Lemon water: what it can and cannot do for your health

What does a glass of lemon water provide?

A glass of lemon water provides mostly water. The vitamin C comes from the squeezed juice, and the amount depends on how much you add [1].

Vitamin C is usually expressed in milligrams [1] [2]. There is no need to convert it to micrograms or international units.

A glass with a little lemon juice provides little fibre [1]. If you want the benefits of fruit, it is better to eat it whole. See also our guide to oranges.

As a safety reference, the US upper limits for total vitamin C intake vary by age; they are not targets for this drink [2]. A limit could not be established for children under 1 year [2].

• Ages 1 to 3: 400 mg/day (400,000 µg/day) [2].
• Ages 4 to 8: 650 mg/day (650,000 µg/day) [2].
• Ages 9 to 13: 1,200 mg/day (1,200,000 µg/day) [2].
• Ages 14 to 18: 1,800 mg/day (1,800,000 µg/day) [2].
• Age 19 and over, including pregnancy and breastfeeding: 2,000 mg/day (2,000,000 µg/day) [2].

The European authority has not established an upper limit for vitamin C at any age because adequate data are lacking [3]. This should not be interpreted as a recommendation to take high amounts.

Does it help you lose weight, “detox” or “alkalise” your body?

Lemon has not been shown to have a specific effect on weight loss. In people with overweight or obesity, a review of trials found no significant reduction in weight, body mass index or waist circumference from drinking more water [4]. The trials also do not demonstrate any additional effect from lemon.

If someone recommends the drink to “detox” you, ask which specific substance it would remove and how this has been measured. The US National Center for Complementary and Integrative Health considers the evidence for cleansing or detox practices insufficient [5]. To learn how to spot other quick-fix promises, see our guide to fad diets.

Your blood’s pH is maintained by buffer systems, the lungs and the kidneys [6]. A glass of lemon water is not a way to “alkalise” your blood. If you have kidney disease, discuss significant dietary changes with your care team.

Is there any benefit to drinking it on an empty stomach?

No benefit of fasting has been demonstrated for this drink compared with having it with a meal or at another time. We have not found a specific clinical comparison of these timings.

Choose when to drink it based on taste and tolerance. If your routine means you have breakfast later, the glass does not replace the food you need. If lemon on an empty stomach gives you heartburn, try plain water and see how you feel.

What real benefit might it have?

Its main use is simple: the flavour may encourage you to drink water if you enjoy it more that way. There is no need to make it a compulsory habit. There is also no time of day when it works better.

If plain water feels boring, adding lemon is one way to change its flavour. The review on weight studied water, not this mixture, and did not find a significant reduction in adiposity in its main outcome [4]. For other options, see flavoured waters.

A question that sometimes comes up in consultations is whether stopping means losing a boost to your metabolism. There is no reason to force yourself to drink it. What matters is that the drink fits into your day and does not cause discomfort.

Who might find it uncomfortable?

Frequent exposure to acidic drinks may contribute to tooth enamel erosion [7]. To reduce contact, drink the glass without holding it in your mouth. Then rinse with water and wait before brushing your teeth [7]. If you notice sensitivity, talk to your dentist.

Citric acid may also be uncomfortable if you have reflux. NIDDK advises identifying foods that worsen your symptoms; citrus fruits are among the possible triggers [8]. If you have repeated heartburn, stop adding lemon and seek an assessment. Our hiatal hernia guide explains how to adapt your diet.

If you have gastritis, do not assume that lemon causes it: according to NIDDK, diet does not play an important role in most cases [11]. If a particular drink bothers you, mention it at your appointment.

How can you make it without any fuss?

Fill a glass with drinking water and squeeze in a little washed lemon. Taste it before adding more. You can use cold or room-temperature water; neither temperature gives lemon any special properties.

A slice adds aroma, but makes it harder to know exactly how much juice ends up in the glass. If you want to compare the vitamin C in different preparations, weigh the squeezed juice. You do not need to do this to enjoy the drink.

Avoid keeping a very acidic bottle beside you and sipping it all day. How often your teeth come into contact with it matters [7]. If you make a jug, keep it chilled and drink it while fresh.

What we see in consultations

The most common question is whether giving up the ritual will make someone gain weight or have worse digestion. We have not found trials comparing stopping this mixture with continuing to drink it. The glass’s composition also does not support attributing a specific digestive effect to it.

We also see confusion between a drink containing vitamin C and meeting your needs with that glass. The amount varies with how much juice you add [1]. Looking at all the fruit and vegetables you eat during the day is more useful than putting all the responsibility on one drink.