Editor's note: This popular story from the Daily Briefing's archives was republished on Aug. 1, 2023.

While some people claim that "cleanses" help rid their body of toxins, improve sleep, boost energy, and sharpen mental clarity, experts have noted that "there's no major research done on most of the cleanses that are out there." Writing for the New York Times, Dani Blum explains why a cleanse may temporarily make you feel good—even if it is not backed by scientific evidence.

Most 'cleanses' are not evidence-based

Every year, companies, celebrities, and social media influencers advertise new "cleanses" that claim to purge the toxins from your body. "Your skin will clear; your stomach will shrink. You will feel, more or less, pure," Blum writes.

The concept of "cleansing" stems from the notion that releasing harmful toxins that have built up inside the body is "the secret to improved health," Blum writes.

However, there is very little evidence backing any of these claims. "There's no major research done on most of the cleanses that are out there," according to Melinda Ring, an integrative medicine specialist at Northwestern Medicine.

"People have this magical impression that what's in the body are weapons of mass destruction, and somehow flushing them out is going to make them better," said Gerard Mullin, an associate professor of medicine at Johns Hopkins Medicine who specializes in gastroenterology.

According to Beth Czerwony, a registered dietitian at Cleveland Clinic's Center for Human Nutrition, our bodies already have plenty of filters—our kidneys, livers, skin, and bladders all remove toxins and waste. "People often forget that," Czerwony said. "Our body's such a beautiful machine that it self-regulates."

In addition, there is no robust research indicating that the ingredients found in many cleanses, including lemon and apple cider vinegar, can speed up the metabolism or help people process waste faster, Ring noted.

Many people think they can reset their gastrointestinal tracts with a liquid diet cleanse, believing that their bodies will be able to absorb nutrients more effectively when they start eating solid food again, Czerwony said. However, she noted that this belief is misinformation, adding that the body will absorb the nutrients regardless.

Why do 'cleanses' make you feel good?

Some people say they feel better during a cleanse, claiming that their sleep has improved, they have more energy, or they can think more clearly.

"Nutrition experts say that people who try cleanses may report positive benefits in the short term — but not because of the specific slush they're drinking," Blum writes.

According to Ring, cleanses may trigger a placebo effect. "If you're convinced that a cleanse will make you feel better, you may persuade yourself that you really are benefiting from it," Blum writes.

In addition, Czerwony noted that some cleanses may help stabilize energy levels, largely because of the things they eliminate from a diet. On a cleanse, people often increase their water consumption and decrease their sugar consumption.

"If they typically eat heavy, processed foods and then swap those out for fruit- and vegetable-based smoothies, they might reap the benefits of cutting back on added sugars and fat," Blum writes. "Foods loaded with refined carbs, like white bread and pastries, can make our blood sugar spike, and then our energy levels may crash as our glucose levels slide back down."

However, even though some people may feel energized on a cleanse, others might feel exhausted, struggling to make it through the day because of a calorie deficit, Czerwony said. "Some people experience headaches and become irritable; they can also develop diarrhea or constipation," Blum adds.

Ultimately, there is no science-backed, individual element of a cleanse that improves health, Czerwony said.

A 2014 review of past studies on detoxes determined that the research surrounding cleanses was largely flawed. Then, a separate 2017 review revealed that juicing and detoxification diets resulted in weight loss over short periods of time because of the low number of calories participants consumed on a cleanse. However, the researchers noted that participants tended to gain weight after they resumed eating normally.

According to Czerwony, people who want to try a cleanse should opt for one that lasts no longer than three days. "The limited time frame is important so you avoid nutrient deficiencies and imbalances in your electrolyte levels," Blum writes. "It's also critical to make sure you're not consuming dangerous levels of vegetables and fruits, which may seem counterintuitive."

Mullin also noted that multiple case reports have found that people on juice cleanses can develop kidney issues. "They don't just do one smoothie — they live on it," Mullin said. "Some people overdo it."

Still, any supposed benefits from a temporary juice cleanse cannot reverse the toll of an unhealthy diet, Ring said. As Mullin said, "the body knows how to take care of itself," so you do not need to rely on a detox to help you feel better. (Blum, New York Times, 1/30)