The Influence of Placebo and Nocebo Effect on Weightlifting Performance: Unveiling the Power of the Mind over Muscle Summary

  • Subjects “believed” that they were taking caffeine, a nocebo effect (i.e., a substance with negative effects on physical activity), or a placebo, and they executed the bench press.
  • Subjects who believed they received caffeine performed 3.8 reps more (i.e., 37% greater performance) than the placebo group, and exercise felt “easier.” The subjects who thought they received a performance-reducing ingredient (i.e., lactate) did not have a decrease in performance compared to the control group. Still, the exercise felt “harder” to perform.
  • The study shows that if you believe a supplement will help your performance, you might perform better and feel less tired. This weightlifting placebo effect can be helpful to develop mental strategies for boosting confidence and promoting positive thinking before competitions or workouts.


Is it possible that your own beliefs, rather than the supplements you take, hold the key to unlocking your full potential in weightlifting? The weightlifting placebo effect, a phenomenon where belief alone can initiate physiological changes, suggests this possibility.

Many of us have heard how clinical trials, where healthcare providers inform participants about a new drug that lowers blood pressure or acts as an antidepressant, result in clinical improvements in symptoms solely due to the power of belief. Placebos not only work in medicine but can also enhance performance.

This article explores the science behind the placebo effect and nocebo effect in resistance training, showcasing their significant influence on strength. It is based on a recent study titled “Caffeine, lactic acid, or nothing: What effect does expectation have on men’s performance and perceived exertion during an upper body muscular endurance task?” This study emphasizes the potency of the placebo response.

The Weightlifting Placebo Effect and Nocebo Effect Is Real

weightlifting placebo effect the nocebo effectHow often have we invested in supplements, fully convinced of their muscle-building promises, only to realize the true power was in our belief? One of the most compelling demonstrations of the weightlifting placebo effect occurred in a study where male athletes, under the impression they were taking steroids, actually received a placebo. Despite this, they added a staggering 100 pounds to their combined lifts in the bench press, squat, and deadlift, showcasing the significant effect size of the placebo. (Gideon, 1972). Interestingly, after they learned that they had been taking fake steroids, their strength subsequently decreased.

A Pill That Immediately Increases Strength

Positive expectations in training are crucial. If you believe you’ll gain muscle, you’re setting the stage to do just that. A randomized controlled trial titled “Top-down influence of ergogenic placebos on muscle work and fatigue,” as explored in the European Journal of Neuroscience revealed a 22% surge in strength among trained athletes who were falsely informed they had taken high-dose caffeine yet had only received a placebo. (Pollo et al., 2008)

weightlifting placebo effect the nocebo effectIn another striking instance, researchers administered a placebo consisting of milk-sugar tablets to individuals shortly before their workouts. They informed the participants that it was a potent amino acid blend with immediate strength-enhancing effects. The outcome? There was a significant increase in strength in both the bench press and seated leg press. However, when the participants were subsequently informed that they had received a placebo in a previous session, their strength declined to match that of the control group. (Kalasountas et al., 2007) Additionally, Aguiar et al. (2022) demonstrated that the belief in consuming creatine, regardless of actual intake, treatment outcomes improved performance in resistance exercises. This underscores the potent influence of belief: if you think a supplement works, it just might.

Thinking You Have Received a Performance Deteriorating Supplement (Nocebo Effect) Makes Exercise Feel Harder

A recent study investigated the impact of subjects’ belief in the performance-enhancing of an ingested substance on muscular endurance performance and perceived exertion. The aim of the study was to determine whether the participants’ performance and perception would differ under different conditions involving a placebo and nocebo response.

The participants completed one set to failure at 80% of their one repetition maximum (1RM), which means they lifted a weight that was 80% of the heaviest weight they could lift just once. They did as many repetitions as possible until they couldn’t do another one with proper form.

All the subjects received a cellulose capsule, which has no ergogenic effects. Still, they were told they were ingesting caffeine (Placebo), lactate (Nocebo), or cellulose (Control), and the researchers provided information on the alleged effects of each substance. Participants were often unaware of the true nature of the supplement or treatment, which ensured that they could attribute the outcomes to their beliefs rather than the treatment itself.

To simply the study, here are the groups:

Group A (PLACEBO): Subjects were told they were receiving caffeine and its benefits for increasing performance before the study. However, they just were taking a placebo (i.e., placebo intake was just cellulose, no active ingredients).

Group B (NOCEBO PHENOMENON): Subjects were told they were receiving lactate and the negative side effects of lactate on performance before the study. They were informed them that lactate could make them tired and impair their performance.

Group C: (CONTROL): The control group was told they were ingesting cellulose, which would not affect their performance.

What is the Nocebo Effect?

A nocebo effect is a substance or treatment that has no therapeutic effect but can cause adverse effects on a person’s health or well-being due to the individual’s belief in its harmful properties. In the context of the study, the term “nocebo effect” refers to the belief that one has ingested something harmful (lactate) and the perceived negative outcome it has on exercise performance.


weightlifting placebo effect the nocebo effectConsistently, the results from these studies indicate that belief significantly impacts resistance training outcomes. Participants who believed they had ingested caffeine (i.e., but actually nothing) performed better than those who knew they had not, regardless of the actual substance ingested. In the study, when the guys thought they took caffeine (but it was actually just a placebo), they did more reps, and their RPE was lower, meaning they could do more, but it didn’t feel as hard. The Placebo condition averaged 14.1 reps, whereas the Control condition averaged 10.3 reps. This means that the group who “thought” they were consuming caffeine performed on average 3.8 more reps than in the control condition.(Campelo et al., 2023)

Believing they were consuming lactate or experiencing the nocebo effect didn’t lead to worse performance compared to taking the pill without any narrative. However, subjects felt that it was harder. In the control group, where subjects weren’t given any specific information, performance was moderate—not as high as when subjects thought they had caffeine, but they didn’t feel as challenged as when they believed they were taking the “bad stuff.”

So, when you believe you are taking a supplement that improves performance, you perform better, and exercise feels easier. If you think you’ve got something that helps, you do better; if you think it’s something bad, it feels harder, even if it doesn’t change your performance. It’s like your brain tricks your body based on what you expect to happen. Cool, right?

Practical Applications

Understanding the placebo effect can lead to more effective training strategies for everyday lifters and athletes. Coaches and trainers can leverage the power of belief by instilling confidence in their athletes’ abilities and the effectiveness of their training regimens.


The study’s insights have several practical implications for those involved in sports, fitness, and psychology. Firstly, in mindset training, the findings suggest that fostering a belief in the efficacy of a supplement can enhance actual performance and reduce fatigue. This psychological strategy can be leveraged to bolster confidence and cultivate a positive mindset before athletic events or training sessions.

Coaches might also integrate harmless placebos in training regimens to help athletes break through psychological barriers and improve their physical performance, training the mind to trust the body’s abilities. The study also enriches the existing research on placebo and nocebo effects, serving as a valuable reference for future research in exercise science, sports medicine, and psychology.


Gideon A, William Saville. Anabolic steroids: the physiological effects of placebos. MEDICINE AND SCIENCE IN SPORTS Vol 4, No 2, pp 124-126 1972. 1972.

Campelo, D., Koch, A. J., & Machado, M. (2023). Caffeine, lactic acid, or nothing: What effect does expectation have on men’s performance and perceived exertion during an upper body muscular endurance task? Int J Health Sci (Qassim), 17(6), 39-42.

Kalasountas, V., Reed, J., & Fitzpatrick, J. (2007). The Effect of Placebo-Induced Changes in Expectancies on Maximal Force Production in College Students. Journal of Applied Sport Psychology, 19(1), 116-124.

Pollo, A., Carlino, E., & Benedetti, F. (2008). The top-down influence of ergogenic placebos on muscle work and fatigue. Eur J Neurosci, 28(2), 379-388.

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