The studies included a total of 1,313 adults, with average ages that rangied from 48 to 66.

The primary outcome was pain as measured on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), a validated questionnaire for assessing osteoarthritis pain.

The turmeric extracts were divided into 3 categories:

Conventional: Turmeric extract that contained curcuminoids like curcumin. This form was tested in 4 studies.
Bioavailable: Turmeric extract (often curcumin specifically) with enhanced bioavailability due to added piperine or using delivery systems like micelles, phytosomes, and liposomes. This form was tested in 11 studies.
Polysaccharide: A water-soluble formulation of turmeric polysaccharides, without curcumin. This form was tested in 2 studies.

The studies compared turmeric supplements to a placebo and to standard medication or compared turmeric supplements plus medication to medication alone. The medication taken was often acetaminophen (paracetamol) or nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil).

Both the conventional and bioavailable turmeric supplements improved knee pain according to the WOMAC, but only bioavailable turmeric supplements improved knee pain to a clinically significant degree (30% improvement in knee pain; a 20% improvement is considered clinically significant).

All 3 of the turmeric supplements — conventional, bioavailable, and polysaccharide — improved knee pain as assessed using a visual analog scale (VAS).

Both the conventional and bioavailable turmeric supplements improved knee function. None of the supplements improved joint stiffness.

The effect of different types of turmeric extract on knee osteoarthritis

*Based on a more than 20% reduction in WOMAC index scores.

The best type of turmeric extract for knee osteoarthritis Original paper