But returning hunters also need to share meat with their families and friends; this is where oxytocin comes into play. It can help overcome the potentially negative social effects of testosterone. Men who were absent for longer seem to need more oxytocin to reconnect with their families; it seems that absence does indeed make the heart grow fonder, via an oxytocin blast.
Oxytocin was also correlated with the longevity of a relationship. Couples with the highest levels were the ones still together six months later. They were also more attuned to each other than the low-oxytocin couples when Feldman asked them to talk about a shared positive experience. The high-oxytocin couples finished each other’s sentences, laughed together and touched each other more often. Feldman says it’s still not clear whether oxytocin was responsible for the stability of the couple’s bond six months later or if couples who weren’t as connected failed to trigger the oxytocin system.
In a landmark 1979 study3, Cort Pedersen and Arthur Prange at the University of North Carolina in Chapel Hill showed that giving oxytocin to virgin rats could trigger maternal behaviours: the animals would build nests, lick or crouch over unfamiliar pups and even return lost pups to the nest. Researchers went on to show that oxytocin signalling in the brains of prairie voles (Microtus ochrogaster) helps the animals to form lifelong pair bonds4 — a rarity among mammals. In 2012, researchers even found a version of oxytocin in the tiny roundworm Caenorhabditis elegans, where it helps the animals find and recognize mates5.
Doctors have noticed cancer patients have a higher amount of Thymosin in the affected tissues than other people. So in the early stages of research, doctors assumed that this meant Thymosin may cause cancer. After more research was conducted, it was discovered that the main action of Thymosin Beta 4 was to produce new white blood cells – so its presence in the body in the areas affected by cancer was likely not a cause of the cancer, but instead, a matter of “showing up” in the body where cancer lived to help the body mount an immune system response.
This current literature is notable for its apparent irrelevancy to an AFL footballer. It begs the question; did Tβ4 make a difference to the Essendon players? The only honest answer is that we don’t know. Most of our understanding exists on a molecular and cellular level, without any significant appreciation of how Tβ4 influences applicable outcomes such as exercise performance, endurance, muscle strength, and time to recovery. Furthermore, as the majority of research has been performed on mice, rat and pig models, any results are not directly translatable to a human, let alone an elite athlete. This is a stark contrast to a supplement such as EPO, which has been investigated thoroughly.
In a 2-week long clinical trial involving 25 overweight diabetic subjects given no dietary restrictions, subjects who received 5-HTP had reduced caloric, carbohydrate, and fat intake compared to placebo. Subjects who received 5-HTP also have reduced body weight, blood sugar, insulin and HbA1C levels after 2 weeks, possibly due to changes in the diet (R).
In years past, oxytocin had the reputation of being an "uncomplicated" hormone, with only a few well-defined activities related to birth and lactation. As has been the case with so many hormones, further research has demonstrated many subtle but profound influences of this little peptide, particularly in regards to its effects in the brain. Oxytocin has been implicated in setting a number of social behaviors in species ranging from mice to humans. For example, secretion or administration of oxytocin in humans appears to enhance trust and cooperation within socially-close groups, while promoting defensive aggression toward unrelated, competing groups.
Interestingly, there are numerous differences in the biology of teleosts and mammals, as well as specific differences in cardiomyocyte cellular structure and anatomy, all of which might contribute to regenerative variability. Unlike mammals, zebrafish can grow throughout most of adulthood, a phenomenon called “indeterminate growth” (Jordan, 1905). In fact, their growth can be affected markedly by changes in nutrition and population density (Goldsmith et al., 2006). It is thus possible that the capacity to replace cardiac tissue rapidly in teleosts has been retained in evolution as a function of the need for robust animal and cardiac growth. Indeed, a recent study has found that experimentally-induced adult cardiac growth in zebrafish is hyperplastic, and appears to rely on the same signals present or required during cardiac regeneration (Wills et al., 2008).
“The study was double-blinded and was for two consecutive 6-wk periods. No diet was prescribed during the first period, a 5040-kJ/d diet was recommended for the second. Significant weight loss was observed in 5-HTP-treated patients during both periods. A reduction in carbohydrate intake and a consistent presence of early satiety were also found. These findings together with the good tolerance observed suggest that 5-HTP may be safely used to treat obesity.”
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In the male mammal, the small peptide hormone oxytocin is produced in similar quantities within the hypothalamo-pituitary magnocellular system as in the female, yet for the male little is known about the physiology associated with this hormone. The present review summarizes what is known about the function of oxytocin in the male mammal and tries to take account of both central and systemic effects, and those linked with a local production of oxytocin within the male reproductive organs. In several species a pulse of systemic oxytocin, presumably of hypothalamic origin, appears to be associated with ejaculation. The systemic hormone could act peripherally stimulating smooth muscle cells of the male reproductive tract, but could also reflect central effects in the brain modulating sexual behaviour. In addition to systemic oxytocin, the peptide is also made locally within the testis, and possibly also the epididymis and prostate. In the former tissue it appears to have an autocrine/paracrine role modulating steroid metabolism, but may in addition be involved in contractility of the seminiferous tubules. However, the latter function may involve the mediacy of Sertoli cells which under some circumstances can also exhibit the components of a local oxytocin system. In the prostate of the rat and the dog oxytocin is linked again to steroid metabolism and may also act as a growth regulator. Finally, oxytocin in seminal fluid is discussed and its possible role in respect to the fate of the semen following ejaculation.
It has been shown that oxytocin differentially affects males and females. Females who are administered oxytocin are overall faster in responding to socially relevant stimuli than males who received oxytocin.[75][86] Additionally, after the administration of oxytocin, females show increased amygdala activity in response to threatening scenes; however, males do not show increased amygdala activation. This phenomenon can be explained by looking at the role of gonadal hormones, specifically estrogen, which modulate the enhanced threat processing seen in females. Estrogen has been shown to stimulate the release of oxytocin from the hypothalamus and promote receptor binding in the amygdala.[86]
This anti-social effect of a social hormone brings some nuance to the story of oxytocin. In one study, researchers found that Dutch students given a snort of the hormone became more positive about fictional Dutch characters, but were more negative about characters with Arab or German names. The finding suggests that oxytocin's social bonding effects are targeted at whomever a person perceives as part of their in-group, the researchers reported in January 2011 in the journal PNAS.

In women, oxytocin is responsible for signaling contractions of the womb during labor. The hormone stimulates the uterine muscles to contract, so labor begins. It also increases the production of prostaglandins, which move labor along and increases the contractions even more. Because of this effect, synthetic oxytocin (pitocin) is sometimes used to induce a woman to start labor if she cannot start naturally, or it can be given to make contractions stronger if a woman's labor is slowing.

Our nutrition team created these easy mix-and-match menus using the same guidelines that helped 5-HTP dieters lose weight at top speed during the University of Rome study. The idea here is simple: You’ll eat balanced meals that keep you feeling energized and awesome, but you’ll also watch portions so you’re not overeating out of habit. While using these menus, be sure to drink plenty of water and add any other zero-cal beverages you like. You’re also encouraged to season meals to your liking with unlimited herbs, spices, vinegar, mustard, and citrus juice. As always, get a doctor’s OK before trying any new plan.


Animal studies have found high levels of both stress and oxytocin in voles that were separated from other voles. However, when the voles were given doses of oxytocin, their levels of anxiety, cardiac stress, and depression fell, suggesting that stress increases internal production of the hormone, while externally supplied doses can help reduce stress.

Interestingly, there are numerous differences in the biology of teleosts and mammals, as well as specific differences in cardiomyocyte cellular structure and anatomy, all of which might contribute to regenerative variability. Unlike mammals, zebrafish can grow throughout most of adulthood, a phenomenon called “indeterminate growth” (Jordan, 1905). In fact, their growth can be affected markedly by changes in nutrition and population density (Goldsmith et al., 2006). It is thus possible that the capacity to replace cardiac tissue rapidly in teleosts has been retained in evolution as a function of the need for robust animal and cardiac growth. Indeed, a recent study has found that experimentally-induced adult cardiac growth in zebrafish is hyperplastic, and appears to rely on the same signals present or required during cardiac regeneration (Wills et al., 2008).

“Ultimately you’re body is going to down-regulate the enzymes needed to convert the tyrosine/l-phenylalanine into dopamine and norepinephrine; this also counts for 5 -htp being converted into serotonin. As far as I’m aware when simply supplementing amino acids to improve neurotransmitter prevalence in the brain, tolerance will build very rapidly within a one week to two week period (from personal experience). Not saying it’s not viable to help out with mood when used sparingly, just saying there’s most likely better ways for continued treatment.”
Despite this, Tβ4’s place on the banned-substances list is warranted. It reflects the possibility that the effects of the supplement may manifest as a tangible improvement in athletes. However, any time a journalist flippantly declares it “heals damaged tissue and speeds recovery”, it should be noted that such claims are a harmful distortion of the facts.
When combined with antidepressants of the MAOI or SSRI class, very high parenteral doses of 5-HTP can cause acute serotonin syndrome in rats.[23][24] It is unclear if such findings have clinical relevance, as most drugs will cause serious adverse events or death in rodents at very high doses. In humans 5-HTP has never been clinically associated with serotonin syndrome, although 5-HTP can precipitate mania when added to an MAOI.[25]
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