Underwear Lab Reports
Every claim we make about these products, and the third-party test results behind it.
Most apparel brands make performance claims. Very few publish the reports behind them. Every figure on our underwear product pages comes from third-party laboratory testing, and every report is here in full — including the verification code that lets you confirm each one directly with the laboratory that issued it.
Testing was carried out by United Testing Services (Foshan) Co., Ltd., an independent laboratory accredited under China's CMA scheme (licence 202319016897) and by CNAS, the national accreditation body, under laboratory code L1842. CNAS is a signatory to the ILAC Mutual Recognition Arrangement, which means its accreditations are recognized internationally.
How to read these standards
Our fabric is made and tested in China, so the reports cite Chinese standards. The prefix tells you what kind of standard you're looking at:
- GB
- — a mandatory national standard. Compliance is required by law.
- GB/T
- — a recommended national standard, usually a test method or a performance benchmark.
- FZ/T
- — an industry standard covering textiles specifically.
- T/GDBX
- — a group standard published by an industry association.
GB 18401-2010 Class B appears on both our products. It's the mandatory national safety standard for textiles, at the tier reserved for garments in direct contact with skin, and it sets limits on formaldehyde, banned dyes, pH and odour.
Grades run to 5 unless stated otherwise, so a colourfastness result of 4–5 sits near the top of the scale.
CatWarm High-Waisted Thermal Underwear
Does the fabric actually generate heat?
Warmth, far-infrared, wicking, static and pilling
| Measurement | Method | Requirement | Result |
|---|---|---|---|
| Moisture-absorption heating, peak rise | FZ/T 73036-2010 | ≥ 4.0°C | 6.4°C |
| Moisture-absorption heating, 30-min average | FZ/T 73036-2010 | ≥ 3.0°C | 3.0°C |
| Far-infrared emissivity | GB/T 30127-2013 | ≥ 0.83 | 0.92 |
| Far-infrared temperature rise | GB/T 30127-2013 | ≥ 1.7°C | 2.0°C |
| One-way moisture transport, before wash | GB/T 21655.2-2019 | grade ≥ 3 | grade 5 |
| One-way moisture transport, after 5 washes | GB/T 21655.2-2019 | grade ≥ 3 | grade 5 |
| Absorption rate, outer face | GB/T 21655.2-2019 | grade ≥ 3 | 63.7 → 76.5 %/s |
| Anti-static, charge half-life | GB/T 12703.1-2021 | ≤ 10 s | 1.7 s |
| Anti-pilling | GB/T 4802.1-2008 | ≥ grade 2–3 | grade 3–4 |
What this measures. Moisture-absorption heating captures how much warmer a fabric gets when it takes up water vapour from the body — the mechanism behind thin thermal base layers. Two figures are recorded: the peak, and the average across thirty minutes. Far-infrared emissivity measures how efficiently the fabric radiates your own body heat back toward your skin. One-way transport measures how strongly the fabric pulls liquid from the skin side to the outer side instead of letting it sit.
What it doesn't. These are measurements of fabric under controlled laboratory conditions, not a guaranteed change in body temperature. The heating and far-infrared figures come from different methods and should never be added together.
Will they hold their shape?
Skew after 100 washes
| Measurement | Method | Requirement | Result |
|---|---|---|---|
| Skew after 100 domestic washes | FZ/T 73020-2019 | ≤ 3.5% | 1.5% |
What this measures. Skew is how far a garment twists out of true after repeated laundering — the reason a well-fitting garment eventually starts to sit crooked. The fabric was washed one hundred times using the standard domestic laundering procedure (GB/T 8629-2017) and then measured.
Is the lining clean, colourfast and safe?
Antibacterial durability, colourfastness and skin safety
| Measurement | Method | Requirement | Result |
|---|---|---|---|
| Bacterial reduction, S. aureus (ATCC 6538) | T/GDBX 056-2022, 7A | ≥ 85% | > 99% |
| Bacterial reduction, E. coli (strain 8099) | T/GDBX 056-2022, 7A | ≥ 70% | 99% |
| Colourfastness to water | GB/T 5713-2013 | ≥ 3 | 4–5 |
| Colourfastness to perspiration | GB/T 3922-2013 | ≥ 3 | 4–5 |
| Colourfastness to rubbing | GB/T 3920-2008 | ≥ 3 / ≥ 2–3 | 4–5 |
| Colourfastness to washing | GB/T 3921-2008 | ≥ 3 | 4–5 |
| Formaldehyde | GB 18401-2010 | ≤ 75 mg/kg | Not detected |
| Banned azo dyes | GB 18401-2010 | Prohibited | Not detected |
| pH value | GB 18401-2010 | 4.0 – 8.5 | 6.8 |
| Odour | GB 18401-2010 | None | None |
What "7A" actually means. The letter count is a wash-durability tier, not a measure of strength. A 7A finish is one that still meets its targets after a set number of wash cycles — here 30 machine programmes, the equivalent of roughly 150 home washes. Activity was measured by the shake-flask method; the closest international equivalents are ASTM E2149 and ISO 20743, and S. aureus ATCC 6538 is the same reference strain those methods use, so the figures are directly comparable.
On skin safety. Formaldehyde and banned azo dyes were both below the laboratory's detection limits — 20 mg/kg and 5 mg/kg respectively.
A note on scope. The full report includes a third test organism; we summarise the two used in the international reference methods.
Souffle Seamless Underwear
Is the lining clean after long-term use?
Antibacterial durability
| Measurement | Method | Requirement | Result |
|---|---|---|---|
| Bacterial reduction, S. aureus (ATCC 6538) | T/GDBX 056-2022, 7A | ≥ 85% | > 99% |
| Bacterial reduction, E. coli (strain 8099) | T/GDBX 056-2022, 7A | ≥ 70% | 99% |
How it was tested. The fabric was washed through 30 machine programmes — the equivalent of roughly 150 home washes — line-dried, and only then tested. Most antibacterial claims in apparel are measured on fabric straight off the roll.
What "7A" means. A wash-durability tier, not a measure of strength. Activity was measured by the shake-flask method; the closest international equivalents are ASTM E2149 and ISO 20743. The full report includes a third test organism; we summarise the two used in the international reference methods.
Is it colourfast and safe against skin?
Colourfastness and skin safety
| Measurement | Method | Requirement | Result |
|---|---|---|---|
| Colourfastness to water | GB/T 5713-2013 | ≥ 3 | 4–5 |
| Colourfastness to perspiration | GB/T 3922-2013 | ≥ 3 | 4–5 |
| Colourfastness to rubbing | GB/T 3920-2008 | ≥ 3 / ≥ 2 | 4–5 |
| Formaldehyde | GB 18401-2010 | ≤ 75 mg/kg | Not detected |
| Banned azo dyes | GB 18401-2010 | Prohibited | Not detected |
| pH value | GB 18401-2010 | 4.0 – 8.5 | 6.3 |
| Odour | GB 18401-2010 | None | None |
Why colourfastness matters here. Souffle is sold as a three-pack you mix yourself, which means three shades ending up in the same wash. These grades are what tell you whether the dark pair will tint the pale one.
On skin safety. Formaldehyde and banned azo dyes were both below the laboratory's detection limits — 20 mg/kg and 5 mg/kg respectively. A pH of 6.3 sits just on the acidic side of neutral, close to healthy skin's own range.
What these results don't tell you
Every report here covers a sample taken from a production run, not every garment we ship. Textile results vary between batches and between dye colours — sometimes noticeably. Where a claim on a product page rests on a single measurement, that measurement is the one published above, and nothing else.
Laboratory conditions are controlled by design. Temperature-rise figures describe how fabric behaves in a test chamber, not how warm you will feel on a particular day. Antibacterial results describe the fabric's own freshness, not any protective effect on the person wearing it — the finish is not a medical treatment and we make no claim that it protects you from infection.
Our garments are made to our specification by a partner factory in Guangdong, China. The original reports carry that factory's own brand name and were commissioned by them. We publish them unedited rather than reissuing summaries in our own name, because an original document you can verify is worth more than a translated claim you can't.
Reports are added as testing is completed. Last updated: 27 August 2026.