What Supplement Should I Take for Low Sodium? A Comprehensive Guide

January 5, 2026 •

4 min read

Normal blood sodium levels are typically 135–145 mEq/L, and when they fall below this range, the condition is known as hyponatremia. Knowing what supplement should I take for low sodium is critical, but the right approach depends heavily on the underlying cause, whether it's overhydration, excessive sweat loss, or a medical condition.

Quick Summary

Managing low sodium involves considering supplements like salt tablets and electrolyte drinks, while certain medical conditions may require urea under supervision. The choice depends on the specific reason for the low sodium, such as excessive exercise or an underlying illness.

Key Points

Prioritize Medical Diagnosis: Always consult a doctor to confirm low sodium levels and determine the underlying cause before starting any supplement.
Consider Salt Tablets: For certain conditions or high sweat loss, sodium chloride tablets provide a concentrated sodium boost but require adequate hydration.
Use Electrolyte Drinks for Exercise: For athletes, electrolyte beverages help replace sodium and other minerals lost during prolonged or intense activity.
Understand Prescription Urea: Urea is a prescription-only medical food for specific forms of hyponatremia, requiring close medical supervision.
Address the Underlying Cause: Supplements treat a symptom, but a doctor must address the root cause, whether it is an illness, medication, or improper fluid balance.
Start with Diet: For mild cases, increasing dietary sodium from sources like broth and salty foods may be recommended first.
Balance Fluid and Sodium: Hyponatremia can be caused by over-hydration, so managing fluid intake is just as important as managing sodium levels.

Understanding Low Sodium (Hyponatremia)

Hyponatremia is the medical term for a dangerously low concentration of sodium in the blood. Sodium is a vital electrolyte that helps regulate fluid balance, nerve function, and muscle contractions. When sodium levels drop, the body's water balance is disrupted, causing cells to swell. The severity of hyponatremia and its treatment approach are determined by the cause, duration, and the individual's overall health.

There are several types of hyponatremia, each with a different cause:

Hypovolemic hyponatremia: Occurs when both water and sodium are lost from the body, but sodium loss is greater. This can result from excessive sweating, severe diarrhea, or vomiting.
Euvolemic hyponatremia: In this type, total body water increases while sodium levels remain unchanged, effectively diluting the sodium in the bloodstream. It can be caused by certain medications, hormone imbalances, or underlying medical conditions.
Hypervolemic hyponatremia: This involves an increase in both water and sodium levels, but with disproportionately higher water retention. It is often seen in conditions like congestive heart failure and kidney or liver disease.

Causes of Low Sodium

Numerous factors can lead to low sodium levels. Pinpointing the root cause is essential for effective management and determining if supplementation is appropriate. Some common causes include:

Excessive sweating: Endurance athletes, or individuals in hot and humid climates, can lose significant amounts of sodium through sweat. This is a frequent cause of hyponatremia in athletic populations, especially if they are over-hydrating with plain water.
Over-hydration: Drinking too much plain water, particularly during or after prolonged exercise, can dilute the body's sodium levels. This is a key reason many sports drinks contain sodium and other electrolytes.
Underlying medical conditions: Chronic diseases like heart, kidney, or liver failure can disrupt the body's fluid and electrolyte balance. Endocrine disorders or adrenal insufficiency can also play a role.
Certain medications: Diuretics (water pills), some antidepressants, and certain pain medications can increase sodium excretion or affect how the body regulates fluid.
Gastrointestinal issues: Severe or prolonged vomiting and diarrhea can cause significant fluid and sodium loss.

Primary Supplements for Low Sodium

Depending on the severity and cause of your low sodium, your doctor may recommend one of several types of supplements. It is crucial to consult a healthcare professional before beginning any supplementation, as correcting levels too quickly can be dangerous.

Salt Tablets (Sodium Chloride)

For those with consistent, but not life-threatening, sodium loss, salt tablets can be a straightforward solution. These are concentrated sodium chloride supplements used to help prevent heat cramps due to excessive sweating.

Common forms: Thermotabs, SaltStick Vitassium, and standard sodium chloride tablets are readily available.
Typical usage: A doctor might recommend taking salt tablets once or twice daily with plenty of water. The dose can be adjusted for increased sweating during warm weather or intense activity.
Key consideration: It is vital to take salt tablets with enough water to prevent dehydration from worsening.

Electrolyte Drink Mixes and Solutions

Popular among athletes and for general hydration support, these mixes are designed to replenish lost electrolytes, including sodium, potassium, calcium, and magnesium.

Examples: Brands like Liquid I.V., Nuun, LMNT, and Gatorlyte offer a variety of options.
Usage: They are particularly effective during or after exercise lasting over an hour to help balance fluid intake and sodium replacement. Some can be used daily for general hydration and electrolyte maintenance.
Making your own: Simple options include vegetable broth, tomato juice, or even coconut water with added sodium.

Urea Supplements

In more severe cases of hyponatremia, specifically those caused by conditions like SIADH (syndrome of inappropriate antidiuretic hormone), a doctor may prescribe a urea supplement.

Action: Urea works by helping the kidneys excrete excess water, thereby safely raising sodium levels.
Form: It comes as a powder or tasteless coated tablets, often managed by a nephrologist.
Important note: This is a prescription medical food and is not for general over-the-counter use.

Supplement Considerations: A Comparison Table


Supplement Type	Use Case	Availability	Key Considerations
Salt Tablets	Consistent, low-level sodium loss (e.g., sweating).	Over-the-counter and prescription.	Must be taken with sufficient water to prevent dehydration.
Electrolyte Drinks	Hydration for athletes, moderate sweat loss.	Widely available, many low-sugar options.	Choose balanced formulas; monitor sugar content.
Broths/Juices	Dietary, non-emergency sodium boost.	Easily accessible at grocery stores.	Natural source, often paired with other electrolytes.
Urea	Medical management of specific conditions like SIADH.	Prescription only, through a physician.	Requires nephrologist supervision; tasteless coated tablets available.

Safety and Side Effects

While supplements can be beneficial, they are not without risks, especially when not used under medical guidance. Over-correcting low sodium levels can be as dangerous as the condition itself. A potential risk is osmotic demyelination syndrome (ODS), which can cause serious nerve damage if sodium is raised too quickly.

Side effects of general over-supplementation can include:

Fluid retention, bloating, and swelling
High blood pressure
Increased thirst
Headaches
Stomach upset

The Role of Diet in Managing Low Sodium

Before turning to supplements, dietary changes are often the first line of defense against low sodium, especially in less severe cases.

Include sodium-rich foods: Incorporate options like salted nuts, cheese, cottage cheese, canned fish, and olives into your diet.
Embrace broths and soups: These can be excellent sources of sodium and are also hydrating.
Season generously: Adding more salt, as well as sodium-containing spices like celery seed, dill, and coriander, can help.

Conclusion: Prioritize Medical Advice

When considering what supplement should I take for low sodium, the most important step is consulting a healthcare professional. A doctor can diagnose the specific cause of your hyponatremia and recommend a safe, personalized treatment plan, which may or may not involve supplementation. For athletes, balancing electrolytes with a sports drink during long events is often sufficient. For those with underlying medical issues, a prescription urea supplement or other medical intervention may be necessary. Never attempt to self-treat moderate to severe hyponatremia, as overly rapid correction can have dangerous neurological consequences.

Mayo Clinic Hyponatremia Overview

Frequently Asked Questions

For mild cases, increasing dietary salt is often recommended, but for clinical hyponatremia (very low levels), medical supervision is essential. Table salt alone is not enough for serious cases and may not be the appropriate treatment depending on the cause.

Salt tablets provide a concentrated dose of sodium chloride, while electrolyte drinks offer a more balanced mix of electrolytes like sodium, potassium, calcium, and magnesium, often formulated for rapid rehydration during exercise.

Athletes, particularly "salty sweaters" or those competing in ultra-endurance events, may need sodium supplements during exercise that lasts over an hour, especially in hot conditions. Dosage should be personalized and supervised by a doctor or sports nutritionist.

Excessive intake can cause fluid retention, high blood pressure, and strain on the kidneys. In severe cases of hyponatremia, correcting sodium levels too quickly can lead to neurological damage.

Severe symptoms like confusion, seizures, or loss of consciousness require immediate emergency care. Milder, chronic symptoms like headaches or fatigue should prompt a doctor's consultation.

Natural sources of sodium include broths, salted nuts, some cheeses, seafood, and certain vegetables like beets and celery. Cooking with herbs and spices can also increase flavor without solely relying on salt.

Over-the-counter options like salt tablets and electrolyte mixes are widely available. However, medical-grade supplements like urea require a prescription and are used under strict medical supervision.

Causes can include certain medications (diuretics), heart, kidney, or liver disease, severe vomiting or diarrhea, excessive water intake, and hormonal imbalances.