Avocado and Soybean Print Page

Common Names: avocado, alligator pear, soy, soybean, ASU
Scientific Names: avocado (Persea americana), soybean (Glycine max)

Bottom Line

Effectiveness: Avocado/soybean unsaponifiable oil (ASU) may modestly improve pain and functionality in knee and hip OA in the short term (2-3 months) but does not seem to maintain this benefit over the long term (2-3 years).

Safety:  Likely safe when used orally at appropriate doses for up to 3 years. Long term safety unknown.

What are avocado and soybean?

  • Avocado is a dark green berry fruit with a single large seed native to Mexico and Central America.
  • Soybean is a legume plant native to East Asia. Its beans are used to make tofu, soy milk, and soy-based foods.
  • Both avocado and soybean are high in nutrients.

What are they used for in people with rheumatic conditions?

  • Combination of avocado and soybean unsaponifiable (ASU) oils may be beneficial in the management of osteoarthritis (OA).

How is it thought to work?

  • Some studies suggest that avocado/soybean oils can increase collagen growth, reduce joint space narrowing, and reduce production of substances that increase inflammation.

Does it Work? What the Science Says:

ASU 300mg/day

  • A short-term study demonstrated that taking ASU 300-600mg/day for 3 months significantly reduced the dose of NSAID needed (~150mg to 50mg diclofenac vs. ~130 to 80mg in placebo arm) in patients with knee OA. 
  • Another study comparing ASU 300mg/day to placebo for 6 months in knee and hip OA found ASU improved baseline pain on VAS (37 vs. 18%) and functionality measured by Lequesne Functional Index (30 vs. 5%, p<0.05)
  • However, longer-term study (2 years and 3 years) did not show any benefit of ASU in reducing joint space loss or in pain and function in patients with mild hip OA. Adverse events in ASU group were not statistically different from placebo group.
  • Well-conducted studies are limited. 
  • ASU may improve symptoms of OA and reduce NSAID use.
  • May be worth trying for 4-8 weeks. 
  • More long-term trials are needed

What are possible side effects and what can I do about them?

  • ASU is generally well tolerated when taken orally at appropriate doses. Stomach upset, nausea/vomiting, headaches, and migraine have also been reported. 
  • Patients allergic to avocado or soybean should avoid ASU. 
  • Allergic reactions have been reported in with latex sensitivity ingesting avocado. Take ASU with caution.


With drugs:

  • Based on case reports, avocado and soymilk may decrease the anticoagulant effect of warfarin, which would increase risk of blood clot. It is unknown if ASU would similar results lose monitoring of INR may be in patient starting or stopping ASU.


For more information about ASU, consult your physician and pharmacist.



(1) Appelboom T, Schuermans J, Verbruggen G, Henrotin Y, Reginster JY. Symptoms modifying effect of avocado/soybean unsaponifiables (ASU) in knee osteoarthritis. A double blind, prospective, placebo-controlled study. Scand J Rheumatol 2001;30(4):242-247.

(2) Blotman F, Maheu E, Wulwik A, Caspard H, Lopez A. Efficacy and safety of avocado/soybean unsaponifiables in the treatment of symptomatic osteoarthritis of the knee and hip. A prospective, multicenter, three-month, randomized, double-blind, placebo-controlled trial. Rev Rhum Engl Ed 1997 Dec;64(12):825-834.

(3) Lequesne M, Maheu E, Cadet C, Dreiser RL. Structural effect of avocado/soybean unsaponifiables on joint space loss in osteoarthritis of the hip. Arthritis Rheum 2002 Feb;47(1):50-58.

(4) Maheu E, Mazieres B, Valat JP, Loyau G, Le Loet X, Bourgeois P, et al. Symptomatic efficacy of avocado/soybean unsaponifiables in the treatment of osteoarthritis of the knee and hip: a prospective, randomized, double-blind, placebo-controlled, multicenter clinical trial with a six-month treatment period and a two-month followup demonstrating a persistent effect. Arthritis Rheum 1998 Jan;41(1):81-91.

(5) Natural Medicine Comprehensive Database

(6) Natural Standard


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