Peptides / Bioregulators

[Steve_Combi]

@Davin8r

that TB4 is the one universally available and the “real” TB500 (the frag) is nearly impossible to find. Are you sure you’ve got that right?

There is some confusion on this one due to the terminology used online.

The TB500’s are typically fragments of Tb-4 but due to ease of online marketing all TB500’s have become generically known as Thymosin b-4, so three “versions”

If we start with the “real” Thymosin beta-4 we can see it is a 43 amino peptide that our body makes. Unless other wise specified the TB500’s are fragments, so the one known as TB500 (Full) or (Full 43) or (Full 43aa) would be the “real” Tb-4

If you see TB500 available online, check to see which version it is.

Thymosin beta-4

[cl-user]

According to ChatGPT the Frag 1-4 is the least useful one:

@ChatGPT o1

• TB500 (Frag 1–4): Very short, uncertain biological effect, minimal data.

• TB500 (Frag 17–23): Commonly sold “active fragment”; reputed to deliver many of the tissue-repair benefits attributed to Thymosin Beta-4 by focusing on the actin-binding domain.

• TB500 (Full 43): Essentially the entire Thymosin Beta-4 sequence; could confer a broader functional profile but may differ in absorption, half-life, or synergy compared to the fragment.

In the current peptide marketplace, most references to “TB-500” are either the 17–23 fragment or a synthetic Tβ4 analog. If you encounter “Frag 1–4” or “Full 43,” proceed with caution, do ample research, and seek professional guidance to ensure safety and proper usage.
[…] About Frag 1-4:
The N-terminal region of Tβ4 does not traditionally contain the actin-sequestering motif, which is better characterized within the peptide’s central region.
it may not yield significant benefits in tissue repair or anti-inflammation.

[Steve_Combi]

@ChatGPT o1

• TB500 (Frag 1–4): Very short, uncertain biological effect, minimal data.

I prefer www.Undermind.ai for technical searches. It provides the referenced articles and studies but those links are lost in this cut and paste.

Detailed summary

The TB500 fragment 1-4 peptide (Ac-SDKP) has been consistently demonstrated in preclinical studies to exhibit significant antifibrotic, anti-inflammatory, and pro-angiogenic properties, with therapeutic potential in tissue regeneration across myocardial, pulmonary, cutaneous, and renal models, primarily through inhibition of TGF-β/Smad signaling and promotion of neovascularization [1, 2, 4, 11, 19, 28].

---

Crucial Findings: 1. Biological Activity and Mechanisms of Action

• Antifibrotic Effects:
  • Ac-SDKP prevents fibroblast-to-myofibroblast differentiation [9, 28] and inhibits collagen deposition across diverse organ models (heart, lungs, kidneys) by suppressing TGF-β/Smad signaling and connective tissue growth factor (CTGF) expression [4, 8, 28].
  • Specifically reduces organ fibrosis and extracellular matrix accumulation in myocardial infarction (MI), pulmonary fibrosis, silicosis, and diabetic nephropathy models [11, 13, 25].
• Anti-inflammatory Activity:
  • Downregulates NF-κB signaling and ICAM-1 expression, reducing macrophage and neutrophil recruitment and mitigating inflammation [8, 23, 26].
  • Switches macrophages to the M2 repair phenotype in myocardial and pulmonary injuries [19].
• Pro-angiogenic Activity:
  • Promotes endothelial cell migration, tube formation, and VEGF upregulation; induces capillary density in ischemic tissues [1, 2, 18].
  • Stimulates matrix metalloproteinase (MMP) activation to aid in tissue remodeling [18, 13].

2. Tissue Regeneration Benefits

• Cardiac Models:
  • Substantial reduction in myocardial fibrosis, improved left ventricular function, and prevention of cardiac rupture post-MI, attributed to decreased collagen deposition and enhanced capillary density [2, 10, 19, 20].
• Pulmonary Fibrosis:
  • In bleomycin-induced models, Ac-SDKP prevents and ameliorates fibrosis, reduces epithelial-mesenchymal transition (EMT), and improves histological and functional lung outcomes [4, 11, 16].
• Cutaneous Wounds:
  • Accelerates skin flap survival and wound repair via angiogenesis and enhanced re-epithelialization [1].
• Renal and Diabetic Fibrosis:
  • Prevents kidney fibrosis through endothelial-mesenchymal modulation and synergistic effects with ACE inhibitors in diabetes-associated organ damage [22, 25].

3. Preclinical Models and Delivery

• Effective in numerous animal studies (mice, rats) across fibrosis and tissue injury models, with methods ranging from systemic injections to localized biomaterial delivery (e.g., peptide hydrogels in myocardial infarction) [4, 12, 13].
• Challenges include Ac-SDKP instability due to rapid degradation by angiotensin-converting enzyme (ACE), mitigated by co-treatment with ACE inhibitors or analog modifications [7, 24].

4. Key Gaps and Translational Challenges

• Long-term Efficacy and Tissue-Specificity:
  • Limited data on chronic injury models, bone repair applications, and differentiation of effects across tissue microenvironments [15, 22].
• Pharmacokinetics:
  • Short half-life remains a barrier for stable therapeutic delivery, though biomaterial or analog advancements hold promise [12, 15].
• Mechanistic Refinement:
  • Further elucidation of the Tβ4-POP-Ac-SDKP cleavage pathway’s role in endogenous fibrosis resolution is needed [3].

---

Conclusion:

Ac-SDKP is a promising candidate for preclinical tissue regeneration due to its potent antifibrotic and angiogenic mechanisms. However, translational challenges, including stability and tissue-specific applicability, must be resolved to harness its therapeutic potential fully.

[cl-user]

@Steve_Combi

I prefer www.Undermind.ai for technical searches. It provides the referenced articles and studies but those links are lost in this cut and paste.

Looks much better than ChatGPT o1 for that kind of questions indeed. Trying my same initial prompt in it and then refined it. Here is what it says.
Interestingly, it’s similar to the answer it gave you except about the angiogenesis. It told you Pro-angiogenic Activity but it tells me Limited Role in Angiogenesis. the 1–4 fragment (Ac-SDKP) has minimal to no angiogenic activity.
I guess we will have to look at that deeper.

@Undermind.ai

Functional Roles of Ac-SDKP

The 1–4 fragment (Ac-SDKP) has distinct biochemical and pharmacological activities, most notably:

1. Anti-Fibrotic Actions:

• Ac-SDKP is a potent fibrogenesis inhibitor, particularly in cardiovascular, renal, and pulmonary models [7, 25].
• It suppresses the TGF-β signaling pathway, which reduces the synthesis and deposition of extracellular matrix components such as collagen and fibronectin.
• This makes it uniquely effective in mitigating fibrosis in chronic inflammatory and ischemic diseases, including post-myocardial infarction fibrosis.

1. Anti-Inflammatory Properties:

• Ac-SDKP has been shown to decrease chronic inflammatory responses by dampening cytokine release and immune cell infiltration [25].
• It modulates the polarization of macrophages, favoring a shift from a pro-inflammatory M1 state to a reparative M2 profile.
• It also suppresses inflammatory cytokines, such as IL-6 and TNF-α, which are associated with chronic disease progression [24, 25].

2. Cardiovascular Protection:

• Ac-SDKP promotes vascular remodeling by inhibiting fibrosis and thickening of the vascular walls. This is particularly important in diseases such as hypertension, coronary artery restenosis, and post-stent repair environments [7, 25].
• It is a well-known negative regulator of angiotensin II-mediated damage. Elevated levels of Ac-SDKP protect against angiotensin II-induced cardiac remodeling, thus reducing hypertrophy and fibrosis.

3. Immunological Role:

• Ac-SDKP diminishes leukocyte recruitment and activation in tissues undergoing chronic stress or damage. This helps attenuate the progression of inflammatory and degenerative diseases [25].
• Remarkably, it shows efficacy in autoimmune scenarios like lupus nephritis by downregulating pro-inflammatory mechanisms at the tissue level.

4. Limited Role in Angiogenesis:

• Unlike the LKKTET motif or full-length thymosin β4, the 1–4 fragment (Ac-SDKP) has minimal to no angiogenic activity. Its primary role in tissue protection comes from its anti-fibrotic and anti-inflammatory effects rather than endothelial cell migration or proliferation [27].
  […]

Specific Advantages and Distinctions of the 1–4 Fragment:

1. Ac-SDKP is highly specialized for fibrosis suppression, far outpacing the other fragments in this role.
2. Unlike the LKKTET motif, Ac-SDKP does not promote angiogenesis, cell migration, or cytoskeletal changes, making its effects distinct and specific.
3. It is uniquely potent in diseases where dysregulated TGF-β activity is central, such as organ scarring or hypertensive fibrosis.
4. However, Ac-SDKP alone lacks the multifaceted ability to promote direct tissue regeneration (e.g., vessel growth, cell migration), which TB-500 and the LKKTET motif excel at.

---

Conclusions on the Ac-SDKP Fragment

The 1–4 fragment (Ac-SDKP) represents a highly specialized and promising anti-fibrotic peptide derived from thymosin β4. Its effects, while narrower in scope compared to TB-500 or the full-length thymosin β4, make it especially powerful in regulating fibrosis (via TGF-β inhibition) and controlling inflammation. However, it has limited direct utility in angiogenesis, actin dynamics, or cellular migration, which are hallmarks of other thymosin β4 fragments like the LKKTET motif.

Thus, Ac-SDKP serves as a complement to other fragments in therapeutic applications, targeting fibrotic and inflammatory processes where other peptides might fall short.

[cl-user]

@Steve_Combi

TB500 (frag 17-23)

Continuing to go deeper on Thymosin β4 17–23 Fragment - LKKTET Motif (Actin-Binding Domain)
Looks like this one is the angiogenesis promoting one.
[EDIT: Added comparisons between the different fragments at the end]

@Undermind.ai

Functional Roles of the LKKTET Motif

The LKKTET sequence serves as the actin-binding domain of thymosin β4 and plays a pivotal role in cytoskeletal and cellular processes.

1. Actin Sequestration and Regulation:

• The LKKTET motif is essential for G-actin sequestration, where it binds to monomeric actin and prevents its polymerization into filamentous actin (F-actin) [11, 19].
• This regulation of actin dynamics allows cells to control their shape, motility, and intracellular transport processes, all of which are critical for tissue repair and immune responses.

2. Angiogenesis:

• LKKTET plays a key role in angiogenesis by stimulating endothelial migration and tubulogenesis (formation of capillary-like structures) [7, 11].
• Thymosin β4 fragments containing the LKKTET sequence support vascular sprouting and new blood vessel growth in response to injury or ischemia.
• Studies suggest that the LKKTET-containing segment is sufficient for promoting angiogenic effects similar to those of full-length thymosin β4 [11].

3. Cell Migration and Wound Healing:

• The LKKTET motif is critical for cell migration by mediating actin polymerization at leading cell edges (lamellipodia and filopodia), processes necessary for wound healing and tissue regeneration [11, 19].
• Directly regulates the cytoskeletal dynamics underpinning cell motility in endothelial cells, fibroblasts, and immune cells [7].

4. Cytoskeletal Remodeling:

• Works in conjunction with integrin receptors (e.g., αvβ3 integrins) and focal adhesion complexes to reorganize the actin cytoskeleton.
• Enables cells to adhere, spread, and migrate, important for physiological processes like angiogenesis and pathological responses such as tissue repair [15, 21].

5. Regeneration After Ischemic Injury:

• Enhances endothelial progenitor cell (EPC) migration and survival, which are essential for repairing ischemic tissues, such as in myocardial infarction or hindlimb ischemia[8, 16].
• Both in vitro (tube formation assays) and in vivo models highlight its direct angiogenic and regenerative potential.
  […]

Key Strengths of LKKTET:

1. Core Actin Dynamics:

• The LKKTET region is indispensable for actin-related processes, driving cell migration and motility in nearly all thymosin β4 biological contexts.
• Without this region, thymosin β4 loses most of its cytoskeletal regulatory capacity [11].

2. Sufficient for Angiogenesis:

• Studies demonstrate that shorter fragments containing the LKKTET motif retain comparable angiogenic activity to full-length thymosin β4 [11, 7].

3. Minimized Complexity:

• Unlike full-length thymosin β4, which combines several motifs with broader roles (e.g., immune modulation, inflammation reduction), the LKKTET motif focuses specifically on angiogenesis, cell mobility, and cytoskeletal renovation, allowing for targeted applications.

Limitations of LKKTET:

1. Limited Anti-Inflammatory Action:

• While it drives migration of wound-healing immune cells like macrophages, its direct involvement in anti-inflammatory and anti-fibrotic signaling (e.g., TGF-β inhibition) is minimal compared to other fragments like Ac-SDKP.

2. Receptor Independence:

• Lacks strong receptor-specific signaling effects unless combined with ancillary sequences or cofactors. Full-length thymosin β4 (or modified versions like TB-500) engages multiple receptor-mediated pathways more effectively.

---

Applications of the 17–23 Fragment (LKKTET Motif)

1. Wound Healing:

• Facilitates epithelial and endothelial cell migration at injury sites, promoting rapid tissue closure and vascular repair.

2. Angiogenesis Therapies:

• Could be used independently to promote blood vessel formation in ischemic tissues (e.g., myocardial infarction, peripheral artery disease) [8, 28].

3. High-Purity Cytoskeletal Studies:

• Serves as a model fragment for probing actin-sequestration dynamics in cellular and molecular research contexts [19].

4. Regenerative Medicine:

• Particularly effective in settings requiring vascular regeneration or migration of progenitor cells, such as in cardiac, cerebral, or dermal repair therapies [13, 16].

To conclude that TB4 topic here are the comparisons between the different fragments.
Looks like 1-4 + 17-23 would get the most benefits.

@undermind.ai

Direct Comparison: LKKTET vs Ac-SDKP

Feature	LKKTET Motif (17–23)	Ac-SDKP (1–4)
Primary Function	Actin dynamics and angiogenesis	Anti-fibrotic and anti-inflammatory
Key Pathway	Cytoskeletal regulation (actin/G-actin)	TGF-β inhibition
Role in Wound Healing	Enhances vascular endothelial migration	Reduces fibroblast-driven scarring
Angiogenesis	Potent	Minimal
Fibrosis Control	Limited	Potent
Immune Modulation	Indirect (macrophage migration)	Strong anti-inflammatory outcomes

Differences Between the 17–23 Fragment (LKKTET Motif) and Other Fragments

Fragment	Primary Role	Key Mechanistic Focus	Unique Strengths	Limitations
Full-Length Tβ4	General tissue repair	Combines actin, immune modulation, and VEGF activation	Multidimensional effects	Low stability and high systemic clearance
1–4 Fragment (Ac-SDKP)	Anti-inflammatory and anti-fibrotic	TGF-β inhibition, cytokine suppression	Potent fibrosis control	No significant angiogenic or actin-migration effects
17–23 Fragment (LKKTET)	Actin regulation, angiogenesis	G-actin binding, PI3K/Akt activation	Cytoskeletal control, endothelial migration	Limited anti-inflammatory and anti-fibrotic effects

[Steve_Combi]

@undermind.ai

|TB-500|Combined regenerative effects|VEGF signaling, NF-κB suppression|Balanced angiogenesis and anti-inflammatory effects|Lacks full-length receptor context

TB500 is either (1-4) or (17-23) or even (43aa) it is not all 3 at once. TB500 is like a generic term for Tβ4 bits and pieces in the peptide community. If you are buying direct from a peptide mfg, the first thing they will ask is what version you want.

I’m going to split a hair here

Not sure where TB500 came from, to be more technically correct one would call all these variations;
Tβ4(43aa),
Tβ4(1-4) or
Tβ4(17-23)

Regardless of my split hairs, TB500 (1-4) works for me and I use it in combination with BPC157 Have not tried (17-23) yet.

If TB500 (1-4) is VEGF signalling and BPC157 is the VEGF receptor enhancer it may explain the synergy people find in using “wolverine blood” as this combo is often called on the interwebs

[Davin8r]

@ChatGPT o1

n the current peptide marketplace, most references to “TB-500” are either the 17–23 fragment or a synthetic Tβ4 analog

I don’t know of any peptide manufacturers/retailers selling actual TB500 (the frag) except for one that had the 17-23 frag briefly. I’ve literally never seen TB500 (1-4) for sale. It’s all TB-4, i.e. the full 43 aa peptide.

[cl-user]

@Steve_Combi

If TB500 (1-4) is VEGF signalling and BPC157 is the VEGF receptor enhancer it may explain the synergy people find in using “wolverine blood” as this combo is often called on the interwebs

Apparently the VEGF signaling is the 17-23 fragment so maybe that’s why the 1-4 + BPC157 is such a good combination as BPC will bring the VEGF activation part that is missing from the 1-4 fragment making it a more complete package.

[desertshores]

Of the companies I buy from, I find BPC-157 / Thymosin Beta 4 Fragment 17-23 only on one site, and it appears to be a nasal spray.
Have you known anyone who used TB500 as a nasal spray?
Apparently, TB-500 has some memory benefits. (If these references have been posted before, I apologize.)

Buy Thymosin Beta 4 Fragment 17-23 (TB-500) | Made in USA

Peptide fragment of thymosin β4 increases hippocampal neurogenesis and...

Thymosin β4 overexpression regulates neuron production and spatial...

[cl-user]

I think @Steve_Combi uses the BPC-157 + TB4 1-4 combo. I’m going to try that too.

The second paper you reference is about TB4 17-23 but the first one is about TB4 1-4.

[Steve_Combi]

Nasal sprays are pretty easy DIY projects, only caveat is pH… Keep it between 5.5-6.5 and it’s all good.

I made a NAC nasal spray before I was aware of this issue (had made a skin lotion with NAC and no issues)… it was like FIRE! took 3 days to completely resolve LoL!

Turns out NAC is quite acidic

When I got the pH right the NAC nasal spray was pretty interesting. Shared it with a few people with TBI and they indicated it was like turning the lights on.

[Steve_Spencer]

I went to their website, but they seem to be out of business. Do you know of any other reputable suppliers? Thanks.

[Agetron]

Hey Steve, you are rocking 67 years… I turn 67 in April… thanks to rapamycin I am feeling amazing.

You said rhat you stopped rapamycin due to a cyst issue. I am curious… are you back on rapamycin? Your benefits?

Thanks Jason

[Steve_Spencer]

Hi Age,

Not me. I’ve never stopped taking rapamycin since I started 3 years ago. In fact, since I’ve started I haven’t been sick, not even a cold.

[Agetron]

Ohhh, gotcha Steve.I mis-read your profile statement. Hahaha.
You took a 3-month hiatus after the cyst and then back on non-stop. Good for you.

Steve_Spencer
I’m 67. I started taking rapamycin in May, but I stopped after a month because a cyst I’d had for 20 years finally became infected and had to be removed.

It is an amazing molecule.

[Tim]

I never tried the full, but I’ve had exceptional results from the two frags. And by exceptional. I mean miraculous.

[DeStrider]

Infected cyst

Same here. Before my increased supplementations and meds, I’d get a cyst infection annually. In the last couple of years, I haven’t had any. Not sure which med/supplement is helping here, but I’d hazard a guess at either Rapa or Taurine or Jardiance.

After having said this, knowing my karma, I’ll probably get one tomorrow.

[Steve_Combi]

This my morning pep stack. I prepare a weeks worth of pins every Sunday to make this as easy as possible

LFG = Lets F’n Go!! or maybe…

L = LL 37+TA-1 - every morning for 3 weeks - 3 to 4 times a year.
F = Follistatin 344 - every morning for 12 weeks - depending may do this one 3 times a year.
G = Gonadorelin - 5 mornings a week - 3 on 1 off for 4 months - probably add to our ongoing routine
Blank is our daily BPC-157+TB500 (frag1-4) that we have been taking daily for 18 months with a week off every 2 months

1 more just before bed as well… CJC 1295 + Ipamorelin

8 peps a day!!!

[Tim]

What do you get or hope to get from the first three, LF&G?

[Steve_Combi]

My primary objective is to evaluate personal results. I like to know what thing do as compared to what it’s claimed they do. Altho my ability to measure a lot of the possible effects is limited, I hope to find some improvements with L F G.

L = immune enhancement, recently exposed to Norovirus for a couple days, so far so good, as is a client who lives with the person sick with this one. Also our first line of defense against cancer is a robust immune system as many cancers modify the immune system.

F = muscle growth stimulation, curious to see if the hype is real. If it is and my muscles grow without (or with minimal) exercise, then this one may be something to combat sarcopenia. I stopped working out end of Oct and had not done a push up since then. Monday I did 25 to see if I could do more than 20 the last 5 were hard LoL!

G - the gonads need support as we age and this one is supposed to help with that. I had a baseline hormone panel done, which I posted a while ago and it looks good. I reported on this one a couple months ago re: semen volume and it has improved