By Dr Chun Tang — MBChB (Manchester), MRCGP, MBA · Practising NHS & Private GP · Founder, Little Ox

Can NMN Help With Allergies? A GP Explains the Science Behind Hay Fever Season

Every spring, a significant proportion of my patients arrive with the same cluster of complaints: itchy eyes, relentless sneezing, a permanently blocked nose, and the exhaustion that comes from poor sleep on top of an immune system in constant overdrive. Hay fever affects roughly one in four UK adults, and for many of them it meaningfully reduces quality of life for weeks or months of the year.

As a GP who is also deeply interested in the emerging science of NAD+ and healthy ageing, I've been asked increasingly often whether NMN supplementation can help with allergic conditions. The honest answer is: not directly, and not as a treatment. But there is a genuinely interesting mechanistic connection between NAD+ levels, sirtuin activity, and the regulation of allergic inflammatory responses — one that I think is worth explaining properly.

What Actually Happens in an Allergic Response

Hay fever is an IgE-mediated hypersensitivity reaction. When pollen enters your airways, your immune system — if you are atopic — incorrectly identifies it as a threat and produces IgE antibodies. These antibodies bind to mast cells in the nasal passages, eyes and airways. On subsequent pollen exposure, the allergen cross-links the IgE on mast cells, triggering degranulation: the rapid release of histamine, prostaglandins and leukotrienes. These mediators cause vasodilation, increased mucus secretion, smooth muscle contraction and nerve sensitisation — producing the symptoms you experience as hay fever.

The severity of your allergic response depends on several factors: your genetic predisposition, your total allergen load, and — critically — the state of your immune regulation. Specifically, the balance between Th1 and Th2 immune responses. Atopy is associated with Th2 dominance: an immune system biased towards allergic rather than antimicrobial responses. Restoring Th1/Th2 balance is one of the targets of immunotherapy (allergy shots), which works by gradually shifting immune responses away from the Th2 pattern.

Where NAD+ and Sirtuins Come In

This is where the NMN science becomes relevant. NAD+ is the essential substrate for sirtuin proteins — a family of enzymes that regulate gene expression, inflammation and immune function. Three sirtuins in particular are directly relevant to allergic inflammation:

SIRT1 is the primary anti-inflammatory sirtuin. It suppresses NF-κB — the master transcription factor that drives production of pro-inflammatory cytokines including the Th2 cytokines IL-4, IL-5 and IL-13 that are central to allergic responses. When NAD+ is plentiful, SIRT1 is active and helps keep inflammatory signalling in check. When NAD+ is depleted — which happens progressively from your 30s onwards — SIRT1 activity falls, NF-κB becomes less regulated, and inflammatory responses including Th2-driven allergy can become more pronounced.

SIRT3 regulates mitochondrial function in immune cells, including mast cells. Mast cell activation and degranulation is an energy-intensive process — it requires mitochondrial ATP production. There is emerging evidence from preclinical studies that SIRT3 activity modulates mast cell degranulation responses, with lower SIRT3 activity associated with heightened mast cell reactivity.

SIRT6 suppresses inflammatory gene expression at the chromatin level, and has been shown in animal models to reduce mast cell activation and allergic airway inflammation. A 2020 study in Nature Communications demonstrated that SIRT6 deficiency in mice significantly worsened allergic airway disease, while SIRT6 activation had the opposite effect.

All three of these sirtuins require NAD+ to function. As NAD+ declines with age, sirtuin activity falls across the board — and the inflammatory regulation they provide becomes less effective. This is part of the biological explanation for why allergic conditions can become more severe or develop de novo in adults in their 40s and 50s, even without any change in allergen exposure.

The Resveratrol Connection

Trans-Resveratrol — the active isomer present in our NMN Plus formula — is a direct SIRT1 activator independently of NAD+ levels. It also has well-documented direct anti-inflammatory properties: it inhibits histamine release from mast cells in vitro, suppresses COX-2 (the enzyme responsible for prostaglandin production), and reduces levels of IL-4 and IL-13 — the key Th2 cytokines driving allergic inflammation.

A 2016 study in Molecular Nutrition and Food Research found that Resveratrol supplementation in patients with mild to moderate allergic rhinitis significantly reduced total nasal symptom scores versus placebo. This is one of the more directly relevant human studies for the NMN Plus formula — because the combination of NMN (raising NAD+ to power sirtuin activity) with Resveratrol (directly activating sirtuins and inhibiting mast cell mediator release) addresses the inflammatory regulation pathway from two complementary angles.

Gut Health and Allergic Sensitisation

One dimension of allergy management that is consistently underappreciated is the gut microbiome. There is robust evidence — from cohort studies, intervention trials and mechanistic research — that gut microbiome diversity is inversely associated with atopic disease. Children raised with depleted microbiomes have significantly higher rates of hay fever, eczema and asthma. Adults with lower microbiome diversity show more pronounced allergic responses to seasonal allergens.

The mechanism is well-characterised: your gut microbiome directly trains your immune system's Th1/Th2 balance through the production of short-chain fatty acids (SCFAs) like butyrate, which promote regulatory T-cell (Treg) development. Tregs actively suppress both Th1 and Th2 extremes, maintaining immune tolerance. Deplete the microbiome, lose SCFA production, lose Treg support, and Th2 responses become less regulated — making allergic sensitisation more likely and allergic reactions more severe.

This is why I routinely recommend our Bio Cultures Complex to patients with hay fever and other atopic conditions — not as a hay fever treatment, but as part of addressing the immune dysregulation that makes allergic responses more severe. The 25 diverse strains and prebiotic FOS and inulin in the formula are specifically chosen to support microbiome diversity, which is the most important variable in the gut-immune axis.

Magnesium and Histamine

One underappreciated connection: magnesium acts as a natural physiological antagonist to histamine. Magnesium stabilises mast cells and reduces their propensity to degranulate; it also inhibits histamine N-methyltransferase, one of the enzymes involved in histamine metabolism. Studies have found an inverse relationship between magnesium levels and histamine sensitivity — lower magnesium correlates with more pronounced histamine responses.

Given that an estimated 70% of UK adults are magnesium-deficient, and that magnesium deficiency directly impairs histamine regulation, correcting a deficiency with our Magnesium Glycinate is a rational adjunct during allergy season — particularly for the sleep disruption that hay fever causes, since magnesium supports both GABA-pathway recovery and overnight routine and the overnight immune regulation that reduces inflammatory sensitisation.

What NMN and These Supplements Won't Do

I want to be honest about the limitations, because that is the standard I hold myself to.

NMN is not an antihistamine. It will not provide the immediate relief of loratadine or cetirizine. If you are having an acute, severe hay fever episode, you need appropriate medication — and your GP or pharmacist can advise on the most suitable antihistamine, nasal steroid spray or other treatment for your pattern of symptoms.

The NAD+/sirtuin mechanisms described above are based on a combination of mechanistic research, animal studies, and early-stage human data. Longer-term, larger human trials specifically targeting allergic conditions with NMN are needed before we can make definitive clinical claims.

What I can say with confidence is this: supporting NAD+ levels, sirtuin activity, gut microbiome diversity and magnesium status addresses the biological infrastructure that modulates how your immune system regulates inflammatory responses — including allergic ones. That is not a promise of symptom relief. It is a rationale for long-term immune regulation support that goes beyond managing acute symptoms.

A Practical Protocol for Allergy Season

Based on the mechanisms above, here is what I personally take and what I discuss with patients who ask:

Morning: NMN Plus (500mg β-NMN + Trans-Resveratrol) — addressing NAD+/sirtuin regulation and Resveratrol's direct anti-inflammatory effects simultaneously. Take with a small amount of fat to optimise Resveratrol absorption.

Morning with food: Bio Cultures Complex — 75bn CFU, 25 strains, supporting the gut-immune axis and Th1/Th2 balance through microbiome diversity.

Evening: Magnesium Glycinate — mast cell stabilisation support and recovery and overnight routine during the weeks when hay fever disrupts sleep most severely.

This is not a hay fever treatment protocol. It is a cellular health and immune regulation protocol that happens to address several of the biological mechanisms underlying allergic hypersensitivity — and one that I believe is worth maintaining year-round, not just in pollen season.

For acute hay fever symptoms, please speak to your GP or pharmacist. For the underlying biology of immune regulation and healthy ageing, the supplements above are as evidence-backed as anything I can recommend.

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This article is for informational purposes and does not constitute medical advice. NMN and other supplements described here are food supplements, not medicines, and are not intended to diagnose, treat, cure or prevent any disease including allergic conditions. If you have hay fever or other allergies, please consult your GP about appropriate treatment. The mechanisms described are based on preclinical and early-stage human research — further clinical trials are needed.