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Last updated
General product information only, not medical advice. It does not describe how any suture is used on a patient.
Short answer
Prolene 5-0 is a size 5-0 blue polypropylene monofilament suture sold by Ethicon (Johnson & Johnson MedTech). Under the USP monograph, 5-0 means an average diameter of 0.10 to 0.149 mm (metric size 1) and a minimum average knot-pull of 0.40 kgf for Class I suture. The size is a range, and 6-0 is finer while 2-0 and 0 are thicker.
Definition and scope
Prolene is Ethicon’s brand name for a non-absorbable, sterile surgical suture made of an isotactic crystalline stereoisomer of polypropylene, described by the manufacturer as a synthetic linear polyolefin. The manufacturer states that the suture is dyed blue to enhance visibility and does not adhere to tissue, and calls it relatively biologically inert (J&J MedTech Prolene product page, checked 2026-11-01).
The number in a name such as Prolene 5-0 is not a brand feature. It is the USP size, defined for all non-absorbable surgical suture in the United States Pharmacopeia-National Formulary monograph “Nonabsorbable Surgical Suture”. Other polypropylene sutures use the same scale, and so do nylon and polyester sutures. For material differences, see Prolene vs nylon, absorbable vs non-absorbable sutures and Novafil, another non-absorbable suture brand.
How USP sizing works
USP sizes count zeros. A label such as 5-0 (also written 5/0 or “five-aught”) is finer than 4-0, and 0 on its own, also called 1-aught, is much thicker than 5-0. The monograph pairs every USP size with a metric size, which is the average diameter in tenths of a millimetre, and gives a diameter range the finished suture must fall inside. A packet conforms if its measured average diameter lies in that range, so two sutures that are both 5-0 can differ slightly in diameter.
The monograph also sets a minimum average knot-pull tensile strength by size and class. Polypropylene monofilament belongs to Class I, which the monograph defines as silk or synthetic fibers of monofilament, twisted or braided construction, giving monofilament nylon or polypropylene as examples. Class III is metal wire, which has different limits, so a Class I figure should not be compared directly with a wire figure. The limits apply to sterilized suture; for non-sterile Class I and Class II suture they are 25 percent higher.
Prolene 6-0, 5-0, 2-0 and 0 compared
The table gives the sizes people most often search next to 5-0. Every figure comes from the USP-NF Nonabsorbable Surgical Suture monograph (USP 35 edition text, checked 2026-11-01). Knot-pull values are the Class I minimums for sterilized suture.
| USP size | Metric size | Average diameter limits (mm) | Min. average knot-pull, Class I (kgf) |
|---|---|---|---|
| 6-0 | 0.7 | 0.070 to 0.099 | 0.20 |
| 5-0 | 1 | 0.10 to 0.149 | 0.40 |
| 2-0 | 3 | 0.30 to 0.339 | 1.44 |
| 0 | 3.5 | 0.35 to 0.399 | 2.16 |
Reading across: moving from 6-0 to 5-0 doubles the minimum knot-pull (0.20 to 0.40 kgf), and size 0 has a minimum more than five times that of 5-0. The monograph gives the same Class I minimums in newtons as 1.96 N (6-0), 3.92 N (5-0), 14.1 N (2-0) and 21.2 N (0).
Prolene 6-0
Finer than 5-0: average diameter 0.070 to 0.099 mm, metric size 0.7.
Prolene 2-0 and Prolene 0
Both are in the heavier part of the table. 2-0 is metric size 3 (0.30 to 0.339 mm) and 0 is metric size 3.5 (0.35 to 0.399 mm). Size 1, next up, is metric size 4 (0.40 to 0.499 mm).
Needle codes, lengths and pairings vary by catalog code and are listed in the manufacturer’s own product documentation, so they are not covered here; see suture needle sizes for how needle codes are read.
What to check on the packet
The same monograph tells you what a conforming packet label must state. It makes a practical checklist for anyone receiving or reconciling suture, since the brand name alone does not carry all of it:
- Material (for example polypropylene) and size (for example 5-0).
- Construction (monofilament, twisted or braided) and length.
- Sterility statement.
- Needle type, where a needle is attached.
- Number of sutures in the packet.
- Lot number and the name of the manufacturer or distributor.
The monograph also requires suture supplied with an eyeless swaged needle to meet the needle attachment test in USP chapter 871. A size on a label is a claim about diameter and strength class, so the label is the place to confirm it, not the product name.
Common misunderstandings
“More zeros means thicker”, or “0 is the finest”
More zeros means finer. 5-0 (0.10 to 0.149 mm) is finer than 2-0 (0.30 to 0.339 mm), and plain 0 (0.35 to 0.399 mm) is thicker than 2-0. In metric terms, 2-0 is metric 3 and 0 is metric 3.5.
“5-0 is one exact diameter”
It is a range of 0.10 to 0.149 mm. Figures such as “about 0.1 mm” in product listings are approximations of that range.
“Any polypropylene suture is Prolene”
Prolene is one brand. Polypropylene as a material is named in the monograph’s Class I examples, and the monograph applies to every maker.
“The knot-pull figure is a guarantee for every strand”
It is a minimum average for the size and class, measured with a knot tied in the strand under the monograph’s test.
Frequently asked questions
What does Prolene 5-0 mean?
It is a polypropylene monofilament suture of USP size 5-0: average diameter 0.10 to 0.149 mm, metric size 1.
Is Prolene 6-0 thicker or thinner than 5-0?
Thinner. USP 6-0 is 0.070 to 0.099 mm, against 0.10 to 0.149 mm for 5-0.
Is Prolene 2-0 thicker than 5-0?
Yes. USP 2-0 is 0.30 to 0.339 mm, roughly three times the 5-0 range.
What is Prolene 0?
Size 0 (1-aught) is USP size 0, metric size 3.5, average diameter 0.35 to 0.399 mm. It is thicker than 2-0.
Is Prolene absorbable?
No. The manufacturer describes Prolene as non-absorbable, and the USP monograph covering it is titled Nonabsorbable Surgical Suture.
Sources
- USP-NF, Nonabsorbable Surgical Suture monograph (USP 35 edition text, mirror: drugfuture.com), checked 2026-11-01. Diameter limits, metric sizes, knot-pull limits, classes and labelling.
- Johnson & Johnson MedTech, Prolene polypropylene suture, checked 2026-11-01. Material description, blue dye, non-absorbable.
- Related on CASRAI: What is a suture, dental sutures.
