How do thiols act as radical scavengers?

Thiols act as efficient radical scavengers by serving as hydrogen atom donors. In this process, a radical ($X^{•}$) abstracts a hydrogen atom from the thiol group ($-SH$), which results in the formation of a thiyl radical ($R{S}^{•}$) and the neutralized species ($XH$).1

Because of this ability to donate hydrogen atoms, thiols are valuable as radioprotective agents, helping to mitigate damage caused by radicals generated by radiation. This scavenging property is also utilized in various other chemical processes and synthetic reactions.1