SS-31 (Elamipretide)

Safety Risk (1.5/5.0). The safety profile is exceptionally clean for a peptide in this class: eight years of clinical development, zero drug-attributed deaths across Phase 2/3 programs, no serious adverse event signal, and FDA raised zero clinical safety concerns at the Forzinity NDA review (FDA 2025). No intrinsic catastrophic adverse event has been documented across Barth, PMM, HFrEF, and AMD trials, so the v0.5 catastrophic risk floor is not triggered. Supply-chain risk (contamination, underpotency, counterfeit in gray-market channels) is real but belongs in the Verdict and legal_disclaimer per v0.5 "score the compound, not the supply chain" rule. Long-term safety on multi-year daily subcutaneous dosing in healthy adults remains limited because no such trial has run that long.

Side Effect Profile (3.0/5.0). The dominant finding is injection-site reactions in roughly 80% of trial subjects per the Forzinity label (erythema, induration, pruritus, occasional pain at the subcutaneous injection site). Rotating sites and warming the vial before injection reduces frequency but does not eliminate it. Headache and dizziness are common, frequency in the 10-20% range across published trials. Nausea and GI upset reported less frequently. Peripheral neuropathy signals appear in a small minority of patients under long-term dosing and are flagged on the Forzinity label; attribution vs underlying mitochondrial disease is not fully settled. Unlike the safety floor (clean), the side-effect tail is legitimately disruptive for daily subcutaneous users, which is the main real-world friction alongside cost.

Financial Cost (3.5/5.0). Forzinity is priced for ultra-rare-disease reimbursement and is effectively prescription-only via specialty pharmacy and insurance in the Barth indication. Gray-market SS-31 at biohacker doses (5-10 mg/day) runs $200-500 per month from research-chemical vendors, which maps to v0.5's ">$200/mo" anchor for the Cost dimension. Attempting the full trial dose (40 mg/day) at gray-market pricing pushes the cost to $1,600-4,000/month, which essentially nobody sustains. Scored at the accessible channel a motivated longevity user would actually use (gray-market, 5-10 mg) per v0.5 cost rules. That channel delivers probable sub-therapeutic exposure for most investigated endpoints, which makes the cost-benefit especially unfavorable for healthy users.

Time/Effort Burden (2.5/5.0). Daily subcutaneous injection is the floor commitment: reconstitute lyophilized peptide with bacteriostatic water, rotate injection sites, sharps disposal, refrigeration. Per-injection time is 2-5 minutes; total monthly compliance overhead is meaningful but not extreme by peptide standards. Travel adds friction (refrigerated transport, sharps declaration at airports, insulin-pen-style discretion is not available). Compared with oral glycine or a topical cream, SS-31 sits at the higher end of self-administration burden; compared with IV-only interventions, it is middle tier. The injection-site-reaction rate (~80%) extends the effort cost beyond the 5 minutes of injection because users rotate sites proactively and deal with post-injection inflammation.

Opportunity Cost (2.0/5.0). Crowds out cheaper mitochondrial interventions in a biohacker's budget: CoQ10 or ubiquinol, urolithin A, NAD+ precursors (NMN, NR), creatine monohydrate, magnesium, and the mechanical-stimulus side of mitogenesis (zone-2 cardio, Norwegian 4×4, strength training). Most of these deliver mitochondrial upside at a fraction of the monthly cost with substantially lower friction. For the indicated population (Barth, documented mitochondrial dysfunction), opportunity cost is near-neutral because SS-31 has a specific mechanism the cheaper options do not match. For the speculative biohacker audience chasing generalized anti-aging, opportunity cost is material: the same budget sunk into SS-31 underfunds the rest of the mitochondrial-medicine stack that has cheaper, better-characterized signal.

Dependency/Withdrawal (2.0/5.0). Functional dependency (need to continue to maintain benefit) is moderate: stopping the peptide lets mitochondrial cardiolipin stabilization fade over days to weeks, and any symptomatic improvement regresses. No addiction liability, no rebound syndrome beyond loss of effect, no autonomic withdrawal, no receptor downregulation. Per v0.5 dependency-vs-addiction rules, this is functional dependency without addiction-type features, which anchors in the 2.0-2.5 range rather than the 4.0+ range reserved for GLP-1-class compounds or benzodiazepine-class agents. For Barth patients, the dependency is clinically acceptable because the alternative is progressive cardiomyopathy; for biohacker users, the dependency is simply the cost of sustained mitochondrial lift.

Reversibility (1.5/5.0). Fully reversible on cessation. Plasma half-life is roughly 2.5 hours; mitochondrial concentration clears over days to weeks after stopping. No structural, epigenetic, or persistent metabolic changes have been documented from chronic elamipretide use across the trial program. Within 2-4 weeks of stopping, all drug-dependent effects (cristae stabilization, supercomplex assembly support, ROS reduction, any subjective lift) return to baseline. This is one of the cleanest reversibility profiles among peptides, behaviorally similar to glycine or electrolytes in that sense: stop anytime, full return to pre-intervention state, no legacy effects to manage.