Tianna Moon, 30, from East Anglia, has what is believed to be the largest breasts in Britain, measuring a 32OO cup. She says they grew rapidly after she began taking the weight-loss drug Mounjaro, progressing from an L cup to a NN and finally to her current size.
Daily life becomes a struggle
Moon explained that the hot weather is particularly difficult. "The hot weather has been far from pleasant," she said. "My boobs are like a heat factory and there isn't really much I can do to keep cool."
She also struggles with stairs, as she cannot see her feet. "Stairs are also a huge problem now. I'm forever tripping up on them. I have to go really slow, as I can't see my feet anymore. It's ridiculous - but it's the truth."
Sleep and health complications
Sleep has become another challenge. "Sleeping is also something I'm really struggling with," she admitted. "Since losing weight, it's easier for me to move in my sleep, meaning I end up on my back more. But I keep waking up frequently, as the added weight on my chest suffocates me."
Moon suffers from gigantomastia, a rare condition causing rapid and excessive growth of breast tissue. She had hoped to find a silver lining in the title, but now all she wants is comfort.
"I'm not the biggest in the world, nor do I want to be. I'm in so much pain now. A breast reduction isn't a cure," she said. "The glandular tissue could continue to grow after a reduction and then I'd have scar tissue to factor in, too. I have thinning on the sides of my breasts, so that skin with a reduction would have a higher chance of ripping open. Nobody knows why I have this condition and so it'd be hard to find a surgeon that would be happy to operate."
Weight loss journey and coping methods
Moon underwent gastric sleeve surgery in November 2025 to lose weight, but her breasts only increased in size. She has since taken up weight training and resistance band training to strengthen her spine and improve her posture.
"I forget how big my boobs are, though, as I live with them. I'm forever knocking stuff over and walking into things since I can't see," she added. "I don't tend to go abroad, but sitting in a car for over an hour does cause a lot of tension and pain in my upper back. This is something that's only started in the last few months; so I've remained at home pretty much."
