The other component of that study is that the subjects ate much less saturated fat. Saturated fats are common in meat, butter, and coconut products, and they’re crucial for your body to function. Saturated fats keep the integrity of your cell membranes, and if you limit carbs and/or do Bulletproof Intermittent Fasting, saturated fats become a phenomenal source of energy for your brain.
AAKG β-hydroxy β-methylbutyrate Carnitine Chondroitin sulfate Cod liver oil Copper gluconate Creatine/Creatine supplements Dietary fiber Echinacea Elemental calcium Ephedra Fish oil Folic acid Ginseng Glucosamine Glutamine Grape seed extract Guarana Iron supplements Japanese Honeysuckle Krill oil Lingzhi Linseed oil Lipoic acid Milk thistle Melatonin Red yeast rice Royal jelly Saw palmetto Spirulina St John's wort Taurine Wheatgrass Wolfberry Yohimbine Zinc gluconate
Great! Start with strength training 🙂 When you’re overweight, my guess is that you want to be preserving the muscle you have while losing the majority of your weight through fat. With strength training, your overall weight loss may seem slower, but you will lose inches faster. Strength training increases your metabolism; as long as you’re still eating in a deficit, you’ll lose weight.

While creatine's influence on physical performance has been well documented since the early twentieth century, it came into public view following the 1992 Olympics in Barcelona. An August 7, 1992 article in The Times reported that Linford Christie, the gold medal winner at 100 meters, had used creatine before the Olympics. An article in Bodybuilding Monthly named Sally Gunnell, who was the gold medalist in the 400-meter hurdles, as another creatine user. In addition, The Times also noted that 100 meter hurdler Colin Jackson began taking creatine before the Olympics.[12][13]

^ Jump up to: a b Barcelos RP, Stefanello ST, Mauriz JL, Gonzalez-Gallego J, Soares FA (2016). "Creatine and the Liver: Metabolism and Possible Interactions". Mini Reviews in Medicinal Chemistry. 16 (1): 12–8. doi:10.2174/1389557515666150722102613. PMID 26202197. The process of creatine synthesis occurs in two steps, catalyzed by L-arginine:glycine amidinotransferase (AGAT) and guanidinoacetate N-methyltransferase (GAMT), which take place mainly in kidney and liver, respectively. This molecule plays an important energy/pH buffer function in tissues, and to guarantee the maintenance of its total body pool, the lost creatine must be replaced from diet or de novo synthesis.

Compound exercises work several muscle groups at once, and include movement around two or more joints. For example, in the leg press, movement occurs around the hip, knee and ankle joints. This exercise is primarily used to develop the quadriceps, but it also involves the hamstrings, glutes and calves. Compound exercises are generally similar to the ways that people naturally push, pull and lift objects, whereas isolation exercises often feel a little unnatural.
Stand lunge-length in front of a bench making sure your knee does not extend past your toes. Hold a dumbbell in each hand and rest the top of your left foot on the bench behind you. Lower your body until your rear knee nearly touches the floor and your front thigh is parallel to the floor. Then push through the heel of your front foot to return to standing, keeping the back foot on the bench. Repeat for required reps then switch legs.
Ladies!  The images of “bulky” women that you are conjuring up are from bodybuilding magazines. This is one of the biggest myth surrounding strength training. When I started strength training, I didn’t get bulky, I got lean, And I’m no outlier, I’m just one example of the rule: Women who strength train get strong and lean, not bulky.  Like Veronica, who got damn strong and certainly lean.
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.
Having a strong butt will get you far—literally. Our glutes are responsible for powering us through everything from long runs to tough strength workouts to a simple jaunt up a flight of stairs. Strong glutes that can take on the brunt of the work can help us avoid overcompensating with smaller muscles during lower-body exercises. Plus, beyond just helping us move, the glutes play an important role in "stabilizing our entire lumbo-pelvic-hip complex," says Cori Lefkowith, NASM-certified personal trainer and owner of Redefining Strength in Costa Mesa, California. That translates to better form, more efficient movement, and a reduced risk of straining your lower back and hips.
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.
How to Take It: If you decide you want to take BCAAs as one of your weight lifting supplements, you can easily get them and take them much like you would protein powders. One scoop provides 2.5g of leucine, 1.25g of isoleucine and 1.25g of valine. Take it before a workout, during or after. As with all supplementation, the aim is to reach your overall daily needs and goals.
Creatine supplementation appears to augment the anti-cancer effects of Vitamin C and methylglyoxal,[463] a metabolic by-product of glycolysis.[464] Methylglycoxal appears to inhibit step 1 of the electron transport chain in isolated mitochondria and cancerous mitochondria, but has not been implicated in doing so in normal tissue, as protective measures in normal cells appear to exist.[465][464]
Great Paleo beef protein, why? Because it doesn't have any preservatives, fillers, Dairy, soy, yeast, corn, or any other additives. No artificial colorings/flavorings. That makes this product not just paleo, but also autoimmune paleo friendly, hard to find. That basically means anti alergic, you dont get the same digestive issues many people get with whey. I think beef protein is underrated, I just finished a batch and went back to my whey. The whey gives me bloating/gas that this product doesnt. Also if you don't like how the amino acid profile stacks up agains Whey protein powder you can add some BCAA to powder, at least thats what I do. In a 30 gram saving you get 28 grams of protein (zero fat and zero carb), not bad!

Yes, genetically some of us put on muscle faster than others, but even then it’s fractions of a degree, not DRASTIC sweeping differences. We tend to get this question from men or women who are so thin and have such fast metabolisms, they probably need to put on 40-50+ pounds of both fat and muscle, before they would ever even think to use the word “too bulky.”

All you need to know about low creatinine levels Creatinine is a waste material in the body, and low levels can suggest a shortfall in liver function or activity. This MNT Knowledge Center feature looks at low creatinine levels., as well as information on what creatinine is, how it affects the body, and how to increase low creatinine levels. Read now

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.

Saw palmetto: Uses, dosage, and side effects Saw palmetto is an extract from the berries of a type of palm tree. The berries have traditionally been used to ease urinary and reproductive problems. The extract is now used in herbal remedies to stabilize testosterone. Learn about its use, its effectiveness, the science behind the claims, and any side effects. Read now
Achy knees are often written off as an inevitable side effect of getting older. And while it’s true knee pain has many age-related causes (namely, arthritis), chances are weak glutes are a big part of the problem, Kline says. If you’ve been diagnosed with arthritis, strengthening your glutes can at least help offset some of the pain you might experience, she says.
A testicular action was linked to circulating blood fractions – now understood to be a family of androgenic hormones – in the early work on castration and testicular transplantation in fowl by Arnold Adolph Berthold (1803–1861).[182] Research on the action of testosterone received a brief boost in 1889, when the Harvard professor Charles-Édouard Brown-Séquard (1817–1894), then in Paris, self-injected subcutaneously a "rejuvenating elixir" consisting of an extract of dog and guinea pig testicle. He reported in The Lancet that his vigor and feeling of well-being were markedly restored but the effects were transient,[183] and Brown-Séquard's hopes for the compound were dashed. Suffering the ridicule of his colleagues, he abandoned his work on the mechanisms and effects of androgens in human beings.
^ Jump up to: a b Sapienza P, Zingales L, Maestripieri D (September 2009). "Gender differences in financial risk aversion and career choices are affected by testosterone". Proceedings of the National Academy of Sciences of the United States of America. 106 (36): 15268–73. Bibcode:2009PNAS..10615268S. doi:10.1073/pnas.0907352106. PMC 2741240. PMID 19706398.

Always consult your doctor before you begin taking a creatine supplement to make sure that there are no negative interactions with whatever diabetes medication you are on. If they deem you to be safe to take creatine, we recommend this unflavored powder from MET-Rx. It’s made without artificial sweeteners, flavors, and colors, so it's just pure creatine monohydrate powder to promote increased muscle strength. One reviewer noted the product is easy to mix and another said the formula was effect for their needs.
Creatine pyruvate (also known as creatine 2-oxopropanoate) in an isomolar dose relative to creatine monohydrate has been shown to produce higher plasma levels of creatine (peak and AUC) with no discernible differences in absorption or excretion values.[83] The same study noted increased performance from creatine pyruvate at low (4.4g creatine equivalence) doses relative to citrate and monohydrate, possibly due to the pyruvate group.
How much of a difference does EPOC make? Well, in one research study of young women, basal metabolic rate spiked by 4.2 percent 16 hours following a strength-training session that lasted an hour and 40 minutes—the equivalent of burning an extra 60 calories, on average. That’s a long workout, and 60 extra calories isn’t exactly huge. Plus, EPOC is not a permanent boost. Research suggests it may last anywhere from 12 hours to a few days, depending on the workout and who is doing it. The calories you burn through EPOC can add up over time, especially if you’re lifting weights three or four times a week, but all in all, it doesn’t have a very big effect on your metabolism.
Replacement therapy may produce desired results, such as greater muscle mass and a stronger sex drive. However, the treatment does carry some side effects. Oily skin and fluid retention are common. The testicles may also shrink, and sperm production could decrease significantly. Some studies have found no greater risk of prostate cancer with testosterone replacement therapy, but it continues to be a topic of ongoing research.

This increased permeability is noted in glioma cells, where it exerts anti-cancer effects related to cell swelling,[99][100] and in other membranes, such as breast cancer cells[101] and skeletal (contractile) muscle cells.[102] The kinetics of cyclocreatine appear to be first-order,[101] with a relative Vmax of 90, Km of 25mM and a KD of 1.2mM.[103]

Creatine is an energy substrate: a small peptide serving as a reservoir for high-energy phosphate groups that can regenerate ATP, the main currency of cellular energy. An increase in creatine intake (through food or supplementation) increases cellular energy stores, promoting the regeneration of ATP in the short term. Stores are limited, however, and glucose or fatty acids are responsible for ATP replenishment over longer durations.
Kerksick, C. M., Wilborn, C. D., Campbell, W. I., Harvey, T. M., Marcello, B. M., Roberts, M. D., Parker, A. G., Byars, A. G., Greenwood, L. D., Almada, A. L., Kreider, R. B., and Greenwood, M. The effects of creatine monohydrate supplementation with and without D-pinitol on resistance training adaptations. J.Strength.Cond.Res. 2009;23(9):2673-2682. View abstract.
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.
One rat study that compared male and female rats and used a forced swim test (as a measure of serotonergic activity of anti-depressants[227]) found that a sexual dimorphism existed, and females exerted a serotonin-mediated anti-depressant response while male rats did not.[228] It appears that these anti-depressive effects are mediated via the 5-HT1A subset of serotonin receptors, as the antidepressant effects can be abolished by 5-HT1A inhibitors.[229]

All of the gluteals must work to perform this movement—the “deep six” external rotators keep each side of the pelvis stable in spite of the different actions in each hip, and the larger gluteals add additional support for the hips. This move forces your buttock muscles to shore up their connection from the thighs through to the lower back to keep the hips and spine stable. 
How to do it: Stand with feet just outside the shoulders and hands behind your head. Squat, keeping your knees behind your toes and squeezing your glutes. After holding this position for two seconds, jump vertically. Pull the toes to your shins in midair to prepare for landing. Land in the starting squat position, hold three seconds and repeat for 10 reps. Be sure to land softly, with the hips back and down.

Chin-Ups. The chin-up is the easiest way to determine someone’s relative strength. If you can knock out sets of bench with your bodyweight but can’t perform at least 5 bodyweight chin-ups then it’s time to re-evaluate your priorities. Chin-ups are an excellent mass builder for the lats, biceps, and upper back so they should take the place of machine variations like lat pulldowns whenever possible.

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.
The rise in testosterone levels during competition predicted aggression in males but not in females.[90] Subjects who interacted with hand guns and an experimental game showed rise in testosterone and aggression.[91] Natural selection might have evolved males to be more sensitive to competitive and status challenge situations and that the interacting roles of testosterone are the essential ingredient for aggressive behaviour in these situations.[92] Testosterone produces aggression by activating subcortical areas in the brain, which may also be inhibited or suppressed by social norms or familial situations while still manifesting in diverse intensities and ways through thoughts, anger, verbal aggression, competition, dominance and physical violence.[93] Testosterone mediates attraction to cruel and violent cues in men by promoting extended viewing of violent stimuli.[94] Testosterone specific structural brain characteristic can predict aggressive behaviour in individuals.[95]
The majority of your workouts should be comprised of compound exercises. Common examples include squats, deadlifts, lunges, bench presses, rows, pull-ups, lat pull-downs, overhead presses, and so on. Isolation exercises should definitely also be a part of your program, just a smaller part in comparison. Common examples include bicep curls, tricep extensions, chest flies, lateral raises, leg curls, leg extensions, calf raises, and so on.
Anti-cancer effects have been observed with the creatine analogue cyclocreatine[456][104][457] and have been replicated with creatine itself. These effects tend to be a reduction in which the rate of implanted tumors progresses.[458][459] It is suspected that these observed effects (inhibition of growth or attenuation of the rate of growth) are not due to the bioenergetic effect of creatine, secondary to creatine kinase. These anti-cancer effects do not have a known reliability, as the expression of creatine kinase varies widely based on the type of tumor.[460] However, some studies suggest an inverse relationship between tumor progression in mice and concentrations of creatine in cells, with creatine depletion coinciding with tumor development.[460]
However, caffeine does not negate the benefits of creatine loading when not coingested, but just taken before exercise in the same dosage.[593] This result indicates that loading creatine without caffeine on a daily basis, but saving caffeine for select workouts, may be an effective strategy, as creatine does not adversely affect caffeine’s ergogenic effects[593][594] and may enhance creatine’s effectiveness in anaerobic exertion if the two compounds are alternated.[595]
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]
Lifters who follow high-volume or high-intensity resistance-training programs, as many bodybuilders do, may also benefit from carbohydrate intake immediately post-workout. Compared with a placebo, carbohydrates combined with protein immediately post-workout and one hour after a bout of resistance exercise have been shown to increase insulin levels and rates of glycogen resynthesis.[19]
In contrast to the above null effects, ingestion of creatine both before and after a workout (alongside protein and carbohydrate) over 10 weeks seems to promote muscle growth more than the same supplement taken in the morning, farther away from the time of the workout.[386] The benefits of creatine around the workout, relative to other times, have been hypothesized[387] to be related to an upregulation of creatine transport secondary to muscle contraction, a known phenomena.[153]
Sculthorpe et al (2010) has shown that a 5 day (25g/d) loading protocol of creatine supplementation followed by a further 3 days of 5 g/d negatively influence both active ankle dorsiflexion and shoulder abduction and extension range of movement (ROM) in young men. There are two possible theories to explain these effects: 1) Creatine supplementation increases intracellular water content resulting in increased muscle stiffness and resistance to stretch; 2) Neural outflow from the muscle spindles is affected due to an increased volume of the muscle cell. The authors highlight that the active ROM measures were taken immediately after the loading phase and the reduced active ROM may not be seen after several weeks of maintenance phase [45]. Hile et al [46] observed an increase in compartment pressure in the anterior compartment of the lower leg, which may also have been responsible for a reduced active ROM.
It was later noted that creatine was able to nonsignificantly augment various proinflammatory cytokines (CCL2, iNOS, ICAM-1, TGF-β, TIMP-1) and the presence of eosinophils in lung tissue, as well as to per se cause lung infiltration of these immune cells without requiring the presence of the allergen.[442] Neutrophils and macrophages were unaffected,[442] reflecting the past study of no influence on macrophages,[440] but the only instance where creatine appeared to either significantly add to ovalbumin or to per se induce statistically significant increases were in IL-5 secretion and goblet cell infiltration, although VCAM-1 expression was close. While creatine per se increased nF-κB activity, it suppressed the ovalbumin-induced increase.[442]
There are countless reasons to lift weights and build strong muscles, including injury prevention, improved bone density, and a lower risk for type 2 diabetes and other diseases—not to forget that bad-ass feeling you get when you can haul a giant piece of furniture up the stairs all by yourself. Another often-cited benefit to strength training is that it will increase your metabolism. But how much does your metabolism increase with strength training? The answer depends on many different factors.

Testosterone is the primary sex hormone in men, and it is responsible for the development of many of the physical characteristics that are considered typically male. Women also produce the hormone in much smaller amounts. Testosterone, part of a hormone class known as androgens, is produced by the testicles after stimulation by the pituitary gland, which is located near the base of the brain, and it sends signals to a male's testicles (or to a woman's ovaries) that spark feelings of sexual desire. (1)
Strong glutes also allow for movements such as bending over, squatting down, standing up straight, pushing off the ground (such as to run) and for maintaining other aspects related to proper posture. A 2005 report published in the Journal of Experimental Biology states that “The human gluteus maximus is a distinctive muscle in terms of size, anatomy and function compared to apes and other non-human primates …. Enlargement of the gluteus maximus was likely important in the evolution of hominid running capabilities.” (1)
We’ll be talking more about this later, but for now, just give it a shot! In strength training you can see your progress so clearly that as you can do more and more, you’ll also be rewarded by seeing your strength progress from level 1 to level 50! If you aren’t a fan of the downtime, put on a book on tape or throw on your favorite playlist while circuit training to ensure you’re always moving (instead of sitting and waiting in between sets).
Medicines used for treating depression are called antidepressants and may be categorized into several classes. Some of these drugs include tricyclic antidepressants such as Nortriptyline and Imipramine, Selective serotonin reuptake inhibitors (SSRIs) including Fluoxetine, Citalopram, and Sertraline, and Selective Norepinephrine Reuptake Inhibitors (SNRIs) including Venlafaxine and Duloxetine. These drugs, generally, act by increasing the amounts of chemical substances that stimulate the brain. Each class of antidepressants has a different safety profile and side effects, so, ensure you consult your doctor for a prescription and dosage recommendations.
A good butt workout should target the muscles of the entire glute complex: the big, power-producing gluteus maximus, and the smaller, stabilizing gluteus medius and minimus. Below, York, Jones, and award-winning personal trainer Katie Gould share 13 effective butt exercises you can do at home with minimal equipment. All you need for these glute exercises is a flat resistance band/mini band and a kettlebell.
As you've probably heard from any muscle-bound behemoth you've ever encountered, protein is the key to building muscle. Just because the shake-pounding meathead has become a trope, however, doesn't mean they're wrong; protein really is the fuel your muscles need to grow. That's real capital-S Science, not just bro-science manufactured by supplements companies.

Although creatine is a natural component of food, the amount of food required to supersaturate the muscle with PCr may not be feasible. For example, it could require 22 pounds of meat daily [8]. If creatine monohydrate is proven to be a safe and effective ergogenic aid, creatine supplementation may be the simplest way to increasing muscle stores. It may be beneficial to avoid caffeine if taking creatine supplements. One study showed that caffeine diminished strength gains seen with creatine use [9].
How long and how often? Two or three weekly 20- to 30-minute, weight-training sessions are sufficient to start reaping noticeable benefits within four to 12 weeks, such as improved energy and muscle tone. Within six months, most people increase their strength 40 percent or more. Give your body at least one recovery day between sessions (although some people may need more, especially in the beginning).
^ Jump up to: a b Barcelos RP, Stefanello ST, Mauriz JL, Gonzalez-Gallego J, Soares FA (2016). "Creatine and the Liver: Metabolism and Possible Interactions". Mini Reviews in Medicinal Chemistry. 16 (1): 12–8. doi:10.2174/1389557515666150722102613. PMID 26202197. The process of creatine synthesis occurs in two steps, catalyzed by L-arginine:glycine amidinotransferase (AGAT) and guanidinoacetate N-methyltransferase (GAMT), which take place mainly in kidney and liver, respectively. This molecule plays an important energy/pH buffer function in tissues, and to guarantee the maintenance of its total body pool, the lost creatine must be replaced from diet or de novo synthesis.
Elsewhere, it has been noted that in chronic progressive external ophthalmoplegia (CPEO, a progressive weakening of the muscles around the eye and a mitochondrial disorder), there was a failure of creatine supplementation to benefit symptoms when subjects were provided 20g daily for four weeks.[483] Creatine supplementation failed again at 150mg/kg for six weeks in people with either CPEO or another disorder associated with single gene deletions affecting the eyes (Kearns–Sayre syndrome, KSS) in improving muscular function.[484]
In weight training, as with most forms of exercise, there is a tendency for the breathing pattern to deepen. This helps to meet increased oxygen requirements. Holding the breath or breathing shallowly is avoided because it may lead to a lack of oxygen, passing out, or an excessive build up of blood pressure. Generally, the recommended breathing technique is to inhale when lowering the weight (the eccentric portion) and exhale when lifting the weight (the concentric portion). However, the reverse, inhaling when lifting and exhaling when lowering, may also be recommended. Some researchers state that there is little difference between the two techniques in terms of their influence on heart rate and blood pressure.[8] It may also be recommended that a weight lifter simply breathes in a manner which feels appropriate.
While this nonessential amino acid may not deliver earth-shattering PRs or extreme muscle growth, it does play an important role in repair and recovery. Glutamine works by removing excess ammonia, which can accumulate during intense exercise, helping to regulate your body's acid-base balance. Individuals who are engaged in heavy resistance training, two-a-day training splits, or are in a calorie deficit may benefit from the extra support of glutamine supplementation.
Co-ingesting creatine with caffeine partially negated the benefits of creatine supplementation (at 5mg/kg bodyweight) during the loading phase in one study.[590] The exact mechanism responsible for this effect is not known, but might be related to opposing actions on muscle contraction time.[591] However, another study in trained men found that co-ingestion of 300mg caffeine per day during creatine loading at 20g per day (split into 4 doses) had no effect on bench press 1RM, time to fatigue, or sprinting ability.[592] However, this study also found that creatine alone or when combined with caffeine had no effect on any of these parameters over placebo, either. Thus, the study may have been underpowered or done in too short a time frame (the test was done after only 5 days of loading) to observe any possible effects.[592]

A muscle imbalance—when one muscle is stronger than its opposing muscle—can limit your ability to exercise effectively, and could lead to injury down the line. “It’s important to recognize whether you’re really working the muscles you think you are and recognize if you’ve developed an imbalance that alters your movement pattern,” says Eric Ingram, physical therapist at Louisiana Physical Therapy Centers of Pineville. One common imbalance in women is stronger quads and weaker, tighter hamstrings, thanks to prolonged sitting, high heels, and improper training. If you suspect you have a muscle imbalance, make an appointment with a physical therapist, who will prescribe exercises to even you out.
The 100% Grass-Fed Whey Protein Isolate comes in the form of powder and can be mixed with any liquid. While the protein powder can be mixed well with water, try mixing it with milk for added calories and protein. You can even add this to smoothies and baked goods to increase the protein profile. Recommended protein intake for adults is 0.8 grams per kilogram. Some athletes may need as much as 1.2-2 grams protein per kilogram. For your specific needs, always consult a registered dietitian.
Testosterone is necessary for normal sperm development. It activates genes in Sertoli cells, which promote differentiation of spermatogonia. It regulates acute HPA (hypothalamic–pituitary–adrenal axis) response under dominance challenge.[22] Androgen including testosterone enhances muscle growth. Testosterone also regulates the population of thromboxane A2 receptors on megakaryocytes and platelets and hence platelet aggregation in humans.[23][24]