From Open Evidence:
"The evidence for Boswellia in the treatment of symptomatic radiation necrosis is limited and primarily extrapolated from studies of its effect on cerebral edema in patients undergoing brain irradiation. The most relevant clinical data come from a prospective, randomized, placebo-controlled, double-blind pilot trial in which Boswellia serrata (4,200 mg/day) was administered to patients with primary or secondary malignant brain tumors during radiotherapy. In this study, Boswellia was associated with a significantly greater reduction in cerebral edema volume on MRI compared to placebo (reduction >75% in 60% of Boswellia-treated patients vs. 26% in placebo; P=0.023P=0.023). However, the study did not specifically enroll patients with established symptomatic radiation necrosis, and the reduction in dexamethasone requirement was not statistically significant. Adverse effects were mild, mainly gastrointestinal discomfort.[1]
Mechanistically, Boswellia and its boswellic acids have demonstrated anti-inflammatory and anti-edematous properties in preclinical models, including inhibition of leukotriene synthesis and modulation of cytokine production, which may be relevant to the pathophysiology of radiation necrosis.[2-5] However, pharmacokinetic limitations and questions about bioavailability remain unresolved.[2]
There are no major society guidelines (e.g., ASTRO, EANO) endorsing Boswellia for the treatment of symptomatic radiation necrosis, and its use should be considered investigational. Standard management remains corticosteroids, with consideration of bevacizumab or surgical intervention in refractory cases.
In summary, Boswellia has shown some efficacy in reducing cerebral edema in irradiated brain tumor patients, but direct evidence for its use in symptomatic radiation necrosis is lacking, and it is not recommended as standard therapy.[1-3]"
Also, in the Cancer (2011) clinical trial cited above, here is what the authors had to say about their Boswellia sourcing:
"BS product H15 (350 mg; Hecht Pharma, Stinstedt, Germany) was selected for use in the study. H15 does not contain any other ingredients apart from BS. The capsules were bought by the pharmacy of the University Hospital Freiburg. Lot numbers of the product were exactly listed."
This is NOT the same as picking it up in your local GNC.