In plain terms: Boswellia serrata has some human trial evidence supporting it, but the evidence is not yet strong enough for EBL to call it established. It is worth knowing about and worth discussing with your clinician.
Boswellia serrata
The evidence as the record states it
Yu et al. (BMC Complementary Medicine and Therapies, 2020; PMID 32680575) and Liu et al. (2018 meta-analysis; PMID 29018060): meta-analyses of randomized trials: Boswellia serrata extract, alone in 3 of the 7 trials Yu pooled and combined with other agents in 4, improved osteoarthritis pain and function. Grade B: replicated randomized evidence on symptom endpoints; the trials are small and of medium to low quality.
Why Grade B and not Grade A
Grade B reflects moderate human evidence -- typically a single strong trial, multiple smaller trials, or surrogate endpoint data without hard clinical outcome replication. To reach Grade A, Boswellia serrata would require at least one additional independent randomized trial demonstrating a hard clinical endpoint or objectively measured functional outcome in a comparable population.
What would move this grade
An independent randomized trial demonstrating a hard clinical endpoint -- mortality, major adverse event, or objectively confirmed functional improvement -- in an adequately powered sample, with results independently replicated, would support Grade A.
How this was studied
Form: Oral Boswellia serrata extracts, mostly standardized branded extracts (Aflapin, 5-Loxin) or boswellic acid; four of the seven pooled trials gave Boswellia combined with another agent (curcuminoids, Elaeagnus extract, or methylsulfonylmethane) (Yu 2020, PMID 32680575). · Dose: Extract trials used 100 mg or 250 mg per day (Aflapin or 5-Loxin); combination trials used boswellic acid 150 mg with curcuminoids 350 mg, or boswellic acid 7.5 to 15 mg with methylsulfonylmethane 5,000 to 10,000 mg (Yu 2020, PMID 32680575). · Population: Adults with knee osteoarthritis, 545 patients in 7 trials from India, Armenia, Iran and Italy, mean ages about 52 to 63 years, with trial entry ages of 40 to 85 years (Yu 2020, PMID 32680575). Liu 2018 pooled hand, hip or knee osteoarthritis trials and included three Boswellia trials (Liu 2018, PMID 29018060; trial count from Yu 2020 full text). · Duration: 4 to 24 weeks (4 weeks in two trials, 12 weeks in three, 24 weeks in two) (Yu 2020, PMID 32680575). Liu 2018 found large effects for Boswellia extract only at short term, and no supplement showed clinically important pain effects at long term (Liu 2018, PMID 29018060).