HARD-WATER CHELATOR
Tetrasodium Glutamate Diacetate
- hard-water chelator
A biodegradable hard-water chelator used in place of EDTA.
- products in our library
- 393
- of researched products
- 6%
- on the label, in our shampoos
- usually #20
- most common in
- Shampoo
- in water
- Water-soluble
At a glance
Four things worth knowing about how this ingredient behaves on hair.
How much of it is left on hair between washes.
What it takes to get it off the hair again.
The housekeeping this class does.
Where it sits on the labels we have, in the category it appears in most.
| Property | Level | Out of |
|---|---|---|
| Buildup risk | Low | 1 of 5 |
| Rinse-out behaviour | Rinses clean | 5 of 5 |
| Job | Ties up hard-water minerals | 4 of 5 |
| Prominence | Secondary | 2 of 5 |
What it does for a formula
What Tetrasodium Glutamate Diacetate does
The general function first, then how the role changes by product type where we have researched it.
Stops calcium and iron in tap water dulling a wash.
Water alone removes it, so it does not accumulate between washes.
Charge
Negatively charged, like the hair surface itself, so hair pushes it away instead of holding on to it. It rinses off easily, and most detergents carry this charge.
Solubility
Rinses out with water alone, so it does not build up on hair between washes.
Where it appears
Where it appears
One row per product category in our library: how many products list it, what share of that category that is, and where it typically sits on the label.
| Product type | How common | Typical position on label ? |
|---|---|---|
Shampoo
132 products
|
secondary · #20 | |
Conditioner
71 products
|
secondary · #24 | |
Leave-in
34 products
|
secondary · #18 | |
Mask / treatment
33 products
|
secondary · #24 | |
Scalp treatment
21 products
|
secondary · #19 | |
Heat protectant
17 products
|
secondary · #20 | |
Styler: gel
16 products
|
secondary · #16 | |
Styler: curl cream
14 products
|
secondary · #19 | |
Styler: mousse
14 products
|
secondary · #19 | |
Co-wash
6 products
|
secondary · #13 |
12 more product types
| Product type | How common | Typical position on label ? |
|---|---|---|
Styler: paste
6 products
|
secondary · #18 | |
Finisher: serum
5 products
|
secondary · #15 | |
Styler: hairspray
5 products
|
secondary · #12 | |
Styler: volumizer
4 products
|
secondary · #16 | |
Dry shampoo
3 products
|
secondary · #19 | |
Styler: texture spray
3 products
|
secondary · #11 | |
Styler: lotion
2 products
|
secondary · #16 | |
Styler: refresh spray
2 products
|
secondary · #19 | |
Styler: smoothing cream
2 products
|
secondary · #24 | |
Finisher: anti frizz finish
1 product
|
secondary · #36 | |
Finisher: shine spray
1 product
|
secondary · #38 | |
Styler: edge control
1 product
|
secondary · #16 |
| Product type | Products | Share of category | Median position | Earliest position | Band |
|---|---|---|---|---|---|
| Shampoo | 132 | 8% | 20 | 7 | secondary |
| Conditioner | 71 | 6% | 24 | 7 | secondary |
| Leave-in | 34 | 5% | 18 | 7 | secondary |
| Mask / treatment | 33 | 6% | 24 | 7 | secondary |
| Scalp treatment | 21 | 7% | 19 | 9 | secondary |
| Heat protectant | 17 | 8% | 20 | 12 | secondary |
| Styler: gel | 16 | 6% | 16 | 9 | secondary |
| Styler: curl cream | 14 | 6% | 19 | 9 | secondary |
| Styler: mousse | 14 | 7% | 19 | 11 | secondary |
| Co-wash | 6 | 6% | 13 | 2 | secondary |
| Styler: paste | 6 | 3% | 18 | 9 | secondary |
| Finisher: serum | 5 | 4% | 15 | 11 | secondary |
| Styler: hairspray | 5 | 2% | 12 | 10 | secondary |
| Styler: volumizer | 4 | 3% | 16 | 10 | secondary |
| Dry shampoo | 3 | 2% | 19 | 14 | secondary |
| Styler: texture spray | 3 | 3% | 11 | 10 | secondary |
| Styler: lotion | 2 | 6% | 16 | 9 | secondary |
| Styler: refresh spray | 2 | 6% | 19 | 14 | secondary |
| Styler: smoothing cream | 2 | 2% | 24 | 22 | secondary |
| Finisher: anti frizz finish | 1 | 3% | 36 | 36 | secondary |
| Finisher: shine spray | 1 | 1% | 38 | 38 | secondary |
| Styler: edge control | 1 | 3% | 16 | 16 | secondary |
We have not researched differences by product type yet. The reading below comes from where it sits on the labels in our library.
Position footprint
Every listing in our library, by position on the label.
| Positions | Zone | Listings |
|---|---|---|
| 1-3 | Leading | 1 |
| 4-8 | Supporting | 9 |
| 9-15 | Secondary | 113 |
| 16-25 | Lower | 169 |
| 26+ | Trace | 101 |
How to read this
US labelling rules put ingredients above 1% in descending order of amount; below 1% they may be listed in any order.
So position tells you about relative amount only above that line, and we never convert a position into a percentage.
Who should pay attention
Formulation guidance for specific hair conditions, limited to the label positions where it applies. It is not a conclusion about any finished product, or about you.
Binds the calcium and magnesium in hard water, which is what stops mineral deposits accumulating on the strand wash after wash.
Copper and iron carried in tap water deposit on the strand and read as a dull, warm cast on gray or light hair. A chelator holds those metals in solution so the wash carries them off.
Read from this ingredient’s chemical class. Where we have researched the ingredient itself, that reading replaces the class one.
Why it matters to shoppers
What seeing this ingredient tells you, what it does not, and the limits of our own method.
- a formula built for hard water
- a rinse-clean feel
- a routine that does not build up
- gray or light hair to stay cool rather than warm
- an exact safety score (we do not publish one for any ingredient)
- how a finished product performs, which depends on the whole formula, not one line of it
- the exact percentage in a bottle, because label position never converts into a number
- a secondary chelator, listed below the main ingredients in our shampoos
- it was on the printed ingredient list of every product we counted (we read labels, not marketing copy)
- that a product is right or wrong for you
We do not publish safety scores or hazard grades. Where a regulator has published a restriction or a use condition, we state it and cite it; otherwise we describe what the ingredient does and stop.
Commonly paired with
The ingredients that most often appear alongside this one in our library. We leave out the near-universal ones, because they pair with everything and tell you nothing.
- Ethylhexylglycerin · 198
- Sodium Hydroxide · 171
- Propanediol · 128
- Behentrimonium Chloride · 121
- Guar Hydroxypropyltrimonium Chloride · 117
- Tocopherol · 114
- Benzyl Alcohol · 110
- Cocamidopropyl Betaine · 107
- Cetrimonium Chloride · 103
- Caprylyl Glycol · 96
The number beside a name is how many products in our library list both.
These ingredients tend to appear together to soften the strand, keep the formula stable, and carry the formula and let it dry.
Found in these products
The most prominent placements first. The badge is the position on that product’s own ingredient list.
Odele · Co-wash
Curl Defining No-Lather Shampoo
#2 on the label · $0.92/oz
Color Wow · Mask / treatment
Dream Filter For Picture-Perfect Color
#7 on the label · $3.88/oz
dpHUE · Conditioner
Gentle Brightening Conditioner
#7 on the label
Gibs Grooming · Shampoo
Biofuel Shampoo
#7 on the label · $1.54/oz
Wondercurl · Leave-in
Get Slick Hair Smoothie
#7 on the label · $2.50/oz
Coco & Eve · Shampoo
Clarifying Detox Shampoo
#8 on the label · $2.85/oz
Hairstory · Mask / treatment
Pre-Wash
#8 on the label · $5.88/oz
Hairstory · Leave-in
Primer
#8 on the label · $4.50/oz
Kitsch · Shampoo
Detox Shampoo Bar
#8 on the label · $0.97/oz
Mielle Organics · Shampoo
Avocado & Tamanu Anti-Frizz Shampoo
#8 on the label · $1.08/oz
AG Care · Styler
Liquid Effects Medium-Hold Weightless Styling Gel
#9 on the label · $3.00/oz
Davines · Scalp treatment
ELEVATING Scalp Recovery Treatment
#9 on the label · $13.91/oz
See all 393 products in the library that list Tetrasodium Glutamate Diacetate
Identity
What this entry is, and what our references call it.
Tetrasodium Glutamate Diacetate
- CAS 51981-21-6
- PubChem 44630158
- tetrasodium glutamate diacetate
- tetrasodium glutamate diacetate (plant-derived cleanser)
For your hair?
Whether Tetrasodium Glutamate Diacetate matters for your hair depends on your hair.
the 7th most-listed chelator or pH adjuster in our libraryWhat this ingredient does, and where it sits on the labels we have researched.
A verdict on any product that contains it, and never a safety grade.
We do not physically test your hair. Everything above comes from the ingredient lists in our library and from published references. The consultation is what turns it into a plan.
References
Sourced Backed by a manufacturer or regulatory source.
This ingredient
- Manufacturer or regulatory PubChem : Compound identity: CID 44630158, CAS 51981-21-6, C9H9NNa4O8 · accessed 2026-08-28
How this page was made
- Every number above is counted from the ingredient lists in our own product library: 393 of 6816 researched products list this ingredient. Nothing on this page is written per ingredient.
- The dots are levels, not scores. Each one comes from what kind of ingredient it is (its chemical class, charge and solubility) or from where it sits on the labels we have.
- US labelling rules put ingredients above 1% in descending order of amount; below 1% they may be listed in any order. Position tells you about relative amount only above that line, and we never convert a position into a percentage.
- The prominence bands (leading, supporting, secondary) are the same ones the product pages use to read a single label, applied here to the median position across a category.
- We do not publish safety scores or hazard grades. Where a regulator has published a restriction or a use condition, we state it and cite it; otherwise we describe what the ingredient does and stop.
- Identifiers and references appear only when a published source is attached to this entry. Without one, we leave the row out rather than fill it in.
- This is cosmetic information, not medical advice, and nothing here diagnoses or treats a health condition.
- Entry last updated 2026-09-22. Product-page methodology: the product library.
