Xanthan gum (CAS 11138-66-2) is the workhorse natural polymer of both cosmetics and home care. It thickens across pH 2–12, tolerates high electrolyte loads, survives surfactant systems and heat, and delivers a short, non-stringy flow. It is also the source of one of the most common manufacturing complaints — "fish eyes," the hydrated lumps that form when powder meets water too quickly. Almost every xanthan problem is a dispersion problem.
Why formulators choose it
- Pseudoplastic flow — high viscosity at rest (suspends particles, prevents creaming), low viscosity under shear (easy pumping, smooth rub-out, no stringiness).
- Electrolyte tolerance — unlike carbomer, xanthan needs no neutralization and keeps working in salt-rich surfactant systems, aloe gels and sweat-resistant sunscreens.
- pH and temperature stability — effective from pH 2 to 12 and stable through repeated freeze-thaw and heat cycles.
- Synergy with other thickeners — combined with guar or HPMC it builds yield value at lower total polymer dose.
Typical use levels
| Application | Use level | Effect |
|---|---|---|
| Shampoos & body washes | 0.1–0.4% | Suspends pearlescers / actives; stabilizes foam |
| O/W creams and lotions | 0.1–0.3% | Long-term emulsion stability, improves body |
| Transparent gels (toner, aloe) | 0.3–1.0% | Primary thickener; clarity depends on grade |
| Toothpaste | 0.4–0.8% | Stand-up paste, flavor suspension |
| Dishwashing & laundry liquids | 0.1–0.5% | Suspends enzymes, fragrance capsules |
How to disperse it without fish eyes
- Pre-disperse in glycol or oil — wet the powder in butylene glycol, glycerin or part of the oil phase, then add to water under vigorous agitation. This is the most reliable lab technique.
- Or use vortex addition — sprinkle slowly into the vortex of fast-moving water; reduce speed only after full dispersion.
- Give it time — full hydration takes 15–45 minutes depending on mesh, temperature and shear. Viscosity that "appears overnight" is usually just delayed hydration.
- Hydrate before adding salt — electrolytes slow hydration dramatically. In surfactant systems, add xanthan to the diluted surfactant-and-water phase first, then salt-thicken afterwards.
- Mild heat helps (40–60°C) but is not required; never rely on heat alone to fix a lumped dispersion.
Mesh (particle size) selection
Standard 80-mesh xanthan is economical and performs well with good agitation. 200-mesh "fast-hydrating" grades disperse more quickly and lump less — worth the premium in cold-process or low-shear manufacturing. Transparent gel applications should specify low-dust, high-clarity grades and confirm clarity in the actual formula, since surfactants and actives interact with the polymer.
Common pitfalls
- Fish eyes — dispersion failure, not a product defect; fix the process, not the supplier (usually).
- Microbial contamination — hydrated xanthan is an excellent bug food; keep preservation robust (see our article on preservation boosters) and never store pre-hydrated batches.
- Skin feel — above ~0.5% in leave-on products, xanthan can feel slightly tacky; balance with emollients or reduce the dose with a co-thickener.
We supply xanthan gum (CAS 11138-66-2) from leading Chinese fermentation plants, with mesh, viscosity grade and full documentation available on request. Contact our team for grade selection support and current pricing.