HIV treatment as prevention
Am I Untransmittable? Understanding U=U
Undetectable = Untransmittable. If you have HIV and stay undetectable on treatment, you cannot pass HIV to a sexual partner. Answer three quick questions, privately, to see whether U=U applies to you yet, and exactly what it does and doesn't cover.
U=U status checker
What U=U does and doesn't cover
This is general information based on CDC guidance and published research, not a diagnosis or medical advice. Your viral load status is confirmed by your provider and your lab results, not this tool.
The basics
What "Undetectable = Untransmittable" means
When someone living with HIV takes treatment consistently, the amount of virus in their blood, their viral load, drops. Keep it below the level a test can measure and you become undetectable. And an undetectable person cannot pass HIV to a sexual partner. That's U=U.
This isn't optimism or harm-reduction spin. Across four major studies following serodifferent couples through more than 100,000 acts of condomless sex, there were zero HIV transmissions from a partner who was durably undetectable. It's one of the most important, and most stigma-shattering, facts in HIV medicine.
The path
Getting to (and staying) untransmittable
Start treatment
Modern HIV medicine is usually one pill a day (or a long-acting shot). Most people reach undetectable within one to six months of starting.
Stay undetectable
Take it consistently. Once you've been undetectable for about six months, U=U applies, and keeps applying as long as you stay suppressed.
Check your viral load
Regular viral-load tests (typically every 3–6 months) confirm you're still suppressed. Your results are the proof, not a guess.
The honest detail
Where U=U is definitive, and where it isn't
Sexual transmission: definitive
This is what the studies measured, and the answer is clear: durably undetectable means you cannot transmit HIV through sex.
Other STIs: not covered
U=U is only about HIV. Gonorrhea, chlamydia, syphilis and others spread regardless of viral load, so condoms and testing still matter.
Breastfeeding: greatly reduced, not zero
Being undetectable substantially lowers the risk to an infant but hasn't been proven to eliminate it. Plan this with your provider.
Shared needles: lowers risk, less studied
An undetectable viral load reduces transmission through shared injection equipment, but this route isn't studied like sex was: don't assume zero.
Next steps
Related tools
PrEP eligibility
For an HIV-negative partner who wants prevention on their own terms.
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A possible HIV exposure in the last 72 hours? Check the emergency window.
Disclosure script writer
A kind, copyable way to talk with a partner about status.
Find testing & care
Clinics, at-home kits and free options near you.
Sources
Where this comes from
U=U is backed by the CDC and by the landmark PARTNER, PARTNER2, HPTN 052 and Opposites Attract studies, which together recorded no HIV transmissions from a durably undetectable partner. We state their conclusion as they do.
Medically Reviewed & Fact-Checked · Updated
Reviewed by EasySTD Editorial Team
Compiled and checked by EasySTD's editorial team against CDC and public-health sources. This is educational information, not a substitute for advice from a licensed clinician. Our editorial guidelines →
3 Sources
Data & references
- CDC: HIV Treatment as Prevention (Undetectable = Untransmittable)https://www.cdc.gov/hiv/risk/art/index.html
- Rodger et al. (PARTNER2), The Lancet, 2019https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(19)30418-0/fulltext
- Prevention Access Campaign: U=U consensus statementhttps://preventionaccess.org/consensus/
EasySTD is an information and comparison directory, not a healthcare provider. This tool is general information based on published guidance and research: it is not medical advice, a diagnosis, or a prescription, and it does not create a doctor-patient relationship. Your viral load and treatment are managed with your HIV care team.
Good to Know
U=U: frequently asked questions
What Undetectable = Untransmittable means, how long it takes, and what it covers.
What does U=U actually mean?
U=U stands for Undetectable = Untransmittable. It means that a person living with HIV who takes their treatment as prescribed and keeps a durably undetectable viral load cannot transmit HIV to a sexual partner. This is not a theory or a rounding-down of the risk, it's the conclusion of large studies (PARTNER, PARTNER2, HPTN 052, Opposites Attract) that recorded zero HIV transmissions from an undetectable partner across many thousands of acts of condomless sex. The CDC, the U.S. HIV guidelines, and health bodies worldwide endorse it.
How long do I need to be undetectable before U=U applies?
The consensus is a viral load that has been undetectable for at least six months, kept there by consistent treatment. Reaching undetectable for the first time is the milestone; staying there is what makes you untransmittable. If you've been undetectable for less than six months, you're on the right path, use condoms or have your partner consider PrEP until your next result confirms sustained suppression.
What counts as 'undetectable'?
Undetectable means the amount of HIV in your blood is below the level a standard viral-load test can measure, usually under 200 copies/mL (many people are under 50, or fully 'not detected'). It does not mean the virus is gone or that you're cured, it means treatment is keeping it suppressed. That's why staying on treatment and getting your viral load checked as your provider recommends matters so much.
Does U=U cover everything, or just sex?
The evidence for U=U is strongest and clearest for sexual transmission, that's what the studies measured, and there it's definitive. For other routes the picture differs: an undetectable viral load greatly lowers the risk of transmission through shared injection equipment, but that route hasn't been studied the same way, so don't treat it as zero. For breastfeeding/chestfeeding, being undetectable substantially reduces but does not fully eliminate the risk, so it's a conversation to have with your provider. U=U also doesn't protect against other STIs, condoms still do.
If I'm undetectable, does my partner still need PrEP or condoms?
For HIV, no, if you're durably undetectable, your partner is protected from HIV without PrEP or condoms. Some couples still choose PrEP for extra peace of mind or for times when treatment might be interrupted, and that's a valid personal choice. Condoms remain worthwhile because U=U says nothing about other STIs like gonorrhea, chlamydia, or syphilis, which spread regardless of HIV viral load.
Is what I enter here private?
Completely. This tool runs entirely in your browser: your answers about your treatment and viral load are never sent to a server, saved, or shared. Close the tab and they're gone. It's educational and can't replace your HIV care team, only your provider and your lab results confirm your viral load status.
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