Short-Term Consumption of Low-Molecular Weight Polyphenols (Oligonol) Is Associated with Improved Post-Exercise Recovery in Healthy Young Men: A Randomized Single-Blind Crossover Study

Polyphenols have been suggested to aid exercise recovery through antioxidant properties, but their efficacy remains controversial, partly due to limited bioavailability. This study investigated whether low-molecular weight polyphenols (LMWPs, oligonol) influence metabolic responses related to fatigue and oxidative stress during and after a maximal exercise test in healthy young men. A randomized, single-blind crossover design includes a placebo, a single dose of LMWP (S-LMWP), and 5-day LMWP (5-LMWP) intervention with ≥2-week washouts. Ten eligible participants completed all conditions. Exercise performance, fatigue-related metabolic parameters, and oxidative stress markers were measured before, immediately after, and 30 min after exercise. Heart rate and lactate were additionally assessed for 5 min post-exercise. Exercise performance and anthropometrics did not differ among conditions. However, both LMWP groups showed significantly lower blood lactate at 30 min recovery compared with the placebo group (placebo: 17.09 ± 1.29; S-LMWP: 8.36 ± 0.73; 5-LMWP: 9.18 ± 0.60; <i>p</i> = 0.005). Malondialdehyde (MDA), elevated immediately post-exercise, returned closer to baseline at 30 min in the LMWP groups, particularly S-LMWP. Percent MDA change was significantly lower in the S-LMWP group than in the placebo group (placebo: 26.80 ± 3.01; S-LMWP: -8.41 ± 4.86; <i>p</i> = 0.007). Short-term LMWP supplementation did not affect performance or immediate responses but was associated with a more favorable recovery profile, including lower lactate and faster normalization of oxidative stress markers. Larger controlled studies are needed to confirm these findings.