Boswellia is often presented as a "natural", and therefore safe, alternative to painkillers. Clinical studies do indeed indicate generally good tolerability, but adverse reactions exist, and some of them require attention. The editorial team has gathered what is known about boswellia's undesirable effects, how often they occur and who should be more careful.
Overall safety profile
In randomized studies lasting from a few weeks to six months, the frequency of side effects in the boswellia groups was, as a rule, comparable to placebo. This conclusion is drawn both by the authors of the meta-analysis by Yu and colleagues (2020) and by review articles devoted to the anti-inflammatory properties of the resin.
However, it is worth understanding the limitations of these data. Most studies are small, do not last long and include selected patients without serious comorbidities. Rare reactions that occur in one case in thousands simply cannot be detected in such a design.
In addition, many different products are sold on the market: from raw resin to highly concentrated AKBA-enriched extracts and complexes with a dozen ingredients. The safety profile of a particular product may differ from what the studies of a single patented extract showed.
Therefore the editorial team suggests viewing boswellia's safety not as "absolute" but as "satisfactory given the available data" - taking into account the individual risk factors discussed below.
Gastrointestinal reactions
The most frequently described adverse effects concern the digestive tract: heartburn, a feeling of heaviness and discomfort in the epigastrium, nausea, and less often diarrhea or abdominal pain. In clinical studies these symptoms were mostly mild and did not require discontinuation.
Interestingly, unlike NSAIDs, boswellia in studies was not associated with stomach ulcers or gastrointestinal bleeding. This is attributed to the fact that boswellic acids do not inhibit cyclooxygenase-1, which maintains the protective mucus in the stomach.
Stomach symptoms can often be reduced by taking the supplement with food. This approach has an additional advantage: according to Sterk and colleagues (2004), food increases the absorption of boswellic acids.
If discomfort persists or worsens, the product should be discontinued and the symptoms discussed with a doctor, especially in the presence of a history of gastritis, peptic ulcer disease or reflux.
Allergy and skin reactions
Boswellia resin, like other plant resins, can cause allergic reactions. Cases of contact dermatitis have been described when frankincense-based products were applied to the skin, as well as itching and rashes when taken orally. People allergic to other plants of the Burseraceae family (for example, myrrh) may theoretically have cross-sensitivity.
Signs of allergy at which intake should be stopped immediately: rash, hives, swelling of the lips or face, difficulty breathing. The last two symptoms require emergency medical care.
Aromatherapy and fumigation with frankincense deserve a separate mention. Smoke from burning the resin contains particles and volatile compounds that can irritate the airways. This does not apply to extract capsules, but it is of practical importance for people with asthma.
| Type of reaction | Approximate frequency | What to do |
|---|---|---|
| Heartburn, nausea, abdominal discomfort | Most common group, usually mild | Take with food, discontinue if necessary |
| Diarrhea | Infrequent | Reduce or discontinue, drink enough water |
| Skin rash, itching | Rare | Discontinue, consult a doctor |
| Facial swelling, difficulty breathing | Isolated cases | Emergency care |
| Signs of liver injury | Isolated reports | Discontinue, liver function tests |
The frequencies in the table are given descriptively, since the studies do not have sufficient power for precise estimates, and post-marketing reports do not allow percentages to be calculated.
Liver and drug interactions
The LiverTox database of the US National Institutes of Health mentions isolated reports of liver injury associated with products containing boswellia. Establishing a causal relationship in such cases is difficult: they often involve multi-component supplements, and in some - possible impurities.
Nevertheless, the practical conclusion is clear: at the appearance of jaundice, darkening of the urine, itchy skin, marked weakness or pain in the right upper abdomen, intake should be stopped and tests taken. For people with liver diseases, the editorial team advises coordinating intake with a hepatologist.
As for interactions, laboratory studies (Frank and Unger, 2006) showed that extracts of different boswellia species can inhibit some cytochrome P450 enzymes that metabolize many drugs. How significant this is in the human body is unknown, but caution is appropriate.
Special attention should be paid to the combination with anticoagulants and antiplatelet agents, immunosuppressants, antiepileptic drugs and other medicines with a narrow therapeutic window. If you take any of these, tell your doctor about the supplement before starting to take it.
It is also not advisable to take several anti-inflammatory supplements and NSAIDs at the same time without supervision - even if each is relatively safe on its own, the combined effect and risks are hard to predict.
How to minimize risks
- Choose standardized extracts from manufacturers who publish the results of tests for heavy metals, microbiology and boswellic acid content.
- Start with the minimum dose studied in clinical work and take it with food.
- Do not exceed the dosage indicated on the label and do not combine several boswellia products at the same time.
- Tell your doctor about the intake if you take prescription drugs or have chronic diseases.
- Discontinue the supplement if a rash, jaundice or marked gastrointestinal symptoms appear.
Safety during pregnancy and breastfeeding has not been studied, so during these periods it is better to avoid boswellia supplements. For children there are also insufficient data.
The duration of intake in studies usually did not exceed six months. Little is known about the safety of continuous multi-year use, so it is reasonable to periodically assess whether the supplement provides real benefit.
For athletes undergoing doping control, a separate risk is supplement contamination. Certification by independent testing programs reduces, though does not completely eliminate, this risk.
Finally, joint pain can be a symptom of an injury or disease that requires diagnosis. A supplement should not delay a visit to the doctor.
Editorial conclusions
Boswellia in clinical studies was generally well tolerated: the most common side effects are mild gastrointestinal symptoms, which often decrease when taken with food.
Allergic reactions occur less often, and isolated reports of liver injury require attention to symptoms, especially in people with liver diseases.
Laboratory data on the effect on cytochrome P450 enzymes mean that when taking medications the supplement should be coordinated with a doctor.
We also advise you to read our materials "Who should not take Boswellia", "How to take Boswellia: dosage, timing, duration" and "Myths about Boswellia".
References
- Yu G, Xiang W, Zhang T, et al. Effectiveness of Boswellia and Boswellia extract for osteoarthritis patients: a systematic review and meta-analysis. BMC Complement Med Ther. 2020;20(1):225.
- Ammon HPT. Boswellic acids in chronic inflammatory diseases. Planta Med. 2006;72(12):1100–1116.
- Sterk V, Büchele B, Simmet T. Effect of food intake on the bioavailability of boswellic acids from a herbal preparation in healthy volunteers. Planta Med. 2004;70(12):1155–1160.
- LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Boswellia. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases.
- Frank A, Unger M. Analysis of frankincense from various Boswellia species with inhibitory activity on human drug metabolising cytochrome P450 enzymes using liquid chromatography mass spectrometry after automated on-line extraction. J Chromatogr A. 2006;1112(1–2):255–262.
- Kimmatkar N, Thawani V, Hingorani L, Khiyani R. Efficacy and tolerability of Boswellia serrata extract in treatment of osteoarthritis of knee – a randomized double blind placebo controlled trial. Phytomedicine. 2003;10(1):3–7.
- Sengupta K, Alluri KV, Satish AR, et al. A double blind, randomized, placebo controlled study of the efficacy and safety of 5-Loxin for treatment of osteoarthritis of the knee. Arthritis Res Ther. 2008;10(4):R85.
Andriy Melnyk
A strength-sports coach and author of programs for beginner and intermediate levels. Writes about training planning.
