SS-31 vs TB-500 (Thymosin Beta-4 Fragment)
Updated November 4, 2026 · Reviewed by the PeptidesDB Editorial team
A data-driven comparison of SS-31 and TB-500 (Thymosin Beta-4 Fragment) (also searched as TB-500 (Thymosin Beta-4 Fragment) vs SS-31) — effect profiles, evidence, side effects, and which suits weight loss, muscle, or healing goals.
Verdict
SS-31 centers on healing, while TB-500 (Thymosin Beta-4 Fragment) leans toward healing. On indexed research, SS-31 is ahead (SS-31: 37 studies, Human evidence; TB-500 (Thymosin Beta-4 Fragment): 9, Human evidence). Choose by goal — and read the primary studies. This is research information, not medical advice.
Key takeaways
- •SS-31 is strongest for healing; TB-500 (Thymosin Beta-4 Fragment) for healing.
- •Evidence: SS-31 Human evidence (37 studies) vs TB-500 (Thymosin Beta-4 Fragment) Human evidence (9).
- •Both are research-use compounds — not FDA-approved.
Effect profiles, overlaid
At a glance
Mitochondrial protection | Heart and neuro health
Cell migration | Tissue repair and regeneration
SS-31 vs TB-500 (Thymosin Beta-4 Fragment): side-by-side
| Metric | SS-31 | TB-500 (Thymosin Beta-4 Fragment) |
|---|---|---|
| Class | Metabolic | Healing |
| Regulatory status | Research use only | Research use only |
| Evidence grade | Human evidence | Human evidence |
| Studies indexed | 37 | 9 |
| Research level | Preclinical | Preclinical |
| Strongest effect | Healing & recovery | Healing & recovery |
| Healing & recovery | 4.0▲ | 4.0▲ |
| Muscle & body comp | 2.0 | 3.0▲ |
| Metabolic & appetite | 3.0▲ | 1.0 |
| Neuro & mood | 4.0▲ | 2.0 |
| Sleep & circadian | 1.0▲ | 1.0▲ |
| Inflammation & immune | 3.0▲ | 3.0▲ |
| Skin & aesthetics | 1.0 | 2.0▲ |
▲ marks the higher AI-assigned effect score (0–5, describing where the literature concentrates — not clinical efficacy).
Mechanism & pharmacokinetics
| Property | SS-31 | TB-500 (Thymosin Beta-4 Fragment) |
|---|---|---|
| Mechanism | Cardiolipin binding to stabilize mitochondrial membrane | Actin-sequestering peptide; promotes cell migration & angiogenesis |
| Route | Subcutaneous injection | Subcutaneous injection (research use) |
Established pharmacology — curated for well-characterized compounds and AI-summarized otherwise. A blank (—) means no reliable single value is published (half-life figures for some peptides genuinely disagree across sources). Verify against primary sources such as FDA labels and ClinicalTrials.gov.
What is SS-31?
SS-31, also known as Elamipretide, is a peptide that has garnered attention for its potential role in mitochondrial protection and its implications in various health conditions, particularly those involving oxidative stress and mitochondrial dysfunction.
Full SS-31 profile, mechanism & studies →What is TB-500 (Thymosin Beta-4 Fragment)?
TB-500, a synthetic derivative of thymosin beta-4, is a peptide that has garnered attention for its potential role in tissue repair and regeneration. Research into TB-500 is ongoing, particularly regarding its applications in equine medicine and its implications in doping control.
Full TB-500 (Thymosin Beta-4 Fragment) profile, mechanism & studies →Which is better for your goal?
| Goal | Better fit | Why |
|---|---|---|
| Healing | Even | Both ~4.0/5 |
| Muscle | TB-500 (Thymosin Beta-4 Fragment) | 3.0/5 effect signal |
| Metabolic | SS-31 | 3.0/5 effect signal |
| Neuro | SS-31 | 4.0/5 effect signal |
| Sleep | Even | Both ~1.0/5 |
| Inflammation | Even | Both ~3.0/5 |
| Skin | TB-500 (Thymosin Beta-4 Fragment) | 2.0/5 effect signal |
Fit reflects community-perceived effect profiles — not head-to-head trials. Read each peptide's studies before deciding.
Can you stack SS-31 and TB-500 (Thymosin Beta-4 Fragment)?
People sometimes combine peptides that target different pathways, but there is little controlled research on this specific pairing and the interactions aren't well characterized. Because neither compound is FDA-approved, we don't publish stacking or dosing protocols here. Any combination should be discussed with a qualified clinician.
SS-31 vs TB-500 (Thymosin Beta-4 Fragment): side effects
No community-reported effects logged yet.
No community-reported effects logged yet.
Anonymous community reports (count = number of reports), not clinical incidence rates.
What the research says
SS-31 has 37 approved studies indexed (Human evidence), and TB-500 (Thymosin Beta-4 Fragment) has 9 (Human evidence). The Librarian re-checks PubMed, Europe PMC and ClinicalTrials daily, so these counts move. Open each profile to read the summaries and sources.
Frequently asked questions
Is SS-31 or TB-500 (Thymosin Beta-4 Fragment) better?
It depends on your goal. SS-31 is strongest for healing; TB-500 (Thymosin Beta-4 Fragment) for healing. SS-31 has more indexed studies (37). See the goal-by-goal breakdown above.
Is SS-31 or TB-500 (Thymosin Beta-4 Fragment) better for weight loss?
SS-31 shows the stronger metabolic & appetite profile (3.0/5) in the AI-assigned effect profile — though weight-loss outcomes depend on the individual and the evidence base.
Is SS-31 or TB-500 (Thymosin Beta-4 Fragment) better for muscle?
TB-500 (Thymosin Beta-4 Fragment) leads on the muscle & body-composition axis (3.0/5).
Which has more research, SS-31 or TB-500 (Thymosin Beta-4 Fragment)?
SS-31 has 37 approved studies indexed (Human evidence); TB-500 (Thymosin Beta-4 Fragment) has 9 (Human evidence). Higher counts mean more to read, not proven superiority.
Can you stack SS-31 and TB-500 (Thymosin Beta-4 Fragment)?
Some users combine peptides, but there's little controlled data on this specific pairing, and interactions aren't well characterized. We don't publish stacking protocols for compounds that aren't FDA-approved. Discuss any combination with a qualified clinician.
What are the side effects of SS-31 vs TB-500 (Thymosin Beta-4 Fragment)?
SS-31: no community-reported effects logged yet. TB-500 (Thymosin Beta-4 Fragment): none logged yet. These are anonymous reports, not incidence rates — see each profile.
Is SS-31 or TB-500 (Thymosin Beta-4 Fragment) FDA-approved?
SS-31 is a research-use compound and is not FDA-approved. TB-500 (Thymosin Beta-4 Fragment) is not FDA-approved. Research-use status is not a legal clearance to compound or use in humans.
Is TB-500 (Thymosin Beta-4 Fragment) better than SS-31?
For healing, TB-500 (Thymosin Beta-4 Fragment) has the edge; for healing, SS-31 does. Neither is universally "better" — it's goal-dependent, and both should be weighed against their evidence base above.
Comparing related peptides
Regulatory & legal status
SS-31 and TB-500 (Thymosin Beta-4 Fragment) are research-use compounds and are not FDA-approved for human use. FDA approval and compounding rules for peptides change frequently, and research-use status is not a legal clearance for human use. The FDA does not review compounded drugs for safety, effectiveness, or quality. Verify current status with primary sources before acting. Last reviewed November 4, 2026.