Double Wood Nattokinase 4,000 FU Review
Double Wood · Last updated 1 June 2026
Trust Checklist2/6 passed
3rd Party Batch Tested
SORA tested (one-off)
Met or Exceeded Label Potency
2,800 FU vs 4,000 FU (70%, under claim)
Public Certificates of Analysis
No public per-batch COAs
GMP Certified
GMP manufacturing
Made in the UK
US brand, imported
Vitamin K2-Free (warfarin safe)
Not independently verified K2-free
Rating Breakdown
Pros & Cons
Pros
- SORA tested — confirmed 2,800 FU vs 4,000 FU claim (70%, just within acceptable threshold)
- Easy to order via Amazon UK
- Budget-friendly versus the top three
- Single-capsule daily serving
Cons
- Low real dose — only 2,800 FU verified despite the 4,000 FU label
- 30% under its label claim (2,800 FU vs 4,000 FU)
- Does not 3rd party test every batch
- Sits at the bottom of the acceptable potency threshold
Product Details
- Form
- Capsule (Nattokinase enzyme)
- Dosage per Serving
- 4,000 FU nattokinase
- Potency
- 4,000 FU (tested 2,800)
- Serving Size
- 1 capsule
- Servings per Container
- 90
- Price
- £15.99
- Price per Serving
- £0.18
- Other Ingredients
- Capsule shell, Rice flour
- Certifications
- SORA Labs Tested (Passed, 70%)
Full Review
Ingredient Quality
Double Wood was SORA-tested at 2,800 FU against a 4,000 FU claim — 70%, which sits right at the bottom of the acceptable threshold. It contains a genuine, active enzyme, but it's meaningfully under its stated potency, so the '4,000 FU' on the front overstates what you actually get.
Value Analysis
It's cheaper than the top three, and on a per-capsule basis still delivers a usable dose. But value should be judged on actual delivered FU — at 2,800 FU you're getting less than the label implies, which narrows the apparent price advantage.
Effectiveness
2,800 FU is still a meaningful nattokinase dose, so it will have an effect. The concern is the gap between claim and reality and the lack of ongoing batch transparency — you can't be sure each batch holds up.
Who Is This Best For?
Budget buyers who want a single-capsule daily dose and accept that the real potency is about 30% below the label.
Where to Buy
Prices are approximate and may vary. As an affiliate, we may earn a commission from qualifying purchases at no extra cost to you. This does not influence our reviews or rankings of Double Wood Nattokinase 4,000 FU.
Double Wood Nattokinase 4,000 FU FAQ
Is Double Wood nattokinase under-dosed?
SORA testing found 2,800 FU against its 4,000 FU claim — about 30% below label, though still within the acceptable 70% threshold. It contains genuine active enzyme, just less than the front of the bottle states.