Cheapest Japanese Knotweed Extract on iHerb
Ranked by real cost per 100 mg of Japanese Knotweed Extract — cheapest value first.
Prices updated Jul 25, 2026 · 5 products · Prices in USD
| # | Product | Dose | Price (USD) | Cost per 100 mg | |
|---|---|---|---|---|---|
| 1 |  | 421 mg | 19.99 | 0.040 | View on iHerb → |
| 2 |  | 250 mg | 21.39 | 0.285 | View on iHerb → |
| 3 |  | 80 mg | 25.49 | 0.531 | View on iHerb → |
| 4 |  | 100 mg | 83.95 | 4.00 | View on iHerb → |
| 5 |  | 5 mg | 16.19 | 7.20 | View on iHerb → |
- 1Cost per 100 mg 0.040
- Dose
- 421 mg
- Servings
- 120
- Price (USD)
- 19.99
- 2Cost per 100 mg 0.285
- Dose
- 250 mg
- Servings
- 30
- Price (USD)
- 21.39
- 3Cost per 100 mg 0.531
- Dose
- 80 mg
- Servings
- 60
- Price (USD)
- 25.49
- 4Cost per 100 mg 4.00
- Dose
- 100 mg
- Servings
- 21
- Price (USD)
- 83.95
- 5Cost per 100 mg 7.20
- Dose
- 5 mg
- Servings
- 45
- Price (USD)
- 16.19
How we rank Japanese Knotweed Extract
Two supplements can list the same dose per serving yet cost very differently once you account for how many servings are in the bottle. We calculate the total nutrient in each container (dose per serving × servings per container), divide the current price by that total, and rank by the resulting cost per unit. Lower is better. Because prices are refreshed automatically, this ranking reflects today's iHerb pricing rather than a snapshot from months ago.
Cost per unit is a starting point, not the whole story — the ideal form, third-party testing, and other ingredients matter too. Always check the label and consult a healthcare professional before starting a supplement.
Prices update automatically and may differ from iHerb at checkout. Rankings are based on cost per unit of the listed nutrient and are for informational purposes only — not medical advice. Links to iHerb are affiliate links.