Oral GP-SOD for Vitiligo: Safety Profile, Dosing, and What's Next

Patients with vitiligo receiving oral gliadin-protected superoxide dismutase (GP-SOD) alongside targeted excimer phototherapy showed significantly greater improvement in both repigmentation and quality of life than those on phototherapy alone at 6 months.

The 6-month, single-center trial enrolled 40 patients with localized non-segmental vitiligo, randomly assigning half to add oral GP-SOD to excimer lamp treatment. Mean VASI improvement was -1.65 in the combination group versus -1.14 with phototherapy alone, a significant between-group difference (mean difference 0.51; 95% CI, 0.28-0.74; P <.0001).1 Quality-of-life scores, measured with VitiQoL, also improved significantly more in the combination group, with a between-group difference of 5.59 (95% CI, 4.01-7.17; P <.0001).1

In an interview with HCPLive, Giovanni Leone, MD, of the Photodermatology and Vitiligo Treatment Center at Israelite Hospital, discussed the safety findings behind those results, including why the combination group saw less treatment-related erythema, his recommended dosing protocol, and where he sees the research heading next.

Recommended GP-SOD Dosing Protocol

Leone recommends 2 capsules of GP-SOD before breakfast and 2 before lunch, for a total of 4 capsules daily. He advised against evening dosing, noting that some patients reported insomnia when taking the supplement later in the day. Aside from that adjustment, he said tolerability has been consistently high.

Why Erythema Was Less Frequent With GP-SOD

Leone said GP-SOD itself produced no reported adverse events in the trial. The only adverse events were cases of erythema from the excimer lamp, a known effect of phototherapy.

He said the lower erythema rate in the combination group likely reflects a systemic photoprotective effect of antioxidants beyond their action on melanocyte-damaging mechanisms. Antioxidants are used clinically to build UV resistance even in patients without vitiligo, he said, which may explain the reduced erythema seen with GP-SOD.

Contraindications for GP-SOD and Phototherapy

Celiac disease or gluten hypersensitivity is an absolute contraindication to GP-SOD, Leone said, since the compound is gluten-based. Beyond that, he said exclusion criteria follow standard phototherapy contraindications: a family history of skin cancer or melanoma, UV-sensitive skin, and photodermatoses.

Next Steps: Polymorphic Light Eruption and New Protocols

Leone said his group is now exploring GP-SOD's photoprotective properties as a potential treatment or preventive strategy for polymorphic light eruption, a common sun-triggered photodermatosis. He said additional vitiligo protocol variations are also under consideration, though the current regimen remains his preferred approach for now.

Key Takeaway for Treating Clinicians

“The most important message is that this treatment is…well tolerated, contributes to lower the risks of long-term phototherapy in terms of shortening the treatment period, [and] is very well accepted by the patients,” Leone said. “The rapidity of the treatment…make it a very good option. Without using very expensive and complicated drugs, we have a good result.”

Watch part 1 of our interview with Leone here: Oral GP-SOD Plus Targeted Phototherapy Boosts Vitiligo Repigmentation.2

Leone has no reported disclosures.

References

1. Leone G, Bertold C, Vidolin AP, Fontas E, Passeron T. Combination of Oral Gliadin-Protected Superoxide Dismutase With Targeted Phototherapy in Vitiligo: A Prospective, Comparative, Randomized, Single-Blinded Study. Photodermatol Photoimmunol Photomed. 2026;42(4):e70105. doi:10.1111/phpp.70105

2. Leone G. Oral GP-SOD Plus Targeted Phototherapy Boosts Vitiligo Repigmentation. HCPLive. Published on July 14, 2026. Accessed July 17, 2026. https://www.hcplive.com/view/oral-gp-sod-plus-targeted-phototherapy-vitiligo-repigmentation.