Bromelain

What it is

Bromelain is not a single substance but a mixture of several protein-splitting enzymes, so-called cysteine proteases. It is obtained mainly from the stem of the pineapple plant. Its activity is stated in F.I.P. units, not in milligrams – two preparations with the same number of milligrams can therefore differ in strength.

Bromelain has two lives. As a tablet it is swallowed, against swelling and inflammation. As a gel on the skin it is used in burn medicine to dissolve dead tissue. This topical form is approved in the EU under the name NexoBrid, and since 2022 also in the US. For you as a supplement user, only the swallowed form is relevant; the burn data cannot be transferred.

In Germany, bromelain is available as an approved medicine. The summary of product characteristics lists as its indication the supportive treatment of acute swelling after surgery and injuries, especially of the nose and sinuses. It is also sold as a dietary supplement.

How it is supposed to work

For a long time the objection was that an enzyme is simply digested in the gut. For bromelain this is only partly true. The systematic review by Leelakanok and colleagues summarizes work according to which bromelain is detectable in serum after swallowing and retains its protein-splitting activity. The German summary of product characteristics describes concentrations in the picomolar range, bound to a transport protein in the blood. That is not much, but something does arrive.

What happens after that has mostly been studied in cell culture and in animal models. There, bromelain slows pro-inflammatory messengers and acts on blood clotting by breaking down fibrin and inhibiting platelets. The idea behind it: if less protein and fluid is retained in the tissue after an injury, the swelling goes down faster. This step has not been measured directly in humans, only via the outcome – less pain, sometimes less swelling.

What bromelain is used for

The classic use is after surgery in the jaw and face area. There are several dedicated meta-analyses on wisdom tooth surgery, which is unusually many for a plant enzyme. It is also used after procedures on the nose and sinuses, which is where the approval comes from.

In the biohacking scene, bromelain is taken more as a general anti-inflammatory, against joint complaints or for faster recovery after training. For these uses the data are considerably thinner; more on this below. Bromelain is also frequently contained in combination products, for example with trypsin and rutoside or with plant extracts. Studies with such mixtures say little about bromelain alone.

What the studies show

Meta-analysis 2023: all areas of use

Leelakanok and colleagues analyzed 54 papers, 39 of them quantitatively, with literature up to August 2022. Orally taken bromelain lowered the pain score by 0.27 points compared with control, measured in 9 studies with low heterogeneity. For sinusitis the authors saw a possible benefit, for cardiovascular disease none. Applied topically, bromelain shortened the time to complete removal of dead tissue by 6.89 days.

Meta-analysis 2019: wisdom tooth surgery

Liu and colleagues pooled 6 randomized, placebo-controlled studies after lower wisdom tooth surgery. Swelling was lower both after 2 to 3 days and after 7 days, pain only after 7 days. Bromelain had no measurable influence on trismus, that is, restricted mouth opening.

Knee osteoarthritis 2006: endpoint missed

Brien and colleagues gave 47 people with moderate to severe knee osteoarthritis 800 mg bromelain daily or placebo for 12 weeks, double-blind. For the primary endpoint, the WOMAC total score for pain, stiffness and function, there was no significant difference. Only 31 participants completed the study; the authors therefore consider a larger follow-up study necessary.

Muscle soreness 2002: no effect, not even for ibuprofen

Stone and colleagues deliberately induced muscle soreness in the upper arm in 40 volunteers without upper-body training. Participants received 300 mg bromelain 3 times daily, 400 mg ibuprofen 3 times daily, placebo or nothing. Over 96 hours, pain, range of motion and strength did not differ between any of the groups.

Where the data stop

On swelling after dental surgery, the meta-analyses contradict each other. Liu 2019 and de Souza 2019 find less swelling; Almeida 2019 and Mendes 2019 find no effect. This is due to a few small studies that are pooled differently depending on the selection. For pain the picture is more stable than for swelling – even though swelling is what bromelain is approved for.

For osteoarthritis there is only one placebo-controlled study, and it missed its goal. A second study with 40 patients found no difference from diclofenac after 4 weeks, but was only single-blind and had no placebo group. For muscle soreness, the only study with pure bromelain is the one from 2002, without effect. For sinusitis, the US health agency NCCIH considers the research insufficient for a recommendation; the German study with 12 patients was open-label and without a control group. No study ran longer than 16 weeks, and many papers test combination products instead of bromelain alone.

Status, approval and legal

In Germany, bromelain is approved as a medicine, for example with 500 F.I.P. units per gastro-resistant tablet. According to the summary of product characteristics, adults and adolescents from 12 years take 1 tablet 1 to 2 times daily, half an hour before meals, and not for longer than 4 to 5 days without medical advice. In parallel, bromelain is sold as a dietary supplement, then without these details. The topical form NexoBrid is approved in the EU and, since 2022, in the US for the treatment of severe burns. For competitive athletes, the general advice of the German National Anti Doping Agency applies: dietary supplements can be contaminated; the Cologne List offers orientation but no guarantee.

Safety

Swallowed, bromelain is generally well tolerated; the most common complaints are upset stomach and diarrhea. The summary of product characteristics lists allergic reactions such as skin rash or asthma-like complaints as common; anyone allergic to pineapple should avoid it. More important is blood clotting: bromelain can prolong bleeding time. According to the summary of product characteristics, it must not be used in clotting disorders or together with blood thinners or platelet inhibitors, and it is stopped as a precaution before surgery. It also raises the blood levels of some antibiotics. It is not recommended for pregnant women, and breastfeeding women should not take it. No liver abnormalities are known. There is no official upper limit from EFSA or BfR.

Sources

• Leelakanok et al., Nutr Health 2023 – meta-analysis on efficacy and safety
• Liu et al., J Oral Maxillofac Surg 2019 – meta-analysis, wisdom tooth surgery
• de A C Almeida et al., Int J Oral Maxillofac Surg 2019 – meta-analysis, wisdom tooth surgery
• Mendes et al., Med Oral Patol Oral Cir Bucal 2019 – meta-analysis, wisdom tooth surgery
• Brien et al., QJM 2006 – knee osteoarthritis, placebo-controlled
• Kasemsuk et al., Clin Rheumatol 2016 – knee osteoarthritis versus diclofenac
• Stone et al., Clin J Sport Med 2002 – muscle soreness, bromelain versus ibuprofen
• Summary of product characteristics (Fachinformation) Bromelain-POS, June 2018
• NCCIH, Bromelain