The aim of this study was to determine the effects of a new formulation of vitamin B12, natural orange extract, and their combination on physical and mental performance.

A triple-blind, randomized, crossover clinical trial will be conducted with three experimental phases (vitamin B12 + natural orange extract, natural orange extract, vitamin B12) and one control phase (placebo), including evaluations of the acute effect after a loading phase (three intakes, one per day including the test day).

Participants

The sample will consist of 20 well-trained male cyclists (road, MTB, or triathlon), training 3-6 sessions per week, aged between 18 and 45 years. The inclusion criteria will be:

• Healthy male (to be certified through medical examination and health analysis).
• Aged 18-45 years.
• Well-trained (3-6 training sessions per week).
• Habitual consumer of citrus fruits (orange, mandarin, lemon, or grapefruit, either whole or as juice).

Tests

• General health analysis: A general blood test (including standard biochemistry and complete blood count) will be performed during the recruitment phase.
• Medical examination: A cardiorespiratory assessment at rest will be conducted to rule out any underlying pathology.
• Specific performance-related blood analysis: Conducted at four time points (total of eight measurements): baseline during recruitment, pre- and post-test in each condition (supplement / placebo). Parameters will include: complete blood count, ferritin, CK, LDH, vitamin B12, transaminases, reticulocytes, homocysteine, C-reactive protein, IL-6, methylmalonic acid, holo-transcobalamin II, 8-OHdG (8-hydroxy-2'-deoxyguanosine), dopamine, serotonin, and Brain-Derived Neurotrophic Factor (BDNF).
• Anthropometry: Determination of body composition parameters to characterize the sample.
• Wingate test: Conducted using the standard load protocol, consisting of five maximal 30-second sprints with 3-minute recovery intervals between repetitions.
• Mental fatigue test using light-based reaction tasks: The time required to complete a light reaction sequence will be measured before and after the fatigue protocol.
• Genetic test: A saliva sample will be collected to analyze genetic profiles related to food intolerances and vitamin absorption. The objective is to identify potential explanations for interindividual differences in absorption capacity.

Inclusion Criteria:

• Healthy male (to be certified through medical examination and health analysis).
• Aged 18-45 years.
• Well-trained (3-6 training sessions per week).
• Habitual consumer of citrus fruits (orange, mandarin, lemon, or grapefruit, either fresh or juiced).

Exclusion Criteria:

• Smokers or regular alcohol drinkers.
• Persons suffering from a metabolic, cardiorespiratory or digestive pathology or anomaly.

digestive system.

• People who have suffered an injury in the last 6 months that limits the performance of the study tests. of the study tests.
• People taking supplements or medication in the 2 weeks before the start of the study.

The company that formulated the supplements and placebo carried out the randomization, so no one on the research team or among the sponsors knew which group each study subject belonged to. The results of the randomization were sent to our laboratory after the study was completed to determine which subjects were in each group.