Benefits
Knee joint comfort and physical function
In a 90-day double-blind trial in 75 adults with knee osteoarthritis, 250 mg a day improved pain, stiffness and function scores more than placebo, while 100 mg improved pain scores but not the WOMAC stiffness or function scores. In a second 90-day trial in 60 adults, 100 mg beat placebo on pain and stiffness but not on function, and Aflapin did better. Both trials were run by the maker.
Joint stiffness and ease of movement
Stiffness was scored with the WOMAC questionnaire. It improved more than with placebo on 250 mg in the first trial and on 100 mg in the second, but not on 100 mg in the first. All participants had knee osteoarthritis; no study has tested whether the extract eases everyday stiffness in people without arthritis.
A cartilage-related lab marker
The first trial reported lower levels of matrix metalloproteinase-3 (MMP-3), an enzyme involved in cartilage breakdown, in joint (synovial) fluid. That is a laboratory marker, not a measure of the joint itself. No study has imaged the joint or otherwise shown that 5-Loxin protects cartilage.
Mechanism of action
5-LOX inhibition
In laboratory research, AKBA inhibits the 5-lipoxygenase enzyme, which lowers production of inflammatory messengers called leukotrienes. This is the proposed explanation for the trial results; leukotrienes were not measured in the human trials.
Change in a cartilage-related enzyme
One trial reported lower MMP-3, an enzyme linked to cartilage breakdown, in joint fluid. Whether that translates into any real protection of joint cartilage over time has not been shown.
Clinical trials
Double-blind randomized placebo-controlled trial of 5-Loxin 100 mg or 250 mg a day for 90 days, with pain and function scored on VAS, Lequesne and WOMAC scales. Run at and funded by Laila Impex R&D Center, the maker's research arm. (Sengupta et al. 2008, Arthritis Res Ther)
75 adults with knee osteoarthritis (25 per group); 70 finished.
Both doses improved pain scores more than placebo, and 250 mg also improved WOMAC stiffness and function scores, with gains from day 7. With 100 mg, WOMAC stiffness and function were not significantly better than placebo. MMP-3, a cartilage-degrading enzyme, was lower in joint fluid. Minor side effects were spread evenly across groups. This trial has not been repeated by an independent group.
Double-blind randomized placebo-controlled trial of 5-Loxin 100 mg, Aflapin 100 mg (a different boswellia extract from the same company) or placebo daily for 90 days. Led by researchers at Laila Impex R&D Center; the paper declared no conflict of interest. (Sengupta et al. 2010, Int J Med Sci)
60 adults with knee osteoarthritis (20 per group); 57 finished.
In the full paper, 100 mg 5-Loxin did better than placebo on VAS pain, WOMAC pain and WOMAC stiffness, but its gains on the Lequesne index and WOMAC function were not statistically significant, although the abstract reports function gains for both extracts. Aflapin improved every measure and did better than 5-Loxin. Safety measures were almost unchanged compared with placebo. Only 20 people took 5-Loxin.