Glycerol-Enhanced Electrolyte Beverages for Fluid Balance

Overseen By Lindsay Baker, PhD

Age: 18 - 65

Sex: Any

Trial Phase: Academic

Sponsor: PepsiCo Global R&D

Must not be taking: Diuretics

Disqualifiers: Cardiovascular, Renal, Metabolic diseases, others

Approved in 2 Jurisdictions This treatment is already approved in other countries

Compensation: Varies

Number of Visits: 2

95 Participants Needed

Trial Summary

What is the purpose of this trial?

The results of a prior study PEP-2311 suggested there was a positive dose-response effect of glycerol and sodium on fluid balance and fluid retention. In addition, inclusion of glycerol resulted in an upward shift in the relationship between sodium concentration and fluid balance. The practical interpretation is that addition of glycerol enables a reduction in sodium concentration compared with a 0% glycerol drink. In this follow-up study, the investigators hypothesize that 1) fluid balance will be sustained (greater than or not different from baseline) and significantly greater than placebo for 120 min after drinking the test no/low/moderate carbohydrate beverages and 2) fluid balance will not differ between the carbohydrate-electrolyte beverages, but both will be greater than placebo.

Will I have to stop taking my current medications?

The trial requires that you do not take medications that may interfere with the study, such as diuretics (medications that help remove excess water from the body). If you are taking any medication, it's best to discuss it with the study investigator to see if it might affect your participation.

What data supports the effectiveness of the treatment Glycerol for fluid balance?

Research shows that glycerol can enhance fluid retention and improve water absorption in the body. Studies in rats and humans indicate that glycerol helps maintain better hydration levels compared to other solutions, making it potentially effective for fluid balance. ^{1 2 3 4 5}

Is glycerol safe for use in electrolyte beverages for fluid balance?

Glycerol is generally safe for use in humans, but some people may experience side effects like nausea, gastrointestinal discomfort, dizziness, and headaches. These side effects are rare, and glycerol is often used to help with hydration in athletes. ^{3 6 7 8 9}

How does the drug glycerol differ from other treatments for fluid balance?

Glycerol is unique because it helps the body retain more fluid by creating an osmotic drive, which means it draws water into the body and keeps it there longer than just drinking water alone. This makes it particularly useful for athletes who need to stay hydrated during intense exercise, as it can improve endurance and delay dehydration. ^{2 3 5 7 9}

Research Team

Lindsay Baker, PhD

Principal Investigator

PepsiCo R&D Life Sciences, Sports Science

Eligibility Criteria

This trial is for healthy men and women who are well-hydrated (euhydrated) and at rest. Specific details about age, health conditions, or other criteria aren't provided here.

Inclusion Criteria

Subject is at least recreationally active (engaged in light to moderate intensity, intermittent, or steady-state exercise at least 3 days per week for at least 30 min at a time)

I am either male or female.

I am not pregnant.

Exclusion Criteria

Subject has participated in a clinical trial within the past 30 days

Subject has participated in any PepsiCo trial within the past 6 months

Subject has a condition or is taking medication that the investigator believes would interfere with his/her ability to provide informed consent, comply with the study protocol, which might confound the interpretation of the study results, or put the person at undue risk

Timeline

Screening

Participants are screened for eligibility to participate in the trial

1-2 weeks

1 visit (in-person)

Part 1 Treatment

Participants consume no/low/moderate carbohydrate drinks with high electrolyte concentrations or placebo to assess fluid balance at rest

1 day per dosing session, with 2-15 days between sessions

Multiple visits (in-person)

Part 2 Treatment

Participants consume moderate carbohydrate drinks with low electrolyte concentrations or placebo to assess fluid balance at rest

1 day per dosing session, with 2-15 days between sessions

Multiple visits (in-person)

Follow-up

Participants are monitored for changes in fluid balance, blood sodium, and other secondary measures after treatment

1-2 weeks

1 visit (in-person)

Treatment Details

Interventions

• Glycerol

Trial Overview The study tests if drinks with glycerol improve fluid balance better than a placebo drink that looks and tastes similar but doesn't have glycerol. Participants will try no/low/moderate carbohydrate beverages to see how they affect hydration over two hours.

Participant Groups

Group I: 6% carbohydrate electrolyte solution without glycerol beverage (Part 2 only) Experimental Treatment 1 Intervention

Group II: 6% carbohydrate electrolyte solution with glycerol beverage (Parts 1 and 2) Experimental Treatment 1 Intervention

Group III: 2% carbohydrate electrolyte solution without glycerol beverage (Part 2 only) Experimental Treatment 1 Intervention

Group IV: 1% carbohydrate electrolyte solution with glycerol beverage (Parts 1 and 2) Experimental Treatment 1 Intervention

Group V: 0% carbohydrate electrolyte solution without glycerol beverage (Part 1 only) Experimental Treatment 1 Intervention

Group VI: 0% carbohydrate electrolyte solution with glycerol beverage (Part 1 only) Experimental Treatment 1 Intervention

Group VII: Placebo beverage (Parts 1 and 2) Placebo Group 1 Intervention

Glycerol is already approved in United States, European Union for the following indications:

Approved in United States as Glycerol for:

• Hyperhydration
• Fluid retention

Approved in European Union as Glycerol for:

• Hyperhydration
• Fluid retention

Who Is Running the Clinical Trial?

PepsiCo Global R&D

Lead Sponsor

Trials

99

Recruited

13,600+

Ramon Laguarta

PepsiCo Global R&D

Chief Executive Officer since 2018

MBA from ESADE Business School

Mark Kirkham

PepsiCo Global R&D

Chief Marketing Officer

Bachelor's degree in Business Administration from Trinity College Dublin

Findings from Research

In a study using a rat intestine perfusion model, a high-energy beverage combining glycerol (Gly) and corn syrup (CS) was found to significantly improve water absorption compared to commercial products containing sucrose and glucose-fructose syrups.

Gly not only enhanced water absorption but also reduced sodium release into the intestinal lumen, suggesting it could be an effective ingredient in energy-rich beverages to improve fluid absorption in humans.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Enhancement of intestinal water absorption and sodium transport by glycerol in rats. Wapnir, RA., Sia, MC., Fisher, SE.[2017]

Glycerol ingestion significantly improves fluid retention compared to water alone, with 60% retention versus 32% after 3 hours, likely due to lower urine flow and free water clearance rates in 11 male volunteers.

The study suggests that glycerol may enhance kidney function by increasing the medullary concentration gradient, which aids in water reabsorption, although changes in antidiuretic hormone (ADH) levels were also observed.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Glycerol hyperhydration: hormonal, renal, and vascular fluid responses. Freund, BJ., Montain, SJ., Young, AJ., et al.[2017]

Glycerol ingestion can enhance fluid retention, which helps athletes either hyperhydrate before exercise to delay dehydration or improve rehydration after exercise, leading to better endurance and performance outcomes.

However, athletes should be cautious with glycerol intake, as doses above 0.032 g/kg of lean body mass can lead to detectable urinary excretion, raising concerns about potential doping violations under World Anti-Doping Agency regulations.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Glycerol use in hyperhydration and rehydration: scientific update. van Rosendal, SP., Coombes, JS.[2019]

Glycerol can enhance fluid retention and promote hyperhydration, which may help offset dehydration during athletic activities, but its effectiveness varies across studies due to factors like dosage and exercise conditions.

While some studies suggest glycerol may provide thermoregulatory benefits, the overall evidence does not consistently support significant cardiovascular or performance advantages, indicating that more research is needed to clarify its ergogenic effects.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Exploring the potential ergogenic effects of glycerol hyperhydration. Nelson, JL., Robergs, RA.[2021]

Glycerol-induced hyperhydration (GIH) significantly improves fluid retention compared to water-induced hyperhydration (WIH), with an increase of 7.7 mL/kg body weight, based on a meta-analysis of multiple studies.

GIH also shows a potential improvement in endurance performance by approximately 2.62%, but more research is needed to confirm its effectiveness as an ergogenic aid, as the current data is limited.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A meta-analysis of the effects of glycerol-induced hyperhydration on fluid retention and endurance performance. Goulet, ED., Aubertin-Leheudre, M., Plante, GE., et al.[2019]

Beverages containing glycerol can enhance hydration and potentially improve endurance performance, with some studies showing up to a 24% increase in endurance time to exhaustion and a 5% increase in power.

Despite these potential benefits, results are inconsistent, with some studies showing no performance improvements, and side effects like nausea and dizziness reported in a small number of subjects.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Physiological and performance effects of glycerol hyperhydration and rehydration. van Rosendal, SP., Osborne, MA., Fassett, RG., et al.[2013]

Athletes can improve their hydration status and endurance performance by hyperhydrating with glycerol before exercise, as it helps retain fluid and enhances thermoregulation, allowing for greater tolerance to fluid loss.

To effectively hyperhydrate, athletes should consume glycerol at a dose of 1.2 g/kg body weight in 26 mL/kg body weight of fluid 30 minutes before exercise, with minimal side effects reported.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Guidelines for glycerol use in hyperhydration and rehydration associated with exercise. van Rosendal, SP., Osborne, MA., Fassett, RG., et al.[2021]

In a study with nine subjects cycling for 90 minutes in a warm environment, consuming glycerol solutions led to increased plasma osmolality and helped maintain plasma volume compared to water, but did not show significant benefits for cardiovascular or thermoregulatory responses.

Despite some changes in hormone levels and perceived thirst, the glycerol solutions did not provide substantial advantages over standard carbohydrate-electrolyte beverages or water in terms of exercise performance or metabolic responses.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Physiological responses to glycerol ingestion during exercise. Murray, R., Eddy, DE., Paul, GL., et al.[2017]

Glycerol has been proposed as a hyperhydrating agent that can improve fluid retention and potentially enhance athletic performance, especially in conditions where hydration is critical.

Research on glycerol's effectiveness has shown mixed results due to differences in study methods, but a common recommendation is to ingest 1 g/kg of glycerol with 1.5 L of fluid 60 to 120 minutes before competition, although some individuals may experience side effects like bloating or nausea.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Hyperhydrating with glycerol: implications for athletic performance. Wagner, DR.[2019]

References

1. United States pubmed.ncbi.nlm.nih.gov

Enhancement of intestinal water absorption and sodium transport by glycerol in rats. [2017]

2. United States pubmed.ncbi.nlm.nih.gov

Glycerol hyperhydration: hormonal, renal, and vascular fluid responses. [2017]

3. Switzerland pubmed.ncbi.nlm.nih.gov

Glycerol use in hyperhydration and rehydration: scientific update. [2019]

4. New Zealand pubmed.ncbi.nlm.nih.gov

Exploring the potential ergogenic effects of glycerol hyperhydration. [2021]

5. United States pubmed.ncbi.nlm.nih.gov

A meta-analysis of the effects of glycerol-induced hyperhydration on fluid retention and endurance performance. [2019]

6. United States pubmed.ncbi.nlm.nih.gov

Physiological and performance effects of glycerol hyperhydration and rehydration. [2013]

7. New Zealand pubmed.ncbi.nlm.nih.gov

Guidelines for glycerol use in hyperhydration and rehydration associated with exercise. [2021]

8. United States pubmed.ncbi.nlm.nih.gov

Physiological responses to glycerol ingestion during exercise. [2017]

9. United States pubmed.ncbi.nlm.nih.gov

Hyperhydrating with glycerol: implications for athletic performance. [2019]