A 2026 paper provided details of a 2020-2023 human trial of broccoli sprouts:

“In a 42-month randomized, double-blind, placebo-controlled trial, 26 participants aged 63–90  years with memory impairment were randomly assigned to receive either 30 mg/day of glucoraphanin (GLR) or placebo. The primary outcome was the change in Memory Performance Index (MPI) scores from the mild cognitive impairment (MCI) screen. This study evaluated the long-term efficacy of GLR supplementation on cognitive function in older adults at an elevated risk for Alzheimer’s disease (AD), including those with MCI.

Participants were instructed to take three capsules of either the GLR or placebo supplements daily for 42 months. The GLR supplement contained 30 mg of GLR purified from broccoli sprouts, along with 120 mg of mustard powder per three capsules. Mustard powder was included as a source of exogenous active myrosinase to enhance the enzymatic conversion of GLR to sulforaphane. The placebo supplement contained 0 mg of GLR.

No significant group difference was observed in the initial 6 months. A marginal difference in favor of GLR appeared in the later phase (30 and 42 months), including the 42-month endpoint.

The GLR group demonstrated superior performance on immediate recall and delayed free recall tests. MCI participants showed a greater MPI improvement with GLR.

Long-term GLR supplementation may help preserve cognitive function in individuals at elevated risk for AD, particularly those with MCI. Larger trials are warranted to confirm efficacy and clarify underlying mechanisms.”

https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2026.1740494/full “Efficacy of 42-month oral administration of glucoraphanin in preventing cognitive decline in individuals at elevated risk of dementia, including those with mild cognitive impairment: a randomized, double-blind, placebo-controlled pilot study”

Again, 42 is the answer! 🙂

This study was funded by the supplement provider. There was no explanation of what the supplement’s “purified from broccoli sprouts” entails. Also, I didn’t mention results of voluntary group exercise because there was a long gap in the participants’ data due to government response to covid.

• For comparison of this study’s 30 mg glucoraphanin dose, Our model clinical trial for Changing to a youthful phenotype with broccoli sprouts provided 30 grams of fresh broccoli sprouts that contained an estimated 51 mg of glucoraphanin for ten weeks. That study’s corresponding coauthor said of their 30 gram broccoli sprouts dose in Understanding a clinical trial’s broccoli sprout amount that “When we carried out tests with consumers, previous to the bioavailability studies, higher amounts per day were not easy to consume and to get eaten by participants.” There was no rationale provided for this study’s 30 mg dose other than citing two previous human studies that also used a 30 mg glucoraphanin dose.
• For comparison of this study’s 120 mg mustard powder dose, my daily cruciferous food intake includes sprouted yellow mustard seeds started with 3.5 grams of seeds since five and a half years ago, along with sprouted broccoli and red cabbage started with 3.6 grams of each vegetable’s seeds. I haven’t seen studies that show sprouting affects myrosinase enzyme activity.
• This study cited Does sulforaphane reach the colon? which used 2% mustard seed powder to create sulforaphane from glucoraphanin. This study’s 120 mg mustard seed / 30 mg glucoraphanin is a lot more than 2%. My daily sprout intake started from 3.5 g mustard seeds / (3.6 g broccoli seeds +3.6 g red cabbage seeds) is also a lot more than 2%.

I’ve changed some items along the way, switching supplier from True Leaf to Johnny’s for organic broccoli seeds, and from non-organic Red Acre red cabbage seeds to True Leaf organic red cabbage seeds. I recently had to find another supplier of organic yellow mustard seeds when Naturevibe stopped carrying that product. I tried Food to Live, but their yellow mustard seeds when sprouted aren’t mild. I’ll next try Frontier Co-op to see if those are mild as advertised.