Excessive exercise overproduces reactive oxygen species in skeletal muscles. Sulforaphane activates nuclear factor erythroid 2‐related factor 2 (Nrf2) and induces a protective effect against oxidative stress. Sulforaphane intake has been shown to suppress exercise‐induced oxidative stress and muscle damage in mice. However, its effect on delayed onset muscle soreness after eccentric exercise in humans is unknown. A recent study evaluated the effect of sulforaphane supplement intake in humans regarding delayed onset muscle soreness (DOMS) after eccentric exercise.

The study performed continuous blood sampling and analyzed NQO1 mRNA expression levels to determine the duration of sulforaphane supplementation. It randomized Sixteen young men into sulforaphane and control groups. Each group performed six sets of five eccentric exercises with the nondominant arm in elbow flexion with 70% maximum voluntary contraction.

The study assessed muscle soreness in the biceps using the visual analog scale, range of motion (ROM), muscle damage markers, and oxidative stress markers (malondialdehyde; MDA).

It found-

• Sulforaphane supplement intake for two weeks improved NQO1 mRNA expression in peripheral blood mononuclear cells (PBMCs).
• Muscle soreness on palpation and ROM significantly lowered two days after exercise in the sulforaphane group than the control group.
• Serum MDA levels lowered significantly two days after exercise in the sulforaphane group than the control group.

These findings suggest that sulforaphane intake from 2 weeks before to 4 days after the exercise increases NQO1, a target gene of Nrf2, and suppresses DOMS after two days of eccentric exercise.

Komine S, Miura I, Miyashita N, Oh S, Tokinoya K, Shoda J, Ohmori H. Effect of a sulforaphane supplement on muscle soreness and damage induced by eccentric exercise in young adults: A pilot study. Physiol Rep. 2021 Dec;9(24):e15130. doi: 10.14814/phy2.15130. PMID: 34927380; PMCID: PMC8685487.