Titus Thorne

Last Updated November 17, 2021

Titus Thorne

 November 17, 2021

Are you worried about potential TB-500 side effects?

You’re not alone — injecting a therapeutic peptide primarily used to help race horses improve their performance can be a scary endeavor.

We don’t know a whole lot about the peptide, as TB-500 has not been sufficiently tested in humans to draw any significant conclusions.

But the reports of users online, combined with what I’ve heard from “test subjects”, may give us a clue as to what human users can expect.

So what exactly are the potential side effects of TB-500? Are they deal-breakers or not?

To answer this question, it’s important to understand exactly how TB-500 works and what it could potentially do for you.

Buy TB-500 from the #1 online Peptides vendor in the world: Peptides Sciences

Disclaimer: ResearchPeptides.org contains information about products that are intended for laboratory and research use only, unless otherwise explicitly stated. This information, including any referenced scientific or clinical research, is made available for educational purposes only. ResearchPeptides.org makes every effort to ensure that any information it shares complies with national and international standards for clinical trial information and is committed to the timely disclosure of the design and results of all interventional clinical studies for innovative treatments publicly available or that may be made available. However, research is not considered conclusive. ResearchPeptides.org makes no claims that any products referenced can cure, treat or prevent any conditions, including any conditions referenced on its website or in print materials.

What is TB-500?

TB-500 is the synthetic version of the naturally-occurring peptide Thymosin Beta-4, which is 43 amino acids long.

While it was first isolated from the thymus gland, it is now known to be distributed and located across all cells with the exception of red blood cells.

In particular, Thymosin Beta-4 levels are highest in white blood cells, platelets, and other circulatory cells [1]. While few clinical studies have examined the use of Thymosin Beta-4 in humans, nonclinical trials have discovered numerous health benefits [2]:

  • Tissue protection
  • Wound repair
  • Regeneration in the skin, eye, heart and central nervous system
  • Promotes cell migration, cell survival and prevents cellular death via apoptosis.

The first two benefits in particular are what makes TB-500 so attractive to competitive athletes and bodybuilders.

Injuries and wounds are a common part of their sport, and so they are always on the hunt for something which will accelerate the healing process.

But long before humans had the idea to inject Thymosin Beta-4 into themselves, it was already a popular doping drug in horse racing.

When injected into horses, it can dramatically improve their race-day performance and recover from tissue injuries far faster. Which is why its use in horse racing is heavily frowned upon [3]:

“Trainer Paul Jones faces a longer time on the sidelines than the banned Essendon AFL players after he was charged with possession and administration of peptide Thymosin Beta 4.

… The first of those charges is of administration and carries a minimum mandatory penalty of at least two years disqualification.

…Synthetic peptides are reported to increase muscle size, strength and stamina, enhance tissue repair and reduce recovery time.”

To be clear, TB-500 is NOT marked for human consumption.

Take a look at any online vendor selling peptides and this will be stated explicitly in their disclaimer. While legitimate human clinical trials involving Thymosin Beta-4 are few and far in-between, any benefits claimed to humans are anecdotal at best.

So what are these supposed benefits of TB-500?


Benefits of Thymosin Beta-4

Emerging scientific papers have come out regarding TB-500’s benefits, many in animal/cell cultures and a few promising ones in humans.

This research has shown vast potential with regards to a few benefits.

Here’s what we’ve learned:

Benefit #1: Heart Repair

In a study conducted in mice, blood flow was blocked off to the left ventricle of their hearts.

After injecting Thymosin Beta-4 and following up for 28 days, researchers found that the left ventricle of the mice’s hearts had improved function [4].

Furthermore, there was a preventative effect on ventricular remodelling. This means the heart’s size, structure and function was uncompromised.

One little-known clinical trial published in 2015 examined patients with ischemic heart failure who received stem cell therapy.

In all of the patients who had an improvement in symptoms, their Thymosin Beta-4 plasma levels were elevated [5]. This could potentially open the door for using Thymosin Beta-4 to treat cardiovascular problems.

Benefit #2: Tissue Regeneration

A Phase 1 clinical trial performed in 28 healthy volunteers who received a topical solution of Thymosin Beta-4 revealed the following results [6]:

“The study showed that Tb4 is well tolerated and exhibits no signs of toxicity at any given dose.

Based on these results and that of several nonclinical toxicology and dermal-sensitization studies, it was concluded that the clinical introduction of Tb4 is supported in patients with chronic cutaneous wounds.”

This same phenomenon was also observed in rats who had wounds in the palatal mucosa (a membrane which lines cavities found throughout the body) [7].

Researchers found that the wound healing was attributable to cell migration and angiogenesis (i.e. the formation of new blood vessels).

Benefit #3: Treating Dry Eye Disorders

In a meta-analysis examining the potential therapeutic benefit of Thymosin Beta-4 to treat dry eye disorders, three Phase 2 clinical trials were reviewed.

In all of them, Thymosin Beta-4 showed great promise in healing eye wounds – reducing symptoms and wound size – without any adverse events.

The researchers also noted how separate clinical trials done in patients with pressure and stasis ulcers did not show any adverse events either [8].

Benefit #4: Re-Organizes Connective Tissue

Thymosin Beta-4 has shown great therapeutic potential for re-organizing damaged connective tissue to help promote flexibility and freedom of physical movement.

One rat study where incisional wounds were performed on the rats found that Thymosin Beta-4 did the following to treat wounds [9]:

  • Heal with minimal scarring
  • Wounds healed faster
  • Connective tissues re-organized back into their pre-injured formation

Benefit #5: Anit-Inflammatory

In mice who had an alcohol-induced liver injury, Thymosin Beta-4 demonstrated anti-oxidant and anti-inflammatory properties in healing the injury [10].

This result has led scientists to hypothesize that Thymosin Beta-4 may be useful in treating non-alcoholic fatty liver disease, in which the liver is heavily inflamed [11].

Buy TB-500 from our #1 recommended vendor...


TB-500 Side Effects | What You MUST Know

As I mentioned previously, Thymosin Beta 4 use has not been extensively studied in humans.

As such, the information available on TB-500 side effects is sparse at best. Here are some of the most commonly reported side effects of TB-500 by a few “test subjects” I am in close contact with:

  • Head rush immediately following injection (but subsides within a few minutes)
  • Extreme fatigue/lethargy
  • Possible headache/nausea

Athletes/bodybuilders who share their experience have noted that once the body is used to regular TB-500 injections, the side effects are nonexistent.

This is most likely to the elevated Thymosin Beta 4 levels the body experiences – and consequently its response to this.

My “test subject” told me that TB-500 helped increase their energy levels while training, yet they were slightly depleted after the training session.

Reports of allergic reactions to TB-500 are rare, primarily because they had nothing to do with TB-500 itself. Most likely, the bottle of TB-500 was impure and contaminated, which could explain this phenomenon.

This is entirely separate from skin irritation, which is a common side effect of regularly injecting peptides in general. Of course, all of the above assumes you are correctly preparing and administering a moderate dose of TB-500 [12].

It also assumes you are practicing proper sterile injection techniques.

The previous article written about TB-500 put forth a moderate dosing schedule of TB-500. At 2-4mg of TB-500 administered twice a week – evenly spaced out – it is unlikely for a user to experience long-term adverse events.

But while clinical studies to date have not reported any toxic or serious side effects, and TB-500 appears to be well-tolerated in humans, this does not definitively rule out the possibility of TB-500 side effects.

TB-500 and Cancer

It is presently unknown if there is a definitive link between TB-500 and cancer.

The main premise is that higher levels of Thymosin Beta-4 are associated with the progression of cancer cells [13].

However, this does not prove that Thymosin Beta-4 is directly causing cancer. In fact, one research paper found that Thymosin Beta-4 helps to suppress tumors in mice with multiple myeloma [14].

Furthermore, that same paper revealed a poor prognosis in patients where Thymosin Beta-4 expression was reduced.

Another paper examining relevant cell cultures in non-small cell lung cancer discovered that Thymosin Beta-4 helped suppress the growth and invasion of cancer cells [15].

So what reasonable conclusion can be drawn from this?

It appears that Thymosin Beta-4 levels are higher in cancer patients than healthy individuals because it is actively promoting the formation of new white blood cells. This means that Thymosin Beta-4 levels are being elevated in response to the cancer so the body’s immune system is better equipped to fight the cancer.

However, all of this does not mean Thymosin Beta-4 is a proven anti-cancer agent.

While it shows therapeutic promise, there are few studies done on this topic and the results to this day are in conflict with one another.

Where to Buy Thymosin Beta-4 Online? | 2021 Guide

In fact, when you attempt to buy a peptide from any reputable online company, you will find a disclaimer that goes like this:


This designation allows the use of research chemicals strictly for in vitro testing and laboratory experimentation only. All product information available on this website is for educational purposes only.

Bodily introduction of any kind into humans or animals is strictly forbidden by law. This product should only be handled by licensed, qualified professionals.

This product is not a drug, food or cosmetic and may not be misbranded, misused or mislabeled as a drug, food or cosmetic.”

I’ve personally taken the time to research virtually every peptides company in existence, and there’s no other vendor I would recommend than Peptides Sciences.

Peptides Sciences guarantees 99% purity across all of their peptide products, which means you never have to worry about impurities or contamination. This is done through the use of extremely strict quality control standards and rigorous testing at all stages of production.

High-Performance Liquid Chromatography and Mass Spectrometry are also performed to ensure the accurate identification of each peptide.

You’ll also be relieved to find Peptides Sciences does not use any fillers or binding agents, so you’re getting the purest product available.

I highly recommend Peptides Sciences as the only legitimate place for purchasing research peptides.

P.S: All peptides created and sold by Peptide Sciences are 100% TFA-free! Trifluoroacetic acid is found in many of the peptides from low quality vendors who import from China. While not getting to deep into the science here, TFA can be exceptionally dangerous.


Buy TB-500 from our #1 recommended vendor...


Side Effects of TB-500? | Verdict

When it comes to TB-500 side effects, you really don’t have much to worry about.

The “cancer scare” is still speculative at best and all you will be able to find – for the time being – are anecdotal reports from bodybuilders and biohackers.

But even when you take those into consideration, it seems as if the reported side effects tend to go away as the body adapts to TB-500 use.

Furthermore, TB-500 seems to be very well-tolerated in the few human studies that have been performed to date.

So if you’re worried about the side effects of TB-500, my “test subjects” have assured me you’ll be just fine!

In their experience, it was worthwhile for dealing with nagging injuries and pains that otherwise would have never healed.

Please remember that all of the benefits discussed in relation to TB-500 are entirely speculative due to the lack of legitimate studies conducted in humans.


  1. Goldstein AL, Hannappel E, Sosne G, et al. Thymosin β4: a multi-functional regenerative peptide. Basic properties and clinical applications. Expert Opin Biol Ther. 2012;12(1):37-51. doi: 10.1517/14712598.2012.634793
  2. Crockford D, Turjman N, Allan C, et al. Thymosin beta4: structure, function, and biological properties supporting current and future clinical applications. Ann N Y Acad Sci. 2010;1194:179-89. doi:10.1111/j.1749-6632.2010.05492.x.
  3. Jones facing Thymosin Beta 4 charges. Retrieved February 25, 2020. racing.com
  4. Stark C, Helenius M, Taimen P, et al. Thymosin beta 4 treatment improves left ventricular function after myocardial infarction and is related to Up-regulation of chitinase 3-like-1 in mice. Transl Med Commun. 2016;1(8). doi:10.1186/s41231-016-0008-y
  5. Choudry FA, Yeo C, Mozid A, et al. Increases in plasma Tβ4 after intracardiac cell therapy in chronic ischemic heart failure is associated with symptomatic improvement. Regen Med. 2015;10(4):403-410. doi:10.2217/rme.15.9.
  6. Goldstein AL, Hannappel E, Kleinman HK. Thymosin beta4: actin-sequestering protein moonlights to repair injured tissues. Trends Mol Med. 2005;11(9):421-9.
  7. Zhu T, Park HC, Son KM, et al. Effects of thymosin β4 on wound healing of rat palatal mucosa. Int J Mol Med. 2014;34(3):816-21. doi:10.3892/ijmm.2014.1832
  8. Sosne G, Kleinman HK. Primary Mechanisms of Thymosin β4 Repair Activity in Dry Eye Disorders and Other Tissue Injuries. Invest Ophthalmol Vis Sci. 2015;56(9):5110-7. doi:10.1167/iovs.15-16890.
  9. Ehrlich HP, Hazard SW 3rd. Thymosin beta4 enhances repair by organizing connective tissue and preventing the appearance of myofibroblasts. Ann N Y Acad Sci. 2010;1194:118-24. doi:10.1111/j.1749-6632.2010.05483.x
  10. Shah R, Reyes-Gordillo K, Cheng Y, et al. Thymosin β4 Prevents Oxidative Stress, Inflammation, and Fibrosis in Ethanol- and LPS-Induced Liver Injury in Mice. Oxid Med Cell Longev. 2018;2018:9630175. doi:10.1155/2018/9630175
  11. Jiang Y, Han T, Zhang ZG, et al. Potential role of thymosin beta 4 in the treatment of nonalcoholic fatty liver disease. Chronic Dis Transl Med. 2017;3(3):165–168. doi:10.1016/j.cdtm.2017.06.003
  12. Peptide Mixing and Dosing Calculator. Retrieved February 25, 2020.
  13. Wang WS, Chen PM, Hsiao HL, et al. Overexpression of the thymosin beta-4 gene is associated with malignant progression of SW480 colon cancer cells. Oncogene. 2003;22(21):3297-306.
  14. Caers J, Hose D, Kuipers I, et al. Thymosin β4 has tumor suppressive effects and its decreased expression results in poor prognosis and decreased survival in multiple myeloma. Haematologica. 2010;95(1):163–167. doi:10.3324/haematol.2009.006411
  15. Huang D, Wang S, Wang A, et al. Thymosin beta 4 silencing suppresses proliferation and invasion of non-small cell lung cancer cells by repressing Notch1 activation. Acta Biochim Biophys Sin (Shanghai). 2016;48(9):788-94. doi:10.1093/abbs/gmw070

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