The Diary Of A CEO · 2026-04-20 · Steven Bartlett (host), Alex Tatem
Peptide Expert: What Do Peptides Actually Do? (EXPLAINED) - Dr Alex Tatem
61 research-tied claims examined: 3 contradicted 8 overstated 45 supported 5 unverified
3 Contradicted by research
Tirzepatide produces more weight loss per milligram than any other commercially available GLP-1 drug.
"So, Mounjaro is the brand name for tirzepatide, all right? Tirzepatide being the leading GLP-1 product right now from Lilly. So, this produces more weight loss per milligram than any other product that we've got out right now." (said at 0:29:08)
The claim that tirzepatide produces more weight loss per milligram than any other GLP-1 drug is contradicted by clinical trial data. While tirzepatide yields greater overall (total) weight loss at its maximal clinical doses (10 mg to 15 mg weekly) than semaglutide at its approved doses (1.0 mg to 2.4 mg weekly), semaglutide is substantially more potent on a per-milligram basis. For example, in head-to-head phase 3 clinical trials, semaglutide 2.4 mg weekly achieves approximately 13% to 15% body weight reduction (~5.4% weight loss per milligram), whereas tirzepatide 15 mg weekly achieves approximately 20% body weight reduction (~1.3% weight loss per milligram). Similarly, in the SURPASS-2 trial comparing tirzepatide (5 mg, 10 mg, 15 mg) to semaglutide (1 mg), semaglutide produced 5.7 kg weight loss (5.7 kg/mg) versus 7.6 kg to 11.2 kg weight loss for tirzepatide (0.75 kg/mg to 1.52 kg/mg).
- contradicts: Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes. (The New England journal of medicine 2021) · cited 1985x in the literature
"Reductions in body weight were greater with tirzepatide than with semaglutide (least-squares mean estimated treatment difference, -1.9 kg, -3.6 kg, and -5.5 kg, respectively; P<0.001 for all comparisons)." (abstract, results, passage verified)
pubmedfull study (doi) - contradicts: Tirzepatide compared with semaglutide in obesity disease: a subpopulation analysis applyin… (Current medical research and opinion 2026)
"At Week 72, the least-squares mean (LSM) percent change in body weight was significantly greater for tirzepatide (-20.1% [SE 0.76%]) versus semaglutide (-12.9% [0.74%]), with an LSM difference of -7.2 (95% CI = -9.3 to -5.1; p <.001)." (abstract, results, passage verified)
pubmedfull study (doi)
Roledumab and trevogrumab are monoclonal antibody myostatin inhibitors designed to maintain muscle mass in a caloric deficit.
"And then you have roledumab and trevogrumab, which are two other compounds owned by different pharmaceutical company that are all designed to maintain muscle even in a significant caloric deficit." (said at 0:45:14)
The claim incorrectly identifies roledumab as a muscle-maintaining myostatin inhibitor. While trevogrumab is indeed a monoclonal antibody that targets myostatin and activin signaling to preserve lean body mass during weight loss, roledumab is actually a recombinant monoclonal anti-RhD antibody developed to prevent RhD allo-immunization in Rh-negative individuals, with no role or design in myostatin inhibition or muscle preservation.
- contradicts: Pharmacokinetics and safety of roledumab, a novel human recombinant monoclonal anti-RhD an… (Vox sanguinis 2012) · cited 24x in the literature
"Pharmacokinetics and safety of roledumab, a novel human recombinant monoclonal anti-RhD antibody with an optimized Fc for improved engagement of FCγRIII, in healthy volunteers." (abstract, title, passage verified)
pubmedfull study (doi) - supports: The impact of weight loss on fat-free mass, muscle, bone and hematopoiesis health: Implica… (Metabolism: clinical and experimental 2024) · cited 123x in the literature
"Novel compounds in the pipeline, such as Bimagrumab, Trevogrumab, and Garetosmab-which inhibit activin and myostatin signaling-have demonstrated promise in preventing muscle loss while promoting fat loss." (abstract, results, passage verified)
pubmedfull study (doi) - supports: Pharmacological intervention: Challenges and promising outcomes for fat loss and preservat… (Diabetes, obesity & metabolism 2026) · cited 7x in the literature
"Similar effects were observed for myostatin and activin A inhibitors (trevogrumab, garetosmab), latent myostatin inhibitors (apitegromab, SRK-439), and Selective Androgen Receptor Modulators (enobosarm)." (abstract, results, passage verified)
pubmedfull study (doi)
Oral erectile dysfunction medications fail in approximately 15% of men on initial use.
"And if you look at statistics, the oral medications are going to fail in 15% of those men the first time they feel that." (said at 1:25:43)
Published systematic reviews and clinical trial data indicate that the non-response or failure rate for oral phosphodiesterase type 5 inhibitors (PDE5is) in erectile dysfunction is approximately 30% to 40%, not 15%. Initial failure rates in clinical practice can be even higher before proper dose titration, timing adjustments, and patient education (e.g., ensuring adequate sexual stimulation and avoiding heavy meals).
Unverified means no publication matching the claim was located; it does not prove the claim false. Spotted an error? See the corrections policy - disputes from the people quoted are prioritized.