Caffeine-Induced Thermogenesis Assessed by Infrared Thermography

NCT07868302 | Completed

• 1 other identifier: ISTUN-CAFF-IRT-2025
• Study Type: interventional
• Target: 36
• Locations: 1 country
• Sites: 1

Brief Summary

This study evaluated thermogenic and physiological responses to 200 mg of caffeine administered following a carbohydrate gel in healthy adults. A total of 36 participants were included and grouped according to body mass index as normal weight, overweight, or obesity. The experimental protocol lasted 120 minutes. Participants received a carbohydrate gel at the beginning of the study, followed by 200 mg of caffeine 45 minutes later. Infrared thermography was used to assess temperature changes in the supraclavicular region, an area associated with brown adipose tissue activity. Core temperature, blood pressure, and heart rate were also measured at several time points. The study aimed to determine whether thermogenic and physiological responses differed according to body mass index and sex. It also evaluated whether absolute temperature values obtained directly from infrared thermography were sufficient on their own to characterize brown adipose tissue-related thermal responses. In addition, the study examined whether other thermal parameters provided complementary information for the interpretation of these responses.

Conditions

Caffeine-Induced Thermogenesis; Brown Adipose Tissue Activation

Keywords

caffeine; Infrared Thermography; Brown Adipose Tissue; Thermogenesis; Body Mass Index; Sex

Outcome Measures

Primary Outcomes (4)

• Supraclavicular Temperature (Tscv)

  Right and left supraclavicular regions of interest (ROIs) were manually delineated as triangular areas on infrared thermographic images. For each ROI, the infrared thermography software calculated the mean temperature of the entire delineated area, yielding separate right and left Tscv values. Mean Tscv was then calculated as the arithmetic mean of the right and left Tscv values. Temperature was expressed in degrees Celsius (°C).

  Infrared thermography measurements were repeated every 15 minutes throughout the 120-minute experimental protocol, at baseline (0 min) and at 15, 30, 45, 60, 75, 90, 105, and 120 min.

• Reference Region Temperature (Tref)

  A circular region of interest (ROI) was manually delineated over the BAT-free sternal region on infrared thermographic images. The infrared thermography software calculated the mean temperature of the entire delineated ROI, yielding the reference region temperature (Tref). Temperature was expressed in degrees Celsius (°C).

  IRT measurements were repeated every 15 minutes throughout the 120-minute experimental protocol, at baseline (0 min) and at 15, 30, 45, 60, 75, 90, 105, and 120 min.

• Relative Supraclavicular Temperature (Trel)

  Relative supraclavicular temperature (Trel) was calculated as the difference between supraclavicular temperature (Tscv) and reference region temperature (Tref) at each measurement time point (Trel = Tscv - Tref). Right and left Trel values were calculated separately using the corresponding right and left Tscv values and the Tref value. Mean Trel was then calculated as the arithmetic mean of the right and left Trel values. Trel was expressed in degrees Celsius (°C).

  Trel was calculated using the Tscv and Tref values measured by infrared thermography at each time point of the 120-minute experimental protocol: baseline (0 min) and 15, 30, 45, 60, 75, 90, 105, and 120 min.

• Delta Temperature (ΔT)

  Delta temperature (ΔT) was calculated as the change in supraclavicular temperature from the resting/baseline temperature (Td). The supraclavicular temperature measured at baseline (0 min), before carbohydrate gel administration, was defined as Td. Carbohydrate gel was administered after the baseline measurement, and caffeine was administered at 45 min. Supraclavicular temperatures measured at each subsequent time point (15, 30, 45, 60, 75, 90, 105, and 120 min) were considered stimulated temperatures (Ts), and ΔT was calculated as Ts - Td. Thus, ΔT at each time point represented the change in supraclavicular temperature relative to the baseline value. Right and left ΔT values were calculated separately, and mean ΔT was calculated as the arithmetic mean of the right and left ΔT values. ΔT was expressed in degrees Celsius (°C).

  ΔT was calculated using supraclavicular temperature (Tscv) values measured by infrared thermography (IRT), with the baseline (0 min) Tscv value used as the resting temperature (Td), at 15, 30, 45, 60, 75, 90, 105, and 120 min during the 120-minute experi

Secondary Outcomes (4)

• Estimated Core Temperature

  Estimated core temperature was measured at baseline (0 min) and at 15, 30, 45, 60, 75, 90, 105, and 120 min during the 120-minute experimental protocol.

• Systolic Blood Pressure

  Systolic blood pressure was measured at baseline (0 min) and at 15, 30, 45, 60, 75, 90, 105, and 120 min during the 120-minute experimental protocol.

• Diastolic Blood Pressure

  Diastolic blood pressure was measured at baseline (0 min) and at 15, 30, 45, 60, 75, 90, 105, and 120 min during the 120-minute experimental protocol.

• Heart Rate

  Heart rate was measured at baseline (0 min) and at 15, 30, 45, 60, 75, 90, 105, and 120 min during the 120-minute experimental protocol.

Study Arms (1)

Carbohydrate Gel Followed by Caffeine

EXPERIMENTAL

All participants received a carbohydrate gel at the beginning of the 120-minute experimental protocol, followed by 200 mg of caffeine at 45 minutes

Dietary Supplement: Carbohydrate Gel; Dietary Supplement: Caffeine

Interventions

Carbohydrate Gel DIETARY_SUPPLEMENT

Participants received a carbohydrate gel providing 53 g of carbohydrate (PowerGel Mojito, Ingobio, Türkiye) at the beginning of the 120-minute experimental protocol.

Carbohydrate Gel Followed by Caffeine

Caffeine DIETARY_SUPPLEMENT

Participants received one capsule containing 200 mg of caffeine (Nature's Supreme Caffeine, Türkiye) at 45 minutes during the 120-minute experimental protocol.

Carbohydrate Gel Followed by Caffeine

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Healthy adults aged 18 years or older.
• Male or female participants.
• For female participants, regular menstrual cycles and participation during the follicular phase (days 4-8 of the menstrual cycle).
• Provision of written informed consent.

You may not qualify if:

• Diabetes or other metabolic diseases.
• Use of prescribed medication.
• Specific treatment for obesity, including bariatric surgery or anti-obesity medication.
• Caffeine intolerance or caffeine allergy.
• Regular exercise or physical activity for ≥6 months.
• Use of supplements that may increase brown adipose tissue activity for ≥3 months (e.g., fish oil, caffeine, or EGCG).
• Irregular menstrual cycles.
• Pregnancy or lactation.
• Habitual alcohol consumption.

Sponsors & Collaborators

• Istanbul Health and Technology University: lead

Study Sites (1)

Istanbul Health and Technology University

Istanbul, Istanbul, 34445, Turkey (Türkiye)

Location

MeSH Terms

Conditions

Coitus

Interventions

Caffeine

Condition Hierarchy (Ancestors)

Sexual Behavior; Behavior

Intervention Hierarchy (Ancestors)

Xanthines; Alkaloids; Heterocyclic Compounds; Purinones; Purines; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring

Study Officials

• Zeynep Ercan Karakaya, PhD

  Istanbul Health and Technology University

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: All participants received a carbohydrate gel at the beginning of the protocol, followed by 200 mg of caffeine at 45 minutes during the same 120-minute experimental session.

Study Record Dates

• First Submitted: October 3, 2026
• First Posted: October 9, 2026
• Study Start: December 10, 2024
• Primary Completion: May 12, 2025
• Study Completion: May 12, 2025
• Last Updated: October 9, 2026

Record last verified: 2026-10

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)