Effect of Arthrospira (Spirulina) maxima Supplementation and a Systematic Physical Exercise Program on the Body Composition and Cardiorespiratory Fitness of Overweight or Obese Subjects: A Double-Blind, Randomized, and Crossover Controlled Trial

Double-blind, randomized, placebo-controlled, counterbalanced crossover study in 52 sedentary overweight or obese adult men in Ciudad Juárez, Mexico. Participants were overweight or obese with BMI over 25 kg/m^2; the study compared Spirulina maxima with placebo, with and without a supervised exercise program.

Arthrospira maxima (Spirulina maxima) was given as 4.5 g/day in encapsulated dark capsules during six-week treatment periods within a randomized, double-blind, placebo-controlled crossover trial. The active supplement was evaluated alone and alongside a supervised exercise program; the placebo arm received 4.5 g/day of low-calorie saccharine powder in capsules.

Spirulina maxima improved body composition and cardiorespiratory fitness, and the combination with exercise produced the strongest overall effects. Compared with control, body fat percentage was reduced in the SE, Sm, and Ex groups (p < 0.05), and body weight decreased by -2.2 kg in SE, -1.6 kg in Sm, and -0.8 kg in Ex. VO2max improved in the SE, Sm, and Ex groups, and time to fatigue, OBLA, and resting heart rate improved in the Spirulina-supplemented groups; the authors concluded the benefits were more pronounced in obese participants and synergistic with exercise. No adverse effects of dietary or S. maxima supplementation were reported.

The trial was small and included only sedentary adult men, limiting generalizability. Per-arm randomized/analyzed sample sizes and several outcome estimates were not explicitly reported, and the crossover design with relatively short treatment periods may limit precision and durability of the findings. Some exercise-description details were also inconsistent across sections of the report.