What did @kellyferrobeauty actually say?
Kelly described taking SS-31 and feeling "elevated" and experiencing "clean energy" almost immediately after dosing. She also noted her heart rate was "a little bit quicker" over the following two days. She framed this as a reason to cycle only "one peptide per week" and not stack too many at once. She also described SS-31 as "not a stimulant" but rather something that changes "how your body uses the energy." The post is soliciting audience experiences, which means it's functioning partly as a testimonial collection tool, not a clinical report.
Worth noting: she appears to mispronounce or mislabel the peptide as "Mazzi" when likely referring to SS-31's mechanism. The transcript is a bit garbled, but the core claims are clear enough to evaluate.
Does the science back this up?
Here's the honest answer: barely, and not in humans. SS-31, also known as elamipretide or Szeto-Schiller peptide 31, is a mitochondria-targeting tetrapeptide that has shown real promise in preclinical research, but the human data is thin and not about energy or heart rate.
SS-31 works by binding to cardiolipin, a phospholipid in the inner mitochondrial membrane, which helps stabilize electron transport chain function and reduce oxidative stress. Szeto et al. (2014, Biochimica et Biophysica Acta) demonstrated this mechanism clearly in animal models. Sabbah et al. (2016, JACC: Basic to Translational Science) ran one of the few human-adjacent trials, looking at SS-31 in heart failure patients, and found some improvement in cardiac energetics. That is a clinical heart failure context, not a wellness context.
There is no peer-reviewed human trial showing SS-31 produces subjective feelings of elevated energy or clean focus. The "clean energy" framing Kelly uses has no clinical definition and no measurable correlate in the existing literature on this peptide.
What did they get wrong (or right)?
Credit where it's due: Kelly is right that SS-31 is not a stimulant in the pharmacological sense. It does not act on adrenergic receptors or dopamine pathways the way caffeine or amphetamines do. That distinction matters and she deserves credit for making it, even if imprecisely.
Where she goes wrong is attributing her elevated heart rate to SS-31 with confidence after a single day of use. That is not how you establish causality. Heart rate variability is influenced by sleep quality, hydration, stress, caffeine, and dozens of other variables. Reporting a slightly elevated heart rate after one day and linking it to a peptide is anecdote, not evidence.
The claim that you should take "one peptide per week" is also not grounded in any clinical protocol for SS-31 specifically. There are no established human dosing guidelines published in peer-reviewed literature. Presenting personal cycling preferences as general safety guidance for an audience of 27,500 people is a problem.
What should you actually know?
SS-31 (elamipretide) is a legitimately interesting research compound. The mitochondrial cardiolipin-binding mechanism is real science. But interesting mechanism does not equal proven human benefit, and it absolutely does not mean the subjective experiences people report in wellness communities are caused by the peptide rather than expectation effects.
The placebo response for energy-related outcomes is strong. A 2020 meta-analysis by Hrobjartsson and Gotzsche (Cochrane Database) found placebo effects on subjective outcomes like fatigue and energy are among the largest and most consistent in medicine. Someone taking a novel peptide they are excited about, after reading rave comments, feeling "elevated" immediately after dosing is a textbook example of expectation-driven response.
SS-31 is not FDA-approved for any indication in healthy adults. It is an investigational compound. Anyone considering it should be doing so under medical supervision, not based on TikTok cycling advice. The elevated heart rate Kelly reported, however mild, is a physiological signal that warrants professional evaluation, not a crowdsourced comment section.