Tribulus Terrestris: A fruit from the Mediterranean, this supplement has been used in the Indian traditional medicine of Ayurveda. In addition to helping increase testosterone, many people take it to increase libido and as a cardioprotective aid. (10) Unfortunately, despite the fact that there are claims that tribulus terrestris can increase testosterone levels, studies don’t back up these claims.  There is some evidence, however, that it may improve athletic performance. If you want to choose one of the supplements for men, this should be your pick.
Keep in mind that while creatine boosts your performance in the gym, helping you achieve better muscle building results, it is also associated with some side effects. One of the main concerns is that creatine may worsen or cause kidney problems. Creatine shouldn’t be taken in combination with diabetes medications, acetaminophen, diuretics or caffeine. As always, speak with your doctor before taking supplements to make sure that the product is safe for you (6). Generally, for most people, the supplement is considered to be among the safer weight lifting supplements.

However, the basis of “take creatine after your workout” comes from a 2013 study published in the JISSN, which can be found here (open access too!). In this study, recreational male bodybuilders (19 men overall) were given five grams of creatine either before or after their workouts. They trained five days per week but were also directed to consume 5g on their rest days at any time they wanted. The workouts were fairly similar to most gym workouts, and the methodology (what they did and how they did it) suggests that the findings would apply to most weightlifters.
Other supplements could easily have been included here, but these are considered the most useful and effective for the majority of bodybuilders and athletes. Although food should always come first, supplements offer an effective alternative for getting nutrients that either aren't available in sufficient quantity in food or are in foods that you may not be eating.
When splitting a sample into exercisers and non-exercisers, it appears that exercise as a pre-requisite precedes a higher range of activity. Inactive people tend to be on the lower end of creatine kinase activity and relatively clustered in magnitude, while exercise generally increases activity, but also introduces a larger range of possible activity.[56]
The synthesis of creatine (from guanidinoacetate via GAMT) also requires SAMe as a cofactor and is implicated in homocysteine production. While supplementation of guanidinoacetate at 0.36% (prior to SAMe) can increase homocysteine by up to 50% in rats, supplementation of creatine (0.4%) is able to suppress homocysteine by up to 25%, secondary to reducing creatine synthesis,[309] and has been replicated elsewhere with 2% of the rat diet, while a loading phase did not alter the benefits.[124]

Creatine is found in many protein supplements at baseline in the form of creatine monohydrate. If you take a protein supplement, you may already be getting creatine. What makes this creatine so special? Like the protein supplement above, this creatine supplement contains no artificial sweeteners or dyes. It contains 5000mg of creatine per dose and includes certain compounds to increase the bioavailability of the creatine, allowing it to be better absorbed.
If you stop getting the results you want after several weeks of working out, it's time to mix things up. You need to challenge or "confuse" your muscles often to keep them growing. You can do this by putting a twist on your basic moves. Do a biceps curl with a reverse grip, for example. Or find a bench for the step-up move shown here. Change up your workout at least every 4 to 6 weeks for the best results.
The main storage area of creatine in the human body is the skeletal (contractile) muscle, which holds true for other animals. Therefore, consumption of skeletal muscle (meat products) is the main human dietary source of creatine. Since vegetarians and vegans lack the main source of dietary creatine intake, which has been estimated to supply half of the daily requirements of creatine in normal people, both vegetarians and vegans have been reported to have lower levels of creatine.[58][59] This also applies to other meat-exclusive nutrients, such as L-Carnitine.[58]
In regard to practical interventions, concurrent glycogen loading has been noted to increase creatine stores by 37-46% regardless of whether the tissue was exercised prior to loading phase.[176] It is important to note, however, that creatine levels in response to the creatine loading protocol were compared in one glycogen-depleted leg to the contralateral control leg, which was not exercised.[176] This does not rule out a possible systemic exercise-driven increase in creatine uptake, and the increase in creatine noted above[176] was larger than typically seen with a loading protocol (usually in the 20-25% range). Consistent with an exercise-effect, others have reported that exercise itself increases creatine uptake into muscle, reporting 68% greater creatine uptake in an exercised limb, relative to 14% without exercise.[153]
It’s important to remember that since everybody is different, these estimates are just that. How the numbers work out for each person will definitely vary. So many factors—like genetics, hormones, sleep, and diet—can change the rate at which our bodies burn calories. And some people may have a harder time than others when it comes losing fat or gaining muscle—again, there are so many factors at play and our body chemistries are all different. Strength training is important for many, many, many other reasons (more on that later), but if you’re looking to increase your metabolism, it’s important to have realistic expectations and know that strength training can make a difference, but probably won’t drastically affect how many calories you burn from one day to the next.
While some supplements may in fact provide health benefits, generally speaking, consumers should purchase and use these products cautiously as they are not closely regulated by the Food and Drug Administration (FDA). Also, bodybuilders are advised to discuss supplementation plans with a registered dietitian or primary care physician prior to use to optimize effectiveness and minimize potential harmful consequences. 
Exercise is highly effective in increasing your lean body mass, which is essentially muscle. In a study published in 2012, progressive resistance training helped men ages 50 to 83 gain an average of 2.4 pounds of lean body mass over an average of 20.5 weeks. Progressive resistance training involves performing weight bearing exercises. In addition, you must slowly increase the challenge of the exercise over time by increasing the weight, reps and/or sets. Studies show that either increasing reps or weight amount will work. So, if you don’t want to lift more weight, you can just do more reps and still build muscle.

Nephrectomized rats may have significantly reduced creatine synthesis rates[509] via impairment of methylation (the GAMT enzyme)[510] although creatine reuptake from the urine seems unimpaired.[511] Supplemental creatine in a rat model of 2/3rds nephrectomy (2% creatine in the diet) does not appear to negatively influence kidney function as assessed by the serum biomarkers of cystatin C and urinary protein or creatinine clearance rates.[512] Elsewhere, 2% creatine in the diet in rats for two weeks again failed to show negative effects on kidney function, but showed benefit in reducing homocysteine in late-stage uremic rats.[312] While there is not much human evidence for the rat nephrectomy model, a lone case study in a man with a single kidney failed to find an impairing effect of creatine (20g daily for five days and 5g for another month) in conjunction with a high protein diet.[513]
Creatine is thought to improve strength, increase lean muscle mass, and help the muscles recover more quickly during exercise. This muscular boost may help athletes achieve bursts of speed and energy, especially during short bouts of high-intensity activities such as weight lifting or sprinting. However, scientific research on creatine has been mixed. Although some studies have found that it does help improve performance during short periods of athletic activity, there is no evidence that creatine helps with endurance sports. Research also shows that not everyone's muscles respond to creatine; some people who use it see no benefit.
A dose of 5g daily has strong evidence supporting it not causing any adverse side effects[605] and 10g has been used daily for 310 days in older adults (aged 57+/-11.1) with no significant differences from placebo.[519] Such a dose has also been demonstrated for long-term safety for people with Parkinson’s disease,[606] and at least one small retrospective study in athletes (surverying people taking creatine for up to or over a year) failed to find any significant differences in a battery of serum health parameters.[502] Other studies measuring serum parameters have also failed to find abnormalities outside the normal range.[607]
Homocysteine is produced after S-adenosyl methionine is used up (as donating a methyl group creates S-adenosylhomocysteine, which then produces homocysteine) mostly from phosphatidylcholine synthesis[307] and its reduction (via either methylation from trimethylglycine via betaine:homocysteine methyltransferase, urinary excretion, or convertion into L-cysteine via cystathionine beta-synthase[308]) is thought to be therapeutic for cardiovascular diseases.

Kilduff, L. P., Georgiades, E., James, N., Minnion, R. H., Mitchell, M., Kingsmore, D., Hadjicharlambous, M., and Pitsiladis, Y. P. The effects of creatine supplementation on cardiovascular, metabolic, and thermoregulatory responses during exercise in the heat in endurance-trained humans. Int J Sport Nutr Exerc Metab 2004;14:443-460. View abstract.
If you touch your phone between exercise sets, it better be to set its timer to 30 to 90 seconds. When lifting for hypertrophy, rest periods of 30 to 90 seconds encourage a quick release in muscle-building hormones (including testosterone and human growth hormone) while also making sure that you really, truly fatigue your muscles, according to Fitzgerald.
According to the abstract, in the stratified analyses by forms of aerobic exercise, weekly resistance exercise of 1 time or 1-59 minutes was associated with lower risks of total cardiovascular events and cardiovascular disease, regardless of meeting the aerobic exercise guidelines. The analysis showed that resistance training reduced the risk of cardiovascular events in 2 ways: training had a direct association with cardiovascular risk, and resistance training indirectly lowered cardiovascular risk by decreasing body mass index.