Home Ingredients Glucose / Dextrose
HydrationAthletic PerformanceEnergy

Glucose / Dextrose

Evidence Level
Strong
4 Clinical Trials
2 Documented Benefits
4/5 Evidence Score

Glucose, sold in pure crystalline form as dextrose, is the body's main circulating sugar and a fast-absorbed carbohydrate. In the gut it is taken up through a sodium-dependent transporter called SGLT1, which is why oral rehydration solutions pair glucose with sodium. These solutions are a medical treatment for dehydration from diarrhoeal illness, and a systematic review estimated they may prevent 93% of diarrhoea deaths in young children. In healthy men, an oral rehydration solution kept more fluid in the body over 4 hours than water, while a typical sports drink did not. During long endurance exercise, carbohydrate feeding keeps blood sugar up and can delay fatigue, and a single sugar such as glucose can be burned at up to about 60 g an hour. A sports drink is not an oral rehydration solution, and ongoing vomiting or diarrhoea needs medical care.

Studied Dose During endurance exercise: up to about 60 g of carbohydrate an hour from a single sugar such as glucose (2 to 3 hours); about 90 g an hour for ultra-endurance only with mixed sugars. For rehydration: as part of a measured oral rehydration solution
Active Compound D-glucose (dextrose, anhydrous or monohydrate); endurance products often combine it with fructose, for example in a 2:1 ratio

Benefits

Pairs with sodium to aid water absorption in oral rehydration solutions

Glucose is absorbed through SGLT1, a sodium-dependent transporter, which is why oral rehydration solutions combine glucose with sodium. In healthy volunteers, glucose-electrolyte solutions were well absorbed in the small intestine, and in 72 healthy men an oral rehydration solution kept more fluid in the body than water over 4 hours, while a sports drink did not. Ongoing vomiting or diarrhoea needs medical care.

Supported by Trial 2, Trial 3

Endurance exercise fuel and delayed fatigue

A meta-analysis of 136 studies found that carbohydrate taken during endurance exercise improved performance versus placebo, most in longer events and time-to-exhaustion tests, and the type of carbohydrate did not change the effect. In one cycling study a glucose polymer drink let riders go about an hour longer. A single sugar such as glucose can be burned at up to about 60 g an hour.

Supported by Trial 4

Mechanism of action

1

SGLT1 sodium-glucose transport

Glucose is thought to be absorbed mainly through SGLT1, a sodium-dependent transporter in the small intestine, so glucose and sodium are taken up together and water absorption follows. This is the basis for pairing glucose with sodium in oral rehydration solutions.

2

Solution makeup and water absorption

In healthy human small intestine, a lower-osmolality glucose-electrolyte solution (60 mmol/L sodium, 90 mmol/L glucose) gave more water absorption than other solutions tested, including the WHO solution, and solutions with two sugars gave more water absorption at a given osmolality than single-sugar solutions.

3

Carbohydrate oxidation during exercise

SGLT1 is believed to become saturated at about 60 g of glucose an hour. Adding fructose, which uses a different transporter, raised carbohydrate oxidation above 1 g a minute (1.26 g/min) in one study, which is why ultra-endurance fuelling plans use mixed sugars.

Clinical trials

1
Oral Rehydration Solution and Childhood Diarrhoea Deaths: Systematic Review
PubMed

Systematic review and meta-analysis of studies on the efficacy and effectiveness of oral rehydration solution and recommended home fluids, with evidence graded using CHERG rules. (Munos et al. 2010, Int J Epidemiol)

Children under 5 with diarrhoea; 157 papers were included in the oral rehydration solution meta-analyses.

Oral rehydration solution was estimated to prevent 93% of diarrhoea deaths and was effective in home, community and facility settings. Evidence was insufficient for recommended home fluids. This is medical treatment of an illness, not a sports or supplement use.

2
Beverage Hydration Index: Randomized Trial of 13 Drinks
PubMed

Randomized trial: euhydrated, fasted men drank 1 L of still water or one of 13 common drinks over 30 minutes, and urine was collected for 4 hours. (Maughan et al. 2016, Am J Clin Nutr)

72 healthy men.

Four-hour urine output was lower than with water after an oral rehydration solution (1038 vs 1337 g), full-fat milk and skimmed milk; the hydration index at 2 hours was 1.54 for the oral rehydration solution. Cola, tea, coffee, lager, orange juice, sparkling water and a sports drink did not differ from water.

3
Carbohydrate Feeding and Time to Fatigue in Trained Cyclists
PubMed

Crossover trial: cyclists rode at 71% of VO2max to fatigue while drinking flavored water or a glucose polymer solution (2.0 g/kg at 20 minutes, then 0.4 g/kg every 20 minutes). (Coyle et al. 1986, J Appl Physiol (1985))

7 endurance-trained cyclists.

Fatigue came at 3.02 hours with placebo and 4.02 hours with carbohydrate (P < 0.01). Carbohydrate kept blood glucose and carbohydrate oxidation up late in exercise; muscle glycogen use did not differ in the first 3 hours. A small study using a glucose polymer rather than pure glucose.

4
Carbohydrate During Endurance Exercise: Meta-Analysis of 136 Studies
PubMed

Systematic review, meta-analysis and meta-regression of studies comparing carbohydrate intake during endurance exercise with placebo or control, testing moderators such as dose, carbohydrate type and event duration. (Ramos-Campo et al. 2024, Crit Rev Food Sci Nutr)

136 studies of carbohydrate ingestion during endurance exercise.

Carbohydrate significantly improved endurance performance versus placebo or control. Effects were larger in time-to-exhaustion tests than time trials, in longer events and in less trained people. Dose, ergometer, form of intake and type of carbohydrate did not change the size of the effect. Perceived exertion was lower with carbohydrate.

Side effects and drug interactions

Common Potential side effects

Raises blood sugar quickly; people with diabetes or on glucose-lowering medicine should check with their clinician before using glucose products
Large carbohydrate intakes during exercise can upset the gut in some athletes; a review notes the gut can adapt with regular practice

Important Drug interactions

Insulin and other glucose-lowering medicines: glucose raises blood sugar, so coordinate any use with your diabetes care plan

More Hydration Ingredients

Hydration
Glycerol (Glycerin)
Glycerol (glycerin or glycerine) is a small three-carbon sugar alcohol that forms the back…
Hydration
Coconut Water
Coconut water is the clear liquid inside young green coconuts (Cocos nucifera). It is natu…
Hydration
Cococin® (Freeze-Dried Coconut Water — Sabinsa)
Cococin is Sabinsa's freeze-dried (lyophilized) coconut water powder, made from the liquid…
Cardiovascular
Potassium Chloride
Potassium chloride (KCl) is a salt that supplies about 52% potassium by weight. It is a co…

Frequently asked questions about Glucose / Dextrose

What is dextrose (glucose) used for in supplements?

Dextrose is glucose, a fast-absorbed sugar. Athletes use it as fuel during long endurance exercise, and it is paired with sodium in oral rehydration solutions. People with diabetes should follow their own clinician's plan for any glucose use.

When should I take dextrose?

It is most useful during prolonged exercise lasting 2 hours or more, where up to about 60 g of carbohydrate an hour from a single sugar is recommended. Outside sport or medical situations there is little reason to take pure glucose.

Is a sports drink the same as an oral rehydration solution?

No. In a trial in healthy men, an oral rehydration solution kept more fluid in the body than water, but a sports drink did not. Oral rehydration solutions are medical products for dehydration, and ongoing vomiting or diarrhoea needs medical care.

Is dextrose bad for you?

As a pure, rapidly absorbed sugar, dextrose raises blood sugar quickly. That is useful during long exercise but not for everyday use, especially for people managing blood sugar or weight.

What is Glucose / Dextrose?

Glucose, sold in pure crystalline form as dextrose, is the body's main circulating sugar and a fast-absorbed carbohydrate. In the gut it is taken up through a sodium-dependent transporter called SGLT1, which is why oral rehydration solutions pair glucose with sodium.

What is Glucose / Dextrose used for?

Glucose / Dextrose is researched primarily for Hydration, Athletic Performance, and Energy. Glucose is absorbed through SGLT1, a sodium-dependent transporter, which is why oral rehydration solutions combine glucose with sodium.

What is the recommended dosage of Glucose / Dextrose?

The clinically studied dose is During endurance exercise: up to about 60 g of carbohydrate an hour from a single sugar such as glucose (2 to 3 hours); about 90 g an hour for ultra-endurance only with mixed sugars. For rehydration: as part of a measured oral rehydration solution Always follow the product label and check with a healthcare provider for personal advice.

Is Glucose / Dextrose safe, and does it have side effects?

For most healthy adults, Glucose / Dextrose is well tolerated at studied doses. Reported effects can include: Raises blood sugar quickly; people with diabetes or on glucose-lowering medicine should check with their clinician before using glucose products Large carbohydrate intakes during exercise can upset the gut in some athletes; a review notes the gut can adapt with regular practice It may also interact with some medications. Glucose / Dextrose is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does Glucose / Dextrose interact with any medications?

Possible interactions include: Insulin and other glucose-lowering medicines: glucose raises blood sugar, so coordinate any use with your diabetes care plan If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Glucose / Dextrose?

NutraSmarts rates the evidence for Glucose / Dextrose as Strong (4 out of 5). It is backed by 4 clinical trials and 8 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(8 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Jeukendrup A. A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Med. 2014;44 Suppl 1(Suppl 1):S25-33. doi: 10.1007/s40279-014-0148-z.PubMedUsed to support: Review of carbohydrate intake during endurance exercise: a mouth rinse or small amounts can help in events of about 1 hour; a single carbohydrate source can be oxidized at up to about 60 g/h, recommended for 2 to 3 hour exercise; about 90 g/h is recommended for ultra-endurance events and must come from multiple transportable carbohydrates. The full text notes SGLT1 saturates at about 60 g/h and glucose plus fructose raised oxidation to 1.26 g/min in one study.
  2. Coyle EF, Coggan AR, Hemmert MK, Ivy JL. Muscle glycogen utilization during prolonged strenuous exercise when fed carbohydrate. J Appl Physiol (1985). 1986;61(1):165-72. doi: 10.1152/jappl.1986.61.1.165.PubMedUsed to support: Crossover study in 7 endurance-trained cyclists at 71% VO2max: a glucose polymer drink maintained plasma glucose and carbohydrate oxidation and extended time to fatigue from 3.02 to 4.02 hours vs flavored water; muscle glycogen use did not differ during the first 3 hours.
  3. Munos MK, Walker CL, Black RE. The effect of oral rehydration solution and recommended home fluids on diarrhoea mortality. Int J Epidemiol. 2010;39 Suppl 1(Suppl 1):i75-87. doi: 10.1093/ije/dyq025.PubMedUsed to support: Systematic review and meta-analysis (157 papers in the ORS analyses) of oral rehydration solution and recommended home fluids for diarrhoea in children under 5: ORS may prevent 93% of diarrhoea deaths and is effective in home, community and facility settings; evidence for home fluids was insufficient.
  4. Victora CG, Bryce J, Fontaine O, Monasch R. Reducing deaths from diarrhoea through oral rehydration therapy. Bull World Health Organ. 2000;78(10):1246-55.PubMedUsed to support: WHO bulletin review: oral rehydration therapy, introduced in 1979, became the cornerstone of diarrhoea control programmes; annual diarrhoea deaths in children under 5 fell from about 4.6 million in 1980 to about 1.5 million, with country case studies linking rising ORT use to falling mortality.
  5. Maughan RJ, Watson P, Cordery PA, Walsh NP, Oliver SJ, Dolci A, Rodriguez-Sanchez N, Galloway SD. A randomized trial to assess the potential of different beverages to affect hydration status: development of a beverage hydration index. Am J Clin Nutr. 2016;103(3):717-23. doi: 10.3945/ajcn.115.114769.PubMedUsed to support: Randomized trial in 72 euhydrated, fasted healthy men drinking 1 L of water or one of 13 beverages: 4-hour urine output was lower than water after an oral rehydration solution (1038 vs 1337 g), full-fat milk and skimmed milk; beverage hydration index at 2 h was 1.54 for the ORS. A sports drink, cola, tea, coffee, lager and orange juice did not differ from water.
  6. Hunt JB, Elliott EJ, Fairclough PD, Clark ML, Farthing MJ. Water and solute absorption from hypotonic glucose-electrolyte solutions in human jejunum. Gut. 1992;33(4):479-83. doi: 10.1136/gut.33.4.479.PubMedUsed to support: Jejunal perfusion study in healthy adult volunteers: hypotonic glucose-electrolyte solutions (90 mmol/L glucose) were compared with the WHO solution; the solution with 60 mmol/L sodium gave the greatest water absorption, with sodium absorption similar to WHO-ORS.
  7. Shi X, Summers RW, Schedl HP, Flanagan SW, Chang R, Gisolfi CV. Effects of carbohydrate type and concentration and solution osmolality on water absorption. Med Sci Sports Exerc. 1995;27(12):1607-15.PubMedUsed to support: Segmental intestinal perfusion in 8 healthy men: solutions with two transportable carbohydrates (glucose plus fructose, or sucrose) produced greater water absorption at a given osmolality than single-carbohydrate solutions; solute flux mattered more than osmolality.
  8. Ramos-Campo DJ, Clemente-Suárez VJ, Cupeiro R, Benítez-Muñoz JA, Andreu Caravaca L, Rubio-Arias JÁ. The ergogenic effects of acute carbohydrate feeding on endurance performance: a systematic review, meta-analysis and meta-regression. Crit Rev Food Sci Nutr. 2024;64(30):11196-11205. doi: 10.1080/10408398.2023.2233633.PubMedUsed to support: Systematic review and meta-analysis of 136 studies: carbohydrate intake during endurance exercise significantly improved performance versus placebo or control, with larger effects in time-to-exhaustion tests, longer events and less trained participants; dose, ergometer, type of intake and type of carbohydrate did not moderate the effect; perceived exertion was lower.