DAO vs HNMT: Why Histamine Supplements Don’t Always Work (and What to Do Instead)

If you’ve ever tried a histamine supplement and thought…

"Why didn’t this work for me?"

It might be because you were supporting the wrong pathway.

Your body has two main enzymes that break down histamine:

DAO (Diamine Oxidase)
– Works in your gut lining
– Handles histamine from food

HNMT (Histamine‑N‑Methyltransferase)
– Works inside your cells
– Handles histamine your body makes (brain, liver, immune system)

🧩 How to Know Which One You Need

Meal-related symptoms (hives, flushing, bloating) → DAO support can help

Random flares, nighttime anxiety, brain fog → HNMT/liver support is key

A major clinical trial in Spain (ISRCTN64888465) is currently testing how a low‑histamine diet + DAO supplementation impacts symptoms and DAO levels in 400 participants. Early results confirm what I see in practice:

• DAO helps for food triggers

• HNMT support is crucial when the problem is internal histamine buildup

💡 What HNMT / Liver Support Looks Like

Because HNMT relies on methylation and liver Phase II detox, I focus on:

• B2, Folinic Acid, Hydroxo B12 → fuel methylation for histamine breakdown

• Sulforaphane → supports liver Phase II and COMT

• Phosphatidylcholine → helps bile flow & liver repair

When combined with lifestyle strategies and targeted DAO use (if meals are a trigger), this is how I help clients get off the histamine rollercoaster.

Feeling confused about when to use what support?

Book your discovery call and let’s uncover your root causes so you can finally feel like yourself again and get back to the life you deserve.