Creatine has been a beloved supplement in the fitness industry for years now. Different types of athletes have used it to increase the amount of muscles they gain, their endurance, and to get overall strength increases. However, little did they know they have probably been getting smarter all along – yes, you’ve read that right.
Creatine monohydrate has an important role in the brain energy homeostasis. Therefore, different studies in the past have observed outcomes that are a consequence of creatine supplementation during different tasks. I will leave out the muscle gains/endurance/strength increase part of creatine out of this article as I believe a lot has been written on the topic already.
So without further ado, let’s start with the five effects of creatine you didn’t know about:
- Improves brain performance
One study was assessing whether there would be any differences between vegetarians who would take 5 g of creatine for six weeks and vegetarians who didn’t. It was a double-blind, placebo-controlled, cross-over trial – as good as they get. They found that the vegetarians, who were taking creatine, had better results on two different measures. They were better at remembering numbers in a backwards order; their working memory was better, and they scored higher on a test of general intelligence. The creatine supplement group scored 4 points more, on average, than their non-creatine counterparts on the Raven’s progressive matrices test. 
- Improves mood
In this study they were assessing mood. People in the creatine group received 5 g of creatine 4x per day for 7 days in a row. They had to do different tasks that involved cycling, verbal and spatial recall, choice reaction tasks, and static balance. They also had to fill out a mood state questionnaire at 0, 6, 12, and 24h of sleep deprivation with cycling exercise in between. Then they compared people and their performance during different hours of sleep deprivation. Those who had taken creatine had less fatigue, a reduced performance decline, and improved mood, after 24h of sleep deprivation. 
- Improves depressive symptoms
Two studies addressed the use of creatine in patients with treatment resistant depression; this means their current treatment was not working particularly well for them. Patients received 3-5 g of creatine for four weeks in the first study, and 4 g of creatine for 8 weeks in the second one. In both, their depressive symptomatics were alleviated, their mood improved, and their brain phosphocreatine concentrations increased – the last improvement was reported in the second study. 
- Improves PTSD symptoms
One particular case study in the form of an intervention trial noted the therapeutic effect of creatine for treating PTSD. A woman who was suffering from PTSD, depression, and fibromyalgia, reported that following a daily supplementation of creatine, she saw improvements on measures of depression, fibromyalgia, and had a 30% improvement in overall quality of life.
A second study was assessing the effects of creatine supplementation on treatment resistant PTSD. People reported improvements in PTSD symptoms, this was further enhanced in patients who had a double diagnosis of PTSD and depression. 
- The supposed side-effects?
A lot of research done on this topic has shown that supplementing with creatine dosages between 5 g to 20 g seems to be without any serious side-effects . One meta-analysis from 2008 found that there was no adverse effects because of creatine supplementation in renal, hepatic, cardiac, or muscle function.  Kidney damage due to creatine supplementation has been overthrown as well. 
That was it, those are five effects you probably had no idea about. And as we can see, the mentioned role of a creatine supplementation far exceeds the well known role of it as a fitness supplement.