NOM 051: Mexico Warning Labels and Octagon Rules
NOM 051 explained for food labels in Mexico, including EXCESO warning octagons, nutrient thresholds, precautionary legends and labeling requirements.
NOM 051 requires foods that exceed Mexico's applicable limits for calories, sugars, saturated fat, trans fat or sodium to carry black octagonal warning seals on the front of the package. Each exceeded nutrient receives its own EXCESO, meaning "excess of," warning.
The requirement comes from the 2020 modification to NOM-051-SCFI/SSA1-2010, Mexico's general labeling standard. The modification added a warning-seal system modeled on the Pan American Health Organization (PAHO) nutrient profile to the country's existing labeling requirements.
Enforcement began in October 2020, making the octagons one of the most important compliance checks for brands selling packaged food in Mexico.
NOM 051's five warning octagons and two precautionary legends
The five Mexico warning labels are:
- EXCESO CALORÍAS: excess calories.
- EXCESO AZÚCARES: excess sugars.
- EXCESO GRASAS SATURADAS: excess saturated fat.
- EXCESO GRASAS TRANS: excess trans fat.
- EXCESO SODIO: excess sodium.
NOM-051 also requires two rectangular precautionary legends when applicable.
One is a caffeine legend advising that the product should be avoided by children. The other is a sweetener legend stating that non-caloric sweeteners are not recommended for children.
A single food can therefore carry multiple warning octagons together with a precautionary legend.
The seals must appear in the upper-right area of the principal display panel, using prescribed sizes relative to the package.
NOM-051 labeling thresholds: how the warning seals work
The evaluation system is derived from the PAHO nutrient profile and uses energy-based calculations for most of the warning seals.
In broad terms, for products containing added sugars, fats or sodium:
- Sugars: the warning triggers when free sugars contribute 10% or more of the product's total energy.
- Saturated fat: the warning triggers when saturated fat provides 10% or more of total energy.
- Trans fat: the warning triggers when trans fat provides 1% or more of total energy.
- Sodium: the warning uses a sodium-to-energy ratio, on the order of 1 mg per kcal, together with an absolute floor for low-calorie products.
- Calories: the warning uses energy-density thresholds per 100 g for solid foods and per 100 ml for beverages.
NOM-051 was introduced through several phases.
The initial phase began in October 2020, the second phase began in October 2023, and the third phase began in October 2025. The criteria tightened as the system moved through those stages.
Because the applicable numbers depend on the phase currently in force and whether the product is a solid or liquid, evaluate the product using the current-phase tables rather than relying on a general summary.
The calculation also depends on accurate per-100 g or per-100 ml nutrient data. That basis needs to be correct before any NOM 051 warning-seal logic is applied.
Marketing consequences of NOM 051 warning labels
The black octagons affect more than the front-of-pack design.
Products carrying any warning seal face restrictions on child-directed marketing elements on the package. Restricted elements include:
- Cartoon characters.
- Celebrities and athletes.
- Interactive elements.
- Toy or game tie-ins.
For a food brand whose identity depends heavily on a mascot or similar child-directed element, reformulating below the applicable thresholds can be the only way to retain that character on the front of the package.
Products carrying warning seals also face restrictions in school food environments.
These consequences make NOM-051 labeling a formulation and marketing issue as well as a packaging compliance requirement.
How Mexico warning labels compare with neighboring markets
| Country | Symbol | Wording | Model |
|---|---|---|---|
| Mexico | Black octagon | EXCESO … | PAHO, energy-based |
| Chile | Black octagon | ALTO EN … | Absolute per-100g cutoffs |
| Argentina | Black octagon | EXCESO EN … | PAHO, energy-based |
| Brazil | Black magnifier | ALTO EM … | Absolute per-100g/ml cutoffs |
The same formulation can therefore produce different front-of-package warnings in different countries. A product that receives no warning in Brazil, for example, may still trigger two octagons in Mexico because the systems use different criteria.
For other Latin American requirements, compare Chile's ALTO EN seals, Argentina's Ley 27.642, and Brazil's ANVISA magnifier.
Practical NOM-051 labeling workflow
NOM 051 warning-seal logic is deterministic: nutrient data goes in and the applicable warning octagons come out. That makes it well suited to automated calculation rather than a spreadsheet checked only once a year.
A practical workflow is:
- Maintain accurate formulation data on a per-100 g or per-100 ml basis.
- Evaluate the product against the current NOM-051 phase criteria.
- Determine which EXCESO octagons and precautionary legends apply.
- Render them at the required size and position on the principal display panel.
- Recalculate the warnings every time the formulation changes.
The NFL generator calculates NOM-051 seals from your per-100 g values and renders the Mexican label format directly. The coverage index lists the other Latin American labeling formats supported alongside it.
Reformulation should follow the same process. A sodium or sugar reduction that moves the product below an applicable threshold can remove a warning seal entirely. Showing exactly which seals a formulation triggers, and by how much, gives product and marketing teams a concrete target for reformulation.
NOM 051 frequently asked questions
Do NOM 051 octagons replace the nutrition information table?
No. The front-of-package warning octagons are additional to the nutrition declaration required by NOM-051. A product that requires warning seals still needs the applicable nutrition information table. Both should be generated from the same underlying nutrient data so that the front-of-package warnings and nutrition declaration remain consistent.
Do products without added sugar, fat or sodium need NOM 051 seal evaluation?
The evaluation system focuses on products containing added sugars, added fats or added sodium. Unprocessed foods and certain exempt products can fall outside the warning-seal system. Do not assume a product is exempt based only on its formulation. Verify its status against NOM-051 before deciding that warning-seal evaluation is unnecessary.
Can I ship a US-labeled product into Mexico with a NOM-051 sticker?
Imported products must comply with NOM-051 before retail sale in Mexico, including any applicable warning seals. Compliant over-labeling is used in practice, but a sticker does not create an exception to the labeling rules. The over-label must still meet the applicable content, size and placement requirements for the Mexican market.
Selling into Mexico? Enter your per-100 g values in the free NFL generator to determine which EXCESO seals your product triggers.
