What did @myweightlossjourney048 actually say?
The creator came to clarify a previous video about breast reduction surgery. She says she considered it, went to a consultation, but did not go through with the procedure. Her main claim is this: she reduced her bra size from a 40F to a 34C "through weight loss injections," losing 30 kilos in the process. She attributes the breast volume loss to the fact that "most of your boob is fat." She also briefly mentions a condition she describes as "giant mammary glands," which she suggests can make breast reduction surgery medically necessary rather than cosmetic, potentially affecting insurance coverage. The surgery update is the wrapper. The actual claim doing the real work here is that GLP-1 receptor agonist injections drove significant, measurable breast size reduction as a direct consequence of fat loss.
Does the science back this up?
On the core biology, she is correct. Breast tissue is composed of glandular tissue and adipose (fat) tissue, and the ratio varies considerably between individuals. Studies show that in many women, adipose tissue accounts for a substantial portion of breast volume, which means significant body fat loss can reduce breast size. A 30-kilogram loss is not trivial. That is a substantial reduction in total body fat, and it would be surprising if breast volume did not change.
GLP-1 receptor agonists like semaglutide and tirzepatide produce weight loss primarily through appetite suppression and slowed gastric emptying. The SURMOUNT-1 trial (Jastreboff et al., 2022, New England Journal of Medicine) showed tirzepatide produced up to 22.5% body weight reduction in people with obesity. The STEP 1 trial (Wilding et al., 2021, NEJM) showed semaglutide at 2.4mg produced approximately 14.9% mean weight loss. At those magnitudes, changes in breast volume are plausible and expected, though no trial has specifically measured bra size as an outcome.
What did they get wrong (or right)?
She got the underlying biology right: adipose tissue in the breast does shrink with fat loss. That is not controversial. Where things get murkier is the implication that GLP-1 injections specifically target breast fat. They do not. These medications produce generalized fat loss. The body decides where it loses fat based on genetics, sex hormones, and fat distribution patterns, not the drug. Some women will lose breast volume with weight loss. Others will lose it from the abdomen or thighs first. There is no evidence that GLP-1 agonists selectively reduce breast adipose tissue.
The mention of "giant mammary glands" appears to be a reference to macromastia or gigantomastia, a recognized medical condition. She is correct that breast reduction for documented macromastia can be considered medically necessary rather than purely cosmetic in some insurance frameworks. That framing is generally accurate, though coverage criteria vary significantly by insurer and country.
What should you actually know?
If you are using a GLP-1 medication and experiencing changes in breast size, that is a real and reported phenomenon, but it is a downstream effect of fat loss, not a unique property of the drug. Breast volume changes during weight loss are well-documented in the bariatric surgery literature. A review by Losken et al. (2004, Plastic and Reconstructive Surgery) noted breast ptosis and volume reduction as common consequences of significant weight loss.
A few things worth knowing before assuming your experience will mirror hers:
- Individual fat distribution varies. Some people store more fat in breast tissue than others. Dense, glandular breasts will change less with weight loss than fatty ones.
- 30 kilograms of weight loss is substantial. Smaller losses are unlikely to produce changes of this magnitude.
- Bra sizing is notoriously inconsistent across brands and countries. A change from 40F to 34C involves both a band size reduction and a cup volume change, which are not directly comparable without professional fitting context.
- Skin laxity after significant weight loss is a real consideration. Volume reduction without accompanying skin tightening can lead to ptosis (sagging), which is sometimes why people pursue surgery even after weight loss.
- No GLP-1 medication is approved or indicated specifically for breast reduction.