Some ingredients found in dietary supplements marketed for bodybuilding or performance enhancement—such as whey protein, creatine, and caffeine—generally aren’t associated with any serious safety concerns (when used appropriately). However, they still have the potential for side effects. Before you take any dietary supplement, talk to your healthcare provider. You also can read the articles below about some of these ingredients:
If you’re not lifting super-heavy weights, doing high-intensity workouts, or eating a mainly vegan or vegetarian diet, your body probably makes as much creatine as it needs. “Creatine is naturally found in animal-based products,” says Bates, “so your body can make plenty of creatine as long as you have a balanced diet that includes animal-based products.” Protein sources like beef, chicken, pork, and fish help your body produce the creatine it needs — it varies depending on the source, but, in general, a 3-ounce serving of meat will have about 0.4 grams (g) of creatine, Bates says. (6)

For beginners, your own body weight might be enough to get you started. However, it can be hard to challenge your body without any additional resistance, so to progress, you'll need some equipment. If you decide to strength train at home, you'll want to invest in some basics, such as resistance bands, weights, and an exercise ball. Try to have a range of weights: a light set (3 to 5 pounds for women, 5 to 8 pounds for men), a medium set (5 to 10 pounds for women, 10 to 15 pounds for men), and a heavy set (10 to 20 pounds for women, 15 to 30 pounds for men).

The reasons for differences in the effect of creatine on testosterone vs. DHT across studies are not clear, but also not mutually exclusive. A measured increase in DHT could indicate that testosterone levels were increased by creatine, but rapidly converted to DHT through a homeostatic mechanism. Differences in study subject populations, methodology, or the presence and type of concurrent exercise could also be contributing factors. At any rate, the literature collectively suggests that creatine has the general ability to cause a modest increase in androgen levels in men.
McArdle’s disease is a myopathy associated with impaired glucose release from glycogen and impairments in muscle function at times when glucose would be the primary energy substrate. Creatine is thought to be therapeutic, but has shown differing effects in the two trials so far (both benefit and worsening of symptoms) for currently unknown reasons.

2-4 Minutes Rest: Ideal for “tension exercises,” which includes most primary compound exercises. I personally take 3 minutes for the big stuff, sometimes going into the 3-4 minute range depending on exactly what I’m doing and what I feel like I need at the time. Since making strength gains is the main focus of these exercises, longer rest periods like this will be optimal for making it happen.
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In addition to the basic principles of strength training, a further consideration added by weight training is the equipment used. Types of equipment include barbells, dumbbells, pulleys and stacks in the form of weight machines, and the body's own weight in the case of chin-ups and push-ups. Different types of weights will give different types of resistance, and often the same absolute weight can have different relative weights depending on the type of equipment used. For example, lifting 10 kilograms using a dumbbell sometimes requires more force than moving 10 kilograms on a weight stack if certain pulley arrangements are used. In other cases, the weight stack may require more force than the equivalent dumbbell weight due to additional torque or resistance in the machine. Additionally, although they may display the same weight stack, different machines may be heavier or lighter depending on the number of pulleys and their arrangements.
These supplements can vary considerably from product to product in ingredients, serving sizes, and more. But the goal of each of them is generally quite similar. Most bodybuilding supplements are designed to help stimulate new muscle growth, cut away excess fat, and improve the recovery process so that you can get the most out of each trip to the gym.
Neurological and cognitive function has also been shown to be improved by creatine supplementation [47,48]. Rawson and Venezia [49] review the effects of creatine supplementation on cognitive function highlighting that higher brain creatine has been associated with improved neuropsychological performance. Creatine supplementation protocols have been shown to increase brain creatine and phosphocreatine contents. Cognitive processing hindered due to sleep deprivation and natural impairment due to aging can be improved by creatine supplementation. This review also highlights other possible benefits of creatine ingestion to older adults, such as improvements in: fatigue resistance, strength, muscle mass, bone mineral density, and performance of activities of daily living. Some of these benefits occur without concurrent exercise. The authors inform that discrepancies between studies do exist and are hard to explain but may be possibly due to differences in diet, race and/or supplementation protocols. However, the ideal dose of creatine to maximize brain uptake is not known. Patients have been supplemented with 40 g while in healthy adults positive results have been reported with around 20 g per day [49].
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]

One case study exists of a man with focal segmental glomerulosclerosis who experienced an accelerated rate of GFR decline during supplementation (5g thrice daily for loading, then a 2g maintenance for seven weeks) which was partially reversed upon supplement cessation. This was deemed strong circumstantial evidence, and the brand of supplement was not named.[616] Elsewhere, interstitial nephritis associated with creatine supplementation has been reported in a man, although symptoms arose four weeks after supplementation started with no evidence to support correlation.[617] Some studies involving athletes and various dietary supplements have attempted to draw a correlation with creatine and cases of rhabdomyolysis.[618][619][620][621] Finally, one study in a diabetic person ingesting both metformin and creatine resulting in metabolic acidosis has attempted to place causation on creatine, but it did not establish causation or circumstantial evidence.[622]