Follow Your Swallow

IDDSI Level 1

Slightly Thick

Thicker than water, still drinkable through a straw.

Flows a little slower than water. Often used for infants, but some adults are prescribed it.

Similar to many anti-regurgitation infant formulas or naturally thick nectars.

video: Level 1 testing method

10 mL syringe flow test: 1–4 mL remains after 10 seconds.

Run the guided syringe test
  • Commercially pre-thickened waters labeled Level 1
  • Some buttermilks
  • Some nutrition shakes
Products can vary by batch. Always verify with the IDDSI tests before serving.How to test →
  • Eyeballing it — Level 1 is hard to judge visually. Always confirm with the syringe test.
  • Letting thickened drinks sit — many keep thickening over time.
Browse verified Level 1 products →