which is unhelpful in diabetes and worth monitoring
- 🚫 With opioids, there is a real risk of serious breathing depression — the combination needs explicit medical supervision
- 💊 Antacids reduce absorption — leave two hours between them
- 🍺 Alcohol multiplies the drowsiness
- 🧠 Misuse does happen with this class, more so alongside opioids or in people with a history of substance use, and it is controlled in some countries
🧼 The daily routine, and the things that cause burns
Five minutes, every day, permanently.
- 👀 Look at the whole foot — top, sole, heel, sides, and between every toe. Use a mirror on the floor or ask someone if you cannot see the sole. Looking for: redness, a warm spot, a blister, a crack, a callus, a colour change, anything new
- 🧴 Wash and dry thoroughly, particularly between the toes, where trapped moisture breaks skin down
- 💧 Moisturise the soles and heels but not between the toes
- 👟 Check inside your shoes with your hand before putting them on — every time. A stone, a seam, a drawing pin. You will not feel it later
- 🧦 Seamless socks, changed daily, nothing with tight elastic
- ✂️ Nails cut straight across, not down the corners
- 👣 Never barefoot, indoors included. Not on the beach, not by the pool
- 👞 New shoes worn in an hour at a time, checking the feet afterwards
🚫 These cause the injuries, and all of them are preventable:
🔹 Hot water bottles, heating pads, electric blankets and radiators on numb feet. Burns happen without being felt. Test bath water with an elbow or a thermometer, never with the foot
🔹 Cutting your own corns or calluses, or using a blade or razor. That belongs to a podiatrist
🔹 Over-the-counter corn removers and medicated plasters. They work by burning tissue with acid, on a foot that cannot report it
🔹 Walking off a new blister or carrying on in the shoe that caused it
For night pain specifically: keep the bedroom cool, use light loose bedding, and a frame or cradle to hold the sheets off the feet makes a genuine difference when touch is painful.
🦿 The foot problem that is not an infection
Worth its own section because it is misdiagnosed and the consequence is permanent.
Charcot foot presents as a foot that is warm, swollen and red, often with no wound and little or no pain. It gets called a sprain, or gout, or cellulitis. What is actually happening is that bones and joints in a foot without protective sensation are fracturing and collapsing under ordinary walking.
Treated immediately with complete offloading —> a cast or boot and no weight on it — the architecture can be preserved. Walked on for weeks, the arch collapses into a rocker shape that ulcerates for the rest of the person life.
A warm swollen foot in someone with neuropathy is urgent, even without pain and even without a wound. Say the word Charcot at the appointment; it prompts the right imaging.
🫀 When the automatic nerves are involved
Autonomic neuropathy affects the nerves running the organs. The symptoms look unrelated to each other, which is why they go unreported, and two of them are safety issues rather than inconveniences.
🚨 The two that matter most:
❤️ A heart attack can happen without chest pain. When the cardiac nerves are damaged, the warning signal is absent. Unexplained breathlessness, sudden sweating, nausea, extreme fatigue or confusion may be the only presentation — and these must be treated as potentially cardiac rather than waiting for pain that will not come.
🍬 You may stop feeling low blood sugar. Autonomic damage removes the shaking, sweating and palpitations that normally warn of hypoglycaemia, so the first sign becomes confusion or collapse. If your lows have become harder to notice, say so — glucose targets and monitoring need adjusting, and it affects driving.
The rest, with what helps:
- 💤 Dizziness on standing. Rise in stages, sit on the bed edge first; raise the head of the bed; compression stockings; adequate fluid and salt unless told otherwise; avoid large high-carbohydrate meals and hot baths. Review any blood pressure medicines and their timing
- 🍽️ Early fullness, bloating, nausea, unpredictable glucose after meals — delayed stomach emptying. Smaller, more frequent, lower-fat and lower-fibre meals, and insulin timing may need changing
- 🚽 Bladder emptying incompletely, or repeated urine infections — timed voiding, and this needs assessing
- 💧 Sweating changes — too little on the feet, sometimes drenching on the face after eating
- 🚹 Erectile dysfunction, which is very common in diabetes and often the first autonomic sign. See our guide to erectile dysfunction as an early warning
- 💩 Diarrhoea alternating with constipation, often worse at night
🏃 The part that is not medication
- 🚶 Keep walking. Low-impact activity improves circulation and balance, and there is reasonable evidence it slows progression. Inspect the feet afterwards
- 🦿 Balance and strength work reduces falls, which is a bigger threat than most people assume once position sense is reduced
- 🛏️ Consistent sleep timing. Night pain and poor sleep amplify each other, and breaking that loop reduces reported pain independently of any drug
- 📊 Track pain weekly on a 0 to 10 scale rather than daily. Daily variation is noise; the trend is what tells you whether treatment is working
- 🧑⚕️ Ask to be referred to podiatry if sensation is reduced. Professional callus care, pressure assessment and proper insoles prevent more ulcers than anything you can buy
- 🧠 Treat the mood side. Chronic nerve pain and low mood reinforce each other, and duloxetine or amitriptyline treat both at once — see our guide to low mood and drive
📞 When to seek help
🚨 Same day, urgently:
🔹 Any new ulcer, open wound, discharge or smell from a foot — however small and however painless
🔹 Spreading redness or warmth, or red streaks up the leg
🔹 Fever or feeling unwell with any foot wound
🔹 Blackened or dusky tissue, or a toe changing colour
🔹 A warm, swollen, red foot with no wound — possible Charcot, needs offloading now
🔹 A cold, pale, painful foot or absent pulses — circulation emergency
🔹 Breathlessness, sweating, nausea or sudden exhaustion — treat as possible heart attack, with or without chest pain
Promptly:
- Any new numbness, tingling or burning in the feet — early is when it is most modifiable
- A callus, corn or hot spot that keeps returning — a pressure point announcing itself before it ulcerates
- On long-term metformin with nerve symptoms — ask specifically for vitamin B12
- Any of the atypical features listed earlier — asymmetry, rapid onset, weakness, hands first
- Severe burning beginning just as glucose control improves sharply
- Drowsiness, confusion or unsteadiness on gabapentin — ask whether the dose matches your kidney function
- Dizziness on standing, early fullness after small meals, or bladder changes
- Low blood sugars you no longer feel coming — this changes targets and affects driving
- Falls, or near-falls in the dark
- Pain disrupting sleep most nights — treatable, and not something to accept
- No benefit after eight weeks at a proper dose — time to switch or combine, not to give up
❓ Frequently asked questions
Why is numbness more dangerous than pain?
Pain reports the stone in the shoe or the too-hot bath. Without it, injuries happen and continue unnoticed, and most non-traumatic lower-limb amputations in diabetes begin as a small unfelt wound.
Could metformin be causing my neuropathy?
Indirectly, yes. Metformin impairs vitamin B12 absorption, and B12 deficiency causes an almost identical neuropathy that is reversible if caught early. Anyone on long-term metformin with nerve symptoms should have B12 measured.
What is the gabapentin dose for nerve pain?
Start 300 mg at bedtime, or 100 mg if older or frail, increasing every three to seven days to 900 to 3600 mg daily in three divided doses. Allow four to eight weeks at the target dose.
Does gabapentin need a lower dose with kidney problems?
Yes, and this matters in diabetes. Gabapentin is cleared entirely by the kidneys, so reduced function causes accumulation with drowsiness, confusion, unsteadiness and falls. The dose must be set by kidney function.
Why do painkillers not help my burning feet?
Because this is misfiring nerve signalling rather than inflammation, so paracetamol and anti-inflammatories work poorly. Gabapentin, duloxetine and amitriptyline alter the signalling itself, which is why they help.
Which medicine is licensed specifically for diabetic nerve pain?
Duloxetine, usually 30 mg for a week then 60 mg once daily. Gabapentin and amitriptyline are also first-line options. Realistic improvement is around a third to a half reduction in pain, not elimination.
My pain got worse after my blood sugar improved. Why?
A rapid fall in HbA1c of two or three percentage points can trigger an acute burning neuropathy. It is real and temporary, settling over months. The answer is steadier improvement, not letting control slip back.
My foot is warm and swollen but there is no wound. Is that serious?
Yes, urgently. That can be Charcot foot, where bones collapse under ordinary walking in a foot without protective sensation. Immediate offloading preserves the architecture; weeks of walking does not.
Can a heart attack happen without chest pain in diabetes?
Yes. Autonomic neuropathy can remove the pain signal, so breathlessness, sweating, nausea, extreme fatigue or confusion may be the only presentation. Treat those as potentially cardiac rather than waiting for pain.
What should I never do to numb feet?
No hot water bottles, heating pads or radiators, since burns happen unfelt. Test bath water with an elbow. Never cut your own corns or use acid corn removers, and never go barefoot, indoors included.
📑 Sources and editorial
- Diabetes association position statements on diabetic neuropathy, including screening intervals from diagnosis, clinical assessment methods and treatment recommendations
- Neurology society guidelines on the treatment of painful diabetic polyneuropathy, including comparative efficacy of gabapentinoids, serotonin-noradrenaline reuptake inhibitors, tricyclics and topical agents
- Epidemiological data on lifetime foot ulcer incidence in diabetes, the proportion of non-traumatic lower-limb amputations preceded by ulceration, and ulcer recurrence rates at one and five years
- Validation studies of the 10 g monofilament examination as a predictor of foot ulceration
- Diabetes Control and Complications Trial and long-term follow-up data on intensive glycaemic control and neuropathy incidence in type 1 diabetes
- ACCORD, ADVANCE and VADT trial data on intensive glucose lowering and neuropathy outcomes in type 2 diabetes, and analyses of additional metabolic and vascular risk factors
- Literature on treatment-induced neuropathy of diabetes following rapid glycaemic improvement, including onset thresholds and natural history
- Studies of metformin-associated vitamin B12 deficiency, its prevalence by treatment duration, and recommendations for periodic measurement in patients with neuropathy
- Reviews of alternative and reversible causes of polyneuropathy in people with diabetes, including thyroid disease, alcohol, pyridoxine excess, monoclonal gammopathy and medication effects
- Prescribing information for gabapentin, including titration schedules, divided dosing, renal dose adjustment by estimated glomerular filtration rate, peripheral oedema, taper requirements, antacid interaction and the warning on respiratory depression with opioids
- Prescribing information for duloxetine in diabetic peripheral neuropathic pain, and for amitriptyline and venlafaxine in neuropathic pain
- Trials of alpha-lipoic acid, high-concentration capsaicin and topical lidocaine in diabetic neuropathy
- Guidance on recognition and management of Charcot neuroarthropathy, including the role of immediate offloading
- Literature on cardiac autonomic neuropathy, silent myocardial ischaemia and impaired awareness of hypoglycaemia in diabetes
- Guidance on gastroparesis, orthostatic hypotension and bladder dysfunction in diabetic autonomic neuropathy
- Related reading: type 2 diabetes, combination therapy in type 2 diabetes, erectile dysfunction as an early warning, smoking cessation aids, cholesterol
- Related products: Gabatop (Gabapentin), Neurontin (Gabapentin), Cymbalta (Duloxetine), Elavil (Amitriptyline), anticonvulsants category
- RXshop Editorial Team — reviewed by James Carter, MD — Neurologist & Sleep Medicine Specialist
Medical Disclaimer: The information in this article is for educational and informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek guidance from a qualified healthcare provider with any questions you may have regarding a medical condition, and before starting, stopping or changing any medication.