It seems that short-term use of ibutamoren after short-term stress reduces anxiety while long-term use during chronic stress increases anxiety. A new paper  describes a mechanism wherein a ghrelin mimetic (ibutamoren mesylate) can enhance fear learning in rats in the context of chronic stress. The said mechanism showed that a ghrelin agonist did not activate HPA stress axis, whose downstream effector hormone is cortisol. Ghrelin is a stress hormone by itself. Growth hormone receptors were up-regulated during repeated stressful events, ghrelin agonist increased growth hormone levels and the fear learning of the rats grew in response to growth hormone. The mechanism was confirmed by using ghrelin antagonist that blocked the enhanced fear learning. In case of the short time frame, the opposite seems to be true, as short time stress followed by ghrelin agonist reduces stress symptoms in mice . Fourth study also demonstrated that ghrelin weakens fear learning in generally unstressed rodents while chronically stressed rats had elevated levels of hunger hormone and fear learning ended up with fewer ghrelin receptors. High expression of ghrelin receptors reduces anxiety , while low levels have the opposite effect. Hence, it seems that long-term ibutamoren may exacerbate long-term stress, and brain ghrelin receptor down-regulation is the probable explanation. It seems likely, that transient or occasional increases in ghrelin receptor activation (such as after interval exercise ) may be more adaptive than chronic elevation regime.
Overview of SARMs dosages used in human studies.
SARM/Nootropic and dosage used:
Ostarine 3 mg 
Ligandrol 1 mg 
PRL-5-83 5 mg 
Yohimbine Usually 5…30 mg ,
Hordenine Unknown but present in beer 1…6 mg 
PEA Unknown but see ,
In 1989 there was a study that investigated the behavior of animals. Caffeine was anxiogenic in the context of exploration and social interaction while yohimbine was anxiogenic in the context of exploration but displayed anti-conflict properties in social interaction . Unexpectedly, caffeine and yohimbine cancelled each others’ effects out.
An interesting study investigated rat vocalizations under the influence of either caffeine, yohimbine or amphetamine. 22 kHz sounds were interpreted as signals of alarm or distress while 50 kHz voice were interpreted as response to rewarding stimuli while mentioning that it is unknown whether the same signal is associated with anxiety . Caffeine and amphetamine increased 50 kHz calls, yohimbine did not. In addition, it was shown that while caffeine and amphetamine were locomotor stimulants, yohimbine was not.
Yohimbine can promote fat loss by mildly increasing lipolysis when not counteracted by eating because after a meal the lipolysis-enhancement does not work . In lower doses it does not increase blood pressure, heart rate or cause anxiety as much as ephedrine but larger doses have both cardiovascular and anxiogenic effects.
A human cardiology study investigated caffeine, ephedrine and yohimbine in obese women during exercise (handgrip and cycloergometer). Caffeine and ephedrine increased heart ejection fraction during cycling (amount of blood pumped out of left ventricle, an increase may be considered usually beneficial) and did not alter the hemodynamics while resting. Addition of yohimbine increased diastolic blood pressure (that may be considered quite undesirable in this context) and heart rate (same interpretation) but decreased ejection fraction (same interpetation) and stroke index during rest (same interpretation). During exercise, yohimbine decreased ejection fraction during both exercises and increased cardiac load during exercise.
Bottom line: while yohimbine seems useful for fasted long-duration low-intensity fat burning training, it seems that combining it with substantial amounts of caffeine may be asking for trouble. Most importantly, yohimbine seems a very unwise choice for hard exercise (weightlifting, sprint, high-intensity interval training, intense cardio, and, if I may suggest, also pushing the limits with rough sex).
We have updated overview article of Unifiram.
Unifiram (CAS# 272786-64-8) is a substance that was reported in year 2000 to have similar properties to piracetam but more potent in a mouse passive avoidance test. However, unifiram has shown pro-cognitive effects for mice by preventing amnesia induced by scopolamine (muscarinic antagonist), mecamylamine (nicotinic antagonist), baclofen (GABA-B agonist), clonidine (alpha-2 agonist), NBQX (AMPA antagonist) in passive avoidance test. Read more about Unifiram.
Unifiram is also available in our shop.
We have now available Unifiram in 5mg capsules.
Unifiram is an experimental drug that has antiamnesic and other effects in animal studies with far greater potency than piracetam. Read more about Unifiram.
Yohimbine is usually considered an agent that helps to reduce body fat, increase sexual desire and ability for men as well as a stimulant that may cause unpleasant adverse effect of anxiety together with elevation of blood pressure.
However, according to the literature, yohimbine has some other effects as well, including effects on cognition, memory and sleep that may be of interest. Yohimbine (30 mg) reduced errors on letter flank test . A simple version of letter flank test that shows ability to filter out irrelevant stimuli from detecting target letter is available online . However, it increases rapid response impulsivity and errors in a somewhat more complex immediate memory test that has numbers instead of a single letter; the used dosage was a comparable 30 mg dose for a 75 kg person. The problem that occurred with yohimbine was that the test subjects did not read the number thoroughly and prematurely thought that the number was similar to another number presented just before the current. The test is explained online  but is not freely available.
Interestingly, yohimbine seems to have a truly interesting sex-specific effects on both memory and cognition of fear. Without affecting learning, it interrupted ability of women to generalize from learned memories . Furthermore, the effect of yohimbine for processing fear-related signals (alteration of amygdala activity) is opposite for men and women .
A small study with medical students as subjects used a low dose. It was found that yohimbine improved following cognitive abilities: reaction time (single choice, not multiple choice), critical flicker fusion threshold and working memory (as measured by 1-back and 2-back tests) . However, during glucocorticoid treatment or during high stress, yohimbine may be counterproductive for higher, flexible thought: yohimbine and cortisol together may reduce goal-directed behavior in favor of habitual behavior .
We have opened our online shop at ENHANCETECH.eu address. It is possible to buy all products provided by Enhancetech.
Online shop for nhancetech products is now opened. All our customers can buy now our provided SARMs and other products.
All products can be ordered with different ingredient amount.
Also we are pointing out, that all products are for research purposes. SARMs are not medicines or food supplements. Please read our sale terms also before buying from e-shop.