Ultimate Creatine Guide - Benefits, Dosages and Side Effects
- Supplies energy to all human body cells, through ATP replenishment which can improve power output and anaerobic exercise performance.
- Promotes lean mass and strength gains.
- Helps to mitigate perceived fatigue during activities requiring muscular endurance.
- Increases the body's water content, which minimizes instances of performance-related issues due to dehydration.
Creatine Recommended Dosages and UseCreatine is most commonly consumed in powdered form, but you can also find it in pill and liquid forms. Creatine monohydrate is the most popular form of creatine, but some users find that they tolerate or respond better to other forms of creatine.
- Creatine Monohydrate (Loading Protocol) Consume (0.3g/300mg) per kilogram of body weight for 5-7 days, then continue taking (5g/5,000mg) per day after the loading period. 
- Creatine Monohydrate (Daily Protocol) Consume (2g/2,000mg) per day to maintain average creatine stores and up (5g/5,000mg) per day to maximize creatine stores. 
- Creatine HCL Consume (0.75-1.5g/750-1,500mg) daily regardless of bodyweight. 
- Creatine Ethyl Ester Consume (3-6g/3,000-6,000mg) daily regardless of bodyweight. 
- Kre-Alkalyn Consume (1.5-4.5g/1,500-4,500mg) daily dependent upon bodyweight. 
- Creatine Nitrate Consume (1-2g/1,000-2,000mg) daily regardless of bodyweight. 
Creatine and Muscular Strength & Power Output
Muscular strength and power output are two crucial components of exercise performance. The inclusion of creatine into your supplement stack can improve both.
Three studies found that creatine supplementation produced greater muscular output and increases in 1RM than placebo for both upper and lower body exercise (e.g. bench press, bicep curl, squat, leg press, leg extension).  One study even showed that 28 continuous days of dosing 5g of creatine per day increased upper body strength without the presence of resistance training.  Additional research also revealed that creatine improves neuromuscular function, which is responsible for how efficiently the signals within your muscles are firing; improving this function can translate to increased strength and power output. 
Regarding non-weightlifting activities, creatine supplementation improved sprint portions of a 400-meter swim, improved block jump and spike jump performance in volleyball players compared to placebo, increased total power, mean power, and peak power during Wingate Anaerobic Tests.  Creatine is an excellent supplement for improving strength and power output across numerous anaerobic activities.
Benefit With increased muscular strength, bone, tendon, and joints also strengthen. With increased power output, your body becomes more efficient at generating force at a faster rate.
Creatine and Lean Mass Gain
Multiple studies identify creatine as an exceptional supplement for building muscle/lean mass gain. One study involving non-resistance trained university students indicated that creatine supplementation and resistance training increased upper-body and lower-body muscle thickness to a greater degree than resistance training alone. 
Creatine, when stacked with beta-alanine, also lead to a larger amount of lean mass gain and body fat percentage decrease compared to a placebo or creatine alone.  Creatine can also increase muscle mass in individuals with serious illnesses or disease states (e.g. cancer). 
One study suggests that the muscle building qualities of creatine may be due to increased bone mineral content and "greater tension on bones at sites of muscle attachment."  Another study showed that creatine supplementation paired with resistance training decreases myostatin levels and GASP-1. This may explain creatine's muscle-building qualities. 
Creatine and Anaerobic Exercise Performance
During anaerobic exercise, lactate is formed, fast twitch muscle fibers are firing and the body is harnessing energy in the absence of oxygen. Examples of anaerobic exercise include intense short duration activities such as weightlifting, sprinting, jumping, wrestling and max-effort cycling.
Creatine supplementation can increase anaerobic running capacity, maximum oxygen consumption, increase time to exhaustion (re: stave off fatigue), and increase ventilatory threshold (re: point at which your breathing becomes labored and oxygen needs are greater than the oxygen your body is currently able to intake).  Creatine increased anaerobic metabolism as well as anaerobic work capacity in both upper and lower body muscles. 
In the weight room this increase in anaerobic metabolism and work capacity could make the difference when attempting a personal record (PR) lift or adding extra reps to a set. Creatine supplementation appears to improve performance in both untrained and trained individuals of both genders.
Creatine and Testosterone
One study examined testosterone, cortisol and growth hormone pre and post-creatine supplementation for males and females but did not find any changes.  However, male collegiate football players exhibited elevated resting testosterone levels after 10 weeks of consuming creatine and embarking on a resistance training program compared to no supplementation. 
Yet another study provided creatine monohydrate to amateur male swimmers and found that growth hormone and cortisol levels did not change during the creatine loading phase, but testosterone levels significantly increased compared to placebo after the 6-day supplementation period. 
Creatine and Muscular EnduranceAlthough creatine supplementation did not improve push-up performance, it did improve muscle energy balance during one hour of intense aerobic cycling.  When the muscle energy balance diminishes, participants are more likely to feel fatigue and cycle a shorter distance in that one hour time period.
Another study gave 20g of creatine per day for a week to trained females and found that their mean muscular endurance on knee extensions improved, along with their performance on resistance exercises. This focused on their 10 repetition maximums (10RM) and cycling.  Creatine does not appear to work as effectively as beta-alanine for improving muscular endurance but may still be helpful if stacked with beta-alanine.
Creatine and Hydration
Creatine is commonly thought to be a dehydrator in the human body, but this could not be further from the truth. Multiple studies indicate that creatine does not dehydrate but rather hydrates. 
8 participants ingested creatine which increased the body's water content and volume of inter-cellular compartment (re: hydration).  When 9 NCAA Division I football athletes consumed creatine over 9 weeks using a loading protocol they improved their cell hydration status. 
If you're prone to dehydration then consider incorporating creatine to your supplement stack to encourage full-body hydration.
Creatine and LongevityCreatine has demonstrated direct antioxidant effects through the reduction of oxidative DNA damage due to both exercise and stress-associated disease states.  Creatine supplementation has also been shown to prevent mitochondrial DNA mutations and encourage mitochondrial DNA stability which could delay the aging process in humans. 
Creatine's ability to encourage healthy DNA and eliminate problematic DNA suggests that creatine may be able to prevent or improve disease states related to DNA mutations.
Creatine Side Effects
Creatine is an extremely safe supplement because it's already synthesized by the human body and present in the foods we eat. However, some users report nausea and diarrhea when they take large doses of creatine, such as during the load phase if you're following the loading protocol. 
This is another reason supporting the daily protocol dosing discussed above, as those quantities of creatine will not cause gastrointestinal discomfort. If you do happen to experience cramping, nausea, or diarrhea then discontinue using that form of creatine usage immediately.
In addition to seeking advice from a medical professional you can also consider trying a different form of creatine to see if it's more agreeable with your digestive tract.
When 17 study participants were given 30g of creatine per day for 2 weeks followed by 15g per day for 2 weeks, bodyweights increased by fat mass and lean mass measurements did not change, which suggests large doses of creatine can cause water retention.  At more reasonable doses creatine ingestion increased the body's water content (re: hydration) but did lead to water retention. 
Assuming you're consuming enough fluids prior to starting creatine, and you do not ingest large doses, water retention should not be an issue. If you happen to experience bloating, before discontinuing creatine consider other lifestyle factors (e.g. stress, diet, salt intake, etc ) as they may also contribute to the water retention.
Creatine Frequently Asked Questions
Is creatine found in any common foods?
Creatine is found in meats such as chicken, pork, and beef as well as in fish such as herring, salmon, tuna, and cod.   To consume the recommended dose of creatine per day (5g) you would need to consume 1kg of beef or pork (raw weight), 1.11 kg of salmon, or 1.25kg of tuna.  Fruits, vegetables, and grains only contain trace amounts of creatine, so supplementing is especially wise for vegetarian and vegan athletes.
Is creatine a steroid?
Creatine is not a steroid. Creatine is an organic compound naturally produced by the human body, found in meats, and found in fish. Creatine is allowed by the International Olympic Committee, National Collegiate Athletic Association (NCAA), and professional sports organizations (e.g. MLB, NFL, NBA, etc...).
Do I have to load creatine?
You do not have to load creatine but some find that loading leads yields the positive effects of creatine at a slightly faster rate.
Do I need to take creatine with grape juice/dextrose/sugar?
Although you do not have to consume creatine with a simple carbohydrate, some studies indicate that the co-ingestion of simple sugars and creatine can increase muscular creatine levels to a greater degree than consuming creatine alone.
If you enjoy consuming simple sugars and have the caloric flexibility to do so, it's not going to hurt but it's doubtful that it will also significantly help you maximize the benefits of creatine.
Is creatine bad for your kidneys?
Assuming you're a healthy individual with no pre-existing medical conditions, specifically renal diseases, creatine supplementation does not impact kidney function. 
Are there any supplements creatine shouldn't be combined with?
Creatine monohydrate is an extremely safe supplement that can be safely combined with any other legal supplement on the market.
Can you stack creatine with any other supplements to increase benefits?
Absolutely! Stack creatine with one or more of the following supplements to increase benefits:
Beta Alanine Combing creatine and beta-alanine decreased body fat percentage and increased lean mass compared to consuming creatine alone.  Unfortunately the study did not indicate the possible reasons or mechanisms by which this could be achieved. Stacking creatine and beta-alanine or consuming creatine alone resulted in equivalent amounts of increased strength. Stacking creatine and beta-alanine is a clear winner if you're looking to increase strength, increase muscle mass, and decrease your body fat percentage.
β-hydroxy-β-methylbutyrate (HMB) HMB is a metabolic byproduct of L-Leucine; combining HMB and creatine can increase strength and lean mass levels, but they don't appear to work synergistically but rather additively.  Therefore, HMB and creatine are a great combination but don't need to be ingested at the same time to maximize benefits as they appear to act on different pathways.
Carbohydrates One study found that combining 5 grams of creatine with 93 grams of simple carbohydrates from dextrose or grape juice 4 times per day for 5 consecutive days increased muscular creatine levels 60% more than consuming creatine alone. 
Alpha Liopic Acid (ALA) Combining ALA, creatine, and sugar increased muscular creatine levels to a greater degree than consuming creatine and sugar or creatine alone.  Adding ALA to a creatine, glycerol and sugar stack decreases the required amount of sugar needed to maximize cardiovascular performance (e.g. heart rate and core temperature).  ALA is a great addition to a creatine plus sugar stack in an effort to maximize muscular creatine levels and improve exercise performance.
Caffeine Combining caffeine with creatine has yielded mixed reviews. One study indicated that co-ingesting caffeine with creatine negated the performance enhancing benefits of creatine during intense exercise but does not affect muscular creatine levels.  However, another study found that spacing out the consumption of caffeine and creatine increased key performance indicators over consuming caffeine alone. 
Yet another study indicated that combining caffeine and creatine improved anaerobic performance but did not affect aerobic performance.  It's safe to combine creatine and caffeine so I encourage you to experiment with the timing of each supplement to see what optimizes performance for you.