Mannitol: Benefits, Side Effects & Dosage

What is Mannitol?

Mannitol naturally occurs as a sugar or sugar alcohol in fruits and vegetables (x). It can be used as both a sweetener and a medicinal treatment. It is processed in the large intestine and converted by gut bacteria into gases and short-chain fatty acids (SCFA). Once the body finally absorbs it, mannitol can help provide energy (x). When used as a drug, it is a diuretic that can cause urine production in people who have acute kidney failure (x). Additionally, it is used in prescription drugs formulated to reduce pressure in the brain (x).

Mannitol is naturally present in marine algae, strawberries, mushrooms, celery, onions and pumpkins (x). However, when used as a food additive and sweetener, it is produced by adding hydrogen to fructose. Prior to being converted into mannitol, fructose is first converted into mannose. This is how mannitol got its name (x).

Benefits of Mannitol

Medical Uses

Mannitol can be used to reduce cerebral edema or swelling in the brain. Doctors also use it to reduce intraocular pressure, which is pressure in or around the eye (x). However, it’s most common use in the medical world is to help patients with kidney disease.

Kidney/Urinary Health

Doctors often recommend mannitol to help people with acute kidney failure. This is because it forces urine production by removing excess water and toxins from the body. Increased urine production helps keep the kidneys from shutting down and helps speed up the elimination of harmful, toxic substances in the body (x).

Mannitol also contains beneficial properties that help widen blood vessels in the kidneys. This then helps reduce vascular resistance, relaxes smooth muscle cells and increases blood flow in the body’s organs (x).

Blood Sugar Regulation

The body doesn’t fully absorb the sugar alcohol of mannitol, and this can reduce levels of blood glucose and insulin. As a result, this can also lead to a decreased risk of diabetes (x).

Other Benefits and Uses

According to the Journal of Biological Chemistry, outside of medical uses, mannitol is sometimes used as a sweetener in candy, jams, pudding and powdered drink mixes. For example, have you ever wondered what that dusting powder is on the piece of gum you just put in your mouth? It could be mannitol (x).

Mannitol Benefits

Mannitol Dosage and Side Effects


It is best that you follow the appropriate dosage prescribed by your doctor or healthcare professional. For example, your doctor may order that you take mannitol slowly through IV. He/she may also have to regularly test your blood and heart function as well as your electrolyte levels. This is to make sure the mannitol is helping your condition and not causing any unwanted, harmful side effects (x).

As a supplement, you can take any amount below 20 grams (x). Specifically, if you plan to use mannitol as a sweetener, use four grams or half a tablespoon, which you can do up to five times a day. Greater than 20 grams in one day may cause a laxative effect.

Side Effects

Mannitol may cause some unwanted, yet common side effects that can include:

  • Headaches
  • Dizziness
  • Dehydration
  • Frequent Urination
  • Increased heart rate
  • Rash or hives
  • Blurry vision

Seek emergency medical attention if you have any signs of an allergic reaction. For example, difficulty breathing, hives and the swelling of your lips, eyes, tongue or throat (x).

If you are taking mannitol and experience the following serious side effects, you should stop using it and call your doctor immediately:

  • Congestive heart failure
  • Seizures or coma
  • Kidney problems, including kidney failure
  • Tissue damage at the site of injection

When to Avoid

You should avoid taking and using mannitol if you are:

  • Allergic to mannitol or its ingredients
  • Finding it hard to urinate, if you aren’t urinating at all
  • Dehydrated
  • Have fluid buildup in the lungs
  • Have bleeding within your skull

Always consult your doctor or physician before taking mannitol, especially if you have a history of kidney disease, heart disease or an electrolyte imbalance (x).

Because it’s unclear if mannitol can cause harm to an unborn or nursing baby, you should consult your doctor if you are pregnant, plan to become pregnant or are breastfeeding before you start supplementing.

You should also avoid mannitol if you have severe kidney disease, lung swelling/congestion or severe dehydration (x).

Interactions with Medications

If you are using tobramycin, you should not take mannitol (x).

Mannitol may have serious interactions with the following medications:

  • Depression medications
  • Heartburn medications
  • Diabetes drugs
  • Drugs that contain either canagliflozin or dapagliflozin
  • Lithium
  • Bowel preparation medications
  • Minitran, Nitromist, Nitrostat, Rectiv or Natrecor

The Bottom Line

Mannitol is a naturally occurring sugar alcohol that can be converted into either a sweetener supplement or drug used for medical benefits. Specifically, doctors commonly use it as a diuretic to force urine production in people with acute kidney failure. Doctors also use it to relieve intracranial and eye pressure. There are a number of drugs that interact with mannitol, so it is important to consult your doctor or physician before using it as a supplement or a sweetener.

Author: BulkSupplements Staff