Giovanni Leone, MD, from Israelite Hospital.

Giovanni Leone, MD

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

 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 nonsegmental vitiligo and randomly assigned half to receive oral GP-SOD in addition to excimer lamp treatment. Mean Vitiligo Area Scoring Index improvement was –1.65 in the combination group vs –1.14 with phototherapy alone, a significant between-group difference (mean difference 0.51; 95% CI, 0.28-0.74; 

 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;

, 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.

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 enhance UV resistance, even in patients without vitiligo, he said, which may explain the reduced erythema observed 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.

“The most important message is that this treatment is…well tolerated, contributes to lowering 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…makes 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

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. 

Leone G. Oral GP-SOD plus targeted phototherapy boosts vitiligo repigmentation. HCPLive. July 14, 2026. Accessed July 17, 2026. 

https://www.hcplive.com/view/oral-gp-sod-plus-targeted-phototherapy-vitiligo-repigmentation

Videos

Erythema was less frequent with combination therapy than with phototherapy alone, according to Giovanni Leone, MD.

 Oral GP-SOD Plus Targeted Phototherapy Boosts Vitiligo Repigmentation

Adding oral gliadin-protected superoxide dismutase (GP-SOD) to targeted excimer phototherapy produced significantly greater repigmentation than phototherapy alone in patients with localized non-segmental 

, according to a new randomized, single-blinded study.

The trial, published ahead of World Vitiligo Day, was led by Giovanni Leone, MD, of the Photodermatology and Vitiligo Treatment Center at Israelite Hospital.

“[The study] was not just [intended] to confirm the effectiveness of GP sod together with UVB but to see if by using a more powerful source for targeted phototherapy…we could obtain even better results, and that has been the case,” Leone told 

GP-SOD and Targeted Phototherapy Study Design

The 6-month trial enrolled 40 adults with localized non-segmental vitiligo. All participants received targeted excimer lamp phototherapy, and half also received oral GP-SOD. Patients on the combination regimen showed significantly greater repigmentation than those on phototherapy alone, along with significantly greater improvements in quality of life. No serious adverse events were reported.

Leone said the trial builds on earlier work from Nice testing GP-SOD with conventional narrowband UVB booths.

 Switching to a more targeted excimer source, he said, produced stronger repigmentation than the earlier booth-based results while limiting UV exposure to lesional skin.

Vitiligo Repigmentation Outcomes by Skin Phototype

Most enrolled patients had Fitzpatrick skin types III and IV, reflecting the study's Italian patient population.

 Leone said this worked in the trial's favor clinically.

“As in other publications in the literature on vitiligo, it has been clearly demonstrated that the response to phototherapy is better in darker skin types,” he said.

VASI Score Timeline: When to Assess Treatment Benefit

Leone said the between-group difference in Vitiligo Area Scoring Index (VASI) improvement was statistically significant by week 12 and widened by week 24. He said 6 months remains the standard window for judging benefit, though earlier improvement at 3 months suggests clinicians may eventually be able to shorten phototherapy courses and reduce cumulative UV exposure.

GP-SOD Versus JAK Inhibitors in Vitiligo Treatment

Asked how GP-SOD fits alongside JAK inhibitors now used in vitiligo, Leone said the combination logic is similar. JAK inhibitors and GP-SOD both limit autoimmune damage to melanocytes, he said, but neither drives melanocyte proliferation on its own. Phototherapy remains the primary stimulus for melanocyte growth, making it a natural pairing for either approach.

Quality of Life Gains Outpace Repigmentation Scores

Leone said quality-of-life improvement outpaced objective VASI gains, which he attributed partly to the tolerability of targeted phototherapy compared with conventional whole-body narrowband UVB. He said easier treatment adherence, alongside the biological effect of GP-SOD, likely contributed to the larger quality-of-life signal.

“The therapy is easier to follow and has [fewer] side effects as compared to systemic or conventional total body narrowband UVB,” he said.

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. 

Fontas E, Montaudié H, Passeron T. Oral gliadin-protected superoxide dismutase in addition to phototherapy for treating non-segmental vitiligo: A 24-week prospective randomized placebo-controlled study. 

. 2021;35(8):1725-1729. doi:10.1111/jdv.17331

Combination therapy outperformed excimer light alone for vitiligo, according to Giovanni Leone, MD.

Giovanni Leone, MD

Articles