adiDAO® and adiDAO® Veg: active dietary ingredient DAO, derived from either animal or plants. We can also help you develop customised solutions to meet the complex medical needs of diverse patient populations.

What is DAO Deficiency?

Diamine oxidase or DAO is an enzyme naturally present in the gut. Its main function is to break down the histamine we ingest from many of the foods we eat.

DAO Deficiency is one of the world's most common enzyme-related metabolic disorders and occurs when this enzyme is less active. This means that dietary histamine may not be metabolised properly, so it gets absorbed through the intestinal lining (epithelium). This, in turn, can potentially trigger various symptoms like migraines, fibromyalgia, skin disorders, digestive problems and ADHD. Symptoms can vary depending on individual DAO activity levels.

How does adiDAO® help?

Increase DAO levels in the gut
Highly active and efficient enzymatic activity
Enhance the breakdown of histamine to prevent absorption
Improved therapeutic efficacy reducing symptoms associated with DAO Deficiency

Why choose adiDAO®?

Our streamlined approach ensures flexibility and customisation in delivering high-quality DAO products.

  • Active dietary ingredient available in both animal or plant-derived (adiDAO Veg®) options
  • We can help you develop customised solutions to meet the needs of diverse patient populations
  • Solutions can be branded or unbranded according your requirements
  • Can be used as a standalone supplement or we offer a range of galenic solutions including mini-tablets, capsules and powders
  • adiDAO® Microencapsulated also available for incorporation into functional foods or topical applications

Science supporting adiDAO®

Over 100 clinical and scientific studies have been conducted on diamine oxidase.

Histamine intolerance occurs when impaired DAO activity in the intestine leads to reduced histamine breakdown

If histamine is not metabolised properly, it can get absorbed through the intestinal lining, accumulate in the bloodstream and potentially trigger various gastrointestinal and extra-intestinal symptoms.

DAO supplementation improves symptoms of migraine and reduces consumption of anti-migraine medication.

Migraine is a disabling disease characterised by regular headaches which can be accompanied by visual or sensory symptoms. A 2018 study by Izquierdo-Casas J et al. showed 87% of migraine patients had reduced DAO activity1. In a subsequent study, they found that DAO supplementation resulted in participants having fewer migraine attacks and a reduced consumption of anti-migraine medication, Triptan. The chart below shows the percentage of patients who used Triptan before and after one month of treatment with placebo (on the left) or DAO (on the right).

75% of fibromyalgia patients have a genetic DAO deficiency. DAO supplementation has proven effective in alleviating symptoms.

Fibromyalgia is characterised by chronic pain, fatigue, mood and sleep disorders, anxiety, depression, and extreme sensitivity. Around 75% of fibromyalgia sufferers have a genetic DAO deficiency.

Trials with fibromyalgia patients by Okutan G et al2 showed favourable changes in symptoms, following DAO supplementation, especially in fatigue, stiffness, and depression.

ADHD is highly impacted by dysregulation of histamine metabolism.

Attention Deficit Hyperactivity Disorder (ADHD) is the most prevalent neurodevelopmental disorder, diagnosed in around 5% of children worldwide. DAO deficiency has been found to be highly prevalent in those diagnosed with ADHD (82%)3. Impaired histamine metabolisation due to malfunctioning of the DAO enzyme has also been found to impact on neuroinflammation and play a role in ADHD physiopathology4


DAO is effective in managing symptoms associated with conditions related to DAO deficiency and histamine intolerance such as: migraine and headaches; ADHD; digestive disorders; atopic dermatitis; fibromyalgia; and muscle pain. 

adiDAO® features a diamine oxidase (DAO) enzyme derived from pig kidney protein extracts.

adiDAO® Veg features a plant-based diamine oxidase (DAO) enzyme derived from dehydrated pea (Pisum sativum) sprouts

Application: Food for Special Medical Purposes (FSMP) / Food Supplements


4.2mg per serving

The DAO enzyme in our active ingredient demonstrates an activity level exceeding 298 mU/g, equivalent to over 14,500 HDU/g.

One mU corresponds to the degradation of 1 nmol of histamine per minute. Typically, the DAO activity in finished doses is approximately 0.61 mU/dose (30,000 HDU/dose), although this can vary based on the pharmaceutical form.

Regulatory and certifications

  • EU: Classified as Novel Food under EU Regulation 2018/1023.
  • US: Recognized as Generally Safe (GRAS) under FDA regulations.

Why choose ABbiotek Health?

  • We combine the latest science with a proven expertise in the fermentation to address a wide range of health disorders.
  • Working with the medical profession, pharma companies, and food producers, we provide natural solutions that work in harmony with drug therapies.
  • We're focused on microbiome-modulating solutions which harness the full power of bacteria, yeast, and enzyme biological systems working in synergy.
  • We serve a global customer base thanks to our advanced supply chain infrastructure.


1. Izquierdo-Casas J, et al. Diamine oxidase (DAO) supplement reduces headache in episodic migraine patients with DAO deficiency: A randomized double-blind trial. Clin Nutr 2019;38(1):152-158.
2. Okutan, G. et al. Prevalence of Genetic Diamine Oxidase (DAO) Deficiency in Female Patients with Fibromyalgia in Spain. Biomedicines 2023, 11, 660.
Okutan, G. et al. Cumulative effect of AOC1 gene variants on symptoms and pathological conditions in adult women with fibromyalgia: a pilot study Front. Genet. Sec. Genetics of Common and Rare Diseases, 14, 2023
Okutan, G. et al. Exogenous Supplementation with DAO Enzyme in Women with Fibromyalgia: A Double-Blind Placebo-Controlled Clinical Trial. J. Clin. Med. 2023, 12, 6449
3. Blasco-Fontecilla, H. et al. 2022. Prevalence and clinical profile of deficiency diamino oxidase (DAO) in patients with Attention Deficit and Hyperactivity Disorder (ADHD). Rev. Psiquiatr. Inf. Juv. 2022, 39 suppl.
4. Blasco-Fontecilla, H. Is Histamine and Not Acetylcholine the Missing Link between ADHD and Allergies? Speer Allergic Tension Fatigue Syndrome Re-Visited. J. Clin. Med. 2023, 12, 5350.

This website is intended to provide information about ABbiotek Health’s ingredients, used in various food/dietary supplement products around the world. It is only intended for business to business and to provide information to food/dietary supplement professionals and is not designed for the general public.  Statements used on this website have not been evaluated by the Food and Drug Administration or any other competent authority. Products are not intended to diagnose, treat, cure or prevent any disease.