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  • Ortho Molecular, Formula: 524040 - Natural D-Hist - 40 Capsules
  • Ingredients Label for Ortho Molecular Natural D-Hist

Natural D-Hist

524040|Ortho Molecular

Product Description


Natural D-Hist is a targeted blend of flavonoids, antioxidants, proteolytic enzymes and botanicals designed to provide comprehensive support for seasonal challenges caused by common environmental allergens. The formula includes quercetin, bromelain, stinging nettles leaf, and N-acetyl cysteine. The powerful combination actively promotes healthy nasal and sinus passages for individuals with elevated histamine and respiratory irritation.

Suggested Use:

Loading Dose: 2 capsules three times per day for 7-10 days or as recommended by your health care professional

Maintenance: 1 or more capsules per day or as recommended by your health care professional



Quercetin has strong antioxidant activity and has been shown to support immune health by mediating the release of inflammatory compounds including leukotrienes and prostaglandins. Quercetin is known for its ability to stabilize mast cells, diminishing the release of histamine, the compound known to cause hypersensitivity reactions during seasonal changes.

Stinging Nettles Leaf Extract

Stinging nettles leaf is a plant that has been shown to balance immune response, specifically in the airways and nasal passages. Studies have shown that the extract of stinging nettles leaf balances a variety of inflammatory activities that affect respiratory health.


Bromelain is a plant enzyme naturally found on the stem and fruit of the pineapple plant. Bromelain is a proteolytic (protein-digesting) enzyme that aids in in the breakdown of large protein complexes, including antigenic compounds, and has been shown to enhance the absorption of quercetin. Bromelain has been shown to reduce circulating allergenic protein complexes associated with hyper-immune sensitivity and seasonal discomfort.

N-Acetyl Cysteine

N-acetyl cysteine (NAC) is an amino acid precursor to one of the most important antioxidants in the body, glutathione. Both glutathione and NAC help reduce the viscosity of the mucus allowing for clearing of the airways and improved respiratory health.

Vitamin C

Vitamin C cannot be synthesized by humans and is therefore an essential nutrient that must be consumed in the diet. Among its numerous health-promoting properties, vitamin C is an essential vitamin that supports the immune system and is also a potent antioxidant. When the body is under a significant amount of stress, vitamin C is excreted rapidly. Vitamin C has many immune boosting properties, but is distinctively beneficial for individuals with seasonal discomfort because of its ability to deactivate histamine.

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Ortho Molecular Products' logo, text, trademarks, graphics, and photo images are the property of Ortho Molecular Products, Inc. and are used with permission. Copyright © 2022

This product is intended to be used with the guidance of your healthcare professional and shall not be resold. Ortho Molecular uses only authorized resellers and may seek legal action against those reselling this product.

For California Residents: California Health and Safety Code section 25249.5 et seq. (Proposition 65) Warning - This product can expose you to lead, which is known to the State of California to cause birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov/food

*FDA Disclaimer: The information about this product and statements made are provided by the manufacturer, except customer reviews which are not evaluated. See www.orthomolecularproducts.com for information about the relationship between this product and any claims made. Results may vary from person to person based on body size and other factors, and the effectiveness is not guaranteed for you. Always seek the advice of your healthcare professional about taking dietary, nutritional, herbal or homeopathic supplements.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.


Recommended Use

Loading Dose: 2 capsules three times per day for 7-10 days or as recommended by your health care professional

Maintenance:1 or more capsules per day or as recommended by your health care professional


Product Reviews

  1. Effective Product 5 Star Review

    Posted by on 1st Jun 2021

    Great product! Good shipping. Ordered again!

    About shipping: I needed it quickly so I ordered from this company thinking it would have an advantage being in the same state but unsure about the shipping info. I called after placing my order and they were friendly and verified it would ship the same day and I should get it Wednesday. I got a status update that it was sent to the distributor and then that they shipped it the next day. I didn’t get it until Thursday but that’s still before I needed it and totally realistic for handing off an order to the distributor, even if they’re using 2 day air shipping. I ordered more today— I’m happy to support an Oregon company vs some other random one that pops up in my Google search.

    About the product: I was taking tons of antihistamines and then learned there were subtle side effects (and about antihistamine dependence) so I looked for alternatives. I think working on adrenal also helped so I won’t say it’s all d-hist, but this spring my allergies are so much better. I had previously tried a Quercetin supplement and it wasn’t enough so it must be the other ingredients or the combination of them in this product that makes a huge difference.

  2. Amazing 5 Star Review

    Posted by on 5th Mar 2021

    I get seasonal allergies, but recently I've been congested through the dry winter. It was suggested I try D-Hist in place of Flonase. Within a week, I was able to stop taking Flonase. I was still a little stuffy, but much better.

    I ran out and didn't start taking it again for a week. I couldn't believe how much it was helping. I had to go back on Flonase for a few days until D-Hist kicked in again.

    I make sure I keep plenty on hand now. Again, I'm still a little stuffy, but it's nothing like it would be if I was taking nothing.

*FDA Required Statement: These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.