12mg of capsaicin moved neither strength endurance nor jump height
In short
In a double-blind, counterbalanced crossover trial with 16 advanced resistance-trained men, taking 12mg of capsaicin 40 minutes before testing produced no difference in either total repetitions on a 45° leg press strength endurance test (capsaicin 55±15, placebo 52±16, control 54±16, p=0.854) or countermovement jump height (36.0±3.3cm, 36.3±3.6cm, 36.2±3.7cm, p=0.976). No positive or negative expectancy effects from believing they had taken capsaicin were detected either.
Experimental evidence that capsaicin improves calcium metabolism in skeletal muscle has kept its ergogenic potential in circulation. This trial cleaned up the methodological biases in earlier work and asked again. The answer is short — no difference.
How was it tested?
Participants were 16 advanced resistance-trained men (24±4 years, 73.9±2.7kg, 1.73±0.06m). One-rep max testing established eligibility and set the intensity for the endurance test. Strength endurance was four sets at 70% of 1RM on a 45° leg press, with countermovement jump testing alongside.
The design is the point here. After thorough familiarisation, participants completed all three conditions with at least 72 hours between sessions, in a double-blind, counterbalanced crossover. The conditions were control with no supplementation, placebo, and 12mg of capsaicin, with capsules taken 40 minutes before testing.
What came out?
- Total repetitions — capsaicin 55±15, placebo 52±16, control 54±16 (p=0.854).
- Jump height — capsaicin 36.0±3.3cm, placebo 36.3±3.6cm, control 36.2±3.7cm (p=0.976).
- Expectancy — neither positive nor negative expectancy effects from ingesting capsaicin were detected (both p>0.05).
The capsaicin condition does sit highest on repetitions, but it is three reps above placebo with a standard deviation of 15. A p-value of 0.854 says that gap is comfortably inside the noise. On jump height, placebo was marginally higher.
Why does the expectancy result matter?
A common trap in supplement research is expectancy: if believing you took something changes performance, you cannot separate that from the ingredient. This trial checked which condition participants thought they had received, and found that belief neither pushed nor dragged the results.
These findings apply to acute supplementation — a single dose 40 minutes before testing. The population, 16 advanced resistance-trained men, narrows it further. This is not data against longer-term supplementation or effects in other groups.
How this connects to your Muscle Index
Nothing here argues against spicy food. What the trial rules out is the strategy of taking a capsaicin capsule before training to lift more. Time and money aimed at your Big 3 go further in the programme than in the pre-workout ingredient panel.
How thin the evidence base is across supplements, and what risk attaches to multi-ingredient products, is in supplement contamination and doping risk. For a case of an ingredient that fails at absorption, see the polyphenol absorption problem.
Frequently asked questions
Does capsaicin supplementation improve lifting performance?
Not in this trial. Giving 16 advanced resistance-trained men 12mg of capsaicin 40 minutes before testing produced no significant difference from placebo or control in either total repetitions on a 45° leg press endurance test or countermovement jump height.
How much was taken, and when?
12mg of capsaicin in capsule form, ingested 40 minutes before testing. The design was a double-blind, counterbalanced crossover in which each participant completed all three conditions — control, placebo and capsaicin — separated by at least 72 hours.
What was the rationale for capsaicin in the first place?
Experimental evidence suggests capsaicin improves calcium metabolism in skeletal muscle, which raised the possibility of an ergogenic effect. Previous studies on the question carried numerous methodological biases, and this trial was designed to address those limitations.
Could believing you took it produce an effect on its own?
No such expectancy effect was detected here. The researchers checked which condition participants believed they had received, and neither positive nor negative expectancy significantly affected performance outcomes.
Does this mean I should eat less spicy food?
No. The trial tested whether a capsaicin capsule taken shortly before training improves performance, and concluded it does not. It is not a study of everyday dietary habits.
Source: Nutrition and Health