This 2021 rodent study investigated effects of sulforaphane on skin damage from irradiation:

“Radiotherapy is currently the main treatment for various cancers. We observed the protective effect of sulforaphane (SFN) on radiation-induced skin injury (RISI), including oxidative stress and inflammatory response indexes, and Nrf2 expression with its downstream antioxidant genes:

• SFN prevented DNA damage caused by radiation.
• SFN prevented and treated radiation-induced skin inflammation.
• SFN prevented radiation-induced oxidative stress in skin.
• Activation of Nrf2 and expressions of its downstream genes in skin induced by SFN.

Mice were randomly assigned to one of four groups (n = 8), including control group (CON), SFN group, irradiation (IR) group, and IR plus SFN (IR/SFN) group (* p < 0.05 vs. CON; & p < 0.05 vs. IR).

Our most innovative discovery was that SFN provided skin protection from IR. At present, there are a few drugs to treat RISI in clinical patients, but the effect is not very ideal, or some may cause certain side effects.

SFN extracted from natural broccoli has no toxicity and is easily accepted for usage in clinic. According to our findings, SFN will provide a new strategy for clinical treatment and prevention of RISI in the future.”

https://www.mdpi.com/2076-3921/10/11/1850/htm “Sulforaphane-Mediated Nrf2 Activation Prevents Radiation-Induced Skin Injury through Inhibiting the Oxidative-Stress-Activated DNA Damage and NLRP3 Inflammasome”

This study’s findings probably also apply to less-severe skin damage caused by sun exposure.