Skip to content

8 Signs Your Immune System May Be Weak, According To Doctors

Stephanie Eckelkamp
Author: Expert reviewer:
Updated on June 3, 2021
Stephanie Eckelkamp
Contributing Health & Nutrition Editor
By Stephanie Eckelkamp
Contributing Health & Nutrition Editor
Stephanie Eckelkamp is a writer and editor who has been working for leading health publications for the past 10 years. She received her B.S. in journalism from Syracuse University with a minor in nutrition.
Ashley Jordan Ferira, Ph.D., RDN
Expert review by
Ashley Jordan Ferira, Ph.D., RDN
mbg Vice President of Scientific Affairs
Ashley Jordan Ferira, Ph.D., RDN is Vice President of Scientific Affairs at mindbodygreen. She received her bachelor's degree in Biological Basis of Behavior from the University of Pennsylvania and Ph.D. in Foods and Nutrition from the University of Georgia.
Last updated on June 3, 2021

While supporting the immune system is important, it raises the question: How do we know if our immune system could be stronger in the first place?

Chronic diseases or autoimmune diseases are the most obvious risk factors for impaired immunity. But "there are definitely things lifestyle-wise that can set you up for infection," says Randy Horwitz, M.D., Ph.D., immunologist and medical director of the Arizona Center for Integrative Medicine. For the generally healthy population with no underlying medical conditions, these can include an unhealthy diet, a high-stress job or home environment, and poor sleep.

This ad is displayed using third party content and we do not control its accessibility features.

All of these factors, in turn, may lead to physical and even psychological manifestations (feeling chronically overwhelmed and exhausted) that could indicate your immune health is less than ideal. 

Below, experts break down these and other warning signs—and how to give your immune system some extra TLC. 

Potential signs of a weak immune system.

It's important to keep in mind that the signs and symptoms below are not specific to a weakened immune system—they could also be related to a number of other factors or health conditions. For example, you might get sick all the time because you have a kindergartner who's constantly bringing home nasty germs. Or you might have chronic diarrhea because you keep eating dairy and you're actually lactose intolerant. 

But here, experts share insight on how these signs relate to a weakened or taxed immune system that's not optimized, and what you can do about it:

1. You're constantly getting colds, and symptoms last forever.

"For the general population, for people who do get sick more frequently with a cold, or flu, or even pneumonia, it usually means that there's some break down in the immune system," says Heather Moday, M.D., physician and integrative immunologist. 

According to the CDC1, it's considered normal for adults to get two to three colds per year; and most people recover in seven to 10 days. In healthy people, this is plenty of time for your body to develop antibodies and fight off the disease. But if it takes you longer to recover—or you keep getting colds, sinus infections, ear infections, or really any infection—your immune system is struggling to keep up. 

Try this: Whenever you have a persistent infection, head to your doctor to be safe. Also take steps to support your body in as many ways as possible, from reducing stress to getting more sleep to eating a nutritious diet. Certain supplements like zinc, vitamin D3, and vitamin C may also give your immune system the edge it needs, says Moday.*

This ad is displayed using third party content and we do not control its accessibility features.

You're often exhausted, and your sleep isn't consistent.

If you don't have good sleep hygiene and snag less than eight hours of quality shut-eye per night, you're missing out on some pretty big benefits—and you can pretty much guarantee your immune function isn't optimal. 

Melatonin, the hormone your body releases when it gets dark so you get sleepy, is actually a really important immune mediator, too. "It causes certain immune cells to release cytokines, which, in turn, activate immune cells to fight infections," says Moday. "So when we sleep, we often have more recruitment and activity of certain white blood cells like macrophages and neutrophils, and natural killer (NK) cells, which have antiviral and anti-cancer actions in the body."

Subpar sleep, on the other hand, can suppress the activity of these cells, and "we also see less vigorous antibody responses—we don't make antibodies as well," says Moday.

Try this: Your best bet is to get at least seven to eight hours of sleep per night. Establishing a consistent bedtime routine and minimizing light exposure and screen time in the evenings can be helpful. If you toss and turn at night, consider a magnesium supplement to promote quality sleep.*


Your stress levels are off the charts.

If your work demands are nuts and you feel perpetually stuck in fight-or-flight mode, chances are high that your chronic stress is messing with your immune system. As with poor sleep, chronic stress can reduce the recruitment and action of certain immune cells and prevent the body from mounting the optimal antibody response, says Moday.

In fact, one study found that students' immunity decreased during a stressful three-day exam period. They produced fewer NK cells and their infection-fighting T-cells were less responsive. 

Excessive stress also means excessive levels of the "stress hormone" cortisol are pumping through your system, which "can weaken the immune system by weakening the gut-immune barrier," says Moday. "It does that specifically by lowering an antibody called IgA, which lines all of our mucus layers through the digestive tract and acts as a first line of protection." When this happens, viruses are able to more readily invade through the lining of the intestinal tract.

Try this: If you can't get out of your stressful life situation or job, incorporate a daily habit that requires mindfulness such as meditation, breathwork (try this breathing exercise), or yoga. Getting adequate sleep also goes a long way in reducing stress. 

This ad is displayed using third party content and we do not control its accessibility features.

You feel depressed or you've recently faced a loss.

Depression and grief are other examples of emotional stressors that can impair immune function. In fact, there's a whole field of immunology called psychoneuroimmunology, which examines the connection between the emotions and the immune system. 

"In a famous study2, [the researcher] went to people who had just lost their partners or spouses in the hospital and drew their blood, and he showed that extreme grief is linked to an acute drop in immune reactivity," says Horwitz. "So your B-cells and T-cells aren't as responsive in periods of extreme stress and grief."

Additionally, even mild depression among older people can suppress the immune system, and feelings of loneliness and isolation have been linked to weakened immunity in college students.

Try this: Lifestyle factors such as regular exercise and a nutritious diet can help improve mental health and reduce emotional stress, but if you're really struggling, seek out the help of a therapist or other mental health professional. 


You have chronic diarrhea or other GI problems. 

Chronic diarrhea could indicate a weakened immune system for a number of reasons. For one, your diarrhea could potentially be caused by an infection or a parasite—and if you just can't seem to shake it, that might be an indicator your body isn't mounting a strong enough immune response to kill it, says Moday.

Chronic diarrhea could also be caused by a dysbiotic, or imbalanced gut microbiome, in which certain bacteria proliferate when they shouldn't. This can promote inflammation, reduce the integrity of the gut lining—both of which impair immunity. Think about it: About 70% of the body's immune system tissue3 is found in the gut, so it makes sense that unhealthy imbalances here would have reverberating effects on overall immunity.

Chronic diarrhea—whatever the cause—can also prevent you from absorbing all the nutrients from your diet. For example, if you're not absorbing enough fat, that could, in turn, prevent you from optimally absorbing fat-soluble nutrients, including vitamin D, that play a key role in immune health.

Try this: Get checked out by your doc to see if you have an infection or parasite (chronic diarrhea always warrants a doctor's visit). You can also support the gut microbiome, and thus overall immune health, by taking a probiotic* and eating a wide variety of fiber-rich plant foods—ideally ones that are colorful since polyphenol pigments are helpful to the gut, says Moday. 

This ad is displayed using third party content and we do not control its accessibility features.

Your diet is high in sugar or refined carbs. 

"When you eat a high-carbohydrate diet, or consume refined processed carbs and sugar, you are putting your immune system at a disadvantage," says Ali Miller, R.D., L.D., CDE, registered dietitian and certified diabetes educator. 

According to Miller—and the scientific research—there are two mechanisms in which the immune system is hindered by blood sugar elevations: 

This ad is displayed using third party content and we do not control its accessibility features.

Your weight is another thing to consider—particularly if you fall into the obese category and/or have a high body fat percentage. Adipocytes (or fat cells) are pro-inflammatory and drive insulin resistance, which weakens the immune response. 

Try this: Start eating a whole foods, nutrient-dense diet rich in healthy fats, antioxidants, and low in added sugar and refined carbs. The empowering news: You don't need to go on a crash diet or lose crazy amounts of weight to see an immune benefit if you're overweight. "The changes you make now can make quite a rapid impact," says Miller. "Studies support that insulin resistance can start to improve in as little as nine days, so every bite counts."


Your skin is often itchy, inflamed, or slow to heal. 

The skin is often a window into what's going on in the body—including the immune system, which can regulate inflammation and affect the barrier function and microbiome of the skin.   

"Recent research7 has highlighted that the immune system influences the types of microorganisms that live on your skin and affect your risk for disease," says Keira Barr, M.D., holistic and board-certified dermatologist. "So when the immune system is weakened, it can show up on the skin as eczema; allergic reactions; poor wound healing; bacterial, fungal, and viral infections such as herpes—and, depending on how weak the immune system is, the area affected could be localized or widespread." 

Skin symptoms related to the immune system could be manifesting for a number of reasons. For example, a poor diet and stress, which can cause immunosuppression and make your skin more vulnerable to problems, says Barr. 

Try this: Address these issues at the skin level and from within. Using gentle, unscented personal care products including cleansers and detergents, and keeping skin moisturized, can help support a healthy skin microbiome. Taking steps to reduce stress and improve your diet will also help support the immune system and boost the skin's ability to be resilient. 


You've been drinking more alcohol than usual.

If your alcohol consumption has spiked lately, there are more than a few reasons to scale back. But as it relates to immunity, "even if you're not an alcoholic, alcohol actually directly weakens white blood cells," says Moday. "It also causes a lot of inflammation of the gut, which can distress that gut-immune barrier."

Try this: No one's going to tell you not to have a casual glass of wine now and then, but if you've been leaning on alcohol to de-stress (and you certainly wouldn't be alone), consider a healthy stress-busting alternative like full-spectrum hemp extract.* And if drinking is more about the ritual, consider sipping on kombucha or a booze-free craft cocktail, instead.

How to support your immune system naturally. 

The signs above are some of the more obvious indicators that your immune system may be weak—or that it could be soon. To get it back into fighting shape, the suggested lifestyle changes can make all the difference. Here's a recap, plus a few more ways to support your immune system:

  • Aim for at least eight hours of quality sleep per night.
  • Reduce stress through mindfulness practices like deep breathing or yoga.
  • Scale back on sugar and refined carbs, and load up on colorful, nutrient-dense whole foods—consider making lunch your biggest meal of the day, too.
  • Give your body extra support in the form of nutrients like vitamin D3, vitamin C, zinc, probiotics, and plant bioactives like beta-glucan, quercetin, and medicinal mushrooms.*
  • Breathe through your nose instead of your mouth (weird but true!).
  • Move your body every day—exercise promotes improved circulation and oxygenation, which helps blood cells do their job.
  • Reduce your alcohol intake and find healthier ways to chill, like hemp.
  • Manage any underlying health conditions you may have. 
Stephanie Eckelkamp author page.
Stephanie Eckelkamp
Contributing Health & Nutrition Editor

Stephanie Eckelkamp is a writer and editor who has been working for leading health publications for the past 10 years. She received her B.S. in journalism from Syracuse University with a minor in nutrition. In addition to contributing to mindbodygreen, she has written for Women's Health, Prevention, and Health. She is also a certified holistic health coach through the Institute for Integrative Nutrition. She has a passion for natural, toxin-free living, particularly when it comes to managing issues like anxiety and chronic Lyme disease (read about how she personally overcame Lyme disease here).