HSN Caffeine Put to the Test

HSN Caffeine Put to the Test

A scientific Study on HSN Caffeine by the University of Granada.

Scientific Study on HSN Caffeine by the University of Granada

Scientific Study on HSN Caffeine by the University of Granada


What’s the study?

The PROFTH “PROmoting FITness and Health Through Physical Activity” research group, associated with the University of Granada, has carried out a randomised controlled trial to determine the effects of caffeine intake on diurnal variation in fatty acid oxidation.Authors of the study

Title and authors of the study using HSN caffeine.

In other words, the hypotheses to be tested were:

  • The acute intake of caffeine will increase the maximal rate of fat oxidation, the exercise intensity at which this maximal rate of fat oxidation is achieved, and the maximal oxygen consumption.
  • There will be a diurnal variation in the 3 parameters indicated above, with values being higher in the evening than in the morning.

Natural caffeine

The study used HSN caffeine in anhydrous powder from green coffee beans to test the hypothesis.

We tell you absolutely everything you need to know about Caffeine in this Post.

Study characteristics

The study has the following methodological characteristics that allow any type of bias due to lack of knowledge or interests to be controlled, guaranteeing that, in this way, they do not exist.

The study has a triple-blind methodology (subjects, researchers and statisticians), i.e. no one knew at any time what product was being given to the subjects, nor to whom the data sent to the mathematicians corresponded.

The study was controlled with placebo:
  • Both caffeine (experimental, with physiological effects) and cellulose (control, with no physiological effects) were given to subjects mixed in 250ml of water, 30 minutes before testing.
  • Both mixtures had no taste, colour, or odour, and were given in an opaque container, each indistinguishable from one another.
The trial has was conducted in crossover, i.e. all subjects were tested under both experimental and control circumstances – everyone was evaluated for:
  • Practice with caffeine in the morning.
  • Practice with placebo in the morning.
  • Practice with caffeine in the afternoon.
  • Practice with placebo in the afternoon.

Study protocol

Graphic representation of the study protocol.

It was conducted with 15 active young volunteers with a BMI of 18.5-28 kg/m2 and at least two years of endurance training experience.

They could not be used to caffeine consumption (<50mg/day), nor smokers, nor suffer from caffeine allergies, nor pathologies requiring medical attention.

HSN caffeine study protocol

The study was carried out over 5 visits:

  • Visit 1: Biometric data (weight, height, body composition and chronotype determination) was collected.
  • Visit 2: Morning test with caffeine.
  • Visit 3: Afternoon test with placebo.
  • Visit 4: Morning test with placebo.
  • Visit 5: Afternoon test with caffeine.
Based on anthropometric data, the amount of caffeine to be used was calculated (3mg/kg body weight).

The visits were 7 days apart, where an incremental aerobic protocol was carried out up to the maximum volitional effort (maximal effort test). This protocol was carried out on a cycloergometer and was structured as follows:

A first block of graded exercise at submax intensity:
  • Starting at 50W at a rate of 60-100 rpm for 3 minutes (warm-up).
  • Increasing 25W every 3 minutes until reaching a RER of 1.0 (the balance point between O2 consumption and CO2 production, aka, maximum utilisation of carbohydrates as an energy substrate).

After this, a five minutes rest with free access to water.

A second block of graded exercise at max intensity:
  • Starting at 50W at a rate of 60-100 rpm for 3 minutes (warm-up).
  • Increasing by 50W every 1 minute until self-reported exhaustion is reached.
Two tests were conducted during this period:
  • Indirect calorimetry with a breath-by-breath gas analyser.
  • Metabolic sensor for additional respiratory data.
  • Heart rate monitor.

Study results

The results confirmed the hypothesis formulated by the research group:

Subjects had better aerobic performance in the afternoon than in the morning, their fatty acid oxidation was higher, as was the intensity required to reach this point.

This means that in the afternoon, metabolic flexibility is greater, as more fatty acids can be used as an energy substrate, and muscle and liver glycogen can be “protected”, which is highly desirable in endurance athletes.

In terms of caffeine, the results were positive in the 3 variables evaluated:

The caffeine increased the fat oxidation rate by 10.7% in the morning (P= <0.001) and by 29% in the afternoon (P= <0.001) on average.

Rate of fat oxidation

Variations in the rate of fat oxidation across the morning and afternoon, with placebo and caffeine

Caffeine increased the peak intensity at which the maximum fat oxidation rate is reached by 11.1% in the morning and 13.1% in the afternoon (P= 0.0058).

Variations in intensity

Variations in intensity to achieve maximal fat oxidation between morning and afternoon, with placebo and caffeine.

It increased peak oxygen consumption by 3.9% in the morning and 3.2% in the afternoon (P= >0.7).

Peak oxygen uptake

Variations in peak oxygen uptake between morning and afternoon, with placebo and caffeine.

All data show a positive trend for caffeine intake versus placebo, although due to the variability of the individual response to caffeine (encoded by cytochrome P450 genes), only the fatty acid oxidation ratio was statistically significant.


The conclusions of the study were:

  • Caffeine increases the fat oxidation rate, the intensity at which maximum fatty acid oxidation is achieved, and maximum oxygen consumption, regardless of the time of day.
  • The highest values for these variables were always obtained in the afternoon, after caffeine intake.
  • Caffeine used in the morning increases the fat oxidation rate to a value similar to the rate achieved in the afternoon without caffeine.
  • The combination of acute caffeine intake and moderate-intensity physical exercise in the afternoon provides the best scenario for people seeking to increase the fat oxidation rate.

Natural caffeine caps

We also have Caffeine in vegetable capsules from EssentialSeries.

Now in a simplified format:

If you’re looking to oxidise more fat, it’s best to do your aerobic exercise in the afternoon, and in any case, caffeine intake will help you “burn more fat”

This has a positive effect (or desirable) on two aspects:

  • With sports -> Since greater fat oxidation means less use of glucose from glycogen reserves; one of the largest energy reserves in the body of athletes, it’s in their interest to preserve it.
  • For aesthetics -> As increased fat oxidation can potentially transfer into greater fat loss in the long term, improving body composition.
Ingesting of 3mg/kg HSN caffeine 30 minutes before exercise improves aerobic performance and metabolic flexibility for fatty acid use.

HSN and scientific research

At HSN we are committed to scientific research as the most objective, safe and appropriate means of obtaining knowledge.

Our dietary supplements are developed following maximum quality standards in the production process, certified and audited by multiple independent bodies at different points, and relating to different levels of this.

This is why the results of using our caffeine are positive, because the purity of the caffeine we sell, as well as that of other dietary supplements, is at its highest.

The authors declare that they have no conflicts of interest and that the results of the study have been presented clearly, honestly and without fabrication, falsification or inappropriate manipulation of data.

HSN only provided technical support as a distributor of the dietary supplement used, and was not involved in subject selection, experimentation, data collection, data processing or interpretation.

Bibliographic References

  1. Ramírez-Maldonado, M., Jurado-Fasoli, L., del Coso, J., R. Ruiz, J., & Amaro-Gahete, F. J. (2021). Caffeine increases maximal fat oxidation during a graded exercise test: is there a diurnal variation? Journal of the International Society of Sports Nutrition, 18(1), 5.

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Review of HSN Caffeine Study

Characteristics - 100%

Protocol - 100%

Results - 100%

HSN Caffeine - 100%


HSN Evaluation: 5 /5
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About Alfredo Valdés
Alfredo Valdés
He is a specialist in metabolic physiopathology training and in the biomolecular effects of food and physical exercise.
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