Instead of buying supplements, most people would be better off getting most of their vitamins, minerals and nutrients from a balanced diet.
However, the food you eat today bears no resemblance to what your grandparents ate. It’s sprayed with chemicals a stays on shelves for weeks on end.
Proper supplementation can be the difference between 'normal' health, i.e. being sick like the rest of the population, and being fully optimized.
The supplements you choose will come down to your financial situation, biochemical individuality and needs. What works for some might not work for you, so you should do your research and experiment to figure out what's best for you.
It's important to understand that one nutrient or vitamin alone isn't going to move the dial for you.
It's about leading a lifestyle that promotes health in the first place.
I'll share with you the vitamins that I take and break it down into two sections: health and performance.
Due to current practices, most foods are depleted of crucial vitamins and nutrients. A good multivitamin is a must-have to make sure you're getting everything you need.
I don't have any preference over brand here, but I like the multivitamin from Nu U – a UK-based company. Their company philosophy appears to be sound, their supplements are rigorously tested, and everything is made in Britain, which I find reassuring.
I take one tablet a day.
Vitamin D3 is actually a pro-hormone and not a vitamin. It's important for human health and contributes to immune function, bone growth and hormone synthesis among other things.
Studies show that vitamin D plays a key role in muscle function, as vitamin D receptor sites can be found in muscles. Vitamin D deficiency affects 50% of the population worldwide and is linked to cancer, heart disease, type 2 diabetes and depression among other things. 
I like Nu U's vitamin D3 here. You should take vitamin D3 based on blood work and you should consult your doctor if you need guidance on dosage.
I take 5000 iu's a day, which is a relatively high but necessary dose when you live in the UK!
Vitamin C plays a key role in the maintenance of connective tissue. It also plays a role in metabolism, fighting infection, as well as wound healing. Studies suggest supplementation with vitamin C can reduce inflammation, and lower blood pressure and cardiovascular risk. [2,3]
Apparently, it also plays a role in fat loss...According to research, individuals with adequate vitamin C levels are able to burn 30% more fat during exercise than those who are deficient. 
It's vital to immune function as it helps your body produce white blood cells and antibodies that fight off infection.
All in all, it’s a great supplement to take if you're a man. I use the vitamin C from Nu U and take 3-4 grams a day to stay healthy and avoid infections.
Omega-3s are essential fatty acids that play an important role in health, and they cannot be produced by the human body. They help lower inflammation and they've been linked to lower risk of cardiovascular disease. 
Give your body can't make it and modern living is so toxic (i.e. highly inflammatory), I believe omega-3s are another must-have in your supplement arsenal.
I suggest staying away from capsules, as they sit on shelves for several months before someone takes a bottle home.
If you want high-quality fish oil, your best bet is to go for cod liver oil in the liquid form. I use one from Seven Seas and take one tablespoon a day.
Acetyl-L-Carnitine, or L-Carnitine, is an amino acid that naturally occurs in the body and is produced in the liver and kidneys. Carnitine plays an important role in fat burning and oxidation.
It has been used in many studies to research its potential beneficial effect on heart disease, although the overall scientific consensus on it is conflicting.
L-carnitine is not only important for burning fat, but has been shown to increase training output by 11% over 30 minute durations in controlled trials. This is thought to be through improved fatty acid mobilization. 
I take 500mg first thing in the morning on an empty stomach. I use l-carnitine from MyProtein.
Beta alanine is a non-essential amino acid can be found in small quantities in fish and meat. Beta Alanine is a precursor for the synthesis of carnosine.
Studies show that increased levels of carnosine promote an ergogenic effect, i.e. increased exercise capacity. Research suggests a dose between 1.2 and 4.8g a day may be required for improved exercise performance. 
I've recommended it to clients in the past and they've noticed improved stamina during workouts.
I take 2g pre workout, and 2g post workout and use MyProtein's brand.
Research is well established on the benefits of creatine supplementation to exercise performance. You can buy many different forms of creatine, but to be honest, most of them are marketing gimmicks. The one you want is creatine monohydrate.
Creatine helps regenerate adenosine triphosphate (ATP) stores – the main source of energy for your body. Essentially, more ATP in your muscles means you can go harder for longer in your workouts.
Most studies show creatine can improve strength, power, workout performance, and maximal effort muscle contractions.
Research shows a loading dose followed by a smaller maintenance dose is most beneficial. It also appears that it’s beneficial to cycle on and off creatine for certain periods. 
I supplement with MyProtein's creatine monohydrate. I take 5g in my post-workout shake on training days, and 5g with water on non-training days.
Citrulline malate is an amino acid, produced when the body converts arginine into nitric oxide (NO). Citrulline supplementation can increase the amount of arginine in the blood, which in turns leads to more NO.
Ultimately, more nitric oxide will lead to better blood flow to the muscles during exercise and a better pump! So this means you get more out of your muscle when you workout.
On another note, a major cause of erectile dysfunction (ED) is lack of blood flow. Therefore, if you have ED, it's not a bad idea to regularly (and safely) use a supplement, such as citrulline malate, that promotes increased blood flow. I've had several clients who have done this successfully.
I take 4-6g 1 hour before workouts and use MyProtein's citrulline malate.
Proper supplementation can be a game changer if you already have your nutrition, exercise routine and overall lifestyle dialed in. But if you don't have basics down, you have no business taking them.
If you’re not used to taking supplements, I recommend you place reminders in your smartphone calendar to remind you to take them. It's also a good idea to get a supplement to stay organized.. I use one which you can find here. (Amazon UK)
Copyright 2019, Optimized Army