Frequently Asked Questions

NMN (Nicotinamide Mononucleotide) is a naturally occurring molecule found in small quantities in foods such as broccoli, edamame, and cucumber. It is a direct precursor to NAD+ (nicotinamide adenine dinucleotide) — a coenzyme your cells need to produce energy, repair DNA, and regulate the proteins that control ageing. The problem is that NAD+ levels decline steadily from your late 30s onward, dropping by roughly 50% by the time you reach 60. NMN bypasses the rate-limiting step in NAD+ synthesis, entering cells via specific transporter proteins and converting rapidly to NAD+. Human Nutrients NMN + Resveratrol provides 250 mg of pharmaceutical-grade NMN per capsule to support that restoration.

NAD+ (nicotinamide adenine dinucleotide) is present in every cell in your body and is essential for two processes that matter for ageing: mitochondrial energy production (the ATP cycle) and activation of sirtuins — the proteins that repair DNA, regulate inflammation, and control cell senescence. NAD+ decline appears to be driven by several competing factors: PARP enzymes consume more NAD+ as DNA damage accumulates; CD38, an enzyme that degrades NAD+, becomes more active with age; and precursor availability decreases as diet and metabolism shift. The net result is a progressive energy and repair deficit that shows up as fatigue, slower recovery, and accelerated ageing at the cellular level.

Human trials are still early-stage but the results are directionally consistent. A 2021 Yoshino et al. study (Science, PMID 33888596) found that 250 mg/day NMN supplementation for 10 weeks significantly improved muscle insulin sensitivity in postmenopausal women with prediabetes. A 2022 University of Tsukuba trial (PMC9158788) showed that 250 mg/day NMN increased blood NAD+ metabolite levels and improved physical performance metrics in older adults. A 2023 review (PMID 37619764) summarised the safety and anti-ageing evidence and concluded NMN is well tolerated across doses from 100 mg to 1,200 mg/day. The science is not yet at the level of established drug efficacy — these are early human trials, not long-term randomised controlled trials at scale — but the mechanistic rationale is solid and the safety profile is reassuring.

Sirtuins (SIRT1–SIRT7) are a family of proteins that David Sinclair's lab at Harvard has characterised as central regulators of the ageing process. They deacetylate histones and other proteins that control DNA repair, inflammation, mitochondrial biogenesis, and cell survival — but they can only do this when NAD+ is available. Think of NAD+ as the fuel and sirtuins as the engine. When NAD+ declines, sirtuin activity drops, and the repair mechanisms they govern start to fail. NMN restores NAD+ availability, which reactivates sirtuin function. Resveratrol — the second ingredient in Human Nutrients NMN + Resveratrol — is a SIRT1 activator that makes the engine more responsive to the fuel. The combination is the basis of what Sinclair describes as a synergistic longevity strategy.

They are related but not the same. Niacin (vitamin B3) and niacinamide (nicotinamide) are precursors several steps upstream of NAD+. Nicotinamide Riboside (NR) is one step upstream of NMN in the salvage pathway. NMN is the most direct precursor — it sits a single enzymatic step away from NAD+ itself. The practical significance is conversion efficiency and which tissues benefit most. NMN has been shown to enter cells via specific transporters (Slc12a8 in mice; similar transporters likely operate in humans), suggesting it can raise NAD+ in tissues that NR and niacin reach less effectively. Human Nutrients uses NMN specifically because the evidence for direct cellular uptake and rapid NAD+ conversion is strongest at this step in the pathway.

NMN raises NAD+ levels. Resveratrol activates SIRT1 — the sirtuin that depends on NAD+ to drive DNA repair, fat metabolism, and mitochondrial health. On their own, each compound does something useful. Together, they complete a circuit: more NAD+ (fuel) meets an activated sirtuin (engine). David Sinclair, whose research group at Harvard has published extensively on both molecules, has described taking NMN and resveratrol together as part of his personal longevity protocol. Human Nutrients NMN + Resveratrol provides 250 mg NMN and a standardised resveratrol extract in each capsule, formulated specifically for this synergistic mechanism.

The human trials that have shown measurable effects — including the Yoshino insulin sensitivity study and the Tsukuba physical performance trial — used 250 mg/day. That is the dose in each Human Nutrients NMN + Resveratrol capsule, and it is the dose we recommend for general longevity support. Some practitioners suggest higher doses (500–1,000 mg/day) for people over 50 with significant energy deficits, but the evidence base thins above 250 mg. Take one capsule daily with your morning meal. Because resveratrol is fat-soluble, taking it with food significantly improves bioavailability. Do not take late in the evening — increased NAD+ is mildly activating for some people.

NMN currently holds Novel Food status in Great Britain under FSA novel food regulations and is not authorised as a food supplement under current FSA guidance. Human Nutrients NMN + Resveratrol products are sold for research and personal use only. Novel Food status means the ingredient requires pre-market authorisation before it can be legally marketed as a food supplement — it does not mean the substance is banned or controlled. If you are in any doubt about suitability for your circumstances, consult your GP before purchase. Especially relevant if you are taking anticoagulants or antiplatelet medications.

Fish don't actually synthesise DHA — they accumulate it by eating marine algae. Sourcing directly from algae cuts out every contamination step in the middle: no mercury, no PCBs, no dioxins, no microplastics, no aquaculture antibiotics or pesticides from farmed salmon. It is also how you get DHA without putting a fish through commercial oil extraction, which heats, solvent-strips, bleaches and deodorises the oil — steps that degrade the DHA helix structure and, in Mark Howard's strong view, leave a pre-oxidised molecule that is no longer structurally useful for neuronal or retinal membranes. Human Nutrients sources DHA from Schizochytrium algae: the organism that synthesises DHA from scratch. Algae is the origin. Fish are just the polluted middleman.

DHA is the omega-3 that physically builds your brain and your retina. It is the dominant structural fatty acid in neuronal cell membranes and in the photoreceptor outer segments of the eye. EPA plays a separate role in inflammatory signalling — useful, but not structural. The biochemistry here is asymmetric: the human body can retro-convert DHA to EPA via partial beta-oxidation, but the forward EPA-to-DHA conversion pathway is inefficient and unreliable in humans. If you supply DHA, your body also gets the EPA it needs downstream. If you supply only EPA, you stay short on DHA. The rational approach is to supplement the molecule the brain is actually built from and let the body make the EPA it requires. This is why Human Nutrients Omega-3 DHA is DHA-led — not a conventional EPA:DHA blended fish oil.

Harder than almost any other essential nutrient. DHA is present at meaningful concentrations essentially only in oily fish. UK oily-fish consumption is consistently well below NHS-recommended levels — even among people who think they eat well. Plant-based alpha-linolenic acid (ALA) from flax, chia, or walnuts converts to DHA at roughly 0–5% in humans, which is effectively a rounding error. EFSA has established that 250 mg/day of DHA contributes to normal brain function and normal vision — a standard that most UK adults cannot reach through food alone without eating oily fish multiple times per week. For vegans and vegetarians, dietary DHA is structurally unattainable without supplementation. For omnivores who don't eat oily fish regularly, the situation is almost as limited.

Observational research has repeatedly associated lower blood-DHA status with faster cognitive decline and higher all-cause dementia risk. The Framingham Offspring cohort — one of the most cited longitudinal datasets in brain health research — reported that adults in the top quartile of red-blood-cell DHA had substantially lower dementia incidence and less brain volume loss than those in the bottom quartile. This is association, not proof of prevention, and it is Mark Howard's strong personal position — not settled medical consensus — that DHA deficiency is a root cause of today's dementia crisis. The logic of the risk/reward calculation is clear: DHA is the brain's most abundant omega-3, most adults are measurably deficient, and the downside of correcting that deficiency is essentially zero. Discuss with your GP if you have a family history of cognitive disease. We do not claim this product prevents or treats any condition.

Human Nutrients sources DHA from Schizochytrium algae cultivated in closed, controlled bio-pods — not harvested from the open ocean. The bio-pod environment means zero exposure to mercury, lead, cadmium, PCBs, dioxins, microplastics, aquaculture antibiotics, or parasiticides. Every contamination risk associated with ocean-sourced products is eliminated at source. This matters because persistent organic pollutants like PCBs and dioxins bio-accumulate up the food chain, and are most concentrated in the fatty tissues of fish that most fish-oil capsules are derived from. Sourcing from algae directly — where DHA is synthesised and before any bio-accumulation has occurred — is the only way to guarantee a clean-start molecule.

DHA is a long-chain polyunsaturated fatty acid with a tightly coiled helix structure, and it oxidises rapidly when exposed to heat or oxygen. Standard commercial fish-oil processing — heat extraction, solvent stripping, bleaching, deodorisation — degrades this structure and typically leaves a product that is already substantially oxidised before it reaches the shelf. Human Nutrients algae oil is cold-pressed (no heat degradation), handled under a nitrogen atmosphere to displace oxygen throughout processing, and encapsulated inside an inert-gas environment. The molecule that arrives in your gut is structurally intact. This is not a marketing footnote — the structural integrity of DHA is the whole point. A pre-oxidised DHA molecule is not the same thing as the DHA your neuronal membranes and retinal photoreceptors are built from.

Yes, entirely. The DHA oil is extracted from Schizochytrium algae, and the softgel shell is plant-based. No fish, no animal derivatives, no gelatin. Human Nutrients Omega-3 DHA is 100% vegan — which is also what makes it the logical choice for anyone who wants DHA without the ethical and contamination concerns that come with fish-derived products. Algae-sourced DHA is the same molecular form of DHA found in fish, because fish accumulate it from algae. We simply source it before it passes through the fish.

Yes, and the combination is deliberate. NMN + Resveratrol supports cellular energy, NAD+ restoration, and sirtuin-driven DNA repair — working primarily at the mitochondrial and nuclear level. Omega-3 DHA supports the structural integrity of neuronal membranes, retinal function, and the inflammatory signalling environment that affects long-term brain health. The two products address different mechanisms of ageing and are not competing — they are complementary. Many Human Nutrients customers take both daily as part of a structured longevity protocol. There are no known adverse interactions between these compounds.

Take NMN + Resveratrol with your first meal of the day. Morning is preferred because increased NAD+ is mildly stimulating for some people, and resveratrol's fat-soluble nature means it absorbs significantly better when taken with food containing dietary fat. Take Omega-3 DHA with any meal that contains fat — breakfast or lunch work well. DHA is a fat-soluble molecule and bile secretion triggered by food intake drives substantially better absorption than taking it fasted. If you are taking both products, taking them with the same morning meal is perfectly fine and makes adherence easier.

NMN works at the cellular level — raising NAD+ is not something you feel immediately in the way a stimulant would. Some people report improved energy and sleep quality within 2–4 weeks. The Yoshino et al. study measured significant effects on muscle insulin sensitivity after 10 weeks at 250 mg/day. For the longer-term benefits — cellular repair, mitochondrial health, sirtuin activity — you are playing a multi-month game, not a week-long experiment. Omega-3 DHA works similarly: the structural incorporation of DHA into neuronal membranes is gradual. Red blood cell DHA levels (the clinical measure used in research) typically take 8–12 weeks of consistent supplementation to shift meaningfully. Both products are long-term investments in cellular health, not short-term performance boosters.

NMN is well tolerated in human trials at doses from 100 mg to 1,200 mg/day, with no serious adverse events reported in published studies. A small number of people report mild digestive discomfort at higher doses, particularly if taken on an empty stomach — taking it with food resolves this in most cases. NMN should be avoided during pregnancy and breastfeeding, as there are no safety data in these populations. Omega-3 DHA at standard doses (250–500 mg/day) has an excellent safety record consistent with the EFSA-endorsed intake level. At higher doses, omega-3 fatty acids can have mild anticoagulant effects. Fish-oil-style burping or reflux is not a concern with algae-derived DHA in plant-based softgels.

If you are taking any prescription medication, consult your GP before starting either supplement. The specific interactions to be aware of: NMN can theoretically affect enzymes involved in drug metabolism (CYP450 pathways) at high doses, though this has not been demonstrated at the 250 mg clinical dose. Omega-3 fatty acids at doses above 1 g/day have mild anticoagulant properties — if you are taking warfarin, aspirin, clopidogrel, or other antiplatelet or anticoagulant medications, discuss DHA supplementation with your GP or anticoagulation clinic before starting. At the standard dose in Human Nutrients Omega-3 DHA, the anticoagulant effect is modest, but clinical guidance takes priority.

The published human data on NMN extends to about 12 months. Within that window, no safety signals have emerged at doses up to 1,200 mg/day. The mechanistic rationale for long-term NAD+ support is strong, and NMN appears naturally in the diet — it is not a novel foreign compound. Omega-3 DHA has a far longer safety record: populations with high dietary DHA intake have been studied for decades without adverse signals. EFSA considers 250 mg/day established as safe and beneficial for normal brain and vision function. Long-term DHA supplementation at physiological doses is considered low-risk by current evidence.

NMN + Resveratrol: not recommended during pregnancy or breastfeeding (insufficient safety data). People with a history of oestrogen-sensitive conditions should discuss resveratrol with their specialist, as resveratrol has mild phytoestrogenic activity. Those with known liver conditions should consult their GP before use. Omega-3 DHA: people on anticoagulant or antiplatelet therapy should consult their GP before taking DHA at any dose. Those with algae allergies (rare) should avoid this product. Neither product is intended for use by children under 18 without medical guidance.

Yes. Every batch of Human Nutrients NMN + Resveratrol and Omega-3 DHA is independently tested by accredited third-party laboratories for purity, potency, heavy metals, and microbial contaminants before it is released for sale. For the algae-derived Omega-3 DHA specifically, testing confirms the absence of mercury, lead, cadmium, PCBs, and dioxins — the contaminants that make fish-oil quality control problematic. Certificates of analysis are available on request by emailing support@humannutrients.com with your batch number (printed on the product label).

Both products are manufactured in GMP-certified facilities operating under UK food supplement manufacturing standards. The NMN raw material is sourced from a pharmaceutical-grade supplier and tested for identity, purity, and NMN content before it enters production. The algae oil undergoes cold-press extraction and nitrogen-atmosphere encapsulation in a controlled environment that prevents oxidation at every stage. Finished products are then independently re-tested by a third-party laboratory before dispatch. This two-stage testing approach — raw material and finished product — is what lets us guarantee label accuracy on potency and purity.

Standard UK delivery takes 2–4 working days from dispatch. Orders placed before 2 pm on working days are typically dispatched the same day. You will receive a dispatch confirmation email with tracking information. Expedited next-working-day delivery is available at checkout for an additional fee. All products are dispatched from our UK fulfilment centre.

We currently ship to the UK, EU, and the United States. International orders typically arrive within 5–10 working days depending on destination and customs processing. Import duties and local taxes may apply and are the responsibility of the customer. EU customers should note that post-Brexit customs declarations may result in small processing delays. Contact us at support@humannutrients.com if you have a query about a specific destination.

Human Nutrients offers a 30-day money-back guarantee on all products. If you are not satisfied for any reason — whether the product did not meet your expectations or you have simply changed your mind — contact us within 30 days of delivery and we will arrange a full refund. Products must be returned in their original packaging. This guarantee applies to one-time purchases and to the first order of any subscription. We do not require customers to jump through hoops to claim a refund.

Email support@humannutrients.com with your order number and a brief note on your reason for return. We will respond within one working day with a prepaid return label and instructions. Refunds are processed within 5–7 working days of receiving the returned product and will be issued to your original payment method. If your product arrived damaged or incorrect, we will reship at no cost — no return required.

Select Subscribe & Save on any product page to receive 10% off every order automatically. Your supplements are dispatched every 30 days by default, or at your preferred interval — 30, 60, or 90-day options are available on request. There are no contracts, no commitments, and no cancellation penalties. Subscribers also receive priority dispatch and early access to new products. Managing your subscription is straightforward: email support@humannutrients.com to pause, skip an order, adjust frequency, or cancel.

Yes. There are no lock-in periods and no cancellation fees. Email support@humannutrients.com at any time to pause, skip an order, change your delivery frequency, or cancel entirely. Cancellations take effect before your next scheduled dispatch — if you cancel after a dispatch has already been processed, that order will still arrive but no further orders will be placed. We aim to confirm all subscription changes within one working day.