Order protocol
Sleep & recovery Whole topic
Hormones & energy Whole topic
Metabolism & nutrition Whole topic
Brain & mind Whole topic
Longevity & body Whole topic
Women & family Whole topic
Basics & environment Whole topic
Biohacking & technology Whole topic
Fénix Methode

Tired of generic advice? A protocol built on your numbers.

Order protocol
All articles Every article is based on a chapter of the book NAVRHNUTÝ and peer-reviewed studies.
Biohacker score2 minutes – find out where your body holds you back Results checkNormal vs. optimal for your blood values Biological ageHow old your body is – from 9 blood values CalculatorsBMI, waist, protein, sleep, caffeine, VO2max Daily helperDaily routines, light, sleep and breathing on your phone My stackCheck supplements & medication + daily plan ChallengesSmall daily habits with reminders Fitness testVO2max, fitness age, strength and balance at home Biological twinAll your data in a 3D body What to get testedPrintable list of blood tests Sample protocolSee what you get E-numbers & sugarsWhat is on the label and what to avoid Online advisorAnswers to common questions about body and results SupplementsForms, timing and combination check RecipesMeals without hidden sugars or needless additives GlossaryBiohacking explained from A to Z Gift voucherGive health – the protocol or the book
← Back to the E-number overview
E551Caution

Silicon dioxide (silica)

Group: Other

Harm level3 of 5In moderation

In plain words

Silicon dioxide is a fine white powder that stops dry foods from clumping. You find it in spice mixes, instant soups, salt, powdered creamers and food supplements.

Where you find it: spices, powdered mixes, salt

Our recommendation

No reason for alarm, but it is sensible to limit it, especially in ultra-processed foods.

Possible risks and effects

  • Possible effects of nanoparticles are not fully studied.
  • No direct harm shown at normal intake.

For experts

Synthetic amorphous silica (fumed or precipitated) used as an anti-caking agent and carrier; it is barely absorbed from the gut. In 2018 EFSA found no evidence of harm but, because of data gaps especially on the nano-sized fraction, did not confirm an ADI and requested more data.

Check another E-number

More from this group

E554Sodium aluminium silicateE900DimethylpolysiloxaneE1520Propylene glycolE535–E538FerrocyanidesE290Carbon dioxideE422GlycerolE509Calcium chlorideE516Calcium sulphate

This information is educational and based on EFSA assessments and available studies; it does not replace medical advice. With allergies, intolerances or illness, follow your doctor’s advice.