A randomized, placebo-controlled, crossover clinical trial to evaluate the effect of a turmeric formulation on muscle soreness and function recovery in moderately active adults.

Background: Turmeric may alleviate exercise-induced muscle soreness (delayed onset muscle soreness) and muscular function loss due to the strong anti-inflammatory and antioxidant activities of its active compounds, the curcuminoids. The primary objective of this trial was to evaluate the effect of a highly bioavailable turmeric formulation on delayed onset muscle soreness in male adults.

Methods: In a randomized, double-blind, placebo-controlled, crossover trial (ClinicalTrials.gov NCT04946981), 44 moderately active adults (34 males, 10 females, mean [SD] age = 33.7 [6.4] years) ingested a turmeric formulation (300 mg/day, thereof 90 mg of active curcuminoids) or placebo for five days. On the second day, muscle damage was induced with exercise (30 min downhill run at 70% VO₂ max). Immediately before and 0, 24, 48, and 72 hours post-exercise, muscle soreness during squat on quadriceps (visual analog scale), muscular function (knee extension dynamometer), muscle power (vertical jump test), muscle damage (serum creatine kinase), range of motion (knee flexion), and perceived wellness and wellbeing (questionnaire) were assessed. During exercise, exhaustion was assessed using the Borg Rating of Perceived Exertion. The primary trial population consisted of the male participants, outcomes in females were considered exploratory. Adjusted least squares means with standard errors (SE) were obtained from mixed models for repeated measures.

Results: There were no significant differences between the turmeric formulation and placebo in muscle soreness area under the curve from pre-exercise to 72 hours post-exercise and at all timepoints, except for a trend observed in males 72 hours after exercise (adjusted mean [SE] for difference from placebo = -4.8 [2.7] mm, p = 0.0776). Muscle soreness recovery (difference between soreness at 72 hours and maximal post-exercise soreness) was significantly greater with the turmeric formulation compared to placebo (adjusted mean [SE] for difference from placebo = -10.7% [4.3%], p = 0.0184 for the male participants, and -7.9% [3.6%], p = 0.0346 for the total sample). Furthermore, in males, the decrease from pre-exercise to 24 hours after exercise in isokinetic peak torque was significantly lower with the turmeric formulation (adjusted mean [SE] for difference from placebo = 11.0 [4.9] Nm, p = 0.0275), as was the decrease in isokinetic max rep work (adjusted mean [SE] for difference from placebo = 11.6 [4.9] J, p = 0.0195), while vertical jump peak power at 24 hours after exercise was higher (median [interquartile range] with the turmeric formulation vs. placebo = 931.1 [825.9; 1001.1] W vs. 916.5 [824.8; 989.5] W, p = 0.0445).

Conclusions: Supplementation with the turmeric formulation can accelerate exercise-induced muscle soreness recovery and could attenuate muscular function loss and improve performance after unaccustomed exercise in young, moderately active, male adults.