# Condoms

A condom's material and fit decide whether it protects reliably and compatibly with other products a buyer already owns, not its brand or novelty features. External (worn on a penis) and internal (worn in the vagina or anus) condoms are different products with different materials, standards, and sizing systems entirely.

## How it works

A condom is a thin elastic sheath that forms a physical barrier against semen and skin contact: an external condom unrolls onto the penis, while an internal condom is a loose pouch with an inner ring that anchors inside the body and an outer ring that stays outside. Latex and polyisoprene stretch and grip for a snug fit but are damaged by oil-based lubricants; polyurethane and nitrile are less elastic but tolerate oil and don't trigger latex allergy. Nominal width and length set the fit, and every material and design must pass a national or international dimensional and burst test before it can carry a contraceptive or STI-protection claim.

## How an expert narrows the choice

```mermaid
timeline
  section 1 · External or internal
    external : ask Fit (nominal width), Length, Thickness, Texture : skip Internal condom insertion
    internal : ask Internal condom insertion : skip Fit (nominal width), Length, Thickness, Texture
  section 2 · Material
    latex / polyurethane / polyisoprene / nitrile / lambskin : skip Oil-based lubricant safe?
  section 3 · Intended act
    oral : ask Flavored : skip Lubricant coating
```

1. **External or internal.** External, worn on a penis, or internal, inside the body?
   External and internal condoms use different materials, sizing systems, and standards, so this fork decides the whole facet set that follows.
   If external: ask Fit (nominal width), Length, Thickness, Texture; skip Internal condom insertion.
   If internal: ask Internal condom insertion; skip Fit (nominal width), Length, Thickness, Texture.
   Skip if already known: a query that already names 'external', 'male', 'internal', or 'female' condom, an earlier answer naming a penis or a vagina/anus as where the condom goes.

2. **Material.** Latex, polyurethane, polyisoprene, nitrile, or lambskin?
   Material decides latex-allergy safety and whether oil-based lubricants, massage oils, or certain medications can touch the condom without weakening it.
   If latex or polyurethane or polyisoprene or nitrile or lambskin: skip Oil-based lubricant safe?.
   Skip if already known: an earlier answer naming a latex allergy, an earlier answer naming an oil-based lubricant the buyer already owns.

3. **Intended act.** Mainly for vaginal, anal, or oral sex?
   Anal sex needs more lubricant and a thicker or sturdier condom to resist tearing; oral sex rules out spermicide and sugar-flavored coatings going anywhere else.
   If oral: ask Flavored; skip Lubricant coating.
   Skip if already known: an earlier answer naming vaginal, anal, or oral sex.

## What to surface

### External or internal

Whether the condom is worn externally on a penis or is an internal pouch inserted into the vagina or anus. The two are different product classes: external condoms are latex, polyisoprene, polyurethane or lambskin sheaths sized to a shaft, while internal condoms are a looser nitrile or polyurethane pouch with an anchoring ring, regulated and sized differently, and insertable ahead of time. [1] [2]

Values: external, internal.
Question to ask: External, worn on a penis, or internal, inside the body?

Used as: top-level split, filter. Data: derived from listing fields, backfill cost low. Look for it as: Almost always in the title ('male condom' / 'female condom' / 'internal condom') or the product category.
Title keyword match on 'internal'/'female' condom vs. default to external, which is the overwhelming majority of listings.

### Material

What the condom sheath is made of: natural rubber latex, polyurethane, polyisoprene, nitrile, or lambskin (sheep intestine membrane). Latex is the stretchiest and cheapest but can't touch oil-based lubricants and triggers allergic reactions in some users; polyurethane and nitrile tolerate oil and are allergen-free but are less elastic and more prone to slipping; polyisoprene keeps latex's stretch without the allergen but still can't touch oil; lambskin blocks sperm but is porous to viruses. [1] [2]

Values: latex, polyurethane, polyisoprene, nitrile, lambskin, unspecified.
Question to ask: Latex, polyurethane, polyisoprene, nitrile, or lambskin?

Used as: top-level split, filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Almost always stated in the title or first bullet; lambskin and nitrile are near-always called out by name since they're the minority material.
Title keyword match; default to latex when unstated, since it is the overwhelming majority material for external condoms.
Chart: position on an elasticity-vs-oil-compatibility axis.

### Intended act

Whether the condom is mainly intended for vaginal, anal, or oral sex. Anal sex sees higher breakage without extra lubricant and benefits from a thicker, oil-compatible or extra-strong condom; oral sex rules out spermicide (unpleasant and a GI irritant) and makes flavored, sugar-coated condoms the only ones meant to go in that direction, not vaginally or anally. [9] [1]

Values: vaginal, anal, oral.
Question to ask: Mainly for vaginal, anal, or oral sex?

Used as: top-level split, filter. Data: derived from listing fields, backfill cost medium. Look for it as: Rarely a stated field; infer from 'flavored'/'oral sex' wording (oral) versus general-purpose listings (vaginal/anal, treated the same by most brands).
Default to vaginal/anal (general-purpose) unless the title or description says 'flavored' or 'oral'.

### Texture

Whether the surface is smooth, ribbed, studded/dotted, or both ribbed and studded. Ribs and studs add sensation for one or both partners and can be placed to target specific stimulation, but some people experience vaginal irritation from studded condoms, which a smooth condom avoids. [1]

Values: smooth, ribbed, studded_dotted, ribbed_and_studded.
Question to ask: Smooth, ribbed, or studded for extra sensation?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Almost always in the title ('Ribbed', 'Studded', 'Dotted', 'Extreme Ribs').
Title keyword match; default to smooth when nothing is stated.

### Lubricant coating

What, if anything, the condom comes pre-coated with: nothing (dry), a water-based lubricant, a silicone-based lubricant, or a spermicidal (nonoxynol-9) coating. A spermicidal coating adds no proven extra pregnancy protection over a plain condom, has a shorter shelf life, and the WHO says it should no longer be promoted because frequent use may raise HIV transmission risk; dry condoms are the only kind meant for cutting open as a dental dam or for use under oral-sex-only flavored coatings. [1] [8]

Values: dry_unlubricated, water_based, silicone_based, spermicidal_n9.
Question to ask: Lubricated, dry, or spermicide-coated?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Almost always in the title or bullets ('Lubricated', 'Non-Lubricated', 'Spermicidal').
Title keyword match; default to water_based lubricated when nothing is stated, since unlubricated is a minority listing.

### Thickness

How thick the sheath's wall is, marketed as ultra-thin/hyperthin, standard, or extra-strong. Thinner is marketed for more sensation and is a separate product line, not simply a lower grade of a standard condom, since the international standard also defines a distinct extra-strong class with its own burst requirements for anal sex or heavier use. [5] [4]

Values: ultra_thin, standard, extra_strong, unspecified.
Question to ask: Ultra-thin for sensation, standard, or extra-strong?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Almost always in the title ('Ultra Thin', 'Hyperthin', 'Extra Strength').
Title keyword match; default to standard when nothing is stated.
Chart: position on a thin-to-thick axis.

### Oil-based lubricant safe?

Whether the condom's material tolerates oil-based lubricants, massage oils, or oil-based medications without weakening. Latex and polyisoprene degrade and are more likely to break or slip after contact with oil-based substances (petroleum jelly, cooking or massage oil, many vaginal creams); polyurethane and nitrile don't have this restriction, which matters if a buyer already owns an oil-based product. [1] [2]

Values: oil_safe, water_silicone_only.

Used as: filter, shown on the card. Data: derived from listing fields, backfill cost low. Look for it as: Not a stated field; derive from the material facet (polyurethane and nitrile are oil_safe, latex/polyisoprene/lambskin are water_silicone_only).
Direct lookup from material; no independent fetch needed per listing.

### Flavored

Whether the condom carries a flavored, sugar-based coating made for oral sex. Flavored condoms are formulated for oral use only; the sugar-based coating can cause yeast infections or bacterial vaginosis if used vaginally or anally, so this is a safety-relevant distinction, not just a taste preference. [9] [1]

Values: unflavored, flavored_oral_only.
Question to ask: Flavored for oral sex?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Almost always in the title ('Flavored', 'Strawberry', 'Mint').
Title keyword match on flavor names; default to unflavored when nothing is stated.

### Fit (nominal width)

The condom's flat width measured just inside the open end, grouped into snug, standard, and large bands. A too-wide condom is the single biggest cause of slipping, and a too-narrow one is the biggest cause of discomfort or breakage; nominal width, not length, is what buyers should match to girth, and it's printed on the box far less prominently than brand name. [5] [6]

Values: snug, standard, large, unspecified.
Question to ask: Snug, standard, or large fit?

Used as: filter, shown on the card. Data: needs research, backfill cost medium. Look for it as: Usually on the box as 'snug'/'close fit', 'standard', or 'large'/'XL'; the band is rarely a stated field in the online listing itself and the numeric nominal width in mm is rarer still, so this is backfilled rather than read off the listing.
Keyword match on brand-name/size cues ('snug'/'slim'/'close' vs 'large'/'XL'/'magnum') in the title, since the band itself is not a stated listing field; default to standard when nothing is stated, since it's the majority listing.
Chart: position on a width axis, snug to large (roughly 40-64mm nominal width).

### STI protection

Whether the condom material fully blocks viruses as well as sperm, or only reliably blocks sperm while remaining porous to some viruses. Lambskin is an effective contraceptive but its natural pores, while too small for sperm, are large enough for viruses like HIV and herpes to pass through, so the FDA requires lambskin condoms to be labeled as not protecting against STIs; latex, polyurethane, polyisoprene, and nitrile all fully block both. [1] [9]

Values: full_barrier, sperm_only_porous.

Used as: filter, shown on the card. Data: derived from listing fields, backfill cost low. Look for it as: Not a stated field; derive from material ('lambskin' = sperm_only_porous, all others = full_barrier). FDA-mandated warning text, where present, confirms it.
Direct lookup from material; lambskin listings almost always name the material in the title.

### Internal condom insertion

How the internal condom is placed and anchored: a flexible inner ring or foam disc the user pushes in, or a dissolving capsule that releases the pouch. The inner-ring design (the common FC2-style product) can be inserted ahead of time and is removed by twisting the outer ring closed; capsule designs dissolve on insertion and are a newer, less widely available alternative with a different learning curve. [2]

Values: ring_and_foam, dissolving_capsule.

Used as: shown on the card. Data: needs research, backfill cost high. Look for it as: Not a stated field on most listings; ring-and-foam (FC2 and similar) is the overwhelming majority of what's sold.
Default to ring_and_foam; capsule designs are a small minority and usually say so explicitly in the product description.

### Length

The condom's unrolled length in millimetres, which must be at least 160mm under the international standard. A condom that's too short for a longer shaft can unroll incompletely or slip off the base during use; it matters less than width for most buyers but is the fix when width alone doesn't solve fit complaints. [4] [6]

Range: 160 to 220 mm.

Used as: filter. Data: on the listing, backfill cost medium. Look for it as: Printed on the box, rarely in the online title; brand spec sheets or size charts carry it when the listing doesn't.
Default to the standard ~170-190mm band when unstated; only worth asking when a buyer has already flagged a length-specific fit problem.

### Certification

Which safety and performance standard the condom is tested and labeled against: ISO 4074 (the international latex standard), WHO prequalification, FDA clearance (US), or CE marking (EU). A condom without a stated standard or regulatory clearance has not had its dimensions, burst strength, and shelf-life claim independently verified; ISO 4074 sets the length (over 160mm), width tolerance (±2mm of the stated nominal width), and an inflation-burst test every certified lot must pass. [4] [1]

Values: iso_4074, who_prequalified, fda_cleared, ce_marked, none_stated.

Used as: filter, shown on the card. Data: needs research, backfill cost high. Look for it as: Rarely in the title; sometimes on the box or in a certifications/compliance bullet. Most major-brand listings imply FDA clearance (US) or CE marking (EU) by market without stating it outright.
Default to 'none_stated' unless the listing or brand page names a standard; cross-checking brand pages for FDA/CE claims is slow and not worth it for most listings.

## What you give up

- A brand's hyperthin condom and its extra-strong condom are both certified, but they're built and tested as different products; choosing thin for feel means giving up the extra-strong line's higher-stress design, not just accepting a theoretically weaker version of the same one. [5] [4] Board branch: "Thinner for sensation, or extra-strong for reassurance".
- Latex is the stretchiest, cheapest, and most common material, but it's damaged by oil-based lubricants and massage oils and can't be used by someone with a latex allergy; polyurethane and nitrile give up some of that stretch to solve both problems. [1] Board branch: "More stretch and grip, or oil- and allergy-safe".
- A spermicidal coating adds no proven extra pregnancy protection over a plain condom, shortens shelf life by about two years, and the WHO says it should no longer be promoted because frequent use may raise HIV transmission risk, though it still recommends one over no condom at all. [1] [8] [7] Board branch: "Spermicide-coated, or plain lubricated".

## Words you will meet

- **Nominal width**. The condom's flat width measured just inside the open end, printed on most boxes and used to size fit.
- **Girth**. The circumference of the erect penis; roughly double the condom's nominal width, used to pick a fit.
- **Latex allergy**. An immune reaction to proteins in natural rubber latex, ranging from skin irritation to a life-threatening reaction, that rules out latex condoms.
- **Polyurethane**. A thin plastic sheath material; tolerates oil-based lubricants and doesn't trigger latex allergy, but stretches less than latex and is more prone to slipping.
- **Polyisoprene**. A synthetic rubber that copies latex's stretch and softness without the allergy-triggering protein, but still can't touch oil-based lubricant.
- **Nitrile**. A synthetic rubber used in most internal condoms; tolerant of oil-based lubricants and not affected by heat or humidity the way latex is.
- **Lambskin condom**. A condom made from a sheep's intestine membrane; blocks sperm but has natural pores small viruses can pass through.
- **Nonoxynol-9**. The spermicidal chemical used to coat some condoms; the WHO says it should no longer be promoted due to a possible HIV-risk increase with frequent use.
- **ISO 4074**. The international standard that sets the length, width tolerance, and burst-test requirements a latex condom must pass to be sold as one.
- **WHO prequalification**. A World Health Organization review confirming a condom meets international quality standards, used for bulk procurement by health programs.
- **Inner ring / outer ring**. On an internal condom, the flexible ring at the closed end that anchors it inside the body, and the ring at the open end that stays outside.
- **Dental dam**. A flat sheet used as an oral-sex barrier; can be improvised by cutting open and unrolling a condom.
- **Typical use vs. perfect use**. Typical-use failure rate counts real-world mistakes like late or incorrect application; perfect-use counts only correct, consistent use every time.

## Where we made a call

- External condoms have a typical-use pregnancy failure rate reported as either about 13% or about 18% per year depending on the dataset. (confidence medium). Sources disagree. Guttmacher's current fact sheet states 13%; Wikipedia's condom infobox cites the Trussell 2011 table at 18%. Both agree perfect-use is 2%; the gap is dataset/year, not a correction of either source. [3] [1]
- Internal (female) condoms are now labeled and regulated as single-use, though older sources describe polyurethane internal condoms as reusable. (confidence medium). Sources disagree. The general condom article says polyurethane internal condoms 'may be used multiple times'; the female-condom-specific article documents the FDA's 2018 reclassification renaming them 'single-use internal condoms.' Current regulatory guidance supersedes the older reuse claim. [1] [2]

## References

1. [Condom](https://en.wikipedia.org/wiki/Condom) (primer). Supports: Materials: latex, polyurethane, polyisoprene, lambskin and their trade-offs; Latex damaged by oil-based lubricants; latex allergy rationale for alternatives; Spermicide/nonoxynol-9 shelf life and WHO HIV-risk caution; Textured/studded and flavored condom descriptions; Typical-use 18% / perfect-use 2% failure rate (Trussell 2011 table).
2. [Female condom](https://en.wikipedia.org/wiki/Female_condom) (primer). Supports: Internal condom structure: inner ring/foam disc, outer ring, 17cm nitrile pouch; FC2 nitrile material and oil/water lubricant compatibility; FDA 2018 reclassification to Class II, renamed single-use internal condom; Vaginal and anal use of internal condoms; Typical-use 21% / perfect-use 5% failure rate (Trussell 2011 table).
3. [Contraceptive Effectiveness in the United States](https://www.guttmacher.org/fact-sheet/contraceptive-effectiveness-united-states) (specialist review). Supports: Male condom typical-use failure rate 13%, perfect-use 2%; Internal condom typical-use failure rate 21%, perfect-use 5%.
4. [Session 5: ISO 4074, the WHO Specification, and Related Standards](https://www.path.org/publications/files/RH_condom_wrkshp_session5_en.pdf) (standards body). Supports: ISO 4074 Clause 5: length over 160mm, width nominal ±2mm, default nominal width 53mm; ISO 4074 Clause 6: air inflation burst test, AQL 1.5%, separate extra-strong condom requirements.
5. [ONE Condoms Size Chart](https://onecondoms.com/blogs/education/condom-size-chart) (spec sheet). Supports: Nominal width defined as lay-flat width near the open end; Brand size range 45-64mm width, 120-235mm length across standard and custom-fit lines; Hyperthin as a named marketed thickness tier.
6. [What Sizes Are Condoms? Snug, Standard and XL](https://scienceinsights.org/what-sizes-are-condoms-snug-standard-and-xl/) (specialist review). Supports: Snug 40-49mm, standard 49-53mm, large 54-60mm nominal width bands; Typical length range 170-220mm.
7. [Do Condoms Expire? Shelf Life by Type](https://condoms.uk/blogs/sex-education/do-condoms-expire-shelf-life) (specialist review). Supports: Latex and polyurethane last up to 5 years; polyisoprene and spermicidal condoms up to 3 years; lambskin about 1 year; ISO 4074:2026 accelerated-aging test at 50°C for 180 days to support a 5-year shelf-life claim.
8. [Spermicide](https://en.wikipedia.org/wiki/Spermicide) (primer). Supports: WHO recommendation that spermicidally-lubricated condoms should no longer be promoted but are preferable to no condom.
9. [Condoms](https://www.plannedparenthood.org/learn/birth-control/condom) (specialist review). Supports: Flavored condoms are for oral sex only; avoid flavored products vaginally or anally due to irritation/yeast infection/BV risk; Lambskin condoms don't protect against STIs; A dental dam can be made by cutting open a condom.