One Bottle or Two? Understanding Nattokinase + Serrapeptase Before You Combine Enzymes
You have already decided nattokinase is worth a closer look. Then serrapeptase keeps appearing beside it, and a very natural question follows: does that mean you should add a second bottle?
Direct answer: Combined nattokinase and serrapeptase products exist, but two individual supplements are not automatically equivalent to a pre-formulated combination. The full formula, activity units, directions, medicines and personal suitability all matter.
Nattokinase and serrapeptase often appear in the same supplement conversation because both are proteolytic enzymes, meaning they act on proteins, and both are sold in enzyme-focused formulas. That does not make them interchangeable. If you want to compare the nattokinase side first, our nattokinase collection brings focused products and combination formulas together in one place.
Before you add a second bottle, read the activity units
If you came here searching nattokinase vs serrapeptase, one of the most useful things to understand is the label. Enzymes are commonly described by activity, not just by their weight in milligrams.
FU belongs to nattokinase
Nattokinase activity is shown in FU, or fibrinolytic units. A label showing 2,000 FU is describing the measured activity of that nattokinase ingredient.
SPU belongs to serrapeptase
Serrapeptase activity is shown in SPU, or serratiopeptidase activity units. A label showing 40,000 SPU is describing serrapeptase activity.
The important point is that FU and SPU are different measurements. You cannot look at 40,000 SPU and 2,000 FU and conclude that one enzyme is stronger simply because its number is larger. It is an FU vs SPU comparison, not a single shared scale.
If you want more background on FU, vitamin K2 and general nattokinase label reading, our complete nattokinase guide goes deeper without needing to repeat all of that here.
Open one real combined formula and the difference becomes clearer
Our current Doctor's Best Natto-Serra gives a useful real-world example of a nattokinase serrapeptase combination. Each veggie capsule provides 2,000 FU of nattokinase and 40,000 SPU of serrapeptase.
The formula uses a delayed-release capsule, and the serrapeptase is supplied with Serrateric. It contains soy. The current directions are one capsule daily without food, or as recommended by a healthcare professional.
What we like about this format is the clarity. You can see both enzyme activities in one capsule, with one set of ingredients and one set of directions. The delayed-release capsule and Serrateric are part of the formula design, but we do not treat those delivery features as a guarantee of better clinical outcomes.
Why we do not treat two separate enzyme bottles as the same as Natto-Serra
This is where the second-bottle question really matters. Our Doctor's Best standalone nattokinase currently supplies 2,000 FU per veggie capsule. Our Doctor's Best standalone serrapeptase is a separate high-potency product providing 120,000 SPU per veggie capsule.
So buying one bottle of each does not recreate Natto-Serra. The nattokinase activity may look familiar, but the serrapeptase activity is different, and the standalone serrapeptase also has its own formulation, directions and precautions.
That is why we do not suggest treating two standalone products as a DIY copy of a combined capsule. You are making a different formula choice, with different total enzyme activity and different label instructions. More ingredients, more capsules or bigger-looking numbers are not automatically better.
A pre-formulated combination can be attractive when you specifically want nattokinase and serrapeptase in one labelled product. A focused nattokinase product can make more sense when you want to keep the formula centred on nattokinase. The right comparison is the complete label, not the number of bottles on the shelf.
When the question moves from shopping to safety
There is a point where can I take serrapeptase with nattokinase stops being a product-comparison question and becomes something to check with a pharmacist or clinician.
Please do that before using these enzymes if you take anticoagulant or antiplatelet medicines, have a bleeding or clotting condition, have surgery planned, are pregnant or breastfeeding, have a soy allergy, or have another health situation where the product label advises caution. Natto-Serra contains soy, and its current label specifically says to consult a doctor before use if you take blood thinners.
Do not stop, replace or change a prescribed medicine because you are considering an enzyme supplement. In New Zealand, Healthify also advises checking with a doctor or pharmacist before adding supplements when you use medicines that affect clotting, because supplements can interact with medicines and may increase bleeding risk.
It is also worth keeping expectations sensible around serrapeptidase. Published clinical evidence is limited, and a systematic review found that long-term safety data were lacking. We still think clear labels and well-defined formulas are useful, but that evidence gap is a good reason not to turn a shopping question into self-prescribed dosing.
Which Healthy shelf makes sense to browse?
If you want a focused nattokinase product, start with the nattokinase options and compare FU, capsule count, ingredients and directions. If you already know you want a combined formula, Natto-Serra is a different product type because nattokinase and serrapeptase are already presented together in one capsule with one set of directions.
You can also browse our heart health collection if you want to see the wider category, but there is no need to treat a longer ingredient list as automatically more suitable.
Our simplest advice is to compare the whole label and choose what fits your situation. For a wider view of focused and combination products, return to our nattokinase collection.
Common questions about nattokinase and serrapeptase
Can you take nattokinase and serrapeptase together?
Combined products containing both enzymes exist, including Natto-Serra. That does not mean everyone should combine separate supplements. Check the full formula, activity units, directions, medicines and your personal suitability, and ask a pharmacist or clinician if medicines or bleeding risk are involved.
Are nattokinase and serrapeptase the same thing?
No. They are different enzymes. Nattokinase activity is measured in FU, while serrapeptase activity is measured in SPU, and products can differ in formulation, directions and precautions.
What is the difference between FU and SPU?
FU are fibrinolytic units used to express nattokinase activity. SPU are serratiopeptidase activity units used to express serrapeptase activity. They are different measurements, so the numbers should not be ranked against each other simply by size.
Is a combined nattokinase and serrapeptase capsule the same as taking two separate supplements?
No. A combined capsule has its own set amounts, delivery format, directions and precautions. Two standalone products can create a different total formula, so they should not be treated as an automatic substitute for a pre-formulated combination.
Why is Natto-Serra taken without food?
The current Natto-Serra directions specify one capsule daily without food. It is a delayed-release enzyme formula, so we recommend following its own label timing rather than borrowing directions from another enzyme or digestive supplement.
Who should check with a doctor or pharmacist before using nattokinase or serrapeptase?
Check first if you take anticoagulant or antiplatelet medicines, have a bleeding or clotting condition, have surgery planned, are pregnant or breastfeeding, have a soy allergy, or have another condition or medicine that may affect suitability.
Does Natto-Serra contain soy?
Yes. Our current Doctor's Best Natto-Serra label states that it contains soy, so it is not suitable for someone with a soy allergy.
Can nattokinase or serrapeptase be used with blood-thinning medicines?
This needs professional advice rather than a self-directed combination. Current labels for these Doctor's Best enzyme products include cautions around blood-thinning or anticoagulant medicines. Do not stop or replace prescribed medicine to use a supplement.
References
- Healthify NZ: Supplements
- Healthify NZ: Anticoagulants and antiplatelets
- Healthify NZ: Preparing for surgery
- Memorial Sloan Kettering Cancer Center: Nattokinase
- PubMed: Serratiopeptidase systematic review
This article is general information only. Supplements are not a substitute for prescribed medicines or individual medical advice. Always follow the product label.