The global fitness community is mourning the death of popular fitness YouTuber and scientist Dr. Stephanie Buttermore, who passed away at the age of 36. The news was confirmed on March 6, 2026, by her longtime partner and fellow fitness creator Jeff Nippard, who shared the announcement through an emotional message on social media.
Canadian bodybuilder and YouTuber Jeff Nippard revealed the news of Buttermore’s death in an Instagram statement describing the loss as deeply painful. The statement said, “It is with profound sorrow that we share the sudden passing of Jeff’s fiancée and partner of ten years, Stephanie.”
The message further described her as someone who meant “the world” to Nippard and asked for privacy while the family processes the tragedy. At the time of the announcement, no official cause of death had been disclosed.
The couple had been together for about a decade and became engaged in October 2022 after building a strong presence together in the online fitness and bodybuilding community.
Stephanie Buttermore was widely respected for her academic background and evidence-based approach to fitness. She held a PhD in pathology and cell biology from the University of South Florida, along with multiple degrees in biomedical sciences.
Live EventsHer doctoral research focused on the molecular mechanisms and early detection of ovarian cancer, an area where she investigated biomarkers that could improve screening methods.
Buttermore built a massive online following through her educational yet personal approach to fitness content. Her YouTube channel attracted more than one million subscribers, while her Instagram audience exceeded 500,000 followers.
One of her most widely discussed projects was the “All-In” diet experiment, where she documented the effects of stopping restrictive dieting to allow the body to reach its natural weight set point. The series sparked widespread discussion about metabolism, hormonal health, and the psychological effects of dieting.
Before news of her death, many fans had noticed that Buttermore had largely stepped away from public platforms. Her final Instagram posts appeared in 2024, when she spoke about stepping back due to severe anxiety and prioritizing her mental health.
In that message, she explained that social media pressure had become “crippling,” but that time away from online life had improved her well-being and allowed her to be more present in everyday life.
Her long absence from content creation had already prompted speculation among fans before the announcement of her death.
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