Abstract
OBJECTIVE: To systematically identify herbal supplements with immunostimulatory properties that may trigger or exacerbate autoimmune skin diseases. METHODS: We conducted a systematic scoping review in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews guidelines. PubMed was searched for studies published before 3 August 2025 using predefined immune, herbal supplement, autoimmune, skin and interferon terms. Articles in English that described immunostimulatory effects of herbal supplements in vitro, in model organisms or in human/clinical studies were included. Data were extracted by four reviewers and synthesised qualitatively, with herbs categorised according to levels of supporting evidence for their immunostimulatory properties. A subgroup of herbs with the strongest evidence was identified based on predefined criteria. RESULTS: From 11 819 unique articles screened, 469 studies met inclusion criteria. Across these, 227 distinct immunostimulatory herbal supplements were identified: 79 supported by human studies, 145 by model organism studies and 148 by in vitro studies. 15 herbs demonstrated the most robust evidence across all three evidence types, supported by more than five single-ingredient studies or more than 25 references overall. These included alfalfa, ashwagandha, astragalus, chlorella, echinacea, garlic, ginseng, green tea extract, Indian mulberry, liquorice, mistletoe, reishi mushroom, skullcap, spirulina and tinospora. These herbs were widely marketed for 'immune support' and shared proinflammatory mechanisms, including toll-like receptor activation, NF-κB/MAPK signalling and increased production of inflammatory cytokines including IL-1β, IL-6, TNF-α, IL-12 and IFN-γ. CONCLUSIONS: We identified 227 herbal supplements with immunostimulatory properties, of which 15 were most strongly supported by the evidence. This article may serve as a reference to help clinicians counsel patients with autoimmune skin diseases on the risks associated with use of specific herbal supplements.