TB-500 and Thymosin Beta-4 are not exactly the same, although you’ll often see the two names used interchangeably in the peptide world (AKA broscience bodybuilding forums).  It’s much harder to get your hands on true Thymosin Beta-4, whether for research use, equine enhancement, athletic performance enhancement or bodybuilding. But TB-500’s peptide sequence shares most of the properties of Thymosin Beta-4, and it’s more economical to produce, thus easier to find.

Thymosin beta 4 (Tβ4) is a highly conserved, naturally occurring, water-soluble regenerative peptide that is found in all tissues and in all cell types, except red blood cells (Goldstein, Hannappel, Sosne, & Kleinman, 2012; Goldstein & Kleinman, 2015). It is also found in the blood and in other body fluids, including tears, saliva, cerebrospinal fluid, and wound fluids (Badamchian et al., 2007; Huang, Wang, Barnes, & Elmets, 2006; Mohring, Kellmann, Jurgens, & Schrader, 2005). Both platelets and leukocytes release Tβ4 into the wound fluid such that the final concentration is 13 μg/mL (Fromm, Gunne, Bergman, et al., 1996; Hannappel & van Kampen, 1987).
“I didn’t think it would be that bad honestly, but since I weight lift multiple times a weak, this supplement is doing me more harm than good. On a typical weight lifting day my workout is split into 5 sections. After taking 5-htp the night before I barely have enough energy to get through 1 section, and that is a serious problem, because of this I am quitting 5-htp all together.”
“This is a very ancient molecule,” says Sue Carter, a neuroscientist at Indiana University in Bloomington, whose lab pioneered many of the early studies of oxytocin in voles. “It has been used and reused for many purposes across the evolution of modern animals, and almost everybody who's tried to look at an effect of oxytocin on anything like social behaviour has found something.”
In reality, SSRIs and 5-HTP aren't so different. Both affect serotonin. SSRIs work by blocking serotonin from being reabsorbed by nerve cells so more serotonin is available to help brain cells work efficiently. As a doctor would later tell me, 5-HTP, on the other hand, "provides your body with the tools to make more serotonin, as opposed to antidepressants, which are just working with the serotonin that you have already."
Delayed Tβ4 treatment increases vascular density in the injured cortex, ipsilateral dentate gyrus, and CA3 region 35 days after TBI. Arrows show vWF-stained vascular structure. TBI alone (B) significantly increases the vascular density in the injured cortex compared to sham controls (A, P < 0.05). Tβ4 treatment (C) further enhances angiogenesis after TBI compared to the saline-treated groups (P < 0.05). The density of vWF-stained vasculature in different regions is shown in (D). Scale bar = 25 μm (C). Data represent mean + SD. *P < 0.05 vs Sham group. #P < 0.05 vs Saline group. N (rats/group) = 6 (Sham); 9 (Saline); and 10 (Tβ4).

In mammals, many mysteries remain. Oxytocin is difficult to measure reliably in the brain, making it hard to know exactly where, when and how much is normally released; nor do scientists understand precisely how it works to alter behaviour. “What we need to start thinking about is the more fundamental role that oxytocin plays in the brain,” Young says. The determination to find out has been strengthened by a growing move in neuroscience to characterize circuits that are important in brain operations. “That's the level that's critical for understanding how the brain is regulating behaviour,” says Thomas Insel, director of the US National Institute of Mental Health in Bethesda, Maryland, who has studied oxytocin in voles.
To explore whether Tβ4 peptide-induced anti-inflammatory and anti-osteoclastogenesis were dependent on the up-regulation of Wnt5a, the effects of recombinant human (rh) Wnt5a (500 ng/mL) and Wnt5a-specific siRNA were assessed. Pretreatment of Wnt5a siRNA reversed the inhibitory effects of Tβ4 peptide on H2O2-induced iNOS and COX-2 expressions, NO and PGE2 productions, osteoclastogenic cytokines, and RANKL expression (Fig 10A–10E). In contrast, pretreatment with rhWnt5a enhanced the anti-inflammatory effects of Tβ4 peptide whereas control siRNA showed no effect on PDLCs. In accordance with anti-inflammatory results, Tβ4 peptide-suppressed osteoclast number and TRAP activity in BMM cells were reversed by exogenous treatment with Wnt5a siRNA but enhanced by rh-Wnt5a (Fig 11A–11C).
In a study measuring oxytocin serum levels in women before and after sexual stimulation, the author suggests it serves an important role in sexual arousal. This study found genital tract stimulation resulted in increased oxytocin immediately after orgasm.[105] Another study reported increases of oxytocin during sexual arousal could be in response to nipple/areola, genital, and/or genital tract stimulation as confirmed in other mammals.[106] Murphy et al. (1987), studying men, found oxytocin levels were raised throughout sexual arousal with no acute increase at orgasm.[107] A more recent study of men found an increase in plasma oxytocin immediately after orgasm, but only in a portion of their sample that did not reach statistical significance. The authors noted these changes "may simply reflect contractile properties on reproductive tissue".[108]
But this isn’t the only study to show the subtle side of oxytocin. Just three months ago, I wrote about research from Heejung Kim at the University of California, which showed how oxytocin’s effects vary across different cultures. To fulfil its many roles, oxytocin has to dock at a protein called the ‘oxytocin receptor’, encoded by a gene called OXTR.

Some work has pointed to a potential dark side to oxytocin. Carter's group found that a single low dose of the hormone given to baby prairie voles improved their pair bonding as adults, but that higher doses interfered with that behaviour — possibly because oxytocin started to activate other receptors16. And human studies have suggested that in certain contexts, a puff of oxytocin can cause people to be more aggressive in defending themselves against outsiders or competitors17. In patients with a psychiatric condition known as borderline personality disorder, a single dose of oxytocin has been found to hinder trust and cooperation18.
At first, the mice showed an irregular smattering of neural impulses when they heard the baby's cries. Then, as the oxytocin kicked in, the signal evolved into a more orderly pattern typical of a maternal brain. The study showed in unusual detail how the hormone changed the behaviour of neurons1. “Oxytocin is helping to transform the brain, to make it respond to those pup calls,” Froemke says.
5-HTP (5-Hydroxytryptophan) is a chemical by-product of the protein building block L-tryptophan. It is also produced commercially from the seeds of an African plant known as Griffonia simplicifolia 5-HTP is used for sleep disorders such as insomnia, depression, anxiety, migraine and tension-type headaches, fibromyalgia, obesity, premenstrual syndrome (PMS), premenstrual dysphoric disorder (PMDD), attention deficit-hyperactivity disorder (ADHD), seizure disorder, and Parkinson's disease..
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