Most people spend very little time thinking about what their underwear is made from. It is worn every day, closest to the body, and for most of us it is almost entirely synthetic: polyester, nylon, or a blend of the two.
We are not here to alarm you. We are here to share what the research says, so you can make your own informed choice. Below you will find links to real studies and credible sources covering four areas: skin irritation, heat and moisture, chemical exposure, and the emerging question of reproductive health.
At the bottom, we explain what bamboo fabric is and what the science says about how it compares.
1. Skin Irritation and Contact Dermatitis
Textile contact dermatitis — skin irritation caused by fabric — is a well-documented condition. Synthetic fabrics are more commonly associated with it than natural fibres, often because of the dyes and chemical finishes used in manufacturing rather than the base material itself.
Dermatologists at DermNet New Zealand describe how polyester and other synthetic fabrics can trigger contact dermatitis in sensitive individuals, particularly in areas of friction and heat — exactly where underwear sits.
"Synthetic fibres such as nylon, polyester, and spandex are more likely to cause contact dermatitis than natural fibres." — DermNet New Zealand
- Textile Contact Dermatitis — DermNet New Zealand — Clinician-reviewed overview of fabric-related skin reactions
- Synthetic Fabrics and Skin Microbiome — OR Basics — How synthetic activewear affects the skin's bacterial balance
2. Heat, Moisture, and Bacterial Environment
Polyester is hydrophobic — it repels moisture rather than absorbing it. This means sweat sits on the skin longer, creating a warmer and more humid environment in areas covered by underwear. Research has consistently shown that heat and moisture in the groin area can encourage the overgrowth of bacteria and yeast.
This is not a new finding. It has been understood in dermatology and gynaecology for decades, and the recommendation to wear breathable, natural-fibre underwear is standard clinical advice for people prone to recurrent infections.
- Health Risks of Synthetic Underwear — UnderwearIQ — Summary of moisture-related health risks linked to synthetic underwear
3. Microplastics and Chemical Exposure
In 2024, researchers at the University of Birmingham published findings showing that toxic chemicals from microplastics can be absorbed through human skin. Polyester clothing sheds microplastic fibres constantly — these fibres carry chemical residues from the manufacturing process, including plasticisers and finishing agents.
The research on skin absorption of these chemicals is relatively new, but it raises legitimate questions about what long-term, close-contact exposure to synthetic fabrics means for the body, particularly in areas of high skin sensitivity.
"Toxic chemicals from microplastics can be absorbed through the skin — raising concerns about everyday clothing exposure." — University of Birmingham, 2024
- Toxic Chemicals from Microplastics Can Be Absorbed Through Skin — University of Birmingham — Peer-reviewed research published 2024
- Microplastics in Dermatology — Journal of Cosmetic Dermatology (Wiley) — Peer-reviewed journal article, 2024
- Toxic Chemicals from Microplastics Absorbed by the Skin — Medical News Today
4. Reproductive Health: The Fertility Question
This is the most debated area, and we want to be straightforward about what the research does and does not show.
In 1992, Dr Ahmed Shafik published a study in the journal Contraception in which 14 fertile men wore a close-fitting polyester scrotal sling continuously for approximately 140 days. By the end of the study, all 14 men had become azoospermic — meaning no detectable sperm in their ejaculate. Sperm counts returned after the sling was removed.
What this research does not prove is that ordinary polyester underwear worn in everyday life causes azoospermia or infertility. The scrotal sling used in these studies was a more extreme form of exposure than standard underwear. However, the studies are real, published in peer-reviewed journals, and raise questions that have not been definitively resolved by subsequent research.
We leave it to you to read the research and draw your own conclusions.
"All 14 subjects became azoospermic during the period of wearing the polyester sling." — Shafik, Contraception, 1992
- Contraceptive Efficacy of Polyester-Induced Azoospermia in Normal Men — PubMed (Shafik, 1992) — Original peer-reviewed study
5. What the Research Says About Bamboo Fabric
Bamboo viscose — the fabric used in YouBamboo products — is derived from the bamboo plant through a process that produces a soft, breathable fibre. Here is what the evidence supports.
Breathability and temperature regulation
Bamboo viscose has a significantly higher moisture absorption and wicking capacity than polyester, helping to keep the skin drier and cooler. This is measurable and well-documented in textile science literature.
Antibacterial properties
Raw bamboo contains a natural bio-agent called "bamboo kun" which gives the plant its natural resistance to bacteria and pests. Whether this property survives the manufacturing process into bamboo viscose is genuinely debated — we do not overstate this claim.
Skin sensitivity
The smooth, round fibre structure of bamboo viscose means it lies flatter against skin than the rougher surface of polyester or even some cottons. This is why bamboo fabric is widely recommended for people with eczema, psoriasis, and sensitive skin.
Chemical profile
The manufacturing process for bamboo viscose does involve chemicals, and not all bamboo fabric is equal. Fabrics certified to OEKO-TEX Standard 100 have been independently tested and verified to be free from harmful levels of chemical residues. Our products carry this certification.
Our Position
We believe people deserve to know what their clothes are made from and what the research says about the materials closest to their body. We are not scientists, and we are not making medical claims. What we are doing is making underwear and bedding from bamboo — a natural, breathable fabric — and pointing you toward the evidence so you can decide for yourself.
This article is for informational purposes only and does not constitute medical advice. YouBamboo makes no medical claims about its products. If you have specific health concerns, please consult a qualified healthcare professional.
