NHS worker lost 4st using DIY Mounjaro regimen as doctors warn of risks

An NHS receptionist said she lost four stone in 11 months after using a do-it-yourself "microdosing" regimen of the diabetes drug Mounjaro, a practice doctors have described as dangerous and said is spreading on social media.

Siobhan Jackson, 40, from Kirby-in-Ashfield, Nottinghamshire, told media she slimmed from 14st 1lb and a size 20 to just under 10st and a size 10–12 after splitting her prescribed injections into smaller, more frequent doses rather than following official guidance. Jackson said she knew the approach went against rules but believed many people were doing the same to save money.

Jackson said she first tried diet and exercise and lost 1st 7lb, but turned to the injectable treatment after struggling to control her weight and blood pressure. She told reporters her blood-pressure readings had at one stage reached 170/140, prompting doctors to increase her medication.

Mounjaro (tirzepatide) is licensed to treat type 2 diabetes and has been used off-label by some patients for weight loss. Medical regulators and clinicians caution that altering prescribed doses or schedules can change how a drug acts in the body and increase the risk of side effects. Doctors quoted in coverage warned that splitting injections and improvising dosing may put lives at risk and goes against official prescribing guidance.

Clinicians have raised several safety concerns about so-called microdosing. Changing the frequency or amount of a medicine designed for a specific dosing schedule can affect blood-sugar control in people with diabetes, increase gastrointestinal side effects, and raise the risk of injection-site problems or infection if preparations are handled incorrectly. Experts also emphasise that the effects and long-term safety of unsanctioned dosing patterns have not been studied in clinical trials.

Jackson said cost was a factor in her decision. Accounts in the media and on social platforms suggest some people are altering doses to make supplies last longer or to manage the cost of treatments that are not prescribed or funded for weight loss in many health systems.

Health professionals have expressed concern about social media amplifying unverified regimens. While individuals share personal accounts of weight loss, clinicians stress that anecdotal results do not replace evidence from clinical trials and formal guidance. Medical authorities recommend patients only use medications as prescribed and discuss any dosing or cost concerns with their prescribers.

NHS guidance and national regulators instruct clinicians and patients to follow approved dosages and administration instructions. Changing these without clinical oversight can complicate medical care, particularly for patients who also take other medications for conditions such as hypertension or diabetes.

The episode adds to broader debates about access to and affordability of anti-obesity medications, and how online communities influence self-management choices. Health services and professional bodies have urged people considering treatments for weight loss to consult their doctor and to report adverse effects arising from off-label or improvised use of prescription drugs.