This is a systemic enzyme formula aimed at circulation and healthy blood flow, built around two proteolytic enzymes measured in activity units rather than milligrams. The **Nattokinase** delivers 2,000 FU per capsule — exactly the dose where a meta-analysis of 6 RCTs found modest blood pressure reductions, so you're sitting right at the effective minimum. It works by supporting your body's natural breakdown of blood clots, which is the strongest evidence-backed reason to take it.

The **Serrapeptase** is dosed at 40,000 SPU, the bottom of the 40,000–120,000 SPU range used in trials, where the typical research dose runs closer to 60,000 SPU daily. Its evidence is thinner — mostly smaller, older studies for post-surgical swelling and sinus congestion — so treat this as a secondary, more speculative ingredient rather than your reason to buy.

One thing you genuinely need to know: nattokinase has measurable clot-thinning effects, so if you're on blood thinners or have a bleeding condition, check with your doctor before using it. The formula also contains soy. At one capsule a day you're getting the minimum effective nattokinase dose and a light serrapeptase dose — workable for general circulatory support, but you'd want a higher SPU count if serrapeptase is your actual target.

BioStacks
Doctor's Best

Natto-Serra (Nattokinase-Serrapeptase)

1 Capsule · 90 servings · $0.30/serving

iHerbAmazon

Best for

Heart

Ingredients (3)

Serrapeptase

100%

Dose

40000 SPU

Target

40000–120000 spu

Form

—

Nattokinase

100%

Dose

2000 FU

Target

2000–4000 fu

Form

—

Calcium

29 mg

Trace amount — not scored

Other Ingredients (7)

MaltodextrinBinder

Spikes blood sugar faster than table sugar (glycemic index 85–105). Research links it to gut bacteria changes that may promote intestinal inflammation (Nickerson et al. 2015). Used as a cheap filler — adds nothing beneficial.

Medium Chain Triglyceride OilCarrier

Fractionated oils rich in C8/C10 triglycerides used as neutral carrier or anti-sticking agent

Calcium StearateLubricant

Calcium salt of stearic acid used as a lubricant and anti-sticking agent

Gellan GumGelling Agent

Microbial polysaccharide produced by Sphingomonas elodea, used as a gelling and stabilizing agent

HypromelloseCapsule

Plant-derived capsule material from cellulose

Calcium CarbonateBuffer

Common calcium salt used as a buffering agent, filler, or mineral fortification in supplements

Purified WaterSolvent

Water meeting USP specifications used as solvent/vehicle in gummies and liquids

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Sources & Scoring

Nutrient data (RDA, UL, and safety thresholds) sourced from: NIH Office of Dietary Supplements and National Academies Dietary Reference Intakes (DRI).

This is not medical advice. Consult a healthcare provider before making changes to your supplement routine.

The score analyzes what's on the label: ingredient doses vs. clinical ranges, chemical forms, evidence levels, and known interactions. It does not verify label accuracy or test for contaminants — for that, look for third-party certifications like USP or NSF.

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