Q: I’ve heard that drinking hot lemon water first thing in the morning can have various health benefits. Is that true?

A: In a video on TikTok, a woman has a lemon in one hand and a mug in the other as she espouses the benefits of her beverage: Within a week of drinking hot lemon water daily, she said, you can expect to burn more calories; become more hydrated; harbor fewer toxins; and have a boosted immune system, better digestion, less bloating, smoother skin and more energy and focus.

But while sipping warm lemon water can be a refreshing and healthy way to start the day, the evidence does not hold up, said Emily Ho, a professor of nutrition and the director of the Linus Pauling Institute at Oregon State University.

Here are a few of the main claims associated with hot lemon water, and whether there is — or isn’t — research to back them.

Hydration : Hot lemon water’s main nutritional asset is that it’s hydrating, Ho said. That’s especially beneficial first thing in the morning, she added, when “you haven’t had anything to drink all night.”

The body needs to be hydrated to maintain its temperature, lubricate and cushion the joints, and remove waste through processes like sweating and urination. Good hydration is also associated with healthier skin, better mood and sharper thinking.

That said, you’d get the same benefits from a glass of regular water, a cup of herbal tea or even a cup of coffee.

Digestion: Fluid is essential for keeping your digestive system moving, whether it’s spiked with lemon or not. In one 2020 study of more than 4,500 adults in Turkey, researchers found that those who drank the most water — more than eight cups per day — had a 29% lower risk of developing constipation compared with those who drank the least water — less than four cups per day.

There is some limited evidence that lemon juice might help break down food in the stomach by stimulating stomach acid secretion.

Immunity: There is a kernel of truth to the idea that hot lemon water can benefit the immune system. Lemons are loaded with vitamin C, Ho said. If you squeeze half of a large lemon into your cup, as many recipes suggest, that provides about a quarter of the recommended daily amount.

Vitamin C is essential for immune function and healing, and it acts as a powerful antioxidant that can thwart DNA damage. But there isn’t much evidence that you’ll boost your immune system by consuming more vitamin C.

Weight loss: If you’re drinking hot lemon water in place of a higher calorie beverage, like a sugary coffee drink, for example, it might help you lose weight, Simon said. However, there’s no solid evidence that hot lemon water has any measurable effect on weight or metabolism, she added.

The bottom line: Hot lemon water is a hydrating drink and a good replacement for sugary options, but it’s not the cure-all that influencers promise.