The effects of supplementation with P-Synephrine alone and in combination with caffeine on resistance exercise performance.
Study Goal
The researchers aimed to examine the effects of caffeine in combination with p-synephrine on free-weight resistance exercise performance, specifically focusing on repetitions, power, and velocity.
Results Summary
The study found that caffeine combined with p-synephrine (SCF) significantly increased mean power and velocity during squats by ~6.2% compared to control and placebo, and improved total repetitions and volume load without affecting blood lactate or perceived exertion.
Population
Twelve healthy, college-aged men.
Effective Dosage
100 mg of caffeine combined with 100 mg of p-synephrine, consumed for 3 days prior to and on the day of the exercise protocol.
Duration
3 days of supplementation prior to testing, with a 1-week washout period between treatments.
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
p-synephrine + caffeine (SCF; 100 mg of p-synephrine plus 100 mg of caffeine) | increase | number of repetitions performed | twelve healthy, college-aged men | by 11.0 ± 8.0% (than CT) and by 6.0 ± 7.0% (than P) | produced a significantly greater number of repetitions performed | #1 |
p-synephrine (S; 100 mg) | increase | number of repetitions performed | twelve healthy, college-aged men | by 11.0 ± 8.0% (than CT) and by 6.0 ± 7.0% (than P) | produced a significantly greater number of repetitions performed | #2 |
p-synephrine + caffeine (SCF; 100 mg of p-synephrine plus 100 mg of caffeine) | increase | volume load per protocol | twelve healthy, college-aged men | 10.6 ± 12.0% greater increase than CT and P | greater increase in volume load per protocol | #3 |
p-synephrine (S; 100 mg) | increase | volume load per protocol | twelve healthy, college-aged men | 10.6 ± 12.0% greater increase than CT and P | greater increase in volume load per protocol | #4 |
p-synephrine + caffeine (SCF; 100 mg of p-synephrine plus 100 mg of caffeine) | increase | mean power and velocity | twelve healthy, college-aged men | by ~6.2 ± 8.0% compared to CT and P | mean power and velocity for all 6 sets were significantly higher | #5 |
p-synephrine + caffeine (SCF; 100 mg of p-synephrine plus 100 mg of caffeine) | no change | RPE | twelve healthy, college-aged men | no significant change | no supplement effects were observed | #6 |
p-synephrine + caffeine (SCF; 100 mg of p-synephrine plus 100 mg of caffeine) | no change | blood lactate | twelve healthy, college-aged men | no significant change | no supplement effects were observed | #7 |
p-synephrine (S; 100 mg) | no change | RPE | twelve healthy, college-aged men | no significant change | no supplement effects were observed | #8 |
p-synephrine (S; 100 mg) | no change | blood lactate | twelve healthy, college-aged men | no significant change | no supplement effects were observed | #9 |
p-synephrine + caffeine (SCF; 100 mg of p-synephrine plus 100 mg of caffeine) | no change | adverse side effects | twelve healthy, college-aged men | no significant change | no adverse side effects were observed or reported | #10 |
p-synephrine (S; 100 mg) | no change | adverse side effects | twelve healthy, college-aged men | no significant change | no adverse side effects were observed or reported | #11 |
p-synephrine + caffeine (SCF; 100 mg of p-synephrine plus 100 mg of caffeine) | increase | total repetitions, volume load | twelve healthy, college-aged men | - | augmented resistance exercise performance | #12 |
p-synephrine (S; 100 mg) | increase | total repetitions, volume load | twelve healthy, college-aged men | - | augmented resistance exercise performance | #13 |
p-synephrine + caffeine (SCF; 100 mg of p-synephrine plus 100 mg of caffeine) | increase | mean power and velocity of squat performance | twelve healthy, college-aged men | - | increased mean power and velocity of squat performance | #14 |
p-synephrine (S; 100 mg) and p-synephrine + caffeine (SCF; 100 mg of p-synephrine plus 100 mg of caffeine) | increase | local muscle endurance during resistance exercise | twelve healthy, college-aged men | - | can enhance local muscle endurance during resistance exercise | #15 |
BACKGROUND: Little is known concerning the potential ergogenic effects of p-synephrine supplementation. Therefore, the purpose of the present study was to examine the effects of supplementation with p-synephrine alone and in combination with caffeine on free-weight resistance exercise performance. METHODS: Twelve healthy, college-aged men performed a control (CT) resistance exercise protocol consisting of 6 sets of squats for up to 10 repetitions per set using 80% of their one repetition-maximum (1RM) with 2 min of rest in between sets. Each subject was randomly assigned (in double-blind, balanced manner) to a treatment sequence consisting of use of 3 supplements: p-synephrine (S; 100 mg), p-synephrine + caffeine (SCF; 100 mg of p-synephrine plus 100 mg of caffeine), or a placebo (P). For each supplement treatment (separated by 1 week), subjects consumed the supplement for 3 days prior to each protocol and the morning of each protocol, and subsequently did not consume any supplements for 3 days following (i.e. wash-out period). On each protocol day, subjects reported to the lab at a standard time, consumed a supplement, sat quietly for 45 min, performed the resistance exercise protocol, and sat quietly for 30 min post exercise. Performance (repetition number, force, velocity and power), blood lactate, and ratings of perceived exertion (RPE) data were collected during each protocol. RESULTS: Supplements SCF and S produced a significantly (P < 0.05) greater number of repetitions performed than CT (by 11.0 ± 8.0%) and P (by 6.0 ± 7.0%) and a 10.6 ± 12.0% greater increase in volume load per protocol than CT and P. Most of the differences were seen during the last 3 sets. Mean power and velocity for all 6 sets were significantly higher in SCF compared to CT and P by ~6.2 ± 8.0%. No supplement effects were observed in RPE or blood lactate, and no adverse side effects were observed or reported. CONCLUSIONS: S and SCF augmented resistance exercise performance (total repetitions, volume load) without increasing blood lactate or RPE. The addition of caffeine in SCF increased mean power and velocity of squat performance. These results indicate supplementation with S and SCF can enhance local muscle endurance during resistance exercise.