STUDresearch · Peptide
TB-4 Fragment variants (non-TB-500 marketing)
Also known as
TB4 frag · TB-4 Frag · TB4-FRAG · TB-4 FRAG · thymosin fragments · Ac-SDKP · N-acetyl-Ser-Asp-Lys-Pro · N-acetyl-seryl-aspartyl-lysyl-proline · TB4 Frag 1-4 · Thymosin Beta-4 Fragment (1-4) · Tβ4 N-terminal fragment · Goralatide · thymosin beta-4 fragments (non-TB-500) · AcSDKP
Community talk. May be wrong. Not medical advice. Not a protocol. Not for human or animal use.
Peptide
Some talk
Mixed
Oral / SubQ
Healing & repair
Systemic Ac-SDKP/TB4-fragment discussion spans anti-fibrotic research and unverified oral/SubQ recovery products; product identity is often unclear.
What people say
A catch-all page for Ac-SDKP and other TB4-fragment products. Human Ac-SDKP research exists, but retail “TB4-FRAG” labels may instead be mixed, unclear or conflated with TB-500/full thymosin beta-4.
Doses people talk about
These are unapproved protocol-blog or product-label amounts, not a progression. TB-500 milligram charts and full-Tβ4 schedules do not transfer.
How it may feel
Oral combo reports conflict: improvement within days, no change after two weeks, and one severe post-stop symptom account. All involved BPC-157 or uncertain product identity, so none isolates Ac-SDKP.
Introductory SubQ chart~200 mcg SubQ once daily for about 1 week
Repeated protocol-blog tolerance-probe pattern; no human sports-injury dose finding.
Common SubQ chart~500 mcg SubQ once daily for about 4–8 weeks
Frequently repeated research-chemical guide amount; product identity may be uncertain.
Oral combination capsule700 mcg total capsule labeled TB4-FRAG plus BPC-157 ARG
Amount from inspected user discussions of a mixed oral product; component ratio and absorption were uncertain.
Half-life & effect duration
- Half-life in the body
- Ac-SDKP fragment · after IV infusionAbout 4.5 minutes
- Felt duration people report
- Mixed oral productsImprovement within 3–4 days, no change at 2 weeks, or severe symptoms after stopping
Cycles people discuss
Protocol blogs describe 4–8-week daily SubQ blocks or bottle-length oral courses. These are community schedules, not Ac-SDKP human dose-finding or evidence for a required cycle.
Timing
Injectable community charts use daily, sometimes twice-daily SubQ schedules across roughly 4–8-week blocks; morning is a common habit, not a proven better clock. Oral marketing uses separate once-daily capsule courses despite unsettled absorption, so the route calendars are not interchangeable.
Stacks
BPC-157, TB-500, GHK-Cu and named blends appear throughout product discussions. The inspected oral reports used combinations, so a stack cannot establish Ac-SDKP benefit or safety.
Watch for
Source quality: Gray-market purity, endotoxin, sterile fill, and actual mg accuracy remain material risks.
Tap a line to jump into the full notes. Research only — may be wrong.
Timing context & sources
Half-life in the body
Mean Ac-SDKP elimination half-life was 4.5 minutes after a 12-hour IV infusion ended.
Six healthy volunteers received 128 nmol/kg by 12-hour IV infusion and single SubQ or IM administration. SubQ and IM Tmax were 0.26 and 0.28 hours; bioavailability was 100% and 81%.
The 4.5-minute value is explicitly the post-infusion IV elimination phase. The abstract does not report separate SC/IM half-lives, and retail oral combo products are not established as equivalent.
- Pharmcokinetics in healthy volunteers and patients of NAc-SDKP (seraspenide), a negative regulator of hematopoiesis (opens in a new tab)Abstract: six healthy volunteers received 128 nmol/kg by 12-hour IV infusion or single SubQ/IM injection; 4.5-minute mean post-infusion half-life, 0.26/0.28-hour Tmax and 100%/81% bioavailability. Five chemotherapy patients were a separate infusion cohort.Old small study; abstract-level review, no separate SC/IM terminal half-life and no equivalence to gray-market oral or SubQ products.
Felt duration people report
No dependable felt-duration clock can be assigned to retail “TB4-FRAG” products.
Mixed oral-product reports include perceived improvement within 3–4 days, no change at two weeks, and severe symptoms emerging after cessation. The products also contained BPC-157 and identity was not independently verified.
Multiple authors, combination products, no assays, different follow-up windows and self-treatment. Post-stop symptoms do not prove persistence of Ac-SDKP in blood.
- Oral TB4-FRAG plus BPC-157 capsule discussion (opens in a new tab)Thread body and replies about capsules labeled 700 mcg TB4-FRAG plus BPC-157 ARG: authors dispute oral plausibility; one later reports tendon improvement within days and near-full motion by about a month, another reports no change after two weeks.Multiple authors, unverified mixed product, unknown component ratio and absorption, concurrent recovery changes and no controlled follow-up.
- Oral BPC-157 ARG plus TB4-FRAG experience (opens in a new tab)First-person chronology: oral 700 mcg combination capsule, perceived benefit within days/three weeks, then severe fatigue, low mood, aches, dizziness and shortness of breath during roughly weeks 1–6 after stopping.Self-posted uncontrolled report, combination product and self-treatment; product identity, medical evaluation and causality are unverified.
What people say
- vs TB-500 mechanism split: Community and review writeups map anti-fibrotic/scar activity to Ac-SDKP (Tβ4 1–4) and cell-migration/actin activity to LKKTETQ (TB-500 class) — TB-500 does not contain the Ac-SDKP sequence. forumtrial
- Inflammation modulation: Anti-inflammatory and macrophage-polarization (M1→M2 style) language appears in research summaries and protocol blogs; user logs sometimes claim “calmer” chronic irritation. animalanecdote
- Soft-tissue recovery (community): Subjective mobility, less stiffness, or faster bounce-back appear in multi-peptide logs; credit is heavily confounded by BPC-157, TB-500, rest, and PT. forum
- Scar / remodeling interest: Users chasing “less scar” or organ-fibrosis goals sometimes pick Ac-SDKP-labeled product over pure TB-500 for that reason — outcome quality still mostly anecdote outside animal models. forumanimal
- Borrowed full-Tβ4 claims: Many marketing bullets for “TB4 frag” quietly restate full 43-aa Tβ4 wound, eye, or cardiac programs — those are not automatic proof for the tetrapeptide alone. forumtrial
- Stack confound: “Wins” often occur inside BPC + TB-500 + Ac-SDKP or GLOW-style blocks; single-frag attribution is unreliable. forum
- Human MSK honesty: Large modern human RCTs of research-chem Ac-SDKP / “TB4-FRAG” for sports soft-tissue injury are sparse to absent; forum and vendor protocol pages dominate that niche. trialforum
- Anti-fibrotic (core claim): Animal models of heart, kidney, lung, and liver fibrosis report reduced collagen deposition and lower fibrotic markers with Ac-SDKP exposure; TGF-β/Smad pathway suppression is the usual mechanism story. animal
- Cardiac / renal protection narratives: Tβ4–Ac-SDKP axis literature links the fragment to less hypertension- and injury-related cardiac and renal fibrosis in animals; ACE-inhibitor benefits are partly discussed as raising endogenous Ac-SDKP. animaltrial
- Angiogenesis / vascular repair talk: Lab writeups describe pro-angiogenic and vascular-support signals for Ac-SDKP alongside parent Tβ4 pathways — not the same as a proven gym soft-tissue RCT. animallab
- Hematopoietic / myeloprotection lore: Older goralatide research framed Ac-SDKP as a reversible inhibitor of hematopoietic progenitor proliferation (G0-style protection under cytotoxic stress) — a different use case than sports recovery. trialanimal
Doses people talk about
- Unit scale: Ac-SDKP / “TB4-FRAG” injectables are almost always discussed in micrograms (mcg) daily — do not copy TB-500 milligram load/maintain charts onto this tetrapeptide. forum
- Introductory SubQ band (protocol blogs): ~200 mcg once daily SubQ for ~1 week as a tolerance probe is a repeated “start low” pattern. forum
- Standard SubQ target (most repeated protocol pages): ~500 mcg once daily SubQ for ~4–8 weeks is the modal “standard” figure across TB-4 FRAG / Ac-SDKP research-chem guides. forum
- Advanced SubQ band: ~750 mcg once daily SubQ for ~4–8 weeks appears as an upper community chart step. forum
- Common daily band summary: Roughly 200–750 mcg/day SubQ covers the bulk of modern “TB4-FRAG / Ac-SDKP” injectable charts; ~500 mcg/day is the midpoint people cite most. forum
- Split-dose variant: ~250 mcg twice daily (AM + PM) SubQ is discussed specifically because plasma half-life is only minutes — some argue split dosing better matches cascade/signaling goals than one bolus. forum
- Higher research-reference band (other guides): Some dosage pages cite a broader research-reference envelope of roughly 0.5–2 mg/day SubQ extrapolated from limited preclinical sources — treat as upper-bound discussion, not a consensus athlete protocol. forumanimal
- Not TB-500 charts: Classic TB-500 loading (~2–2.5 mg 2×/week for 4–6 weeks → weekly maintenance) is a different molecule, different unit culture, and different schedule logic. forum
- Stack concurrent doses (protocol-blog examples, not trials): Ac-SDKP ~500 mcg daily + TB-500 ~2 mg 2×/week; or Ac-SDKP ~500 mcg + BPC-157 ~250 mcg daily; or Ac-SDKP ~500 mcg + GHK-Cu ~200 mcg daily — ratios and durations vary by source. forum
- Not full-Tβ4 charts: Full TB4 community loading (~500 mcg–1 mg daily then maintenance, or multi-mg weekly totals) also does not auto-apply to unlabeled “frag” vials. forum
- Oral capsule marketing: Vendors sell Ac-SDKP / TB4-FRAG oral capsules commonly labeled 500 mcg per capsule (often 60-count bottles); oral bioavailability of short peptides is widely debated and generally considered weak vs SubQ — community ID and absorption skepticism remain high. forum
- Oral schedule talk: Oral marketing often implies once-daily capsule use matching the labeled 500 mcg unit; controlled oral PK for research-chem Ac-SDKP is not a settled human sports literature. forum
- Identity-first rule: Wrong fragment (TB-500 vs Ac-SDKP vs full Tβ4) or empty/underdosed product makes every mcg number meaningless — mass/sequence beats label text. forum
- Preclinical infusion note: Because half-life is minutes, informative animal work often used continuous infusion (mini-pump) rather than once-daily bolus — a once-daily research-chem injection will not hold steady plasma levels. animaltrial
- Framing: Research- and community-discussed ranges only — not medical advice, not FDA-labeled dosing, not validated human dose-finding for sports injury. No peer-reviewed human Ac-SDKP sports protocol standard. forumtrial
How it may feel
- Reported oral-combination experiences: In a thread about capsules labeled 700 mcg TB4-FRAG plus BPC-157 ARG, one user reported improved tendon motion within days and another reported no change after two weeks. A separate author described early benefit followed by severe fatigue, low mood, aches, dizziness and shortness of breath beginning after stopping a similar oral combination. These reports cannot isolate Ac-SDKP. forum
- Week 1 intro (protocol blogs): Some charts start ~200 mcg daily for tolerance; molecular remodeling claims (TGF-β talk) are not something users “feel” day-to-day. forum
- Weeks 1–2: Community protocol pages describe anti-fibrotic signaling as “on” at the cellular level with no reliable visible change yet; soft-tissue users may notice only subtle comfort shifts if anything, often mixed with BPC/rest. forum
- Weeks 3–4: Common reassess window — reduced stiffness talk in some logs; fibrosis-focused writeups claim early marker or “less tight” narratives without validated home biomarkers. forumanecdote
- Weeks 5–8: Longer organ/fibrosis protocol blogs describe remodeling windows and reassess at 4 and 8 weeks; athlete day-by-day “I feel it” diaries are thinner than BPC/TB-500 culture. forum
- No change by ~4 weeks: Check product identity (mass ~487 Da vs ~889 Da TB-500 vs ~4.9 kDa full Tβ4), dose math, concurrent load, and whether expectations were copied from wrong molecule charts. forum
- Months 2–3: Longer fibrosis/organ stories if continued; continuous multi-month gray-market safety data remain thin. forum
- After stop: Residual comfort or fade with load return — classic confounded recovery pattern, not pure PK residual. anecdote
Cycles people discuss
- Typical block (injectable protocol blogs): ~4–8 weeks continuous daily SubQ on, then reassess. forum
- On/off pattern: Common writeups describe 4–8 weeks on, 2–4 weeks off before a re-run — borrowed from broader peptide cycling culture more than Ac-SDKP-specific RCTs. forum
- Short probe: ~1–2 weeks (often at ~200 mcg or half-standard dose) to test tolerance and cost before a full block. forum
- Intro week then standard: Some charts run 1 week introductory then step to ~500 mcg daily for the remainder of a 4–8 week block. forum
- Stop rule (injury users): Many stop when the soft-tissue issue settles or when a 4–6 week checkpoint shows no change. forum
- Fibrosis / organ talk: Longer continuous or repeated blocks appear in cardiac/anti-fibrotic discussion — not the same as a 4-week tendon flare protocol. forum
- Oral capsule blocks: Marketing often implies multi-week daily capsule courses (e.g. 500 mcg unit × bottle duration); adherence and absorption uncertainty dominate. forum
- Re-runs: Later restarts after time off are described; long-term multi-year gray-market safety series for Ac-SDKP research-chem are thin. forum
- Not indefinite by default: Serious threads still treat peptides as time-bounded research blocks, not lifelong daily hormones. forum
Timing
- Why daily (or split daily): Short presence drives community culture toward daily (sometimes twice-daily) dosing rather than TB-500-style twice-weekly multi-mg shots. forum
- Signaling vs occupancy lore: Protocol blogs argue Ac-SDKP acts through short signaling cascades / gene-expression changes rather than sustained receptor occupancy — used to justify consistent daily exposure despite minute-scale PK. forum
- Downstream “process effects”: Users and blogs claim tissue remodeling may outlast measurable peptide in blood — common peptide lore, not formal PK/PD proof for gray-market products. anecdoteforum
- Timing of day: Morning or consistent daily SubQ is the default; no controlled head-to-head of AM vs PM for Ac-SDKP. forum
- ACEI co-presence: Anyone already on an ACE inhibitor has higher endogenous Ac-SDKP background in literature models — community flags this as both a confounder and a theoretical interaction to respect. trialforum
- Do not paste full-Tβ4 study schedules: IV multi-mg/kg animal Tβ4 or clinical ophthalmic/wound-gel windows are different molecules and routes. trialforum
- Human Ac-SDKP pharmacokinetics: In six healthy volunteers given 128 nmol/kg, mean elimination half-life was 4.5 minutes after a 12-hour IV infusion ended. Single SubQ and IM injections peaked at 0.26 and 0.28 hours, with 100% and 81% bioavailability; the abstract does not provide a separate SC or IM terminal half-life. trial
- Degradation pathway: Almost exclusively hydrolyzed by the N-domain of angiotensin-converting enzyme (ACE); ACE inhibitors raise plasma/urine Ac-SDKP (literature discusses roughly multi-fold increases, e.g. several-fold to ~5× in animal/clinical ACEI context). trialanimal
- Continuous infusion contrast: Animal studies often prefer osmotic mini-pumps or continuous delivery to maintain levels; once-daily SubQ bolus is a practical research-chem compromise, not steady-state PK. animal
More on what it is
- What it is: Short pieces of thymosin beta-4 (Tβ4) sold under “TB-4 frag / TB4-FRAG / Ac-SDKP” labels — not full-length Tβ4 (43 aa) and not the same product as classic TB-500 (actin-binding 17–23 fragment). forumtrial
- TB-500 is a different fragment: Common TB-500 analytical ID is Ac-LKKTETQ (Tβ4 ~17–23, ~7 aa, ~889 Da) — migration/actin talk. Ac-SDKP is the opposite end of the parent molecule (anti-fibrotic / anti-inflammatory talk). trialforum
- Three-way naming mess: Forums and vendors blur (1) full Tβ4 ~4,921 Da, (2) TB-500 / LKKTETQ ~889 Da, (3) Ac-SDKP / “TB4 Frag 1-4” ~487 Da — labels alone do not identify the vial. forum
- Not: Not a steroid, not a GH secretagogue, not interchangeable with TB-500 mg charts, not an FDA-approved injury drug, not proven continuous lifelong therapy. trialforum
- Buy rule: Need sequence, mass (COA/mass spec), and vendor honesty — “TB-4 frag” text on a label is not chemical ID. forum
- Main commercial molecule: Ac-SDKP (N-acetyl-Ser-Asp-Lys-Pro) — the N-terminal tetrapeptide of Tβ4 (positions 1–4), also known historically as goralatide. Approximate MW ~487–488 Da. trial
- How the body makes it: Full Tβ4 is cleaved by meprin-α into shorter N-terminal intermediates, then prolyl oligopeptidase (POP) releases Ac-SDKP; it is degraded primarily by the N-domain of ACE. animaltrial
- Why people search it: Scar/fibrosis framing, “what TB-500 is missing,” cardiac/renal organ-repair lore, and oral capsule marketing as “TB4-FRAG.” forum
- Evidence honesty: Stronger animal/mechanism literature on Ac-SDKP anti-fibrotic and ACE-pathway biology than large human sports-injury RCTs of gray-market “TB4 frag.” animaltrial
Stacks
- + TB-500 (fragment pair): Anti-fibrotic Ac-SDKP + migration/actin TB-500 is the explicit “cover both ends of Tβ4” stack — protocol-blog example: Ac-SDKP ~500 mcg daily + TB-500 ~2 mg 2×/week. Not a controlled combo trial. forum
- + BPC-157 (healing dual / triple): Daily BPC (~250–500 mcg SubQ common in broader culture) + Ac-SDKP daily; often a third vial of TB-500 is already in the block. Single-agent credit fails. forum
- + Full Tβ4: Compared or combined when full-length product is available and expensive; identity confusion and double-counting parent vs fragment claims are high. forum
- + GHK-Cu: Tissue-remodel / anti-fibrotic synergy talk; protocol blogs cite examples like Ac-SDKP ~500 mcg + GHK-Cu ~200 mcg daily. forum
- GLOW context: GLOW is commonly BPC + TB-500 + GHK-Cu (vendor ratios vary, e.g. 5:1:1 style talk) — Ac-SDKP is sometimes added as a fourth “anti-fibrotic” vial rather than being inside the named blend. forum
- KLOW context: KLOW typically extends GLOW with KPV; Ac-SDKP is again an optional separate frag, not a standardized KLOW ingredient. forum
- Wolverine (BPC + TB-500): Standard soft-tissue stack; adding “TB4 frag” as Ac-SDKP is a common upsell when scar/fibrosis is the stated goal. forum
- + Thymosin Alpha-1: Immune-modulation + repair narratives appear on protocol pages; confounding is heavy. forum
- + CoQ10 / cardiac basics: Cardiac-repair writeups sometimes pair mitochondrial support (e.g. CoQ10) with Ac-SDKP charts — lifestyle and meds still dominate real cardiac care. forum
- GH-axis (CJC/Ipamorelin etc.): Occasional same-block use for recovery + sleep/GH talk; multi-variable confounds. forum
- ACE inhibitor background: Not a “stack” people seek, but literature on multi-fold endogenous Ac-SDKP rise under ACEI is repeatedly flagged next to exogenous Ac-SDKP discussion. trialforum
- Non-peptide foundations: Load management, PT, sleep, and nutrition still get credit when subjective outcomes look good. forum
Storage notes
- No mix instructions here: STUDresearch does not list reconstitution, diluent volumes, or syringe unit charts. People reconstitute many different ways and vial labels differ — that content creates more confusion than clarity. forum
- Storage (general talk only): Unopened research products are usually kept cool, dry, and away from light per the seller label. Anything after first use is product-specific — follow the label, not a universal forum SOP. forum
Watch for
- Injection site: Redness, itch, stinging, or mild swelling at SubQ sites — most common practical complaint. forum
- Systemic noise: Headache, fatigue, or mild nausea appear in multi-peptide logs and are hard to pin to Ac-SDKP alone. forumanecdote
- Mild hypotension talk (rare): Protocol blogs flag rare BP dip narratives via ACE-pathway adjacency; monitor if combining with antihypertensives. forum
- ACE inhibitor interaction: ACEIs raise endogenous Ac-SDKP substantially in literature; exogenous + ACEI background is an under-studied research-chem combination — BP and clinician awareness matter. trialforum
- Wrong molecule / product identity: Vials may be labeled TB-500, full Tβ4 or Ac-SDKP, or contain an incorrect amount or substance. A COA describing mass/sequence testing does not by itself establish the actual vial contents, purity or sterility. forum
- Borrowed evidence trap: Full Tβ4 wound, eye, or cardiac outcomes do not prove a short commercial frag will do the same. forumtrial
- Angiogenesis / growth pathway caution: Theoretical concern that pro-repair and angiogenic signaling could be undesirable with occult malignancy — not a quantified Ac-SDKP human risk table. forumanimal
- Active bleeding / immediate post-surgery: Some protocol pages advise avoiding in active bleeding or immediately post-op — precautionary, not RCT-based sports guidance. forum
- Pregnancy / breastfeeding: No adequate human safety data; community guides say avoid. forum
- Oral product quality: Capsule “500 mcg TB4-FRAG” SKUs vary; oral absorption of tetrapeptides is uncertain and identity testing is rarer than for injectables. forum
- Source quality: Gray-market purity, endotoxin, sterile fill, and actual mg accuracy remain material risks. forum
- Silence ≠ safe: Sparse human adverse-event databases and thin long-term follow-up are not proof of low risk. trialforum
- Blood-pressure / fibrosis labs (research interest only): Protocol blogs mention optional tracking of BP, renal panels, hs-CRP, and specialty fibrosis markers — none substitute for medical care. forum
- Stem-cell cycling / chemo context: Goralatide history includes reversible hematopoietic progenitor arrest — research framing is cautious around active malignancy and chemotherapy without specialist oversight. trialforum
- Anti-doping: Full Tβ4 family / related substances are high-risk for tested athletes (WADA S2-class related peptide-hormone framing for thymosin beta-4 and related compounds). Treat fragments as related-risk, not “safe loopholes.” forumtrial
Evidence mix
Mostly community / anecdote tags
Full: every bullet (trial + community). Use Scan for a faster bro-science read.