Written by Alexa Heathorn, CNS, Science Writer. A network meta-analysis of 20 randomized controlled trials found that enhanced bioavailability formulations of Boswellia serrata and Curcuma longa significantly improved pain, stiffness, and knee function in individuals with knee osteoarthritis, with modified boswellia formulations showing the most consistent functional benefits and no significant increase in adverse effects.

Knee osteoarthritis (KOA) is a degenerative joint disease characterized by progressive cartilage breakdown, chronic pain, and declining joint function.¹ It is a major global health burden, affecting more than 500 million individuals worldwide and contributing to reduced quality of life, disability, and rising healthcare costs.¹˒² Conventional treatments—including nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, and analgesics—can provide symptom relief but are often limited by gastrointestinal, cardiovascular, hepatic, and renal adverse effects associated with long-term use.¹ As a result, interest in herbal therapies has grown as patients seek safer and more natural approaches for managing KOA symptoms.¹

Several herbal extracts have been studied for their potential to reduce symptoms of KOA, including Curcuma longa (CL), Boswellia serrata (BS), Zingiber officinale, Withania somnifera, and Pistacia atlantica.¹ Among these, curcumin and boswellia have demonstrated particularly promising results, with previous studies and meta-analyses reporting significant improvements in pain and joint function compared to placebo, along with fewer gastrointestinal adverse effects than NSAIDs.¹

Despite these findings, direct comparisons between CL, BS, and their combined formulations remain limited.¹ To address this gap, a systematic review and network meta-analysis was conducted to evaluate the efficacy and safety of CL, BS, and their combined formulations in patients with KOA using data from randomized controlled trials (RCTs).¹

The network meta-analysis included 20 randomized controlled trials comprising 1,633 participants with knee osteoarthritis.¹ The analysis compared the effects of Curcuma longa (CL), modified Curcuma longa formulations (CLM), Boswellia serrata (BS), modified Boswellia serrata formulations (BSM), and combined formulations using both direct and indirect evidence.¹ Pain and functional outcomes were assessed using the Visual Analog Scale (VAS) and the Western Ontario and McMaster Universities Arthritis Index (WOMAC).¹

The modified formulation of Curcuma longa (CLM) demonstrated a significant reduction in pain on the VAS compared to placebo (SMD: −2.82; 95% CI: −5.30 to −0.33).¹ Modified formulations of Boswellia serrata (BSM) showed the greatest improvements in WOMAC pain, stiffness, and knee function scores compared to other intervention groups.¹ No significant differences in adverse events were observed between treatments and placebo.¹

The findings suggest that enhanced formulations designed to improve bioavailability may substantially influence therapeutic outcomes.¹ Mechanistically, boswellia extracts may support joint health through anti-inflammatory effects and promotion of chondrocyte-protective pathways involved in cartilage maintenance.¹ Combination products containing both CL and BS did not demonstrate superior efficacy compared to individual extracts.¹

Several limitations should be considered when interpreting these findings. The included trials showed considerable variability in participant characteristics, disease severity, treatment duration, dosing, and formulation type, which may influence treatment effects and limit direct comparability between studies.¹ In particular, enhanced bioavailability formulations differed substantially from conventional extracts, making dose equivalency difficult to determine.¹

Another important limitation is the limited evidence available for combined formulations of Curcuma longa and Boswellia serrata, with only one randomized controlled trial evaluating each combination type.¹ This restricts the ability to draw strong conclusions regarding potential synergistic effects between the two herbs.¹

Additionally, some analyses suggested possible small-study effects and publication bias, particularly for VAS pain outcomes involving modified curcumin formulations.¹ While overall adverse events were low, many studies were relatively short in duration, limiting understanding of long-term efficacy and safety.¹

This network meta-analysis suggests that both Curcuma longa and Boswellia serrata may provide meaningful benefits for individuals with knee osteoarthritis, particularly when delivered in enhanced formulations designed to improve bioavailability.¹ Modified boswellia formulations (BSM) demonstrated the strongest and most consistent improvements in joint pain, stiffness, and function, while modified curcumin formulations (CLM) showed notable pain-reducing effects.¹

These benefits are likely driven by anti-inflammatory and antioxidant mechanisms involving pathways such as NF-κB, COX-2, and 5-LOX, along with potential protective effects on cartilage health.¹ Importantly, both herbs demonstrated favorable safety profiles with no significant increase in adverse events compared to placebo.¹ However, additional high-quality trials are needed to better understand long-term outcomes and the potential synergistic effects of combined formulations.¹

Source: Inprasit, Chanya, Siriwadee Bunyamahote, Kansak Boonpattharatthiti, Phiyanuch Thimkorn, Suwipa Intakhiao, and Teerapon Dhippayom. “Evaluating the efficacy and safety of Curcuma longa, Boswellia serrata, and their mixed formulation in treating knee osteoarthritis: A systematic review and network meta-analysis.” Complementary therapies in medicine 96 (2026): 103256.

© 2025 The Authors

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Posted May 19, 2026.

Alexa Heathorn, MS, CNS-c, is a clinical nutritionist specializing in metabolic health, hormonal balance, and gastrointestinal restoration through root-cause functional nutrition. She earned her master’s degree in Nutrition from Bastyr University and is currently a Certified Nutrition Specialist (CNS) candidate. Alexa also works as a research writer and functional health consultant, translating complex science into actionable strategies for practitioners and wellness companies. Learn more at www.bloomedwellness.com.

References:

1. Bannuru RR, Osani MC, Al-Eid F, Wang C. Efficacy of curcumin and Boswellia for knee osteoarthritis: Systematic review and meta-analysis. Semin Arthritis Rheum. 2018;48(3):416-429. doi:10.1016/j.semarthrit.2018.03.001
2. Hsu H, Siwiec RM. Knee Osteoarthritis. [Updated 2023 Jun 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK507884/