This 2021 human study investigated effects of pre- and post-workout glucoraphanin intake:

“The tablets used in this study contained 30 mg/3 tablets of sulforaphane glucosinolate [properly termed glucoraphanin], a precursor of sulforaphane (SFN), which is converted to SFN in the intestinal lumen by intestinal microflora. Subjects took one tablet of SFN supplement per meal, three times a day. Healthy men without exercise habits, smoking, or medication were included in the experiment:

Pain on palpation reached its peak 1–2 days after exercise and recovered to baseline 5 days after exercise. Muscle soreness on palpation and range of motion were significantly lower 2 days after exercise in the sulforaphane group:

Serum malondialdehyde, an indicator of exercise-induced oxidative stress, showed significantly lower levels 2 days after exercise in the sulforaphane group. SFN intake may protect the balance of antioxidant capacity and suppress excessive oxidative stress caused by exercise.

Continuation of SFN intake – from 2 weeks before and up to 4 days after eccentric exercise – suppressed exercise-induced oxidative stress and inhibited muscle soreness and muscle damage. To our knowledge, this study is the first to analyze these effects of SFN in humans.”

https://physoc.onlinelibrary.wiley.com/doi/10.14814/phy2.15130 “Effect of a sulforaphane supplement on muscle soreness and damage induced by eccentric exercise in young adults: A pilot study”

This study found that four days wasn’t enough time for 19-to-23-year-old men to fully recover from bicep eccentric exercise, regardless of glucoraphanin treatment or control group status. What’s an appropriate exercise recovery time? found a similar result using taurine as treatment with 20-to-33-year-old recreationally fit men who didn’t fully recover from bicep eccentric exercise after three days.

These researchers referenced Autism biomarkers and sulforaphane to acknowledge that this study’s daily 30 mg of glucoraphanin wasn’t sufficient to fully activate Nrf2 signaling pathways:

“When SFN was added to PBMCs of healthy subjects in ex vivo experiments, NQO1 expression was increased, while HO-1 was not increased at a low SFN concentration (0.5 µM). However, when 2 or 5 µM of SFN was added to PBMCs, both NQO1 and HO-1 gene expression were increased. Concentration of the SFN supplement may be a reason why the amount of supplementation used in our protocol did not increase HO-1 expression.”

I create isothiocyanates by microwaving 3-day-old broccoli / red cabbage / mustard sprouts at 1000 W to 60°C (140°F) shortly before eating them. Unlike this study, I don’t depend on metabolism after the stomach to produce isothiocyanates from glucosinolates:

• Less dependence on these subjects’ gut microbiota for sulforaphane production would have reduced a source of dose variability. Broccoli sprout compounds and gut microbiota first paper reviewed that subject.
• Glucoraphanin intake with nothing else an hour before and after would have also reduced chances of sulforaphane loss by reacting with food. See Week 19 item 2 for two studies that found eating protein, fats, and fiber along with broccoli sprouts lowered isothiocyanates’ bioavailability.

Still, this was a step forward in research. Have fun with New Year’s resolutions.