Written by
Louise W Lu, PhD, MPH, BMLS
Written/Reviewed by
Lilly (Yutong) Liu, Registered Dietitian, PhD Researcher in Nutrition, University of Auckland
As early as 1957, doctors in China discovered that in some rural areas, families who consumed crude, unrefined cottonseed oil over long periods were exposed to a compound called gossypol. As a result, many couples in those regions struggled to conceive.
This finding was later documented in international medical literature, marking one of the earliest global discussions on the link between cooking oil and fertility.
You might think: was this just something that happened decades ago? In fact, it’s not only history. In recent years, Western studies have reported similar observations in animal models: unrefined cottonseed oil can disrupt ovarian function and interfere with reproductive cycles, suggesting potential risks to fertility. In other words, even across different times and regions, the question of “cottonseed oil and infertility” remains worth paying attention to.
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Why Can Cottonseed Oil Affect Fertility? (Causes & Mechanism)
Cottonseed oil is a type of vegetable oil pressed from the seeds of the cotton plant. In some cotton-producing regions, it has been widely used as a daily cooking oil. Because it is inexpensive and produced in large quantities, it once appeared on many household tables. But unlike soybean oil or canola oil, cottonseed oil has a unique issue—it may contain a natural compound called gossypol.
For men, gossypol interferes with the process of “making sperm” in the testes. This leads to fewer sperm being produced, with lower quality—some may lack the energy to swim far or fast, reducing the chances of fertilization. This is also why scientists once studied gossypol as a potential male contraceptive.
For women, gossypol may damage the “egg reserve” in the ovaries. As a result, ovulation becomes less regular, and hormone balance is more easily disrupted. Some studies have found that it can cause irregular menstrual cycles, making it harder to conceive.
In other words, gossypol is the key factor linking cottonseed oil to infertility. Not every drop of cottonseed oil is dangerous, but if it has not been properly refined and gossypol levels remain high, it could quietly weaken fertility and make trying for a baby more difficult.
How Much Could Be Risky?
The impact of gossypol on fertility depends on the type of oil, daily intake, and duration. Crude (unrefined) cottonseed oil carries a clearly higher risk, while refined cottonseed oil is generally safe at normal dietary amounts.
📌 Unrefined Cottonseed Oil (Crude Oil)
- Gossypol content: can be as high as 1–2 g/kg of oil.
- Risky intake: consuming about 30–40 g per day (≈ 2–3 tablespoons) of crude cottonseed oil can deliver 20–30 mg of gossypol daily.
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Time to impact:
- After 2–3 months of continuous intake: reduced sperm count and motility in men.
- After 6+ months: some men may develop temporary infertility; women may experience irregular periods and reduced ovulation.
- In some individuals, recovery can take 3–12 months after stopping exposure.
📌 Refined Cottonseed Oil
- Gossypol residue: typically controlled at ≤ 0.02 g/kg (20 mg/kg), considered a safety threshold.
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Risky intake (by calculation):
- 30 g/day of refined oil (≈ 2 tablespoons) provides only about 0.6 mg gossypol.
- Even at 100 g/day, gossypol intake is only about 2 mg—far below levels linked to fertility effects (≈ 20 mg/day).
- Time to impact: Under normal dietary use, even long‑term intake of compliant refined cottonseed oil does not accumulate to infertility‑level exposure. In other words, within standard limits, refined cottonseed oil is unlikely to cause fertility issues.
In short: Crude oil—small daily amounts over time can be harmful; refined oil—normal use is generally safe. For couples trying to conceive, the key is choosing cottonseed oil from reputable sources that has been properly refined.
Refined vs. Unrefined: Which Cottonseed Oil Is Actually Safe?
Not every product labeled “cottonseed oil” belongs in your kitchen. Different uses and processes vary greatly in refining level, gossypol residue, and labeling compliance. The rule of thumb: only food‑grade, refined, and clearly “degossypolized” cottonseed oil is suitable for eating. Avoid all others.
❌ Do not consume these
- Crude/unrefined cottonseed oil: high gossypol residue; long‑term intake may affect fertility and liver health.
- Industrial/feed‑grade oils: for chemical/feed processing only; not food‑grade.
- Topical oils (medicated/massage/cosmetic): formulated for skin use; not evaluated for oral safety.
- Unlabeled bulk oils: missing manufacturer, batch, expiry, or testing standards; risk is uncontrollable.
✅ Safe to consume (only if all are met)
- Food‑grade refined cottonseed oil: label clearly states Refined or Degossypolized; gossypol ≤ 0.02 g/kg.
- Complete information: manufacturer, batch number, production/expiry dates, and storage conditions.
- Appearance & packaging: clear pale yellow, no off‑odors; sealed original packaging, stored away from light.
| Category | Edible? | Common Use | Key Risk / Control Point |
|---|---|---|---|
| Crude cottonseed oil (unrefined) | ❌ No | Small workshops / bulk cooking | High gossypol; long‑term fertility & liver risks |
| Industrial / feed‑grade cottonseed oil | ❌ No | Chemical, feed processing | Non‑food standards; solvent/heavy‑metal risks |
| Topical grade (medicated/cosmetic) | ❌ External use only | Massage oil, skincare balms | For skin only; not evaluated for ingestion |
| Food‑grade refined cottonseed oil | ✅ Yes | Home / restaurant cooking | Gossypol ≤ 0.02 g/kg; reputable, traceable batches |
Is topical use harmful?
When used on skin as directed, topical products are generally fine because the skin barrier limits systemic absorption of gossypol. Still, note:
- Avoid applying on broken/inflamed skin, infants, and around the mouth/nose.
- Trying to conceive, pregnant, or breastfeeding? Avoid large‑area, frequent use of cottonseed‑derived topicals.
- If you’re allergy‑prone, do a small patch test first; stop and seek care if redness/itching/stinging occurs.
Reminder: “Topical‑safe” ≠ “edible.” Standards for topical vs. edible oils differ (raw materials, impurities, microbes, solvents). Do not swap them.
How to tell from the label?
Look for: ✅ Refined, ✅ Degossypolized vs. ❌ Cold‑Pressed, ❌ Unrefined
Tip: If the bottle only says Cold‑Pressed or Unrefined without “Refined” or “Degossypolized / food‑grade,” do not cook with it. Only oils clearly labeled refined and degossypolized and compliant with food standards are suitable for eating.
Authors:
Lilly (Yutong) Liu
Registered Dietitian, PhD Researcher in Nutrition, University of Auckland
Lilly is a New Zealand Registered Dietitian and PhD candidate at the University of Auckland. She specialises in elderly and post-operative nutrition care through her clinical work with DietRight, and her research focuses on biomarkers and nutrition strategies in pancreatic diseases. With experience in hospital-based nutrition, RedCap data management, and bilingual study coordination, she is committed to delivering evidence-based, culturally informed nutrition solutions.
