Do you mean creatine is bad or good for brain health? I've started taking recently because I heard the positive side argument, is there a negative too? Genuine question :)
Don’t worry, I believe it’s mostly/only good - I’ve also heard it to be good.
I mentioned it specifically because it’s generally considered as a physical body/muscle targeted supplement and not a brain impacting one, but it appears to have an impact on the brain too.
(Anecdotally I did notice a negative impact on sleep personally, but for me it was quite apparent even at a relatively low dose so I realised it quickly, hopefully that’s not the case for you.)
Genuine answer, I am definitely not a sports nutrition expert.
Your body creates all of the creatine that it needs. However, to do this, your body will need to get all of the nutrients that it can't make for itself.
The brain is like the 'kernel' and the body is mere 'user space'. Regardless of what the situation is in the body as a whole, the brain is top priority, and this applies to creatine. Trust your body, it will ensure that it has adequate creatine for the brain, no matter what happens to you.
Clearly there are advantages in supplementing creatine as any person in the gym will tell you. However, you have two options, either you supplement or you don't. If you don't want to take the supplement route then you can optimise your diet so that your body gets all of the raw inputs it needs. This means adequate levels of everything needed, without the junk.
My suspicion is that the brain and liver have a better idea of what level of creatine your body needs than any medical expert or social media influencer on the planet. Primates have been doing this for millions of years, standing on the shoulders of mammal DNA that has been dialling it in for hundreds of millions of years.
For me it is therefore a philosophical question. Do I want to believe in nutrition or do I want to believe in gym-bro science?
Aside from the alleged benefits for the brain, there is also the body. I don't want my muscles to be any larger than they need to be. In highly demanding factory jobs or in the military, the people with 'Rambo' bodies don't seem to be as effective as those that have muscles that have auto-sized to the demands placed on them. There is a cost in calories and nutrients to having excess muscle (and fat, for that matter).
It seems to me that the body works on a use it or lose it basis. Don't use your legs and they wither away. Don't use your brain and the same applies. My theory, for which I have no evidence, is that, with your internal organs, the same applies. If you are getting your creatine from animal products or supplements, will your liver lose the ability to create creatine? I don't know, but why run the risk?
By taking the nutrition route I am not running the risks of side effects. With creatine it began with elite athletes a few decades ago and only recently have fitness industry devotees been taking creatine en-masse. We don't know if there are long term side effects because there are no centenarians around that were taking creatine in the 1940s.
A final aspect to it is integrity. If the belief is in nutrition rather than supplements, then one cannot accuse oneself of cheating. Different strokes for different folks, if people want to pump their bodies with supplements, hormones and whatnot, that is on them. They want to be the fastest or the strongest. I don't. My believe is in what I consider to be a healthy diet with zero supplements apart from vitamin B12.
My advice is to take it and learn from your body, to see what the effects are, then end the experiment to see how you compare on a Mediterranean or a whole food, plant based diet. These diets are the benchmarks for longevity, which is what you might want to optimise for.
Everything else can come from a whole food, plant based diet.
Vitamin B12 is made by bacteria in soil that are important for nitrogen fixation. Animals ingest vitamin B12 because they don't wash their food, we wash our food and therefore any B12 that is in soil.
Meat eaters get second hand B12 that has accumulated in animals, so their requirement is met by eating animal products including dairy and eggs.
Plants don't actually need B12 so there is no B12 in them.
Iodine is something that I choose to get from iodised salt, which is almost supplementation, but I stay clear of all processed foods that have been fortified and supplements. This is also philosophy - I am not an animal. Most livestock gets a smorgasbord of supplements with calories coming from corn, soy or whatever is cheapest.
