Study Overview
This retrospective study evaluated 95 adults with chronic forms of psoriasis treated for up to twelve months using individualised daily doses of vitamin D3 ranging from 30,000 to 60,000 IU per day. All participants discontinued immunosuppressants, corticosteroids, biologics, and phototherapy during the study period, allowing for an isolated assessment of vitamin D3’s effects.
At baseline, 65 percent of patients were vitamin D deficient, with serum 25-hydroxyvitamin D 25(OH)D levels below 30 ng/mL. Within this group, almost 40 percent had levels under 20 ng/mL, representing severe deficiency.
Dosing was stratified by body weight: 30,000 IU per day for individuals between 60 and 75 kg and 40,000 IU per day for those above 75 kg. For patients with 25(OH)D below 20 ng/mL, a loading dose of 600,000 IU administered over ten days (60,000 IU per day) was used before transitioning to daily dosing in close similarity to the 600,000 IU loading dose used for episodic CH upon commencement of the anti-inflammatory regimen. Those with levels between 20 and 29 ng/mL received a 300,000 IU load across five days. Importantly, dosing was adjusted according to parathyroid hormone (PTH) suppression and ionised calcium values rather than 25(OH)D levels alone, a protocol designed to correct vitamin D resistance frequently observed in autoimmune conditions and a foundational premise of the Coimbra protocol.
Clinical Findings
After twelve months, mean PASI (Psoriasis Area and Severity Index) scores improved from 17.83 to 6.52, with 77 percent of participants achieving at least a 50 percent reduction and over 50 percent surpassing 75 percent improvement. Serum 25(OH)D concentrations rose above 100 ng/mL across the cohort, while PTH levels fell from a mean of 52.5 pg/mL to 32.5 pg/mL.
Ionised calcium remained within normal limits throughout, and no cases of hypercalcemia, renal dysfunction or vitamin D toxicity were observed, even in patients receiving up to 60,000 IU per day for several months. This outcome strongly reinforces that when therapy is guided by calcium and PTH monitoring, vitamin D3 can be administered safely at doses far above conventional recommendations.
Why This Matters to Cluster Headache Patients
For cluster headache sufferers using or exploring the Vitamin D3 Anti-Inflammatory Regimen, this study carries particular relevance. The loading protocol in Mahtani’s cohort, 600,000 IU over ten days for patients below 20 ng/mL, is nearly identical to the 600,000 IU loading schedule used in the cluster headache protocol for episodic CH.
However, the key difference lies in maintenance dosing. While the standard CH regimen typically prescribes 10,000 IU per day (or 50,000 IU per week), Mahtani’s patients required 25,000 to 45,000 IU per day on average, with some maintained at 50,000 IU per day for several months before tapering.
For CH patients, this context is highly reassuring. Doses between 10,000 and 20,000 IU per day, often perceived as “high,” are, in reality, modest compared to doses safely employed in other inflammatory diseases such as the Coimbra and LGS protocol. In the psoriasis cohort, even substantially higher doses produced no renal impairment when guided by PTH and calcium monitoring.
Reassessing “High” Doses
In the CH community, many patients are initially anxious about taking 10,000 IU per day, fearing it exceeds safe limits. Yet the Mahtani data make clear that 10,000 IU per day is at the lower end of an established therapeutic range for chronic inflammatory conditions. Even doses four to five times higher have been administered safely under appropriate laboratory oversight. For those with refractory CH who require escalation beyond 10,000 IU per day to achieve PTH suppression and sustained remission, this study provides strong, independent clinical evidence that such dosing can be physiologically tolerated long term.
Conclusion
Mahtani’s 2025 study represents a significant contribution to the broader understanding of vitamin D3’s therapeutic potential. It demonstrates that high-dose daily supplementation, when tailored by individual responsiveness rather than arbitrary limits, can be both effective and safe in chronic immune-mediated disease. For CH patients following the Vitamin D3 Anti-Inflammatory Regimen, it offers an additional layer of reassurance. Both the loading and maintenance strategies align closely with those used in psoriasis but at generally lower doses.
Rather than viewing 10,000 IU per day as excessive, regimen users can take confidence that this amount sits well within a physiologically validated range, and that even higher titrations, if needed for complete CH remission, are safe when done under medical supervision with the appropriate monitoring of labs.
Mahtani R., Singh S., Nair P. M., Singh S. P., Goyal M. (2025). Prolonged high dose daily oral vitamin D3 in the management of psoriasis: A retrospective chart analysis. IP Indian Journal of Clinical and Experimental Dermatology, 11(3), 288-296. https://doi.org/10.18231/j.ijced.89447.1758864688