L-cysteine
L-cysteine carries a source-backed screening score of 3/5 and appears in 1,180 indexed US food products.
Source-backed answer
L-cysteine appears in 1,180 catalogued products. CSPI has no rating attached in this snapshot. Its FDA SAFFA status is “GRAS.” Those source labels describe the ingredient; they do not establish whether a particular product, dose, allergy, or diet is safe.
- 1,180
- catalogued products
- #599
- usage rank of 247,206
- 303
- named brands represented
- 67%
- average depth down ingredient lists
Catalog prevalence comes from Open Food Facts ingredient lists. FDA SAFFA and CSPI Chemical Cuisine labels are shown only when the source record contains them.
L-cysteine: top-decile catalog footprint (#599 of 247,206)
- Usage rank
- #599
- of 247,206 ingredients that appear in at least one catalogued product, listed in more products than 99.8% of them.
- Typical depth in an ingredient list
- 67%
- Of the way down the captured list, averaged across the 1,180 products listing it (mean slot 27.1). L-cysteine usually falls in the lower half of the list; this position does not measure its amount because source formatting, compound ingredients and labeling exceptions vary.
Derived by this site from the ingredient lists of every catalogued product (Open Food Facts), recomputed on each data refresh. 247,206 ingredients have at least one appearance and are ranked here. Usage and list position describe prevalence, not safety.
How to use this page
Audit the co-occurring flags first
50.5% of the linked products contain at least one separately flagged ingredient, making co-occurrence the dominant follow-up question. That figure does not identify L-cysteine as the trigger. Open records such as 100% Whole Wheat Bagels; 100% Whole Wheat Bagels; 100% Whole Wheat Bread and inspect which ingredient row carries the caution marker. The 84.3/100 product average is therefore a triage signal for this surrounding formulation set, not an ingredient verdict. Its 67% average label depth helps locate the term when checking the package.
50.5% of linked products contain a separately flagged ingredient
Processing is unusually concentrated here: Group 4 accounts for 1135 of 1175 NOVA-tagged records. That describes the surrounding products, not the substance. For a useful comparison, hold category and processing level constant, then inspect which named component changes alongside the caution flag; otherwise the product mix will confound the ingredient question.
Next check: open the lowest-scoring linked formulation and locate the exact caution-marked component.
What else is usually in the same product as L-cysteine
Across the 1,180 products on this site that list L-cysteine, these flagged additives appear alongside it most often. The comparison column is how often each one appears across every product with a parsed ingredient list, so the two figures are measured over the same set. Sodium Nitrite shows up about 9.8x more often with L-cysteine than in the catalogue at large.
| Additive | Shared products | Share of L-cysteine products | Share of all products |
|---|---|---|---|
| Sodium Nitrite | 278 | 23.6% | 2.4% |
| BHA | 240 | 20.3% | 0.7% |
| BHT | 218 | 18.5% | 1.1% |
| Azodicarbonamide | 157 | 13.3% | 0.2% |
| Caramel Coloring | 145 | 12.3% | 5.7% |
Co-occurrence describes what manufacturers formulate together. It is not a claim that these additives interact, and it carries no regulatory meaning. Counted over products with parsed ingredient lists; Open Food Facts, 2026-09-01.
Function
DOUGH STRENGTHENER, FLAVOR ENHANCER, FLAVORING AGENT OR ADJUVANT, FLOUR TREATING AGENT, NUTRIENT SUPPLEMENT
How do the sampled products compare?
Each point is one of the 16 sampled products listed below: its overall safety score against how many separately flagged ingredients its label carries. Bubble size is the number of ingredient rows the label actually resolved to.
Safety score vs. flagged-ingredient count for products containing L-cysteine
Products Containing L-cysteine
High-volume slice (16 of 1,180) for products naming L-cysteine:
L-cysteine vs other top-decile catalog footprints
High-volume peers for L-cysteine: 1,180 products, mean screening score 84.3/100. Comparable product-count neighbours: Orange · Green Bell Peppers · Turkey Breast. Axes below stay distinct so count-neighbors do not duplicate score-neighbors.
Similar product count
Nearest other ingredients by Open Food Facts product count (floored at ≥50).
Similar mean product score
Score-axis peers only, mean screening score among ingredients with ≥50 scored products, not a second count list.
What to do with this L-cysteine record
Start from L-cysteine's 1,180 catalogued appearances and the attached source fields, then open the product rows that match your use case.
- Open the product sample for L-cysteine and read how the term sits on real packages. Browse linked labels
- Place L-cysteine next to “Green Bell Peppers” (or another peer) using the same FDA/CSPI and prevalence fields. Open a peer record
- See the join rules behind screening scores before reading them as dietary advice. See source joins
This page describes published source classifications and product-label coverage. It is not dietary, allergy, or medical advice.
Frequently Asked Questions
How should I read safety signals when L-cysteine sits in heavily flagged products? ▼
50.5% of linked products contain at least one separately flagged ingredient, so the first task is locating which row carries the caution marker — not assuming L-cysteine is the trigger. Where a source rating exists, L-cysteine scores 3/5 on this site's screening scale with FDA SAFFA status "GRAS". None of that replaces a product-, dose-, allergy-, or person-specific determination.
Which product shelves show up most often with L-cysteine? ▼
L-cysteine ranks in the top decile by product count (#599 of 247,206), appearing in 1,180 indexed products led by Meals. The sample list below is a slice of that footprint, not the full universe.
What function does L-cysteine serve when it appears beside other flagged additives? ▼
L-cysteine is recorded as a dough strengthener, flavor enhancer, flavoring agent or adjuvant, flour treating agent, nutrient supplement in source technical-effect fields. In high co-flag products, that function coexists with other caution-marked components — inspect the full list rather than isolating this role.
Regulatory status: FDA SAFFA (L-cysteine). Safety ratings: CSPI Chemical Cuisine; product presence: Open Food Facts via PlainFoodSafe (September 2026). Figures are computed from those sources, no editor-typed counts. Methodology · State regulations.