d hist for allergies

D-hist for Allergies

Seasonal allergies can be troublesome for many people. In this article, we’ll discuss histamine, the benefits of using D-Hist for seasonal allergies, and other functional medicine therapies for seasonal allergy sufferers.

Histamine and Seasonal Allergies

Histamine is a chemical messenger your body makes to carry out multiple jobs in the body. For example, histamine is involved in hormone regulation, smooth muscle contraction, digestion, and more (1). 

Normally, your body is fairly effective at degrading histamine. However, certain scenarios may cause your histamine load to build-up and lead to symptoms of histamine intolerance. An increase in environmental pollen and dust during certain times of the year is one such example.

Common symptoms of seasonal allergies include:

  • Nasal congestion
  • Sneezing
  • Runny nose
  • Asthma exacerbations
  • Itchiness
  • Red or watery eyes
If you suffer from these symptoms year-round, there may be other root causes that need to be addressed. Read more about histamine intolerance here.

D-Hist for Allergies

D-Hist (now branded as Root Hista Pro) is a popular supplement containing various antioxidants, enzymes, and plant extracts. The ingredients in D-Hist are intended to degrade the histamine load, reduce inflammation, and thin mucous secretions. Many people use this supplement as a way to reduce seasonal allergy symptoms. 
Hista Pro

Hista Pro

Natural & effective relief for seasonal allergies
Let’s review each of the ingredients in the D-Hist supplement:


Quercetin is an antioxidant from the flavonoid group found naturally in onions, broccoli, and certain types of tea. It is known to have anti-allergic benefits that include lowering inflammation and reducing histamine release from your cells (2). 

Nettles Leaf Extract

Stinging nettles leaf is a natural herb that has significant anti-inflammatory and antihistamine properties (3). As an extract in the Ortho Molecular D-Hist supplement, this potent ingredient has many benefits for people with seasonal allergies.


Bromelain is a natural plant enzyme found in pineapple. This popular ingredient also has effective anti-inflammatory and antihistamine properties.

N-Acetyl Cysteine

N-Acetyl Cysteine (NAC) is a powerful antioxidant that can reduce inflammation and lower oxidative stress in the body. NAC also loosens and thins mucus secretions in your airways which may be helpful in reducing nasal congestion (4).

Vitamin C

Vitamin C is a well-known nutrient with strong antioxidant properties. Besides boosting the immune system and reducing oxidative stress, vitamin C is also required to produce diamine oxidase—the enzyme responsible for breaking down histamine in the body (1). 

How to Take D-Hist for Allergies

D-Hist by Ortho Molecular (now branded as Root Hista Pro) is one of the most popular supplements for allergies. For effective use, begin a loading dose of two capsules of Ortho Molecular D-Hist three times per day for 1 to 2 weeks. From there, you may lower to a maintenance dose of one or more capsules daily based on your seasonal allergy symptoms. We include D hist in our histamine bundle with magnesium which is helpful for stress and sleep and DAO which breaks down histamine in the gut.

Other Considerations for Seasonal Allergies

Besides taking D-Hist for allergies, other functional medicine therapies may reduce your overall histamine load and treat seasonal allergies from the root cause. 

Low-Histamine Diet

If you are experiencing seasonal allergies, you may want to consider following a temporary low-histamine diet. Eliminate foods high in histamines like fermented foods (kombucha, sauerkraut, wine/beer), aged foods (aged meats and cheeses, olives, vinegar, canned meats/fish), and other high sources like tomatoes, avocados, and spinach. 

Improve Gut Health

Gut inflammation, small intestinal bacterial overgrowth (SIBO) and other imbalances of gut bacteria may worsen histamine intolerance and seasonal allergies. While you may be tempted to take a probiotic and call it good, many probiotic strains can actually increase your histamine load and worsen your symptoms. For this reason, it’s helpful to work with a qualified functional medicine practitioner to implement a personalized gut healing protocol.

Reduce Stress

Chronic stress increases histamine production in the body. For this reason, healthy stress management is key in reducing your overall histamine load and treating seasonal allergies. Implement a realistic stress-reducing activity every day and reduce stressful triggers in your life if possible.

Estrogen Dominance

Estrogen triggers histamine release from the immune cells (1). Too much overall estrogen—as seen in estrogen dominance—may overload your histamine tolerance and worsen seasonal allergies. One way to naturally reduce estrogen levels is to include more cruciferous vegetables into your diet like broccoli, cauliflower, Brussel’s sprouts, and cabbage. However, many women require accurate testing and individualized protocols to effectively balance estrogen levels.

D-Hist for Allergies: What You Need to Know

Histamine is a chemical made in the body that has many important jobs. Increased environmental pollen and dust at certain times of the year may lead to histamine overload and symptoms of seasonal allergies.

D-Hist is an anti-inflammatory supplement containing various antioxidants, enzymes, and plant extracts aimed to reduce your overall histamine load. While taking D-Hist alone helps many seasonal allergy sufferers, others may require a more in-depth functional medicine treatment to assess diet, stress, gut health, and hormonal balance. 
Hista Pro

Hista Pro

Natural & effective relief for seasonal allergies
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