The majority of studies focusing on creatine supplementation report an increase in the body’s’ creatine pool [15-17]. There is a positive relationship between muscle creatine uptake and exercise performance [17]. Volek et al [18] observed a significant increase in strength performance after 12 weeks creatine supplementation with a concurrent periodized heavy resistance training protocol. The creatine supplementation protocol consisted of a weeklong loading period of 25 g/d followed by a 5 g maintenance dose for the remainder of the training. These positive effects were attributed to an increased total creatine pool resulting in more rapid adenosine triphosphate (ATP) regeneration between resistance training sets allowing athletes to maintain a higher training intensity and improve the quality of the workouts along the entire training period.

Creatine is a naturally occurring compound found in muscle in large amounts. Creatine monohydrate is the supplement form and combines is a combination of the amino acids arginine, glycine, and methionine. Creatine drives the important creatine phosphate energy pathway, which is important in high-intensity activity such as weightlifting. Creatine can improve body bulk and training performance in high-intensity activities. Be aware that not everyone responds to creatine supplementation and 30 percent of users may not see any improvement. Women may not benefit as much as men. In weight training, increased strength, bulk, and fat loss are reasonably consistent results.

We’re confident you’ll love your Onnit supplements. If the product doesn't perform for you, however, we’re not gonna play games with you. Order any of our entry size supplements, and if you don’t like it, you can keep it! Notify our team, telling us why it wasn't a fit for you, and we’ll get you a refund right there on the spot - no return necessary. We just ask that you try it out for at least two weeks to give it a fair shot.
Terry follows the old-school bodybuilding mentality of isolating each muscle group (back, shoulders, chest, legs and arms) on a five-day cycle. If he’s trying to grow a certain muscle group, he’ll introduce a second workout on the sixth day. Each of Terry’s workouts lasts between 60 and 90 minutes – “any longer and you're either not pushing yourself hard enough or you're talking too much” – and he makes the most of each session by targeting different parts of each muscle.
Isometric exercise provides a maximum amount of resistance based on the force output of the muscle, or muscles pitted against one another. This maximum force maximally strengthens the muscles over all of the joint angles at which the isometric exercise occurs. By comparison, weight training also strengthens the muscle throughout the range of motion the joint is trained in, but only maximally at one angle, causing a lesser increase in physical strength at other angles from the initial through terminating joint angle as compared with isometric exercise. In addition, the risk of injury from weights used in weight training is greater than with isometric exercise (no weights), and the risk of asymmetric training is also greater than with isometric exercise of identical opposing muscles.
Weight trainers commonly spend 5 to 20 minutes warming up their muscles before starting a workout. It is common to stretch the entire body to increase overall flexibility; however, many people stretch just the area being worked that day. The main reason for warming up is injury prevention. Warming up increases blood flow and flexibility, which lessens the chance of a muscle pull or joint pain.

A push–pull workout is a method of arranging a weight training routine so that exercises alternate between push motions and pull motions.[28] A push–pull superset is two complementary segments (one pull/one push) done back-to-back. An example is bench press (push) / bent-over row (pull). Another push–pull technique is to arrange workout routines so that one day involves only push (usually chest, shoulders and triceps) exercises, and an alternate day only pull (usually back and biceps) exercises so the body can get adequate rest.[29]


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Fish oils are an excellent source of omega-3 fatty acids, which provide myriad benefits for the body. For strength athletes and bodybuilders, we're most concerned with their anti-inflammatory and antioxidant properties. Intense resistance training can cause microscopic tears in your muscle fibers, leading to muscle damage and inflammation. While some inflammation is desirable, too much can delay the post-exercise recovery process.
If you have been diagnosed with a certain testosterone deficiency, ask your doctor and/or pharmacist to see if TestoFuel could be beneficial for you. Aside from balancing your testosterone, you may experience increased muscle strength while using this supplement during your intense exercise routine. Here are certain instances where TestoFuel could help correct your testosterone problems:
After all, you’ve probably seen the countless workouts, diets, supplements, programs, products and people claiming that super fast muscle growth is possible. You’ve probably also seen the click-bait headlines (“How To Build 20lbs Of Muscle In Just 6 Weeks!”) and the unbelievable transformations of supposedly “natural” people (bodybuilders, celebrities, athletes, fitness gurus on social media, etc.) that clearly prove it can happen faster than this.
The first open label trial on ALS failed to significantly alter lung function as assessed by FEV (when comparing the rate of decline pretreatment relative to treatment).[545] Creatine has elsewhere failed to benefit lung function at 5g daily for months relative to control[546] and failed to significantly attenuate the rate of lung function deterioration over 16 months at 10g daily[505] and 5g daily over nine months.[507]
Consult your physician and follow all safety instructions before beginning any exercise program or using any supplement or meal replacement product, especially if you have any unique medical conditions or needs. The contents on our website are for informational purposes only, and are not intended to diagnose any medical condition, replace the advice of a healthcare professional, or provide any medical advice, diagnosis, or treatment.
Less muscle breakdown can also help to reduce post-workout muscle soreness levels. During workouts, the body creates lactic acid as it works to generate extra energy. The buildup of lactic acid can cause muscle fatigue, swelling, and tenderness. Improving the ability of the body to recover can help to more effectively clear out lactic acid, reducing inflammation and soreness.
This is another thing I am very tired of hearing. 'No matter what I do or what I eat, I can't gain weight'. I have heard this countless times and I am here to tell you that you are dead wrong. That's OK, because I actually said the same thing until I realized the truth. Most people think they are eating a lot and you just may be. But no matter what you are eating, if you are not gaining, you are not eating enough. Most times, you should re-evaluate your diet as well and focus on more calorie dense foods. But you need to eat more if you are not gaining.

Try this little exercise some time: follow the supplement plan provided above for at least three months. Then quit all supplement use for a further three months and watch what happens. Sure, most supplement marketing involves hype and some companies make laughably outrageous claims, but there is no secret as to why the supplement industry is booming. Supplements work.
Do a single set of repetitions. Theories on the best way to approach weight training abound, including countless repetitions and hours at the gym. But research shows that a single set of exercise with a weight that fatigues your muscle after about 12 to 15 repetitions can build muscle efficiently in most people and can be as effective as three sets of the same exercise.
Although some have voiced concerns about kidney damage with creatine supplementation, it’s generally regarded as a safe supplement when taken responsibly. The Mayo Clinic advises against taking it if you have an allergy. When used properly, the incidence of potential side effects such as low blood sugar and dehydration, are minor in healthy people taking a safe dosage.
Kornblum, C., Schroder, R., Muller, K., Vorgerd, M., Eggers, J., Bogdanow, M., Papassotiropoulos, A., Fabian, K., Klockgether, T., and Zange, J. Creatine has no beneficial effect on skeletal muscle energy metabolism in patients with single mitochondrial DNA deletions: a placebo-controlled, double-blind 31P-MRS crossover study. Eur J Neurol 2005;12(4):300-309. View abstract.
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These effects were noted before in a preliminary study of depressed adolescents (with no placebo group) showing a 55% reduction in depressive symptoms at 4g daily when brain phosphocreatine levels increased.[231] Other prelimnary human studies suggest creatine might lessen unipolar depression[256] and one study on Post-Traumatic Stress Disorder (PTSD) noted improved mood as assessed by the Hamilton Depression Rating Scale.[232]
However, protein isn’t everything. Contrary to popular belief, carbohydrates and calories from fats are also important. To gain muscle, people who are slender or scrawny need to create a calorie surplus in order to bulk up. That means you need proteins and plenty of healthy carbs, vegetables and even some fats (think healthy fats like nuts, avocado, olive oil, etc.). Carbohydrates play a key role in building muscle. This macronutrient has gotten a bad rap for making people fat. However, if you work out properly, eating plenty of carbs is in your best interest. After training, it’s ideal to ingest some carbs in combination with protein to help replenish your muscles’ glycogen stores.
Whether you’re taking a supplement or not, creatine is already functioning inside you, doing its very important job. It’s an amino acid found naturally in the meat and fish you consume and, according to the Mayo Clinic, your liver and kidneys crank it out as well. The creatine is mainly stored as creatine phosphate in your muscles, ready for use in energy production.
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.
Without supplementation, creatine is formed primarily in the liver, with minor contributions from the pancreas and kidneys. The two amino acids, glycine and arginine, combine via the enzyme Arginine:Glycine amidinotransferase (AGAT) to form ornithine and guanidoacetate. This is the first of two steps in creatine synthesis, and although rare, any deficiency of this enzyme can result in mild mental retardation and muscular weakness.[28] AGAT is also the primary regulatory step, and an excess of dietary creatine can suppress activity of AGAT to reduce creatine synthesis[29] by reducing AGAT mRNA levels, rather than resulting in competitive inhibition.[30]

A typical creatine supplementation protocol consists of a loading phase of 20 g CM/d or 0.3 g CM/kg/d split into 4 daily intakes of 5 g each, followed by a maintenance phase of 3-5 g CM/d or 0.03 g CM/kg/d for the duration of the supplementation period [5]. Other supplementation protocols are also used such as a daily single dose of around 3 – 6 g or between 0.03 to 0.1 g/kg/d [15,55] however this method takes longer (between 21 to 28 days) to produce ergogenic effects [5]. Sale et al [56] found that a moderate protocol consisting of 20 g CM taken in 1g doses (evenly ingested at 30-min intervals) for 5 days resulted in reduced urinary creatine and methylamine excretion, leading to an estimated increase in whole body retention of creatine (+13%) when compared with a typical loading supplementation protocol of 4 x 5 g/d during 5 days (evenly ingested at 3 hour intervals). This enhancement in creatine retention would lead to a significantly higher weight gain when people follow a moderate protocol ingestion of several doses of small amounts of CM evenly spread along the day.

Do standard/oblique crunches. Lie down on a mat and position both arms behind your head without locking the hands. Bend your knees so that your feet are flat on the ground. Pushing the small of your back into the ground, slowly roll your shoulders off the ground only a couple of inches (not to a full sitting position). Don't use your momentum to help you up; use slow, regulated movements. Repeat 3 x 20.


Change things up. After six or more weeks of consistent strength training, which is about the amount of time it takes to start seeing improvement in your body, you can change your routine to make it more difficult. Lifting the same weights for the same exercises every week will keep your body in the same place. You can modify weights or repetitions, choose different exercises, or change the order in which you do them. You only have to make one change at a time to make a difference, although more is often better. 

Bryant, a lawyer and sports agent, opened a case of manila file folders and spread them on the desk like playing cards. Each was labeled: Phil Heath Enterprises, Sponsors, Taxes, Travel and so on. Bryant, Heath and Cremona discussed Heath’s clothing line and his sponsorships. They talked about his desire for a shoe deal and a larger hyperbaric chamber at his house.


If you’re a beginner, you should train with three full-body workouts per week. In each one, do a compound pushing movement (like a bench press), a compound pulling movement (like a chinup), and a compound lower-body exercise (squat, trap-bar deadlift, for example). If you want to add in 1–2 other exercises like loaded carries or kettlebell swings as a finisher, that’s fine, but three exercises is enough to work the whole body.
Do standard/oblique crunches. Lie down on a mat and position both arms behind your head without locking the hands. Bend your knees so that your feet are flat on the ground. Pushing the small of your back into the ground, slowly roll your shoulders off the ground only a couple of inches (not to a full sitting position). Don't use your momentum to help you up; use slow, regulated movements. Repeat 3 x 20.
In the last week leading up to a contest, bodybuilders usually decrease their consumption of water, sodium, and carbohydrates, the former two to alter how water is retained by the body and the latter to reduce glycogen in the muscle. The day before the show, water is removed from the diet, and diuretics may be introduced, while carbohydrate loading is undertaken to increase the size of the muscles through replenishment of their glycogen. The goal is to maximize leanness and increase the visibility of veins, or "vascularity". The muscular definition and vascularity are further enhanced immediately before appearing on stage by darkening the skin through tanning products and applying oils to the skin to increase shine. Some competitors will eat sugar-rich foods to increase the visibility of their veins. A final step, called "pumping", consists in performing exercises with light weights or other kinds of low resistance (for instance two athletes can "pump" each other by holding a towel and pulling in turn), just before the contest, to fill the muscles with blood and further increase their size and density.

If you have been diagnosed with a certain testosterone deficiency, ask your doctor and/or pharmacist to see if TestoFuel could be beneficial for you. Aside from balancing your testosterone, you may experience increased muscle strength while using this supplement during your intense exercise routine. Here are certain instances where TestoFuel could help correct your testosterone problems:
In otherwise healthy adults subject to leg immobilization for two weeks while taking 20g creatine daily during immobilization and then 5g daily during eight weeks of rehabilitation, it was noted that the creatine group failed to reduce atrophy during the immobilization (10% reduction in cross sectional area and 22-25% reduction in force output) despite preventing a decrease in phosphocreatine, yet experienced a significantly enhanced rate of regrowth and power recovery.[358] A similarly structured and dosed study has also noted greater expression of skeletal muscle, GLUT4 expression, and a 12% increase in muscle phosphocreatine content.[330]
Overtraining occurs when a bodybuilder has trained to the point where his workload exceeds his recovery capacity. There are many reasons why overtraining occurs, including lack of adequate nutrition, lack of recovery time between workouts, insufficient sleep, and training at a high intensity for too long (a lack of splitting apart workouts). Training at a high intensity too frequently also stimulates the central nervous system (CNS) and can result in a hyperadrenergic state that interferes with sleep patterns.[51] To avoid overtraining, intense frequent training must be met with at least an equal amount of purposeful recovery. Timely provision of carbohydrates, proteins, and various micronutrients such as vitamins, minerals, phytochemicals, even nutritional supplements are acutely critical. A mental disorder informally called “bigorexia” (by analogy with anorexia) may be held accountable of some people overtraining. Sufferers feel as if they are never big enough or muscular enough, which forces them to overtrain in order to try and reach their goal physique.[52]

In well-trained endurance runners, creatine (with glycerol for hyperhydration) caused a relatively large increase in body weight gain (0.90+/-0.40kg) and water weight (0.71+/-0.42L) but failed to negatively influence performance over 30 minutes in the heat.[3] This failure to improve physical performance in the heat with creatine loading (despite water retention) has been noted elsewhere.[346]
^ Jump up to: a b c d e f g h Momaya A, Fawal M, Estes R (April 2015). "Performance-enhancing substances in sports: a review of the literature". Sports Med. 45 (4): 517–531. doi:10.1007/s40279-015-0308-9. PMID 25663250. Wilson et al. [91] demonstrated that when non-resistance trained males received HMB pre-exercise, the rise of lactate dehydrogenase (LDH) levels reduced, and HMB tended to decrease soreness. Knitter et al. [92] showed a decrease in LDH and creatine phosphokinase (CPK), a byproduct of muscle breakdown, by HMB after a prolonged run. ... The utility of HMB does seem to be affected by timing of intake prior to workouts and dosage [97].

If you’re satisfied with your athletic performance but seriously want to bulk up, we recommend these creatine pill supplements from Crazy Muscle. They're made of a blend of three of the most effective types of creatine, Creatine Monohydrate, Creatine Alpha-ketoglutarate and Creatine Pyruvate, instead of just one type like other supplement brands. The formula also promises faster recovery times between workouts so you can push yourself harder even after a big workout the day before.


Who Makes It: This product is made by Cellucor, a sports and fitness supplement firm best-known for their C4 line of pre-workout supplements. While C4 is their best seller (and a top seller overall), Cellucor also manufactures a wide range of high-quality supplements for a variety of uses. They have been in business for over 15 years and are a trusted name in the fitness community.
The motor proteins actin and myosin generate the forces exerted by contracting muscles. Current recommendations suggest that bodybuilders should consume 25–30% of protein per total calorie intake to further their goal of maintaining and improving their body composition.[30] This is a widely debated topic, with many arguing that 1 gram of protein per pound of body weight per day is ideal, some suggesting that less is sufficient, while others recommending 1.5, 2, or more.[31] It is believed that protein needs to be consumed frequently throughout the day, especially during/after a workout, and before sleep.[32] There is also some debate concerning the best type of protein to take. Chicken, turkey, beef, pork, fish, eggs and dairy foods are high in protein, as are some nuts, seeds, beans, and lentils. Casein or whey are often used to supplement the diet with additional protein. Whey protein is the type of protein contained in many popular brands of protein supplements and is preferred by many bodybuilders because of its high Biological Value (BV) and quick absorption rates. Whey protein also has a bigger effect than casein on insulin levels, triggering about double the amount of insulin release.[33] That effect is somewhat overcome by combining casein and whey. Bodybuilders are usually thought to require protein with a higher BV than that of soy, which is additionally avoided due to its claimed estrogenic properties. Still, some nutrition experts believe that soy, flax seeds and many other plants that contain the weak estrogen-like compounds or phytoestrogens, can be used beneficially, as phytoestrogens compete with estrogens for receptor sites in the male body and can block its actions. This can also include some inhibition of pituitary functions while stimulating the P450 system (the system that eliminates hormones, drugs and metabolic waste product from the body) in the liver to more actively process and excrete excess estrogen.[34][35] Cortisol decreases amino acid uptake by muscle, and inhibits protein synthesis.[36]
*Always remember: weight loss results & health changes/improvements vary from individual to individual. Just because these studies cite certain data does not mean you will experience these results/outcomes. Always consult with your doctor before making decisions about your health. This is not medical advice – simply well-researched information and tips to sleep better. Thanks for reading!
Most of us have lives, or jobs, or school, or family, or whatever else that puts some kind of limit on when and how often we can work out. For example, are there certain days that you are able to work out on, and certain days you aren’t? Are you able to train 5 days per week, or would 3-4 be more ideal? Choosing a split that suits your personal schedule and is as convenient for you as possible will be crucial for adherence, and without adherence, nothing is going to work.
Consuming sufficient high-quality protein is essential for building muscle. Current recommendations are to consume a minimum of 0.8g of protein for each kg of body weight, however, this is really only applicable to the average sedentary individual. Current evidence shows that to support muscle development, protein intake is the key, therefore the recommended 0.8g per kg should be increased to 1.5-2.0g of protein per kg of body weight. For an 80 kg individual, that would equate to 120-160 grams of protein per day.

If you're serious about putting on some muscle, then the most efficient way to do it is with three intense resistance training sessions and two lighter intensity workouts per week. “You need to have consistency in a workout program, hitting at least each muscle group two times a week to build muscle,” explains Lovitt. If you’re looking to switch up exercises, Olson suggests swaps such as sumo squats instead of traditional squats; step-ups on a bench instead of lunges; and then rotating back to the former. “These types of variation can be very effective in developing muscles, but the weights must still be fairly heavy that you’re using,” she says.
Of course, cardio is an important part of fitness too, but the benefits of strength training are major. Strength training helps build muscle, and lean muscle is better at burning calories when the body is at rest, which is important whether you're trying to lose weight or maintain it. It also helps strengthens joints and bones, avoid injury, improve your muscular endurance, and will help you give it your all during your other workouts, whether that means setting a new PR if you're a runner or pushing (and pulling) a little harder with your legs during your favorite indoor cycling class.
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Cooke et al [41] observed positive effects of a prior (0.3 g/d kg BW) loading and a post maintenance protocol (0.1 g/d kg BW) to attenuate the loss of strength and muscle damage after an acute supramaximal (3 set x 10 rep with 120% 1RM) eccentric resistance training session in young males. The authors speculate that creatine ingestion prior to exercise may enhance calcium buffering capacity of the muscle and reduce calcium-activated proteases which in turn minimize sarcolemma and further influxes of calcium into the muscle. In addition creatine ingestion post exercise would enhance regenerative responses, favoring a more anabolic environment to avoid severe muscle damage and improve the recovery process. In addition, in vitro studies have demonstrated the antioxidant effects of creatine to remove superoxide anion radicals and peroxinitrite radicals [42]. This antioxidant effect of creatine has been associated with the presence of Arginine in its molecule. Arginine is also a substrate for nitric oxide synthesis and can increase the production of nitric oxide which has higher vasodilatation properties, and acts as a free radical that modulates metabolism, contractibility and glucose uptake in skeletal muscle. Other amino acids contained in the creatine molecule such as glycine and methinine may be especially susceptible to free radical oxidation because of sulfhydryl groups [42]. A more recent in vitro study showed that creatine exerts direct antioxidant activity via a scavenging mechanism in oxidatively injured cultured mammalian cells [43]. In a recent in vivo study Rhaini et al [44] showed a positive effect of 7 days of creatine supplementation (4 x 5 g CM 20 g total) on 27 recreational resistance trained males to attenuate the oxidation of DNA and lipid peroxidation after a strenuous resistance training protocol.

Some protein powders are loaded with junk. We recommend this grass-fed protein isolate because it is a non-GMO product and contains no artificial sweeteners. It is a US-based product, and the whey protein is cultivated from American cows. With 28 grams of protein in one scoop, one spoonful of this powder may provide the equivalent protein profile of a whole meal. What’s even better is that one scoop is only 120 calories. This powder gives you quite a bit of protein for minimal calories, keeping you lean.


In the United States, the manufacturers of dietary supplements do not need to provide the Food and Drug Administration with evidence of product safety prior to marketing.[8] As a result, the incidence of products adulterated with illegal ingredients has continued to rise.[8] In 2013, one-third of the supplements tested were adulterated with unlisted steroids.[9] More recently, the prevalence of designer steroids with unknown safety and pharmacological effects has increased.[10][11]
We’re so confident that you’re going to love our supplements that we offer a 30-day guarantee. If you have any questions about any of our products, please don’t hesitate to call our friendly experts at (512) 394-7995, or feel free to email us at [email protected] The right supplements can make a tremendous difference in your workouts, so don’t wait to get started. Shop the best bodybuilding supplements at Bare Performance Nutrition now.
Safety. In general health terms, most medical opinion is that up to three cups of coffee a day are not harmful, and may even have some benefits, although some people respond to the stimulant properties with more problems than others. Heart palpitations and restlessness are experienced by some caffeine drinkers. In pregnancy, one or two cups each day are thought to be without harm to the fetus.
In addition to ALL of the above, strength training is fun! Whether you are looking for the most effective 20-30 minute workout (to stay fit and look great naked), or are looking for a competitive sport that you can really get into, strength training can help you meet your goals. It’s easy and fun to see progress as you strength train, almost like leveling up. And if you’re looking to improve in other areas (a sport, traditional cardio, or an activity like rock climbing), strength training is an easy choice!
Several studies have used either beet root juice or pomegranate extract in multi-ingredient performance supplements and have observed improvements in strength, hypertrophy, and performance in resistance-trained men. At this point, however, it's difficult to determine if these benefits are from beet root juice and pomegranate extract working alone or synergistically with other ingredients.[11,12]
Beach muscles and Olympic lifts draw more attention. But the many little stabilizer muscles around your shoulders, hips, and midsection — collectively the core — provide a strong foundation. Challenging the stability and mobility of these key muscles with medicine balls, physioballs, mini-bands, and rotational movements (lifting, chopping) pays huge dividends.
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]

Creatine, which is synthesized in the liver and kidneys, is transported through the blood and taken up by tissues with high energy demands, such as the brain and skeletal muscle, through an active transport system. The concentration of ATP in skeletal muscle is usually 2–5 mM, which would result in a muscle contraction of only a few seconds.[22] During times of increased energy demands, the phosphagen (or ATP/PCr) system rapidly resynthesizes ATP from ADP with the use of phosphocreatine (PCr) through a reversible reaction with the enzyme creatine kinase (CK). In skeletal muscle, PCr concentrations may reach 20–35 mM or more. Additionally, in most muscles, the ATP regeneration capacity of CK is very high and is therefore not a limiting factor. Although the cellular concentrations of ATP are small, changes are difficult to detect because ATP is continuously and efficiently replenished from the large pools of PCr and CK.[22] Creatine has the ability to increase muscle stores of PCr, potentially increasing the muscle’s ability to resynthesize ATP from ADP to meet increased energy demands.[23][24][25]


Prohormones are precursors to hormones and are most typically sold to bodybuilders as a precursor to the natural hormone testosterone. This conversion requires naturally occurring enzymes in the body. Side effects are not uncommon, as prohormones can also convert further into DHT and estrogen. To deal with this, many supplements also have aromatase inhibitors and DHT blockers such as chrysin and 4-androstene-3,6,17-trione. To date most prohormone products have not been thoroughly studied, and the health effects of prolonged use are unknown. Although initially available over the counter, their purchase was made illegal without a prescription in the US in 2004, and they hold similar status in many other countries. They remain legal, however, in the United Kingdom and the wider European Union. Their use is prohibited by most sporting bodies.
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