How Long Do Lactose Intolerance Symptoms Last?

A woman holds a glass of milk next to her stomach, which she clutches with her other hand.
  • Lactose intolerance is a digestive disorder caused by the inability to digest the sugar found in dairy products.

  • Symptoms may include bloating, gas, cramps, and nausea, which usually appear within 30 minutes to two hours after consuming foods or drinks containing lactose.

  • Although there is no cure for intolerance, monitoring lactose intake, taking lactase supplements, and seeking medical attention can help manage symptoms.

What Causes Lactose Intolerance?

Lactose intolerance is a common digestive disorder that develops when the body is unable to digest the sugars found in dairy products — this is also called lactose malabsorption.

This usually happens when the body doesn’t produce enough of the lactase enzyme that is responsible for breaking down lactose.

When undigested lactose ferments in the stomach, it can cause a range of gastrointestinal (GI) issues.

If you are lactose intolerant, you may have a primary or secondary condition. Primary intolerance develops as people get older and the body’s natural ability to produce lactase slows down.

Secondary lactose intolerance develops because of an initial condition that affects the digestive system, such as celiac disease, irritable bowel syndrome (IBS), or the use of medications.

What are the Symptoms of Lactose Intolerance?

Symptoms of lactose intolerance vary from person to person. Some people may experience more severe symptoms, while others only have mild discomfort.

Common symptoms of lactose intolerance may include:

  • Bloating

  • Gas

  • Abdominal pain

  • Cramps

  • Diarrhea

  • Nausea

These symptoms usually appear within 30 minutes to two hours after eating dairy and foods or drinks that contain lactose.

Assortment of alternative, lactose-free milks, including different nut and grain milks.

What are the Differences Between Food Allergies and Lactose Intolerance Symptoms?

Lactose and food intolerance are both issues that can affect the digestive system. However, they are caused by different mechanisms and have unique symptoms.

It’s important to know the difference between these two conditions to ensure that you get the right treatment.

Allergies usually develop when the body identifies a specific food as harmful, which triggers a protective immune response. This causes symptoms like:

  • Itching

  • Hives

  • Swelling

  • Nausea

  • Vomiting

Depending on the severity of your food allergy, your symptoms may last for a few hours or several weeks. Food allergies can also be life-threatening, so prompt treatment is essential.

Lactose intolerance, on the other hand, rarely causes fatalities and typically resolves on its own.

How Long Do Symptoms Usually Last?

The duration of lactose intolerance symptoms will differ for each individual and can be influenced by a few factors. These usually include:

  • How much lactose you’ve consumed

  • Your individual tolerance level and ability to digest lactose

In milder cases, symptoms may last for a few hours before resolving without treatment. If you have a more severe intolerance, your symptoms may last 48 hours or longer.

Factors like stress, anxiety, and illness may also worsen symptoms, causing them to last longer than usual.

It’s important to note that you should seek medical attention if your symptoms don’t resolve within two days because this could indicate a more severe condition.

Can You Make Lactose Intolerance Symptoms Go Away Faster?

There is currently no cure for lactose intolerance, but there are several things that you can do to alleviate your symptoms faster.

One way to manage your symptoms is to limit your intake of lactose-containing foods and drinks. You can also try to avoid them completely.

Taking lactase supplements can also help ease your symptoms by improving the body's ability to break down lactose.

You can take these supplements before consuming lactose to reduce the risk of symptoms developing afterwards.

A man self-performs a hydrogen breath test to test for lactose intolerance.

Should You See a Doctor about Your Symptoms?

If you suspect that you have lactose intolerance, it’s important to speak with your doctor to get a professional diagnosis for your condition.

They can also help you to rule out any underlying conditions that may be causing your symptoms.

Your doctor may recommend a lactose tolerance test — like a stool acidity or hydrogen breath test — to determine the severity of your condition.

They can also help you get the right treatment if you test positive for lactose intolerance.

If you experience severe symptoms — like breathing difficulties and swelling in the throat — it’s also recommended to see your doctor as soon as possible.

These symptoms may indicate a milk or lactose allergy which can be fatal if left undiagnosed.

Where Can You Learn More About Lactose Intolerance?

If you’re concerned about any of your lactose intolerance symptoms, you can speak to a board-certified physician or nurse practitioner from the comfort of your home.

Head over to LifeMD to schedule a telehealth appointment.

Dr. Anthony Puopolo

Dr. Puopolo holds a B.A. in Biology from Tufts University, M.A. in Biology from Boston University, and Doctor of Medicine from the Boston University School of Medicine. He also completed a Family Medicine and Psychiatry residency program in the U.S. Army.

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This article is intended for informational purposes only and should not be considered medical advice. Consult a healthcare professional or call a doctor in the case of a medical emergency.

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