Is potassium 99 mg the same as potassium gluconate 595 mg? Understanding the Difference in Nutrition Diet

October 21, 2025 •

4 min read

According to ConsumerLab.com, a supplement labeled “Potassium Gluconate 595 mg” contains only about 99 mg of actual elemental potassium. This common labeling can be misleading for those seeking to understand if potassium 99 mg is the same as potassium gluconate 595 mg for their nutrition diet needs. It’s a key distinction rooted in chemistry and industry regulation that every consumer should know.

Quick Summary

This article clarifies the difference between elemental potassium (99 mg) and its compound form, potassium gluconate (595 mg), explaining why the amounts are not equivalent. It details what each is, the labeling standards, and why understanding the true elemental content is vital for supplementing potassium effectively and safely.

Key Points

Not Equivalent: 99 mg of potassium is the elemental amount contained within a 595 mg tablet of potassium gluconate, not the same total weight.
Compound vs. Element: Potassium gluconate is the chemical compound, while elemental potassium is the pure mineral your body uses.
OTC Limit: Over-the-counter potassium supplements are typically limited to 99 mg of elemental potassium per dose by regulatory bodies for safety.
Label Clarity: Supplement labels may list the compound weight (595 mg potassium gluconate), but the active, elemental potassium content (99 mg) is the crucial figure.
Elemental Source: The 99 mg of elemental potassium is approximately 17% of the total 595 mg potassium gluconate compound.
Consult a Professional: For significant potassium deficiency (hypokalemia), a healthcare provider's advice is necessary, as OTC supplements provide only a small amount compared to a prescription or food sources.

The Chemical Distinction: Elemental vs. Compound

To understand why 99 mg of potassium is not the same as 595 mg of potassium gluconate, one must first grasp the difference between an element and a compound. Elemental potassium (symbol K) is the pure mineral itself, which is highly reactive and cannot exist on its own in a supplement. For this reason, it is always bound to another substance to create a stable compound. Potassium gluconate is one such compound, where the mineral potassium is bonded with gluconic acid.

The 595 mg figure on a supplement label refers to the total weight of the entire potassium gluconate compound. The 99 mg figure, however, represents only the portion of that compound's weight that is elemental potassium. In the case of potassium gluconate, the gluconate portion of the compound accounts for the remaining 496 mg of its total weight.

The Truth About Potassium Gluconate 595 mg

When you see a bottle of over-the-counter potassium labeled as containing 595 mg of potassium gluconate, it’s crucial to read the fine print. You will almost always find that the elemental potassium content is listed separately and is limited to 99 mg per dose. This is not a coincidence or a mistake; it is a result of regulatory restrictions.

Why the Labeling Can Be Confusing

In the U.S., the Food and Drug Administration (FDA) and similar international bodies place limits on the amount of potassium that can be sold in over-the-counter (OTC) supplements. This restriction, which limits elemental potassium to 99 mg per tablet or capsule, is a safety measure to prevent the accidental consumption of dangerously high doses without medical supervision. High doses of potassium can be particularly harmful for individuals with kidney disease or those on certain medications, as it can lead to a condition called hyperkalemia, or excess potassium in the blood. By contrast, prescription-strength potassium supplements contain significantly higher doses, often expressed in milliequivalents (mEq), and are only available under a doctor's care.

Comparison of Potassium Supplements: 99 mg vs. 595 mg (Gluconate)


Feature	99 mg Elemental Potassium	595 mg Potassium Gluconate
Supplement Form	The active mineral portion of a compound.	The total weight of the compound (potassium + gluconate).
Elemental Potassium Content	99 mg (per dose, OTC limit).	99 mg (the actual potassium content within the 595 mg compound).
Compound Weight	N/A (Refers only to the elemental component).	595 mg (Total weight, including the gluconate part).
Purpose	What the body actually uses for function.	The delivery vehicle for the elemental potassium.
Regulatory Status	The regulated, maximum amount for OTC supplements.	The total weight that can be confusing to consumers.

The Role of Potassium in Your Body

Potassium is an essential mineral and electrolyte critical for numerous bodily functions. It plays a vital role in maintaining the health of your kidneys, heart, muscles, and nervous system. Key functions include:

Nerve Transmission: Helps facilitate electrical nerve impulses throughout the body.
Muscle Contraction: Coordinates proper muscle contractions, including those of the heart.
Fluid Balance: Works with sodium to regulate fluid and mineral balance in cells.
Blood Pressure: A high-potassium, low-sodium diet can help manage blood pressure.

Dietary Sources and Recommended Intake

Most people can meet their daily potassium needs through a balanced diet. The National Academy of Medicine recommends an Adequate Intake (AI) of 3,400 mg for adult men and 2,600 mg for adult women. Rich food sources include:

Leafy greens
Beans
Nuts
Dairy foods
Starchy vegetables like winter squash
Dried fruits (raisins, apricots)
Potatoes (with skin)

Bioavailability: How Well is it Absorbed?

Bioavailability refers to how effectively the body can absorb and utilize a nutrient. Studies show that potassium gluconate has a high absorption rate, similar to potassium from whole food sources like potatoes. However, the 99 mg limit on OTC supplements means that even with high absorption, it is difficult to significantly impact overall potassium levels through supplements alone compared to a diet rich in potassium or higher-dose, prescription versions.

Conclusion: Making an Informed Choice

In summary, potassium 99 mg is the elemental potassium content found within a 595 mg tablet of potassium gluconate. They are not equivalent measures; rather, one is a component of the other. The 99 mg value represents the actual amount of usable potassium, while the 595 mg figure is the total weight of the compound. For most people, a diet rich in fruits, vegetables, and other potassium-rich foods is the best way to maintain healthy levels. Supplements, particularly OTC versions limited to 99 mg, are not a replacement for a healthy diet and should not be relied upon to correct a significant deficiency. As with any dietary supplementation, it is always best to consult a healthcare provider to determine your individual needs and to ensure proper, safe dosing, especially if you have pre-existing health conditions or are taking other medications.

Visit the NIH Office of Dietary Supplements for more information on potassium.

Frequently Asked Questions

Elemental potassium is the pure mineral, while potassium gluconate is a compound consisting of potassium bonded to gluconic acid. The total weight of the compound includes both the mineral and the acid.

A 595 mg tablet of potassium gluconate contains approximately 99 mg of elemental, or pure, potassium. The remaining mass is the gluconate portion of the compound.

Regulatory agencies, like the FDA, limit the amount of elemental potassium in OTC supplements to 99 mg per dose as a safety precaution. Higher doses can be dangerous for some people and require a prescription.

No, OTC potassium supplements are not potent enough to treat severe potassium deficiency (hypokalemia). A healthcare provider must manage hypokalemia with higher-dose prescriptions or other treatments.

The most effective way to increase potassium intake is through diet. Focus on consuming potassium-rich foods like fruits, vegetables, beans, and nuts. In some cases, a healthcare provider might recommend a higher-dose, prescription supplement.

Yes, studies have shown that potassium gluconate has a high bioavailability, meaning it is absorbed effectively by the body. Its absorption rate is comparable to the potassium found in whole foods like potatoes.

Individuals with chronic kidney disease and those taking certain blood pressure medications (like ACE inhibitors and potassium-sparing diuretics) should consult their doctor before taking potassium supplements, as they are at higher risk for hyperkalemia.