Shaking hands can be caused by dozens of things, ranging from too much coffee to a neurological condition like essential tremor or Parkinson’s disease. In most cases, the shaking is temporary and tied to something fixable: stress, fatigue, low blood sugar, or a medication side effect. But persistent or worsening tremor deserves a closer look, because the cause shapes what you can do about it.
Normal Tremor Everyone Has
Every person has a tiny, invisible tremor in their hands at all times. It’s called physiological tremor, and it’s simply the result of your muscles making micro-corrections to hold a position. You’ll never notice it under normal circumstances. What you will notice is “enhanced” physiological tremor, which is the same thing amplified by a trigger. Caffeine, anxiety, fatigue, hunger, and certain medications can all dial up this baseline tremor until your hands visibly shake.
The key feature of enhanced physiological tremor is that it goes away once the trigger is removed. Skip the third espresso, get a full night’s sleep, eat something, or calm down after a stressful presentation, and the shaking stops. It’s fine-amplitude, meaning the movements are small and fast, and it affects both hands equally. The National Institute of Neurological Disorders and Stroke classifies it as potentially reversible once the underlying cause is corrected.
Essential Tremor
Essential tremor is the most common movement disorder and the most frequent neurological cause of shaking hands. It affects roughly 0.32% of the general population, but the numbers climb steeply with age: about 0.5% of people in their 50s, nearly 1.5% of those in their 70s, and close to 3% of people over 80. It can start at any age, though, including childhood.
The hallmark of essential tremor is that your hands shake during action, not at rest. Holding a cup of coffee, writing your name, bringing a fork to your mouth: these are the moments the tremor shows up. When you let your hands relax in your lap, the shaking typically stops or fades significantly. Specifically, the shaking during movement (kinetic tremor) tends to be six to seven times larger in amplitude than the shaking when simply holding your arms outstretched. This pattern is a useful clue for distinguishing essential tremor from other causes.
Essential tremor often runs in families and tends to progress slowly over years or decades. It can also affect the head, voice, and legs, though the hands are almost always involved first. Alcohol temporarily reduces the tremor in many people, which is a well-known (though not recommended) diagnostic hint.
Parkinson’s Disease
Parkinson’s tremor looks and behaves differently from essential tremor. The classic presentation is a resting tremor: your hand shakes while it’s sitting on your knee or hanging by your side, and the shaking decreases or stops when you reach for something. Between 76% and 100% of people with Parkinson’s disease have a resting tremor at some point during their illness. It often starts on one side of the body before eventually spreading to the other.
A few clinical details help separate Parkinson’s tremor from essential tremor. In Parkinson’s, resting tremor gets worse while walking. In essential tremor, it does the opposite, calming down during walking. Parkinson’s also comes with other motor symptoms you won’t see in essential tremor: slowness of movement, muscle stiffness, shuffling gait, and balance problems. If your only symptom is shaky hands during activities, Parkinson’s is much less likely.
There is some overlap. About 20% to 30% of people with essential tremor also have a resting tremor, and people with Parkinson’s can have action tremor too. But the dominant pattern, rest versus action, points in different directions.
Medications That Cause Tremor
A surprisingly long list of common medications can make your hands shake. The tremor is typically an enhanced version of normal physiological tremor, and it often appears shortly after starting a new drug or increasing a dose. Medication classes known to cause tremor include:
- Mood stabilizers like lithium
- Antidepressants including SSRIs and tricyclics
- Asthma inhalers containing albuterol or theophylline
- Stimulants including amphetamines and caffeine
- Seizure medications like valproate
- Heart medications such as amiodarone
- Immune-suppressing drugs used after organ transplants
- Steroids and certain antibiotics
- Thyroid medication when the dose is too high
If you notice new hand shaking after starting a medication, it’s worth bringing up with whoever prescribed it. In many cases, adjusting the dose or switching to an alternative resolves the tremor entirely.
Thyroid Problems and Low Blood Sugar
An overactive thyroid (hyperthyroidism) is one of the most common metabolic causes of shaking hands. Tremor shows up in about 76% of people with an overactive thyroid. It looks like a fast, fine shaking in both hands during movement, very similar to enhanced physiological tremor. The mechanism involves an overactivation of your body’s “fight or flight” system: thyroid hormones ramp up the sensitivity of receptors that respond to adrenaline, which makes your nervous system more excitable than normal. Treating the thyroid condition resolves the tremor.
Low blood sugar (hypoglycemia) works through a related pathway. When blood glucose drops, your body releases adrenaline to mobilize energy stores, and that adrenaline surge causes shakiness, sweating, and a racing heart. This is common in people with diabetes who take insulin, but it can happen to anyone who skips meals or exercises heavily without eating. The fix is straightforward: eat something, and the tremor stops within minutes.
Alcohol Withdrawal
Heavy, regular drinking changes your brain chemistry in a way that sets the stage for tremor when you stop. Alcohol stimulates the brain’s main calming system (GABA pathways) while suppressing its main excitatory system (glutamate pathways). Over time, your brain compensates by producing more excitatory signals to maintain balance. When alcohol is suddenly removed, the calming influence disappears but the excess excitatory signaling stays. The result is a nervous system in overdrive: tremor, agitation, rapid heartbeat, and in severe cases, seizures.
Withdrawal tremors can begin within hours of the last drink and typically peak around 72 hours. They’re usually coarse, visible, and affect the whole body, not just the hands. This is a medical situation that benefits from professional support, particularly for anyone who has been drinking heavily for weeks or longer.
Vitamin B12 Deficiency
Vitamin B12 plays a critical role in nerve health, and prolonged deficiency can damage the nervous system in ways that produce tremor, among other movement problems. B12 deficiency most commonly causes numbness and tingling in the hands and feet, but it can also lead to tremor, involuntary jerking movements, and symptoms that resemble Parkinson’s disease. Both adults and infants with B12 deficiency may develop these movement problems, sometimes before the deficiency is even diagnosed. The encouraging part is that B12 deficiency is treatable, and neurological symptoms can improve with replacement therapy, though some damage may be permanent if the deficiency has gone on for a long time.
How Doctors Figure Out the Cause
There’s no single blood test or brain scan that diagnoses most types of tremor. Diagnosis starts with observation: your doctor will watch your hands at rest, while holding a posture, and during specific movements. One widely used test involves drawing a spiral on paper without resting your wrist. The size and pattern of the wobble in your spiral can help distinguish essential tremor from other conditions. In essential tremor, spirals drawn with the right hand show a consistent tremor axis (the shaking is worst at specific clock positions), while the left hand shows a different, predictable axis. Doctors score both the severity of the tremor and the consistency of these patterns.
Beyond the physical exam, blood work can check for thyroid dysfunction, blood sugar problems, and vitamin deficiencies. Medication review is another early step. Imaging of the brain is usually reserved for cases where Parkinson’s disease or another structural cause is suspected.
Signs That Need Prompt Evaluation
Most hand tremor turns out to be benign or related to a correctable trigger. But certain patterns warrant faster medical attention. Tremor that starts suddenly rather than gradually is a red flag, as is onset before age 50 in someone with no family history of tremor. Shaking that comes with other neurological changes, such as difficulty walking, slurred speech, muscle weakness, or confusion, needs evaluation sooner rather than later. A rapid heart rate combined with agitation and tremor can signal thyroid storm, alcohol withdrawal, or other conditions that require urgent care.