Surgical steel, 316L and 304: what the grades mean

The short answer

“316L” is a grade name that a maker can state and a buyer can ask about. “Surgical steel” is a phrase. We looked for a standard, regulator or society page that defines it and did not find one, so this page does not say what it means. What the sources do cover is how much nickel stainless steels release, which is the question that matters for a nickel allergy. For the product-side view, see surgical steel earrings and hypoallergenic stainless steel jewelry.

What we could read about 316L

One 1997 orthodontic study abstract (PMID 9228844) describes “the 316L stainless steel (nickel content: 10 to 14 wt%)” as a bracket material in current use. That is the only composition figure we could read. The usual metallurgy references (ASTM, ISO, the Nickel Institute, worldstainless) were blocked or returned no readable text when fetched, so we give no chromium, molybdenum or 304 percentages rather than quote them from memory. We also found no readable explanation of what the letters and numbers in “316L” and “304” encode.

So the readable fact is simple: 316L contains a substantial amount of nickel. That does not decide whether it reaches skin.

Bulk nickel versus nickel release

A 2022 review of stainless steel toxicity (PMID 35817207) says the chromium(III)-rich surface oxide of stainless steels “efficiently limits the release” of their metal constituents in most physiological environments, and that “comparative metal release, rather than the bulk composition” should be considered when assessing hazard. That is a toxicology review, not a jewelry test.

The jewelry-relevant lab work is older. A 1994 study (PMID 7842681) tested AISI 304, 316L, 303 and 430 steels, nickel and nickel-plated samples. In acidic artificial sweat, nickel-plated samples released about 100 micrograms/cm2/week, low-sulfur stainless steels released less than 0.03, and AISI 303 about 1.5. In patch tests, 96% of the patients were intolerant to nickel-plated samples and 14% to the high-sulfur 303, while low-sulfur nickel-containing steels elicited no reactions. The authors conclude that 304 and 316 steels “should not induce contact dermatitis, while 303 should be avoided.” The same abstract says the DMG spot test “reveals Ni present in the metal bulk but not its dissolution rate”, which is why the nickel spot test guide treats that test with care.

Where the picture is less tidy

Other abstracts show why a grade number is not the whole story:

• A 1994 report (PMID 7867327) found some DMG-negative metals released considerable nickel, and describes a nickel-allergic patient who developed allergic contact dermatitis from stainless steel. It says some types of stainless steel release enough nickel to elicit symptoms.
• A 1996 review (PMID 9007370) says the EU release limit “is currently exceeded by many nickel-containing alloys and jewelery items that are made from high-sulfur stainless steel.”
• A 2024 study (PMID 39286204) tested to EN 1811 and reports that electroplating can induce nickel release “even from 316L”. It identifies the cause as removal of the steel’s passivation layer plus microporosity of the plating, and reports that PVD coatings applied without removing that layer did not release nickel.

The last point matters for gold-coloured steel earrings and rings. A plated or coated piece is a different surface, so the base grade alone does not describe it. See gold plated vs gold filled vs vermeil and PVD-coated jewelry.

The legal yardstick

Under the EU REACH text, nickel is restricted in post assemblies inserted into pierced parts of the body “unless the rate of nickel release from such post assemblies is less than 0,2 μg/cm 2 /week”. For other articles in direct and prolonged skin contact the figure is 0,5 μg/cm 2 /week (EUR-Lex, retrieved 2026-11-14). The rule is written in terms of release, not alloy name, which fits the studies above. The EU nickel rule guide goes through it.

DermNet describes nickel allergy as “one of the most common causes of contact allergic dermatitis” and says it is diagnosed “by the clinical history and by special allergy tests, patch tests.” For your own reactions, ask a dermatologist or allergy clinic.

How to use this when you shop

• Look for a grade, not only a label. A stated grade such as 316L gives you something to ask about. “Surgical grade” alone gives you nothing to check.
• Ask about the surface. Plating and coatings change what touches skin, per the 2024 study.
• Ask for release data. A maker who tests to EN 1811 can say so; “nickel-free” on its own is a claim. See nickel allergy and jewelry and what hypoallergenic jewelry means.
• Compare other metals. Titanium grades for jewelry and titanium vs stainless steel earrings cover the common alternative; hypoallergenic earrings for piercing and hypoallergenic jewelry give the wider picture.

What this page does not cover

We did not test any jewelry. The studies are lab and case-report abstracts, decades old in part, on specific samples. They do not predict how a given earring or ring will perform on your skin.