Learn

The metals, the math,
and where it all comes from.

The five metals in the data

Heavy metals occur naturally in soil and water, so trace amounts reach nearly all food — including formula ingredients. The question is never "zero or not," it's how much, compared to what's achievable.

Lead

CDC · AAP

What it is: A naturally occurring heavy metal with no known biological function in the human body.
How it gets into formula: Trace lead in soil and water is taken up by crops (including rice, oats, and soy) and dairy herds, and can also enter during processing.
Why it matters for infants: The CDC and the American Academy of Pediatrics state that no safe blood lead level in children has been identified. Chronic low-level exposure is associated with developmental and learning effects, and infants absorb ingested lead at a higher rate than adults.

Inorganic Arsenic

FDA · EPA

What it is: The more toxic form of arsenic, classified as a known human carcinogen.
How it gets into formula: Rice and rice derivatives concentrate arsenic from soil and water, which is why rice-containing and some specialty formulas tend to test higher.
Why it matters for infants: Long-term exposure is associated with cancer risk and developmental effects. The FDA has set action levels for inorganic arsenic in infant rice cereal (100 ppb) and apple juice (10 ppb).

Total Arsenic

FDA

What it is: The combined measure of organic and inorganic arsenic in a sample.
How it gets into formula: Same pathways as inorganic arsenic; the organic fraction (common in some marine ingredients) is considered far less toxic.
Why it matters for infants: Total arsenic is a screening measure: a high total reading usually prompts speciated testing to determine how much is the inorganic form.

Cadmium

ATSDR · EFSA

What it is: A heavy metal that accumulates in the kidneys over decades; the body clears it very slowly.
How it gets into formula: Crops — particularly grains, soy, and leafy plants — draw cadmium from phosphate fertilizers and naturally enriched soils.
Why it matters for infants: Chronic dietary exposure is associated with kidney and bone effects. Because clearance is so slow, early-life intake contributes to lifetime body burden.

Aluminum

ATSDR · EFSA

What it is: The most abundant metal in the Earth’s crust; small dietary amounts are common and mostly excreted.
How it gets into formula: Soil uptake by crops, mineral ingredients, and processing equipment. Soy and specialty formulas have historically tested higher.
Why it matters for infants: There is no US federal benchmark for aluminum in formula. Healthy kidneys excrete most ingested aluminum, but researchers have argued for minimizing levels in products consumed as a sole food source by very young infants.

How the Purity Score works

It's relative, on purpose. Each formula's detected levels are compared against every other formula in the same independent test — the only apples-to-apples comparison the data supports. It is not an absolute safety rating; regulators decide safety.
Each metal is placed on the tested range. A formula at the lowest detected level for a metal scores best for that metal; the highest scores worst. We use a log scale so a single extreme outlier doesn't flatten differences among everyone else.
Metals are weighted by infant-toxicity concern:Lead ×0.30Inorganic Arsenic ×0.25Total Arsenic ×0.15Cadmium ×0.20Aluminum ×0.10
A metal that wasn't reported counts in the formula's favor — the test data lists metals of note per product, so absence means it wasn't flagged in that round.
One hard rule: any formula whose arsenic crossed the FDA's 10 ppb action level (the strictest citable federal arsenic benchmark) is capped at a failing score, regardless of how it did elsewhere.

Honest answers

Should I stop using a formula that shows detectable heavy metals?

Not on your own — talk to your pediatrician first. Heavy metals are present at trace levels in nearly all foods because they exist in soil and water. Suddenly switching or diluting formula can be more harmful than the trace exposure itself. Use this data to choose lower-testing options going forward, not to panic about the past.

Why do European formulas appear here?

EU regulations on infant formula composition differ from US rules in ways many parents care about (for example, stricter pesticide rules and lactose-first carbohydrate requirements). Several European and Australian brands now sell US-compliant versions through official channels, and independent testing covered them alongside American brands.

Is a low Purity Score the same as "unsafe"?

No. The score is relative: it tells you how a formula’s detected levels compare with the other formulas in the same independent test. Regulators, not this app, determine safety. A formula at the bottom of the cohort is still legally sold — but if alternatives test meaningfully lower, that information belongs to you.

Where does the data come from?

Heavy-metal levels come from Consumer Reports’ March 2025 independent laboratory testing of 41 powdered infant formulas. Recall history is curated from FDA public announcements. Prices are approximate US retail and vary by store.

Why doesn’t every formula show every metal?

The testing data reports the metals of note detected per product. Where a metal is not listed for a formula, it was not reported at a level of concern in that round of testing — which is why missing metals are treated favorably in scoring.

Sources

Heavy-metal levels: Consumer Reports independent laboratory testing of 41 powdered infant formulas, published March 2025.
Recall history: FDA recalls, market withdrawals & safety alerts archive.
Health context: CDC and AAP guidance on childhood lead exposure; FDA Closer to Zero program; ATSDR toxicological profiles; EFSA opinions on dietary cadmium and aluminum.
Prices: approximate US retail at time of writing; they vary by store and package size.

Good Formula is an independent information tool, not a medical service and not affiliated with any formula maker. Nothing here is medical advice — always consult your pediatrician before choosing or changing your baby's formula.

How this site is funded. Some retailer links earn us a commission at no cost to you. Commissions never influence scores or rankings — every score is computed from the lab data by the published formula above, and formulas that crossed a federal benchmark are never recommended, whatever they pay.