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Avocado/Soybean Unsaponifiables

Common Name(s): A1S2, Arthrocen, ASU, Avocado/soybean unsaponifiables, Piascledine

Medically reviewed by Last updated on Nov 30, 2022.

Clinical Overview


Clinical studies are largely supportive of a place in therapy for avocado/soybean unsaponifiables (ASU) in the treatment of osteoarthritis due to its anti-inflammatory properties; however, due to methodological limitations and sponsorship bias among trials and a lack of radiographic evidence, ASU cannot be recommended for this indication.


Dosages of ASU 300 or 600 mg/day (typical duration, 6 months) have been studied for the treatment of osteoarthritis.


Contraindications have not been identified.


Information regarding efficacy and safety of ASU during pregnancy and lactation is lacking. Avocado fruit and soybean are both considered generally recognized as safe (GRAS) when used as food.


None well documented.

Adverse Reactions

No clinically important adverse effects have been reported. Infrequent mild GI complaints have been documented in reviews, at a similar rate to the comparator or placebo.


No data.

Scientific Family


ASU is derived from avocado (Laurus persea L. or Persea americana Mill.) and soy (Glycine max L. Merr.) plants (see individual Avocado and Soy monographs).


Clinical studies evaluating ASU, primarily conducted by French researchers, first appeared in the literature in the 1970s. Published findings remained limited to a few groups of researchers. Interest in veterinary applications has been growing.Henrotin 2005, Henrotin 1998, Kawcak 2007 ASU has been studied in in vitro and in vivo animal models of experimental arthrosis. A commercial ASU product (Piascledine) has been widely used in Europe (eg, France) for osteoarthritis and has been evaluated as an alternative or adjunctive therapy to standard nonsteroidal anti-inflammatory drugs (NSAIDs).Frondoza 2018, Gluszko 2016, Henroitin 2017


ASU is made up of unsaponifiable fractions of avocado and soybean extracts.Gluszko 2016 Portions of avocado and soybean oils (approximately 1%) are unsaponifiable (ie, cannot be hydrolyzed or made into soap), and are combined to form ASU, generally in a ratio of 1:2 (one-third avocado and two-thirds soybean unsaponifiables).Christiansen 2015, Gluszko 2016, Henrotin 1998, Lippiello 2008 Other ratios of avocado:soybean unsaponifiables have been evaluated.Henrotin 1998

The major components of ASU are the phytosterols beta-sitosterol, campesterol, and stigmasterol, as well as saturated hydrocarbons, squalene, tocopherols, and alcohols.Henrotin 1998, Lippiello 2008

Uses and Pharmacology

Anti-inflammatory effects

Animal and in vitro data

Anti-inflammatory effects have been demonstrated in vitro and in animal studies.(Al-Afify 2018, Christensen 2008, Goudarzi 2018, Henrotin 1998, Kawcak 2007, Lippiello 2008, Oliveira 2016) Several possible mechanisms of action have been described.(Frondoza 2018, Gluszko 2016, Henrotin 2017)

In a murine model of osteoarthritis of the knee, ASU 27.5 mg/kg administered orally daily for 3 weeks attenuated degeneration of the synovium, cartilage, and subchondral bone, as well as decreased the expression of inflammatory mediators such as tumor necrosis factor alpha and matrix metalloproteinase-13, suggesting beneficial structural modifying effects in osteoarthritis.(Al-Afify 2018, Ernst 2003) Additionally, in a rat model of arthritis, ASU administration improved osseointegration, as measured by bone-to-implant contact and bone area between the threads.(dePaula 2018)

In a small study in horses (N=16) with induced osteoarthritis, ASU supplementation did not improve outcomes of pain or lameness; however, the researchers reported reductions in the severity of articular cartilage erosion and synovial hemorrhage, as well as increased articular cartilage glycosaminoglycan synthesis.(Kawcak 2007)

Clinical data

Clinical studies largely support a role for ASU in the treatment of osteoarthritis, due to its anti-inflammatory effects; however, methodological limitations and sponsorship bias exist among studies.(Christiansen 2015, Cornblatt 2016, Ernst 2003) Pain reduction has been reported; however, effectiveness of ASU on structural disease-modifying properties have not been confirmed by radiographic evidence in independent trials.

In a meta-analysis of 4 industry-funded clinical trials conducted prior to 2002 (664 patients with knee and/or hip osteoarthritis), supplemental ASU resulted in improvements in pain scores and functional indices, especially in those with osteoarthritis of the knee.(Christiansen 2008, Ernst 2003)

Further studies similarly report improvements in pain and function. A 6-month multicenter clinical study comparing ASU (ie, Piascledine) with chondroitin in patients with osteoarthritis of the knee (N=364) suggests equivalent efficacy, with decreases in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Lequesne Index scores noted for both groups. No adverse effects were documented in the study.(Pavelka 2010)

A 3-year, industry-sponsored clinical trial in patients with hip osteoarthritis (N=399) receiving ASU 300 mg/day or placebo suggested a protective effect on the joint with ASU therapy, as measured by change in joint space width over the length of the trial. A lower rate of progression (deterioration) was found in the ASU group (40% vs 50%; P=0.04), but no difference in mean joint space width loss was determined. No differences were found for secondary outcomes of Lequesne Index score, WOMAC pain score, or analgesic or NSAID use.(Maheu 2014)

In an open-label study of 4,822 patients with knee osteoarthritis, the effects of ASU 300 mg daily for 6 months were assessed. The proportion of patients taking NSAIDs or other analgesics decreased from 58.8% at baseline to 24.9% after 6 months of therapy (P<0.001). Additionally, functional impairment, as measured using the Lequesne index, significantly improved from baseline to the final visit (median decrease in score from 8 to 4 points [P<0.001]). ASU was also associated with a significant improvement from baseline in pain intensity (P<0.001).(Gluszko 2016)

In a 6-month clinical study evaluating ASU 300 mg daily versus placebo in patients with osteoarthritis of the temporomandibular joint (N=14), decreases in pain and use of rescue analgesic medication were reported among those receiving ASU.(Catunda 2016)

The European League Against Rheumatism's updated recommendations for the management of hand osteoarthritis (2018) indicated that no evidence for clinical efficacy exists for use of avocado-soybean unsaponifiables.(Kloppenburg 2018)

Antimicrobial effects

Animal data

Coadministration of ASU with praziquantel increased elimination of Schistosoma mansoni in mice.(Soliman 2012)

Metabolic syndrome

Clinical data

ASU did not modify insulin sensitivity in a small clinical study of obese adults (N=7).(Martinez-Abundis 2013)

Wound healing

Animal data

A study in rats suggests anti-inflammatory effects of ASU may be responsible for observed increased collagen synthesis and decreased inflammation during wound healing.(de Oliveira 2013, Oryan 2015)


ASU (eg, Piascledine) dosages of 300 or 600 mg/day (typical duration, 6 months) have been studied for the treatment of osteoarthritis (eg, osteoarthritis of the knee, hip, or temporomandibular joint).Catunda 2016, Gluszko 2016, Maheu 2014, Pavelka 2010

Pregnancy / Lactation

Information regarding use of ASU during pregnancy and lactation is lacking. Avocado fruit and soybean are both considered GRAS when used as food.


None well documented.

Adverse Reactions

No clinically important adverse effects have been reported in clinical studies.Catunda 2016, Pavelka 2010 Infrequent mild GI complaints have been documented in reviews, at a similar rate to the comparator or placebo.Christensen 2008, Ernst 2003 In a safety meta-analysis, the adverse effect profile of ASU was similar to that of placebo.Honvo 2019


Information is limited. A lack of short-term toxicity was reported in in vitro studies of unsaponifiable mixtures.Henrotin 1998 See individual Avocado and Soy monographs.



This information relates to an herbal, vitamin, mineral or other dietary supplement. This product has not been reviewed by the FDA to determine whether it is safe or effective and is not subject to the quality standards and safety information collection standards that are applicable to most prescription drugs. This information should not be used to decide whether or not to take this product. This information does not endorse this product as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this product. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this product. This information is not specific medical advice and does not replace information you receive from your health care provider. You should talk with your health care provider for complete information about the risks and benefits of using this product.

This product may adversely interact with certain health and medical conditions, other prescription and over-the-counter drugs, foods, or other dietary supplements. This product may be unsafe when used before surgery or other medical procedures. It is important to fully inform your doctor about the herbal, vitamins, mineral or any other supplements you are taking before any kind of surgery or medical procedure. With the exception of certain products that are generally recognized as safe in normal quantities, including use of folic acid and prenatal vitamins during pregnancy, this product has not been sufficiently studied to determine whether it is safe to use during pregnancy or nursing or by persons younger than 2 years of age.

Al-Afify ASA, El-Akabawy G, El-Sherif NM, El-Safty FEA, El-Habiby MM. Avocado soybean unsaponifiables ameliorates cartilage and subchondral bone degeneration in mono-iodoacetate-induced knee osteoarthritis in rats. Tissue Cell. 2018;52:108-115.29857819
Catunda IS, Vasconcelos BC, Andrade ES, Costa DF. Clinical effects of an avocado-soybean unsaponifiable extract on arthralgia and osteoarthritis of the temporomandibular joint: preliminary study. Int J Oral Maxillofac Surg. 2016;45(8):1015-1022.27026059
Christensen R, Bartels EM, Astrup A, Bliddal H. Symptomatic efficacy of avocado-soybean unsaponifiables (ASU) in osteoarthritis (OA) patients: a meta-analysis of randomized controlled trials. Osteoarthritis Cartilage. 2008;16(4):399-408.18042410
Christiansen BA, Bhatti S, Goudarzi R, Emami S. Management of osteoarthritis with avocado/soybean unsaponifiables. Cartilage. 2015;6:30-44.
Cornblatt, BS. Letter to the editor for "management of osteoarthritis with avocado/soybean unsaponifiables". Cartilage. 2016;7(1):112-113.26958323
de Oliveira AP, Franco Ede S, Rodrigues Barreto R, et al. Effect of semisolid formulation of Persea americana mill (avocado) oil on wound healing in rats. Evid Based Complement Alternat Med. 2013;2013:472382.23573130
de Paula LGF, Lopes de Oliveira GJP, Pinotti FE, Grecchi BB, de Aquino SG, Chiérici Marcantonio RA. Effect of avocado/soybean unsaponifiables (ASU) on osseointegration in rats with experimental arthritis. Int J Oral Maxillofac Implants. 2018;33(3):603-612.29763498
Ernst E. Avocado-soybean unsaponifiables (ASU) for osteoarthritis—a systematic review. Clin Rheumatol. 2003;22(4-5):285-288.14576991
Frondoza CG, Fortuno LV, Grzanna MW, Ownby SL, Au AY, Rashmir-Raven AM. α-Lipoic acid potentiates the anti-inflammatory activity of avocado/soybean unsaponifiables in chondrocyte cultures. Cartilage. 2018;9(3):304-312.29156944
Głuszko P, Stasiek M. Symptom-modifying effects of oral avocado/soybean unsaponifiables in routine treatment of knee osteoarthritis in Poland. An open, prospective observational study of patients adherent to a 6-month treatment. Reumatologia. 2016;54(5):217-226.27994265
Goudarzi R, Reid A, McDougall JJ. Evaluation of the novel avocado/soybean unsaponifiable Arthrocen to alter joint pain and inflammation in a rat model of osteoarthritis. PLoS One. 2018;13(2):e0191906.29489828
Henrotin Y, Sanchez C, Balligand M. Pharmaceutical and nutraceutical management of canine osteoarthritis: present and future perspectives. Vet J. 2005;170(1):113-123.15993795
Henrotin YE. Avocado/soybean unsaponifiables (Piacledine 300) show beneficial effect on the metabolism of osteoarthritic cartilage, synovium and subchondral bone: An overview of the mechanisms. AIMS Medical Science. 2017;5(1):33-52.
Henrotin YE, Labasse AH, Jaspar JM, et al. Effects of three avocado/soybean unsaponifiable mixtures on metalloproteinases, cytokines and prostaglandin E2 production by human articular chondrocytes. Clin Rheumatol. 1998;17(1):31-39.9586676
Honvo G, Reginster JY, Rabenda V, et al. Safety of symptomatic slow-acting drugs for osteoarthritis: Outcomes of a systematic review and meta-analysis. Drugs Aging. 2019;36(suppl 1):S65-S99.31073924
Kawcak CE, Frisbie DD, McIlwraith CW, Werpy NM, Park RD. Evaluation of avocado and soybean unsaponifiable extracts for treatment of horses with experimentally induced osteoarthritis. Am J Vet Res. 2007;68(6):598-604.17542691
Kloppenburg M, Kroon FP, Blanco FJ, et al. 2018 update of the EULAR recommendations for the management of hand osteoarthritis. Ann Rheum Dis. 2019;78(1):16-24. doi:10.1136/annrheumdis-2018-21382630154087
Lippiello L, Nardo JV, Harlan R, Chiou T. Metabolic effects of avocado/soy unsaponifiables on articular chondrocytes. Evid Based Complement Alternat Med. 2008;5(2):191-197.18604259
Maheu E, Cadet C, Marty M, et al. Randomised, controlled trial of avocado-soybean unsaponifiable (Piascledine) effect on structure modification in hip osteoarthritis: the ERADIAS study. Ann Rheum Dis. 2014;73(2):376-384.23345601
Martínez-Abundis E, González-Ortiz M, Mercado-Sesma AR, Reynoso-von-Drateln C, Moreno-Andrade A. Effect of avocado soybean unsaponifiables on insulin secretion and insulin sensitivity in patients with obesity. Obes Facts. 2013;6(5):443-448.24135894
Oliveira GJ, Paula LG, Souza JA, Spin-Neto R, Stavropoulos A, Marcantonio RA. Effect of avocado/soybean unsaponifiables on ligature-induced bone loss and bone repair after ligature removal in rats. J Periodontal Res. 2016;51(3):332-341.26248485
Oryan A, Mohammadalipour A, Moshiri A, Tabandeh MR. Avocado/soybean unsaponifiables: a novel regulator of cutaneous wound healing, modelling and remodeling. Int Wound J. 2015;12(6):674-685.24321012
Pavelka K, Coste P, Géher P, Krejci G. Efficacy and safety of Piascledine 300 versus chondroitin sulfate in a 6 months treatment plus 2 months observation in patients with osteoarthritis of the knee [published correction appears in Clin Rheumatol. 2010;29(7):819-820]. Clin Rheumatol. 2010;29(6):659-670.20179981
Soliman MF. Evaluation of avocado/soybean unsaponifiable alone or concurrently with praziquantel in murine schistosomiasis. Acta Trop. 2012;122(3):261-266.22342904

Further information

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