Despite the popularity of creatine among young people, there has been very little research conducted in children under age 18. Of those studies, a few have suggested a positive effect but the overall evidence is inconclusive. In one study, teenage swimmers performed better after taking creatine; in another study, it helped high school soccer players sprint, dribble, and jump more effectively.
There are also many other variations of squats you can try. Squats can be done with weights held in the front of your body or behind your back, using dumbbells or a stability ball, with your arms held overhead or parallel to the floor, using a chair or wall for support if you’re more limited, held in place while you focus on breathing (as is done in yoga during “chair pose”), and in other ways. Pistol squats are also a great workout for the entire legs and hips. Pistols are one-legged squats with one relaxed hamstring and calf and the other leg straight out in front of you as you lower down.
Escolar, D. M., Buyse, G., Henricson, E., Leshner, R., Florence, J., Mayhew, J., Tesi-Rocha, C., Gorni, K., Pasquali, L., Patel, K. M., McCarter, R., Huang, J., Mayhew, T., Bertorini, T., Carlo, J., Connolly, A. M., Clemens, P. R., Goemans, N., Iannaccone, S. T., Igarashi, M., Nevo, Y., Pestronk, A., Subramony, S. H., Vedanarayanan, V. V., and Wessel, H. CINRG randomized controlled trial of creatine and glutamine in Duchenne muscular dystrophy. Ann Neurol 2005;58:151-155. View abstract.
Practice Sleep Hygiene – For optimal health of your mind and body, it is recommended that adults get 7 to 8 hours of sleep every day. Lower or more amounts of sleep can exacerbate your depressive symptoms. Sleep hygiene practices include limiting daytime naps, scheduling a regular sleep and wake-up times, and ensuring the environment is rid of potential sleep disruptors such as light, noise, and heat.
Tongkat Ali, biologically called Eurycoma longifolia, is a herb found in Southeast Asia which is primarily used to boost male fertility. However, it is also known to boost testosterone levels significantly. Tongkat Ali has a low side-effect profile, been found to be generally safe and well-tolerated. A common side effect reported by users is trouble falling asleep which you can avoid by taking the supplement in the morning, preferably with breakfast.
Perform the exercise pairs (marked A and B) as alternating sets, resting 60 seconds between sets. You’ll complete one set of exercise A and rest; then one set of B and rest again; and repeat until you’ve completed all sets for that pair. On your very first training day, perform only one set for each exercise. Progress to two or more sets (as the set prescriptions below dictate) from your second workout on.
Make no mistake: Eating for muscle is just as important as lifting for muscle. The foods you grab in the morning on the way to work, the meals you pack for lunch and mid-afternoon, what you put into your body immediately following your workout, and your final meal of the day impact your results as much as, if not more than, the number of reps you squeeze out at the end of a set. But in reality, it can be tough to stick to a "“clean"” diet when you'’re busy. We know that adding another layer of complexity to life in the form of reading food labels and studying ingredient lists just isn'’t an option for most of us. Not to mention actually preparing all those healthy meals.
Gain mass: One of the most popular reasons for people to take body building supplements is to gain weight and that is why protein powder is much sought after. Protein is the building block of muscles and therefore, bodybuilders use protein powder to help repair muscles, speed recoveries and preserve muscle mass. They usually consume 1 to 2 grams of protein per pound of body weight every day. 
Common side effects from testosterone medication include acne, swelling, and breast enlargement in males.[10] Serious side effects may include liver toxicity, heart disease, and behavioral changes.[10] Women and children who are exposed may develop virilization.[10] It is recommended that individuals with prostate cancer not use the medication.[10] It can cause harm if used during pregnancy or breastfeeding.[10]
Research shows that strength training is especially effective at raising EPOC. That’s because, generally speaking, strength-training sessions cause more physiological stress to the body compared to cardiovascular exercise, even higher-intensity cardio intervals. However, it’s worth noting that overall exercise intensity is what makes the biggest impact on EPOC. So squats, deadlifts, and bench presses with heavy weights are going to be much more effective at raising EPOC compared to bicep curls and triceps extensions with light weights.
Stand on one foot with the arch and heel hanging off of the edge of a step or platform. Hold onto something if you need help balancing. Drop your heel all the way down below the step, and then rise all the way up on your toes. Hold dumbbells to make it harder. If you can balance without holding on to something, you’ll work your core muscles, too. You'll also build more stable joints in the other leg.
Creatine, through its ability to act as an energy reserve, attenuates neuron death induced by the MPTP toxin that can produce Parkinson’s disease-like effects in research animals,[235] reduces glutamate-induced excitotoxicity,[236] attenuates rotenone-induced toxicity,[120] L-DOPA induced dyskinesia,[237] 3-nitropropinoic acid,[238] and preserves growth rate of neurons during exposure to corticosteroids (like cortisol), which can reduce neuron growth rates.[239] Interestingly, the energetic effect also applies to Alzheimer’s disease, during which creatine phosphate per se attenuates pathogenesis in vitro, yet creatine per se did not.[240]
“Imagine you've fasted for over eight hours,” he says. “At breakfast, you're firing your metabolism off really high. If you don't eat for another five hours, your metabolism starts to slow right down and you have to try and kickstart it again with your next meal. If you eat every two and a half to three hours, it's like chucking a log on a burning fire.”

As mentioned, protein is essential for building muscle. If you are unable to consume the recommended amount of protein through diet alone, add protein powder for building muscle as a supplement. This applies to nearly anyone hoping to gain muscle mass since it’s not easy to pack in nearly 100 grams of protein a day through chicken, eggs and legumes alone.


Muscle imbalances are quite common among strength athletes and are arguably the most common cause of their injuries. Many times this is due to a “weak link” in the kinetic chain of muscles that activate during their activity. Identifying the “weak” muscle and being able to feel, isolate and contract that “weak” muscle makes correctional exercise and rehab much easier. Bodybuilding training, with its focus on “feel” rather than movement, helps to train and develop the mind to muscle connection. This comes in handy when you need to train a muscle imbalance with correctional exercise and, in the case of injury, for rehab.

Creatine is one of the most popular and widely researched natural supplements. The majority of studies have focused on the effects of creatine monohydrate on performance and health; however, many other forms of creatine exist and are commercially available in the sports nutrition/supplement market. Regardless of the form, supplementation with creatine has regularly shown to increase strength, fat free mass, and muscle morphology with concurrent heavy resistance training more than resistance training alone. Creatine may be of benefit in other modes of exercise such as high-intensity sprints or endurance training. However, it appears that the effects of creatine diminish as the length of time spent exercising increases. Even though not all individuals respond similarly to creatine supplementation, it is generally accepted that its supplementation increases creatine storage and promotes a faster regeneration of adenosine triphosphate between high intensity exercises. These improved outcomes will increase performance and promote greater training adaptations. More recent research suggests that creatine supplementation in amounts of 0.1 g/kg of body weight combined with resistance training improves training adaptations at a cellular and sub-cellular level. Finally, although presently ingesting creatine as an oral supplement is considered safe and ethical, the perception of safety cannot be guaranteed, especially when administered for long period of time to different populations (athletes, sedentary, patient, active, young or elderly).
^ Butenandt A, Hanisch G (1935). "Umwandlung des Dehydroandrosterons in Androstendiol und Testosterone; ein Weg zur Darstellung des Testosterons aus Cholestrin" [About Testosterone. Conversion of Dehydro-androsterons into androstendiol and testosterone; a way for the structure assignment of testosterone from cholesterol]. Hoppe-Seyler's Z Physiol Chem (in German). 237 (2): 89–97. doi:10.1515/bchm2.1935.237.1-3.89.
Glycogen synthesis is known to respond directly and positively to cellular swelling. This was demonstrated in an earlier study, during which rat muscle cells were exposed to a hypotonic solution in vitro to induce cell swelling, which increased glycogen synthesis by 75%. In contrast, exposing these same cells to a hypertonic solution hindered glycogen synthesis by 31%. These changes were not due to alterations in glucose uptake, but are blocked by hindering the PI3K/mTOR signaling pathway.[112] It was later noted that stress proteins of the MAPK class (p38 and JNK) as well as heat shock protein 27 (Hsp27) are activated in response to increasing osmolarity.[113][114] Furthermore, activation of MAPK signaling in skeletal muscle cells is known to induce myocyte differentiation[115] via GSK3β and MEF2 signaling, which can induce muscle cell growth.[116][117]
How: Place a resistance band around your legs just above the knees. Lie faceup with knees bent, feet flat on floor, and arms resting at sides. Push knees out slightly so that there is tension on the band. Squeeze glutes and hamstrings to lift hips up off floor, keeping core engaged throughout so body forms a straight line from knees to shoulders. Lower hips and repeat.

Jason Ferruggia is a highly sought after, world renowned strength & conditioning specialist and muscle building expert. Over the last 17 years he has personally trained more than 700 athletes from over 90 different NCAA, NFL, NHL and MLB organizations. He has also worked extensively with firefighters, police officers, military personnel, Hollywood stars and entertainers. Most importantly, Jason has helped over 53,000 skinny guys and hard gainers in 126 different countries build muscle and gain weight faster than they every thought possible.
Many trainees like to cycle between the two methods in order to prevent the body from adapting (maintaining a progressive overload), possibly emphasizing whichever method more suits their goals; typically, a bodybuilder will aim at sarcoplasmic hypertrophy most of the time but may change to a myofibrillar hypertrophy kind of training temporarily in order to move past a plateau. However, no real evidence has been provided to show that trainees ever reach this plateau, and rather was more of a hype created from "muscular confusion".[clarification needed][citation needed]
Weak, underdeveloped glutes can be a problem if you have a history of back pain and can compromise your hip mobility and set the stage for hip impingement (if you’ve ever gotten off your bike and couldn't stand up straight without some effort, you know how that feels). “Strong glutes can prevent those issues,” says McGill. But here’s the good news: You can build yours on and off the bike with a few simple moves.
Testosterone is the primary male sex hormone and an anabolic steroid. In male humans, testosterone plays a key role in the development of male reproductive tissues such as testes and prostate, as well as promoting secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair.[2] In addition, testosterone is involved in health and well-being,[3] and the prevention of osteoporosis.[4] Insufficient levels of testosterone in men may lead to abnormalities including frailty and bone loss.
Cornelissen, V. A., Defoor, J. G., Stevens, A., Schepers, D., Hespel, P., Decramer, M., Mortelmans, L., Dobbels, F., Vanhaecke, J., Fagard, R. H., and Vanhees, L. Effect of creatine supplementation as a potential adjuvant therapy to exercise training in cardiac patients: a randomized controlled trial. Clin.Rehabil. 2010;24(11):988-999. View abstract.

Our bodies store creatine in our muscles so that we have quick access to it for fast, high-intensity movements, like sprinting or powerlifting, explains Autumn Bates, a certified clinical nutritionist and sports nutritionist in private practice in Manhattan Beach, California. “It's a nonessential amino acid, meaning your body creates it and you don't need to primarily get it from food.”
In the following article I will outline the supplements that have helped me to add a massive 10 kilograms (22lbs) of solid muscle to my physique over the past year—taking my body weight from 80 kilograms (176lbs) to 90 kilograms (198lbs)—and explain how these have helped me to improve my performance and enhance my size as a natural bodybuilder, aged 35.
If you're 12 weeks out from a competition, you want to maintain as much muscle as possible while torching fat from every angle. This means low-intensity cardio – high intensity cardio speeds up your metabolism and burns fat very quickly, so you run the risk of burning muscle too, Terry says – either first thing in the morning on an empty stomach, or immediately after your weights session, once you’ve depleted those glycogen levels.
Trouble walking, running or doing other activities — Any physical movement that involves stability, flexibility and strength in the legs and hips can be compromised. For example, yoga, dancing, horseback riding, cycling, hiking, burst training, sprinting, plyometrics or tabata workouts, and other activities will be more difficult with underdeveloped glutes.
Natural remedies for treating erectile dysfunction Erectile dysfunction has many causes, can affect any male, and is often distressing? Some people advocate several different natural remedies, mostly herbs and other plants. Here, we look at their merits and side effects, plus lifestyle changes, and alternative therapies that may bring relief for erectile dysfunction. Read now

When combined with an appropriate exercise program, dietary supplementation with β-hydroxy β-methylbutyrate (HMB) has been shown to dose-dependently augment gains in muscle hypertrophy (i.e., the size of a muscle),[38][39] muscle strength,[38][40][41] and lean body mass,[38][40][41] reduce exercise-induced skeletal muscle damage,[note 1][38][39][41] and expedite recovery from high-intensity exercise.[38][42] HMB is believed to produce these effects by increasing muscle protein synthesis and decreasing muscle protein breakdown by various mechanisms, including activation of the mechanistic target of rapamycin (mTOR) and inhibition of the proteasome in skeletal muscles.[40][43]


At the time, low-potency creatine supplements were available in Britain, but creatine supplements designed for strength enhancement were not commercially available until 1993 when a company called Experimental and Applied Sciences (EAS) introduced the compound to the sports nutrition market under the name Phosphagen.[14] Research performed thereafter demonstrated that the consumption of high glycemic carbohydrates in conjunction with creatine increases creatine muscle stores.[15]
Boosting your workouts with an intra-workout catalyst, Scivation's XTEND holds a revolutionary formula that is both free of sugar and carbohydrates in a powerful BCAA drink mix. Using the 2:1:1 BCAA ratio with 7 grams in each serving, the advanced design of this supplement aids in the building of muscle, incinerating of fat, and shortening of recovery, while supporting hydration with a proprietary blend of electrolytes. XTEND encourages the optimal synthesizing of protein and fuels the body with energy for a power-filled workout. Keep Reading »
Objective: Are you getting stronger? Increasing either weight or reps? If you're measuring individual markers on a daily basis like vertical jump, grip strength, or resting heart rate then what sort of trends are you noticing in these variables? If they're staying the same while your strength is increasing, then you're recovering well. If they're decreasing and you find yourself weaker over time then you're not recovering well.
When lifting to complete fatigue, it takes an average of two to five minutes for your muscles to rest for the next set. When using lighter weight and more repetitions, it takes between 30 seconds and a minute for your muscles to rest. For beginners, working to fatigue isn't necessary, and starting out too strong can lead to too much post-exercise soreness.
Jason Ferruggia is a highly sought after, world renowned strength & conditioning specialist and muscle building expert. Over the last 17 years he has personally trained more than 700 athletes from over 90 different NCAA, NFL, NHL and MLB organizations. He has also worked extensively with firefighters, police officers, military personnel, Hollywood stars and entertainers. Most importantly, Jason has helped over 53,000 skinny guys and hard gainers in 126 different countries build muscle and gain weight faster than they every thought possible.
Weight training also requires the use of 'good form', performing the movements with the appropriate muscle group, and not transferring the weight to different body parts in order to move greater weight (called 'cheating'). Failure to use good form during a training set can result in injury or a failure to meet training goals; since the desired muscle group is not challenged sufficiently, the threshold of overload is never reached and the muscle does not gain in strength. At a particularly advanced level; however, "cheating" can be used to break through strength plateaus and encourage neurological and muscular adaptation.
To succeed and thrive as a bodybuilder, it takes more than overwhelming muscular strength or athletic prowess. Judges select bodybuilding champions based on muscle mass, definition, proportion, symmetry, and an athlete’s stage presence. Given the criteria, it is no surprise that most serious bodybuilders consider supplementation to be an essential component of their training regimen.
When endothelial cells have a higher creatine concentration, they appear to be mildly less permeable when incubated with 0.5-5mM creatine, while the higher concentration (5mM) is able to fully ablate TNF-α-induced neutrophil adhesion and both E-selectin and ICAM-1 expression.[316] This effect was prevented with ZM241385, an A2A (adenosine) receptor antagonist,[316] and since adenosine released by this receptor is known to be protective of endothelial cells,[317][318] it is thought that creatine works vicariously through this receptor and adenosine release, thought to be due to releasing ATP (occurs in response to stress[319][320]) which protects the cell via the A2A signaling system.[316]
In regard to liver fat buildup (steatosis), which is normally associated with reduced availability of S-adenosyl methionine[495][496] and a suppression in expression of genes involved in fatty acid oxidation (PPARα and CPT1), creatine supplementation at 1% of the rat diet alongside a diet that induces fatty liver is able to fully prevent (and nonsignificantly reduce relative to the control given standard diets) the aforementioned changes and the state of steatosis, as well as changes in serum biomarkers (glucose and insulin) that accompany steatosis.[125] 
In addition to adequate protein, you need more calories (your protein intake contributes to your total caloric intake, so these two go hand in hand). Use the following formula to calculate the number you need to take in daily to gain one pound a week, and break down your diet using the macro guidelines listed above. (Give yourself two weeks for results to show up on the scale. If you haven't gained by then, increase your calories by 500 a day.)
Heath says to consume 1.25-2 grams of protein per pound of body weight for growth and he never exceeds a 1:1 meals to protein shake ratio, meaning if he has 3 shakes, he’ll have 3 meals. He suggests if you’re going to drink protein shakes, drink two and have four meals. Also, increase your protein consumption and decrease carbs to look lean. “Once I got to a certain size, I wanted to get leaner so I got to 50% protein, 30% carbs and 20% protein.”
Your glutes serve as the main mover and power output to most of your major and accessory lifts—squat, deadlift, kettbell swings, box jumps—so the more you develop and stimulate your gluteal muscles, the more you’re able to maximize control, strength, and stability. (It doesn’t hurt that women love watching you do leg and glute work in the gym, either.)

When you’re doing higher reps, focus on the muscle you are trying to build and squeeze every ounce of effort out of it. Yes, cheesie as it may sound, visualizing the muscles working and growing while you train them can be helpful. A 2016 study in the European Journal of Applied Physiology found that, when lifters thought about their pecs and triceps during a workout, they activated them better.

In regard to the blood brain barrier (BBB), which is a tightly woven mesh of non-fenestrated microcapillary endothelial cells (MCECs) that prevents passive diffusion of many water-soluble or large compounds into the brain, creatine can be taken into the brain via the SLC6A8 transporter.[192] In contrast, the creatine precursor (guanidinoacetate, or GAA) only appears to enter this transporter during creatine deficiency.[192] More creatine is taken up than effluxed, and more GAA is effluxed rather than taken up, suggesting that creatine utilization in the brain from blood-borne sources[192] is the major source of neural creatine.[193][192] However, “capable of passage” differs from “unregulated passage” and creatine appears to have tightly regulated entry into the brain in vivo[193]. After injecting rats with a large dose of creatine, creatine levels increased and plateaued at 70uM above baseline levels. These baseline levels are about 10mM, so this equates to an 0.7% increase when superloaded.[193] These kinetics may be a reason for the relative lack of neural effects of creatine supplementation in creatine sufficient populations.
The best way to know the real progress you’re making is by recording it on video or taking photos. “Photos mean everything because if you can take them in the same areas and in the same poses, you’ll see your strengths and weaknesses clearly,” says Heath. “Revise your training and diet programs to eliminate weaknesses.” Keep a file of your progress to see just how far you can take your fitness.
The last survivors of the pro-hormone supplements, which were removed from sale last January, estrogen-blocking supplements aren't pro-hormones but do inhibit the enzyme aromatase, which converts androgens into estrogens. In normal men that enzyme is ubiquitous, being present in such tissues as muscle, brain and skin. About 20 percent of the free testosterone circulating in the blood is converted into estrogen by way of aromatase.
2-[carbamimidoyl(methyl)amino]acetic acid, Cr, Creatin, Creatina, Créatine, Créatine Anhydre, Creatine Anhydrous, Creatine Citrate, Créatine Citrate, Creatine Ethyl Ester, Créatine Ethyl Ester, Creatine Ethyl Ester HCl, Créatine Ethyl Ester HCl, Creatine Gluconate, Creatine Hydrochloride, Créatine Kré Alkaline, Creatine Malate, Créatine Malate, Creatine Monohydrate, Créatine Monohydrate, Créatine Monohydratée, Creatine Pyroglutamate, Créatine Pyroglutamate, Creatine Pyruvate, Créatine Pyruvate, Dicreatine Malate, Dicréatine Malate, Di-Creatine Malate, Éthyle Ester de Créatine, Glycine, Kreatin, Kre-Alkalyn Pyruvate, Malate de Tricréatine, N-(aminoiminométhyl)-N-Méthyl, N-(aminoiminomethyl)-N methyl glycine, N-amidinosarcosine, Phosphocreatine, Phosphocréatine, Tricreatine HCA, Tricréatine HCA, Tricreatine Malate, Tricréatine Malate.


In the modern bodybuilding industry, the term "professional" generally means a bodybuilder who has won qualifying competitions as an amateur and has earned a "pro card" from their respective organization. Professionals earn the right to compete in competitions that include monetary prizes. A pro card also prohibits the athlete from competing in federations other than the one from which they have received the pro card.[12] Depending on the level of success, these bodybuilders may receive monetary compensation from sponsors, much like athletes in other sports. 

While seasoned lifters may choose to do different exercises every day during a week-long period (and repeat the same moves the following week), there's no need to follow this type of program when you're just getting comfortable, says Davis. "Stick to the same basic moves two to three times a week to build a basic level of fitness and strength," says Davis. "Why complicate things if you don’t have to? Great results can be made by repeating the same workout but increasing weights as you become stronger." Switching things up can help you avoid a training plateau, explains Davis, but so can increasing weights while doing the same exercises.

Nephrotoxic drugs. Because taking high doses of creatine might harm your kidneys, there is concern about combining creatine with drugs that might damage the kidneys (nephrotoxic drugs). Potentially nephrotoxic drugs include nonsteroidal anti-inflammatory drug (NSAIDs) such as ibuprofen (Advil, Motrin IB, others) and naproxen sodium (Aleve, others), cyclosporine (Neoral, Sandimmune) and others.
^ Jump up to: a b c Brioche T, Pagano AF, Py G, Chopard A (April 2016). "Muscle wasting and aging: Experimental models, fatty infiltrations, and prevention". Mol. Aspects Med. 50: 56–87. doi:10.1016/j.mam.2016.04.006. PMID 27106402. In conclusion, HMB treatment clearly appears to be a safe potent strategy against sarcopenia, and more generally against muscle wasting, because HMB improves muscle mass, muscle strength, and physical performance. It seems that HMB is able to act on three of the four major mechanisms involved in muscle deconditioning (protein turnover, apoptosis, and the regenerative process), whereas it is hypothesized to strongly affect the fourth (mitochondrial dynamics and functions). Moreover, HMB is cheap (~30– 50 US dollars per month at 3 g per day) and may prevent osteopenia (Bruckbauer and Zemel, 2013; Tatara, 2009; Tatara et al., 2007, 2008, 2012) and decrease cardiovascular risks (Nissen et al., 2000). For all these reasons, HMB should be routinely used in muscle-wasting conditions especially in aged people. ... 3 g of CaHMB taken three times a day (1 g each time) is the optimal posology, which allows for continual bioavailability of HMB in the body (Wilson et al., 2013).
It's OK to be a little sore. Your muscles might feel achy or tired the day after a tough training session thanks to DOMS, or delayed onset muscle soreness. When you strength train you're causing microscopic damage to the tissue that will be repaired, that's how you build stronger lean muscle. Speaking of repair and recovery, though, rest days are important. "If you constantly break down muscle without a recovery period, you won’t give the muscle fibers a chance to repair and build back stronger,” explains Davis.
Our Keep-It™ guarantee is valid for the first-time purchase of a formula, and redeemable up to three months (90 days) after the purchase date. Multiple bottles, foods, apparel and gear do not fall under this guarantee, however, they may be applicable for return. Fitness equipment, personal care products, knowledge purchases, and DVDs are not eligible for return or refund. For more information and a full list of products that qualify, visit our Keep-It™ page. Further details can be found on our Refund Policy support page.
There are many potential reasons, but I am going to keep it simple and give you just two. The first and most common reason people suffer from underactive glutes or “glute amnesia” is due to lifestyle. Even when people train hard every day, if they spend the majority of the remainder of the day sitting down, then they are simply not using their glutes. And remember the old saying - if you don’t use it, you lose it. Unfortunately, this is just what happens with your glutes.
At the end of the day, you have to focus on how you feel. “Listen to your body,” says Davis. “It tells you when it needs a day off.” As a rule of thumb, take a rest day if your perceived pain is above a seven on a scale of 10, Davis advises. Or, focus on a different body part (say, if your legs are sore, focus on upper-body moves). Can't stop, won't stop—at least, till your next rest day.
I was building up, bulking, going after the mass, which to me meant 230 pounds of sheer body weight. At that time, I didn’t care about my waist or anything else that would give me a symmetrical look. I just wanted to build a gigantic 250-pound body by handling a lot of weight and blasting my muscles. My mind was into looking huge, into being awesome and powerful. I saw it working. My muscles began bursting out all over. And I knew I was on my way.”
The chemical synthesis of testosterone from cholesterol was achieved in August that year by Butenandt and Hanisch.[188] Only a week later, the Ciba group in Zurich, Leopold Ruzicka (1887–1976) and A. Wettstein, published their synthesis of testosterone.[189] These independent partial syntheses of testosterone from a cholesterol base earned both Butenandt and Ruzicka the joint 1939 Nobel Prize in Chemistry.[187][190] Testosterone was identified as 17β-hydroxyandrost-4-en-3-one (C19H28O2), a solid polycyclic alcohol with a hydroxyl group at the 17th carbon atom. This also made it obvious that additional modifications on the synthesized testosterone could be made, i.e., esterification and alkylation.
Creatine is known to occur in highly concetrated levels in chicken photoreceptors, relative to other parts of the eye (10-15mM[466]) alongside high levels of creatine kinase.[466] The creatine transporter in human eyes also seems to be concentrated in the photoreceptors,[468] which are known to be susceptible to hypoxic cellular death[471][472] which, for humans, usually means retinal detachment.[473]
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