Does Vitamin C Increase the Body Heat Generated By The Nervous System?

The goals of this clinical trial are to determine whether or not vitamin C is able to: (1) increase the body heat generated by the sympathetic nervous system; and, (2) increase circulating vitamin D concentration during sympathetic nervous system stimulation in adult humans aged 18-40 years who meet the criteria for overweight based on body mass index. The main question it aims to answer are:

1. By how much does body temperature increase during stimulation of beta-adrenergic receptors when vitamin C is given.
2. By how much does circulating vitamin D concentration increase during stimulation of beta-adrenergic receptors when vitamin C is given.

Participants will will be asked to:

• undergo measures of body temperature
• have blood sampled on two separate occasions: once during stimulation of beta adrenergic receptors, and once during stimulation of beta-adrenergic receptors while also been given vitamin C.

Study Overview

• Status: Active, not recruiting
• Conditions: Vitamin D; Metabolism Changes
• Intervention / Treatment: Other: Vitamin C

Detailed Description

Participants will be required to visit the lab twice. During each visit, beta-adrenergic receptors will be stimulated with isoproterenol. The two visits are identical in every way with one exception: during one visit the isoproterenol will be delivered with saline only, and during the other visit the isoproterenol will be delivered with saline and vitamin C. The order of the visits will be randomized. Body temperature will be measured with a thermometer and a thermal camera. venous blood will be sampled and circulating vitamin D concentration will be quantified.

• Study Type: Interventional
• Enrollment (Estimated): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Colorado
    • Fort Collins, Colorado, United States, 80523
      • Colorado State University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Age 18-40 years (inclusive)
• Body mass index greater than or equal to 25 kg/m2 and less than 30 kg/m2
• Weight stable (no change in body mass greater than 5 Lbs. within the previous 6 months.
• Willing to abstain from caffeine and alcohol for 24-hours prior to two different study visits
• Competency in English as assessed by comprehension of the Informed Consent. This is study involves invasive procedures and infusion of a systemic vasoactive agent (isoproterenol); for safety reasons, the ability for clear and rapid communication will be necessary between the research participants and the investigators.

Exclusion Criteria:

• History of autonomic, cardio-pulmonary, and/or metabolic disease (including heart failure, hypertension, arrhythmia, vascular disease, and/or diabetes)
• Pregnancy or breast feeding
• Habitual use of tobacco/nicotine products or recreational drugs (2 or more uses within the previous month)
• History of a "sulfite allergy" as it is a relative contraindication to isoproteronol use.
• Has ingested vitamin supplements and/or antioxidant supplements during the previous 4-weeks (e.g. Vitamin C, Vitamin E, Multi-vitamins, etc.)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Response to beta-adrenergic stimulation without vitamin C; Isoproterenol will be infused with saline only
Experimental: Adding vitamin C to beta-adrenergic receptor stilmulation; Isoproterenol will be infused with vitamin C	Other: Vitamin C; Vitamin C will be co-infused with isoproterenol

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body Temperature	Body temperature will be measured using an oral thermometer	Prior to and immediately after a dose of isoproterenol. This corresponds to 0 minutes (baseline) and immediately after each dose of isoproterenol at minutes 30, 60 and 90.
Vitamin D	Circulating vitamin D concentration	Prior to and immediately after a dose of isoproterenol. This corresponds to 0 minutes (baseline) and immediately after each dose of isoproterenol at minutes 30, 60 and 90.

Collaborators and Investigators

• Sponsor: Colorado State University
• Investigators: Principal Investigator: Christopher Bell, PhD, Colorado State University

Study record dates

Study Major Dates

• Study Start (Actual): March 17, 2025
• Primary Completion (Actual): June 8, 2026
• Study Completion (Estimated): December 8, 2026

Study Registration Dates

• First Submitted: December 5, 2025
• First Submitted That Met QC Criteria: January 7, 2026
• First Posted (Actual): January 14, 2026

Study Record Updates

• Last Update Posted (Actual): July 2, 2026
• Last Update Submitted That Met QC Criteria: July 1, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: body temperature; vitamin c; vitamin d; isoproterenol
• Additional Relevant MeSH Terms: Organic Chemicals; Carbohydrates; Sugar Acids; Acids, Acyclic; Carboxylic Acids; Hydroxy Acids; Ascorbic Acid
• Other Study ID Numbers: 6115

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No