Q: My girlfriend and I enjoy oral sex. My girlfriend has a deathly peanut allergy. So I've been avoiding eating anything with peanuts before sex. However, I really enjoy products with peanuts like peanut butter. Is it safe for me to consume peanut products before we engage in oral sex or any other types of sex?
A: I couldn't find a lot of research on this, but there has been one recorded case of a man giving his partner an allergic reaction from having sex with them right after eating nuts. In this case, doctors found that the man's semen did contain nut proteins that may have caused the allergic reaction. While this is far from conclusive, it does show that there is a potential risk of having one's semen contaminated with allergy-causing nut proteins soon after eating peanuts. However, even in this case, the allergic reaction was quite minor (itching, rash).
Most studies find little evidence that people with peanut allergies have major reactions simply from coming into contact with secondary peanut residue. In other words, if a person washes thoroughly with soap and water after being exposed to nuts, there should be no issues with touching someone who has a peanut allergy. But, if your girlfriend does have a very severe reaction to peanuts, it would be safer to not eat nuts for at least one day before having sex with her. After a day has passed, it's very likely that any proteins from the nuts you ingested will be out of your system.
Answers provided by Dr. Ross Avilla
Dr. Ross Avilla has been teaching Human Sexuality since 2013 and has a PhD in psychology from UC Davis. Dr. Avilla is not a clinician and all information and advice offered on this website is for educational purposes only.