Thymosin beta-4, also known as TB-500, stands out as a potent treatment for certain scenarios of combating hair loss or promoting growth. However, it often tends to be overshadowed. Many attribute its oversight to the prevalent belief that most hair loss results from hormonal imbalances, directing people towards DHT blockers. Yet, for those with hair loss resulting from inflammation, research indicates that Thymosin beta-4 could offer support.
So, what exactly is Thymosin beta-4? Originating from the thymus, this peptide boasts a wide range of biological activities, notably impacting wound healing, inflammation, fibrosis, and tissue regeneration. How does this tie in with hair growth stimulation?
Hair Structure and Growth Cycle Review
To grasp this, let’s quickly delve into hair follicle structure and its growth cycle. For a deeper dive, revisit podcast episode 22, which comprehensively explores hair growth mechanics and strategies to combat hair loss. But today, our focus remains on Thymosin beta-4.
Breaking down the hair follicle: its base is the bulb, followed by the bulge, and then there's the arrector pili muscle that essentially anchors the hair follicle.
Now, for the hair growth cycle. It comprises the anagen (growth), catagen (transitional), and telogen (resting) phases. During the anagen phase, stem cells in the follicle's bulge area become active and multiply rapidly. As these cells differentiate, hair growth is spurred. Transitioning to catagen, the hair follicle regresses, and its lower part disconnects from its blood supply, leading to the telogen or resting phase. Here, the hair follicle remains dormant for several weeks to months before shedding and restarting the cycle with the anagen phase.
Now upon active hair growth, the stem cells (within the bulge region of the hair follicle) embark on a journey. In other words, they travel to the follicle's base (or "bulb") during the anagen growth phase. During this process, they are differentiating into matrix cells, forming a new hair shaft. These bulge stem cells also move upwards, aiding in wound healing.
Thymosin beta-
Here's the kicker: Thymosin beta-4 facilitates this migration. It interacts with actin, a cellular substance crucial for cell movement. Thymosin beta-4's unique amino acid sequence attaches to actin, propelling cell migration. It's important to note that Thymosin beta-4 is naturally present, and its expression intensifies during the anagen phase (which makes sense), since this phase requires those stem cells to migrate in order to instigate cell differentiation, and, therefore, hair growth.
So, due to it's ability to induce cell migration, Thymosin beta-4 plays a large role in promoting the transition from the telogen (rest) phase to the anagen (growth) phase. To demonstrate this: A study on rats found that applying Thymosin beta-4 expedited hair growth, and within a week, the number of anagen-phase hair follicles doubled compared to untreated counterparts.
Angiogenesis
Now, one last note: Thymosin beta-4 has also been shown to increase angiogenesis, or the building of new blood vessels. And, considering that inflammation can impair blood circulation, leading to cellular oxygen and nutrient deficiency, it’s understandable that chronic inflammatory conditions might result in hair loss. While it's crucial to address the root cause of inflammation, there have been anecdotal accounts of Thymosin beta-4 assisting hair regrowth in these situations.
Topical
Lastly, most studies have examined it as a topical when it comes to hair growth.
Sources:
Liebert, A., Bicknell, B., Johnstone, D. M., Gordon, L. C., Kiat, H., & Hamblin, M. R. (2019). "Photobiomics": Can Light, Including Photobiomodulation, Alter the Microbiome?. Photobiomodulation, photomedicine, and laser surgery, 37(11), 681–693. https://doi.org/10.1089/photob.2019.4628
Bicknell, B., Liebert, A., Johnstone, D. et al. Photobiomodulation of the microbiome: implications for metabolic and inflammatory diseases. Lasers Med Sci 34, 317–327 (2019). https://doi.org/10.1007/s10103-018-2594-6
Philp D, Goldstein AL, Kleinman HK. Thymosin beta4 promotes angiogenesis, wound healing, and hair follicle development. Mech Ageing Dev. 2004 Feb;125(2):113-5. doi: 10.1016/j.mad.2003.11.005. PMID: 15037013.
Giorgia Renga, Vasilis Oikonomou, Claudia Stincardini, Marilena Pariano, Monica Borghi, Claudio Costantini, Andrea Bartoli, Enrico Garaci, Allan L. Goldstein & Luigina Romani (2018) Thymosin β4 limits inflammation through autophagy, Expert Opinion on Biological Therapy, 18:sup1, 171-175, DOI: 10.1080/14712598.2018.1473854
Walsh, D. A., & Pearson, C. I. (2001). Angiogenesis in the pathogenesis of inflammatory joint and lung diseases. Arthritis research, 3(3), 147–153. https://doi.org/10.1186/ar292
Philp, D., Nguyen, M., Scheremeta, B., St-Surin, S., M. Villa, A., Orgel, A., K. Kleinman, H. and Elkin, M. (2004), Thymosin β4 increases hair growth by activation of hair follicle stem cells. The FASEB Journal, 18: 1-16. https://doi.org/10.1096/fj.03-0244fje
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