Is it safe to have sex with someone who is “undetectable”?

@AskPeaches: I’ve met a guy on Grindr who said he is undetectable. He said that there was nothing for me to worry about if we hooked up. I was just too scared to go through with it. Is what he said true?
—Vincent Tweet
@Vincent: The short answer is, yes. He is correct. Here’s some additional insight for you to know. The term undetectable describes someone’s HIV viral load, meaning that standard load tests cannot detect copies of HIV in the blood. However, more sensitive testing can register them. A person is considered undetectable when their viral load is less than 200 copies/mL in a blood sample taken on that day. This does not mean that they are HIV-negative or cured, but that their antiretroviral therapy (ART) is successfully suppressing the virus. Such therapies have become increasingly effective in the last 15 years and many people can achieve undetectable status within three to six months if they consistently take their medication.
On the question of safety, various studies have indicated that someone with an undetectable viral load cannot transmit the virus. I won’t go into the details of the studies, but you can learn more about them here. I will summarize their key findings, however. What researchers uncovered was that in both gay and straight relationships where one partner was HIV-positive and one was HIV-negative, even with unprotected sex, the one who was HIV-negative did not contract the virus from their partner. In the case of the gay participants, this was the case whether the HIV-positive partner was the top or the bottom. In some cases, some of the participants caught HIV during the studies, but genetic testing later revealed they had contracted it from other sex partners outside of the relationship. This is very insightful, not only because it proves that people with undetectable status don’t transmit the virus, but that you’re at greater odds getting HIV by having unprotected sex with someone whose status you or they don’t know than someone who is undetectable.
The three studies commonly referred to as PARTNER 1, PARTNER 2 and Opposites Attract examined over 4,000 gay and straight couples and 150,000 sexual acts, over a period of between two and eight and a half years. So, it’s become widely accepted by The Centers for Disease Control and Prevention (CDC) and the National Institutes of Health (NIH) that the risk of HIV transmission is effectively zero. Experts recommend that as long as an HIV-positive person consistently takes their medication, is undetectable for at least six months, they will not transmit the virus to their partner. It’s these findings that inspired the “U=U” campaign that undetectable means untransmittable.
With the above, I’m not suggesting that you should have unprotected sex, however. It’s your decision with whom and how you choose to have sex. So, inform yourself, understand the risks and know also that HIV treatments prevent HIV transmissions but do not protect you from contracting other STIs. Since it can be challenging getting recent, if any, STI testing results from a casual sex partner, I recommend you also use a condom. For more information on how you could further protect yourself against HIV check out my post on HIV preventative therapies here.
The @AskPeacheas column is prepared by committee but written from one person’s experience. Send emails to askpeaches [at] freshfruitinc [dot] com with “@AskPeaches” in the subject line. Be sure to give enough background, so the advice can be more specific and relevant.