Neprinol AFD (systemic enzyme blend)
The best-known systemic enzyme blend — serrapeptase, nattokinase, lipase and proteases in one capsule, widely recommended as an upgrade on plain nattokinase. It is a proprietary blend, which is the whole problem: the one number that mattered in the nattokinase trials is the one the label doesn't tell you.
Graded on the blend, not on its ingredients. There is no published controlled trial of Neprinol AFD; the case for it is mechanistic plus manufacturer-reported data with no design or citation attached. Its components grade separately and higher — nattokinase moderate (3/5), serrapeptase moderate for swelling and sinusitis but weak for anything vascular — and a combination is not entitled to the sum of its parts. The proprietary blend compounds it: the nattokinase dose is undisclosed, and that dose is the whole story in the plaque data. Effects on fibrinogen and viscosity, if any, would take 4–8 weeks.
Neprinol AFD (Arthur Andrew Medical) is a 500 mg proprietary blend combining serrapeptase, nattokinase and lipase with a protease trio (Serratia, B. subtilis, A. oryzae) and cofactors — amla, papain, bromelain, rutin and CoQ10. It is the reference product in the 'systemic enzyme' category and the one people mean when they say a blend beats nattokinase alone. The reasoning is intuitive: several fibrinolytic enzymes should out-perform one. It has never been tested. There is no published, peer-reviewed, controlled trial of Neprinol itself; the manufacturer's own clinical-data page cites a 12-week blood-viscosity result with no participant count, no design, no journal and no citation. Everything else it points to is evidence for individual ingredients, which we grade separately — nattokinase at moderate, serrapeptase at weak. Two enzymes with an unproven combination is not the same as an improvement, and 'more enzymes' is a hypothesis, not a finding. Then there is the arithmetic. The marketing headline is 15,000 FU of nattokinase per capsule. NSK-SD, the research-grade nattokinase used in the trials, is standardised at 20,000 FU per gram — so 15,000 FU is 750 mg of it, inside a blend that totals 500 mg and contains nine other named ingredients. That doesn't fit. Either the nattokinase is a far more concentrated grade than the one the trials used, or — as the printed Supplement Facts panel suggests, by grouping serrapeptase, nattokinase and lipase under a single '15,000 FU' line — the figure is the combined fibrinolytic activity of three enzymes rather than nattokinase alone. Both readings lead to the same place: you cannot know how much nattokinase you are taking. That is fatal for the plaque and cholesterol claim specifically, because those effects were sharply dose-dependent — 10,800 FU/day moved carotid plaque and 3,600 FU/day did nothing at all. A dose you can't verify can't be aimed at a threshold. If what you want is the nattokinase effect, a standalone NSK-SD product states its FU and lets you hit the number. Neprinol's honest case is different and narrower: it delivers a real serrapeptase dose (45,000 SPU per capsule, so 135,000 SPU at the 3-a-day maintenance tier — in the range serrapeptase's own literature uses) alongside a fibrinolytic enzyme, in one capsule, for people who want the whole systemic-enzyme approach and accept it is a mechanistic bet rather than an evidenced one.
Key studies
- Serratiopeptidase: a systematic review of the existing evidence (Int J Surg, 2013) — The honest read on the blend's headline enzyme. Reviewing the published trials, the authors found most had small samples, poorly defined enrollment and outcomes, unclear statistics, short duration, and in several cases no reported dose — concluding efficacy is not well established. Serrapeptase is the ingredient Neprinol is dosed most generously with, and it is the weaker half of the evidence.
- Frontiers in Cardiovascular Medicine, 2022 — the nattokinase dose-response — Why an undisclosed dose matters here more than usual. Over 12 months, 10,800 FU/day cut carotid plaque ~36.6%; 3,600 FU/day did nothing. The effect lives at a threshold, so a proprietary blend that won't tell you which side of it you're on can't be aimed. (Read the trial itself with caution too — largely one research orbit, no true placebo arm.)
- Manufacturer's clinical data page — Arthur Andrew Medical — Listed as a primary source so you can check us. It reports a 12-week reduction in blood viscosity for Neprinol with no participant count, no design, no journal and no citation, and otherwise cites work on individual ingredients rather than the blend. Read it and judge for yourself — that absence is the reason for the grade.
- Form
- Capsules of a 500 mg proprietary blend, plus 8 mg magnesium citrate. Not enteric-coated in the conventional sense: Arthur Andrew uses thick cellulose 'Acid Armor' capsules said to delay release for up to an hour, arguing microbial and plant enzymes tolerate pH 2–10 and that an empty stomach clears the capsule in ~30 minutes. That is a reasonable rationale and a manufacturer claim, not an independently verified one — and our own serrapeptase entry treats enteric coating as non-negotiable, so weigh it accordingly.
- Dose
- Manufacturer tiers, all on an empty stomach: 2–3 capsules/day maintenance, 4–6 for 'increased support', up to 9 for 'advanced'. Note what that costs — at ~$0.73/capsule the 9-a-day tier is roughly $200/month. Higher tiers also mean more fibrinolytic activity, so the bleeding caution scales with them.
- Timing
- Empty stomach, with a full glass of water — at least 30–60 minutes before food or 2 hours after. Taken with a meal the enzymes work on your lunch instead of systemically, which is the single most common way people waste this category.
- Schedule
- Daily. Enzyme effects on fibrinogen and viscosity build over 4–8 weeks, not days.
- Side effects
- Generally well tolerated. Mild GI upset, nausea or loose stools, especially at the higher tiers; headache. Easier bruising and longer bleeding from small cuts are the signal to reduce the dose.
- Interactions
- Anticoagulants and antiplatelets (warfarin, DOACs, aspirin, clopidogrel) — additive blood-thinning across several enzymes at once, and the manufacturer's own label says not to take it without your physician's consent if you're on anticoagulants. Antihypertensives — additive BP lowering via the nattokinase fraction. Bromelain in the blend can increase absorption of some antibiotics.
- Contraindications
- Bleeding disorders or on blood thinners without medical supervision. Surgery or dental extraction — stop 7–14 days before. Pregnancy and nursing (manufacturer advises against). Active ulcer or recent GI bleed. Recent stroke or active bleeding. Soy allergy is a question worth asking the manufacturer, since nattokinase is natto-derived even where the finished product is labelled soy-free.
- Lab markers
- Fibrinogen and D-dimer if you're using it for viscosity or microclot reasons. PT/INR if on warfarin. Blood pressure. If the goal is plaque, the honest markers are ApoB, Lp(a) and a repeat scan — not how you feel.
- Food sources
- None as a blend. Natto — fermented soybeans — supplies nattokinase plus the richest dietary MK-7 there is; nothing in the diet supplies serrapeptase.
Pairs with
Nattokinase (standalone, NSK-SD) — if the fibrinolytic effect is the goal, a stated FU beats a blended one; taking both stacks the bleeding risk. Serrapeptase — already in here, don't double it. Vitamin K2 (MK-7), omega-3 EPA, aged garlic extract — the rest of a plaque-directed stack, all with their own evidence.
Where to buy
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