Home Ingredients Attenutin™ (Scutellaria and Acacia Bioflavonoid Blend, Unigen)
Immune Support

Attenutin™ (Scutellaria and Acacia Bioflavonoid Blend, Unigen)

Evidence Level
Preliminary
0 Clinical Trials
3 Documented Benefits
1/5 Evidence Score

Attenutin (coded UP446 in research) is Unigen's blend of a Baikal skullcap (Scutellaria baicalensis) root extract and an Acacia catechu heartwood extract, sold for respiratory and immune support. One small Unigen-funded trial in 50 healthy adults found higher total IgA and IgG antibody levels than placebo after a flu shot, but no difference in flu-specific antibodies, cold and flu symptoms or inflammation markers. The same UP446 blend, sold for joints as Univestin, has two small osteoarthritis trials. The rest of the evidence comes from animal and laboratory studies.

Studied Dose Two capsules a day for 56 days in the flu-vaccine trial (Lewis 2023); the paper gives no mg per capsule and no daily dose is published.
Active Compound UP446 (Unigen): 4:1 mix of Scutellaria baicalensis root extract (at least 75% baicalin) and Acacia catechu (Senegalia catechu) heartwood extract (at least 65% (+)-catechin); blend at least 60% baicalin, at least 10% catechin.

Benefits

Respiratory symptoms: no benefit shown

In the only trial that tracked respiratory symptoms, 50 healthy adults took the blend or a placebo for 56 days and logged cold and flu symptoms every day. There was no difference between groups in symptom severity, duration or frequency, sick days, or use of cold and flu medicine. Few participants got sick during this pandemic-era study, so it could not rule an effect in or out. No study shows that it prevents or treats any respiratory infection.

Antibody levels after a flu shot (one small trial)

In a Unigen-funded trial of 50 healthy adults aged 40 to 80, total IgA and IgG antibody levels rose more with the blend than with placebo in the 28 days after a flu vaccine. Antibodies against the flu strains themselves did not differ from placebo, and neither did T cells, NK cells, CRP or other inflammation markers. Total antibody levels are a lab marker, not proof of fewer or milder infections. Effects on cytokines and NF-kB come from mouse and cell studies only.

Antioxidant enzyme: not different from placebo in people

Glutathione peroxidase, an antioxidant enzyme, rose in mice given the blend. In the human trial it rose 13.6% to 15.7% from baseline in the blend group, but levels were not significantly different from the placebo group at any point, so the rise cannot be credited to the blend.

Mechanism of action

1

COX and LOX enzyme inhibition (laboratory and animal data)

In laboratory and animal studies, the baicalin and catechin blend inhibited the COX and LOX enzymes that make inflammatory signaling molecules. This has not been shown to change inflammation markers in people taking the blend: CRP and ESR did not differ from placebo in the flu-vaccine trial.

2

Antioxidant enzymes (animal data)

The blend raised glutathione peroxidase activity in mice. In the one human trial that measured it, the change was not different from placebo.

Clinical trials

Side effects and drug interactions

Common Potential side effects

Liver warning: Unigen's own papers state that UP446 has been used in a prescription medical food, and flavocoxid (Limbrel), the baicalin and catechin medical food made from these same two plants, caused acute liver injury in a US Drug-Induced Liver Injury Network case series. The FDA requested its recall in 2017 over liver injury and a lung reaction called hypersensitivity pneumonitis. LiverTox rates skullcap as a rare but very likely cause of liver injury. Stop and see a doctor if you notice yellow skin or eyes, dark urine, unusual tiredness, or a new cough or breathlessness. In the 56-day flu-vaccine trial of this blend (50 adults), side effects were similar to placebo and liver tests did not differ from placebo, but a trial that small and short cannot rule out a rare reaction.
Mild digestive upset is occasionally reported.
Discontinue if any unusual reaction occurs.

Important Drug interactions

No interaction studies exist for this blend. Baicalin, its main compound, lowered blood levels of the cholesterol drug rosuvastatin by up to about 47% in a small crossover study in healthy volunteers taking 50 mg three times a day for 14 days, so ask your doctor before combining it with a statin. Because of liver-injury reports with related baicalin and catechin products, avoid combining it with alcohol, flavocoxid-type products, or other supplements and medicines that can stress the liver.
Tell your doctor about all supplements if you take prescription medication.
Use caution if pregnant, breastfeeding, or managing a condition.

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Frequently asked questions about Attenutin™ (Scutellaria and Acacia Bioflavonoid Blend, Unigen)

What is Attenutin?

Attenutin (coded UP446 in research) is Unigen's blend of a Baikal skullcap (Scutellaria baicalensis) root extract and an Acacia catechu heartwood extract, sold for respiratory and immune support.

What is Attenutin used for?

Attenutin is researched primarily for Immune Support. In the only trial that tracked respiratory symptoms, 50 healthy adults took the blend or a placebo for 56 days and logged cold and flu symptoms every day.

What is the recommended dosage of Attenutin?

The clinically studied dose is Two capsules a day for 56 days in the flu-vaccine trial (Lewis 2023); the paper gives no mg per capsule and no daily dose is published. Always follow the product label and check with a healthcare provider for personal advice.

Is Attenutin safe, and does it have side effects?

Side effects and cautions reported for Attenutin include: Liver warning: Unigen's own papers state that UP446 has been used in a prescription medical food, and flavocoxid (Limbrel), the baicalin and catechin medical food made from these same two plants, caused acute liver injury in a US Drug-Induced Liver Injury Network case series. It may also interact with some medications. Attenutin is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does Attenutin interact with any medications?

Possible interactions include: No interaction studies exist for this blend. Baicalin, its main compound, lowered blood levels of the cholesterol drug rosuvastatin by up to about 47% in a small crossover study in healthy volunteers taking 50 mg three times a day for 14 days, so ask your doctor before combining… If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Attenutin?

NutraSmarts rates the evidence for Attenutin as Preliminary (1 out of 5). It is backed by 4 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(4 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Yimam M, Horm T, O'Neal A, Chua P, Jiao P, Hong M, Jia Q Botanical Bioflavonoid Composition from Scutellaria baicalensis- and Acacia catechu-Protected Mice against D-Galactose-Induced Immunosenescence, and Cyclophosphamide Induced Immune Suppression Nutrients. 2024;16(18):3144. doi:10.3390/nu16183144.PubMedUsed to support: Unigen-run study in mice (four of seven authors are Unigen employees). Oral UP446 at 100 and 200 mg/kg increased NK cell and T cell responses, glutathione peroxidase and serum IgA and IgG, preserved the thymus and lowered NF-kB in models of chemically induced immune ageing and cyclophosphamide immune suppression. These are animal results and do not show the same effects in people.
  2. Lewis ED, Crowley DC, Guthrie N, Evans M Role of Acacia catechu and Scutellaria baicalensis in Enhancing Immune Function Following Influenza Vaccination of Healthy Adults: A Randomized, Triple-Blind, Placebo-Controlled Clinical Trial Journal of the American Nutrition Association. 2023;42(7):678-690. doi:10.1080/27697061.2022.2145525.PubMedUsed to support: Unigen-funded randomized, triple-blind, placebo-controlled trial run by KGK Science in 50 healthy adults aged 40 to 80; flu-specific antibody tests were run in Unigen's laboratory. Participants took UP446 (two capsules a day, mg not stated) or placebo for 56 days, with a flu vaccine on day 28. Total IgA and IgG rose more than with placebo after vaccination. The primary immune-cell outcomes (T cells, NK cells) did not differ from placebo, and neither did flu-specific antibodies, CRP, glutathione peroxidase, cold and flu symptoms or quality of life; few participants caught the flu, so the symptom results are inconclusive. Side effects were similar in both groups. One participant taking UP446 was hospitalized with pneumonia and withdrew; investigators judged all adverse events unlikely to be, or not, related to the product.
  3. Chalasani N, Vuppalanchi R, Navarro V, Fontana R, Bonkovsky H, Barnhart H, Kleiner DE, Hoofnagle JH Acute liver injury due to flavocoxid (Limbrel), a medical food for osteoarthritis: a case series Annals of Internal Medicine. 2012;156(12):857-60. doi:10.7326/0003-4819-156-12-201206190-00006.PubMedUsed to support: US Drug-Induced Liver Injury Network case series. Four women aged 57 to 68 developed acute liver injury 1 to 3 months after starting flavocoxid (Limbrel), a prescription medical food blending baicalin and catechins from Scutellaria baicalensis and Acacia catechu. Causality was judged highly likely in three and possible in one, and all recovered within 3 to 12 weeks of stopping. It did not study Attenutin itself.
  4. Sampalis JS, Brownell LA A randomized, double blind, placebo and active comparator controlled pilot study of UP446, a novel dual pathway inhibitor anti-inflammatory agent of botanical origin Nutrition Journal. 2012;11:21. doi:10.1186/1475-2891-11-21.PubMedUsed to support: Pilot trial in 60 adults with hip or knee osteoarthritis (15 per group) comparing UP446 at 250 or 500 mg/day with celecoxib or placebo for 90 days. Pain, stiffness and function scores improved within the UP446 groups, mostly reported as within-group changes from baseline. Liver enzymes and routine blood tests did not change. This is a joint study, not a respiratory or immune study, and it is the source of the 250 to 500 mg/day dose range.