The US Food and Drug Administration (FDA) granted Avemar a status of Generally Recognized As Safe (GRAS), which allows it to be used in foods, drinks, and dietary supplements.

Significant side effects have not been reported since 1998, but mild and transient diarrhea, nausea, flatulence, soft stool, constipation, dizziness, and increase in body weight can accompany the consumption of Avemar. 

Hematologic evaluations of hospitalized cancer patients in Hungary found that the white blood cell count, lymphocyte count, neutrophil granulocyte count, monocyte count, eosinophil granulocyte count, hemoglobin level, red blood cell count, erythrocyte sedimentation rate, hematocrit, platelet count, and prothrombin level were normal after 1-5 years of Avemar treatment.

Boros et al discussed some of the studies in animals and humans that provide an indication of its safety; studies in these species to date suggest few adverse effects of Avemar.

Acute and subacute toxicology tests carried out in a Good Laboratory Practice (GLP) setting revealed minimal side effects. 

Toxicity studies in rat and mouse demonstrated an acute oral LD50 of Avemar in male and female mice and rats of greater than 2,000 mg/kg. The no-observable adverse effect level, which is the greatest concentration or amount of Avemar that causes no detectable adverse alteration, was 2,000 mg/kg/day in rats, and in a subchronic study with mice and rats was found to be 3,000 mg/kg/day.

There is a wide therapeutic window for Avemar. Doses toxic to normal cells are more than 50 times higher than the dosage recommended for therapy, which suggests that a wide range of therapeutic dosages can be tested before the product becomes toxic.

Immunosuppressants
Avemar can increase the activity of the immune system. Some medications, such as those used after a transplant, decrease the activity of the immune system. Taking Avemar along with these medications might decrease the effects of these medications.

Vitamin C
Avemar may be consumed at least 2 hours before or after taking preparations with vitamin C content.

Tamoxifen

Tamoxifen and Avemar have been studied in combination for potential benefits in estrogen receptor-positive (ER+) breast cancer treatment. Research indicates their combined use enhances apoptosis in cancer cells more effectively than either alone. This suggests Avemar may serve as a supplementary therapy to boost tamoxifen's efficacy. A 2004 study on MCF-7 breast cancer cells showed tamoxifen alone reduced S-phase but had minimal impact on apoptosis, while Avemar alone increased apoptosis after 48 hours. The combination significantly boosted apoptosis within 24 hours and further suppressed estrogen receptor activity. Avemar appeared to counteract its own estrogen-enhancing effect when paired with tamoxifen. Research on Pubmed

Cisplatin
Avemar enhances cisplatin's antiproliferative effects and induces cell death in ovarian, liver, and oral cancer cell lines. It potentiates cisplatin-induced apoptosis and reduces required dosages in hepatocellular carcinoma models.

Irinotecan, 5-FU, Oxaliplatin

Avemar interacts synergistically with irinotecan in preclinical models, enhancing antitumor effects without antagonism.

Studies on human colon cancer cell lines show simultaneous exposure to Avemar and irinotecan yields additive to synergistic cytotoxicity, measured via sulforhodamine B assay and IC50 values. Sequential exposure maintains these benefits, unlike with 5-FU where order matters, supporting potential combination regimens. Preclinical data align with clinical observations in colorectal cancer patients, where Avemar plus 5-FU-based therapies (often including irinotecan) improved survival and reduced metastasis, without impairing chemo efficacy. No increased toxicity or adverse interactions reported in supportive studies. Research on PubMed

Androgen Deprivation Therapy (ADT)

Avemar has been studied as an adjunct to androgen deprivation therapy (ADT), particularly in castration-resistant prostate cancer (CRPC) patients who progress despite GnRH analogs. A pilot clinical trial showed that combining Avemar with conventional GnRH therapy slowed disease progression, as indicated by prolonged prostate-specific antigen doubling time (PSADT) in 36 CRPC patients, with no reported adverse effects. Research on PubMed

Dacarbazine

Avemar has been studied in combination with dacarbazine (DTIC), a chemotherapy drug used for melanoma. Clinical trials show that adding Avemar to dacarbazine therapy significantly improves overall survival in high-risk stage III melanoma patients compared to dacarbazine alone. A randomized phase II trial at the N.N. Blokhin Cancer Center involved 52 patients post-surgery, where those receiving dacarbazine plus Avemar for one year survived a median of 66.2 months, versus 44.7 months for dacarbazine alone—a 48% improvement. Avemar also reduced severe side effects of dacarbazine, such as nausea and hematotoxicity, enhancing quality of life during treatment. Avemar synergizes with dacarbazine by inhibiting angiogenesis through reduced VEGF and Cox-2 expression in tumor cells, boosting anti-tumor effects without added toxicity. In vitro studies confirm it enhances dacarbazine's impact on cell viability in melanoma models while preserving PARP inhibition for cancer cell death. This positions Avemar as a promising adjuvant for dacarbazine-based regimens in melanoma immunotherapy. Research on PubMed

• Avemar is contraindicated during pregnancy and breastfeeding. 

• Avemar is strictly contraindicated for patients undergoing organ or tissue transplantations.

• Avemar should not be consumed by patients suffering from malabsorption syndrome (serious impairment of absorption).

• Avemar must not be consumed by patients suffering from bleeding erosions and/or ulcers of the gastrointestinal tract (stomach and duodenal ulcers), enteritis/colitis (severe inflammations of the gastrointestinal tract).

• Avemar is contraindicated in gluten sensitive enteropathies (celiac sprue) or for patients with hypersensitivity to any of the components or ingredients of the product.

• Avemar may contain traces of gluten: macroscopically, wheat germ does not contain flour, but it may contain it as contamination. We cannot detect gluten in Avemar using simple analytical methods (e.g., gel electrophoresis). Nevertheless, it may be present, and the intestinal villi of people who are very sensitive to gluten may react to even a single (!) gluten molecule. Therefore, for the sake of simplicity and safety, we say that anyone suffering from the autoimmune disease known as gluten intolerance should not take Avemar, or should weigh up the risk/benefit ratio and, if the predicted benefit far outweighs the risk, they can try it. Then they can either continue or stop.

• Suspend the application of Avemar at least two days before a planned gastroenteral diagnostic procedure (like PET/CT), in which oral administration of contrast material (such as barium sulfate) to the intestinal tract will be used. The consumption may be continued the day after the procedure.

• When examinations or procedures should  be carried out on an empty stomach that must be taken into consideration relating to the consumption of Avemar also.