Yes. Vitamins are an essential part of my training process, although it's just an additional element for healthy food with enough proteins, fats and carbs.
I usually take vitamins and supplements daily and I do the break in the off-season.
What do I prefer:
Before running in the morning
L-carnitine - Carnitine is an amino acid. It has a key role in the production of energy
In the morning at least 30 mins before food
Multivitamin - my choice is Opti-Women by Optimum Nutrition, and I take 1 capsule, 2 is too much for me. But it can be any good multivitamin complex, for example, prenatal vitamins contain sufficient amount of components.
Folic Acid - one of the B vitamins also known as Vitamin B9 or folate (the natural form of Vitamin B9). Folic acid can help runners improving blood flow and reducing their risk of heart problems.
Omega 3 - in general, it's a very useful thing, which can bring some good benefits to your health, such as the decreased risk of heart disease or help to fight against depression. For runners especially, it can improve a recovery process by decreasing inflammation in muscles.
Iron - it’s an essential component of hemoglobin, the protein in red blood cells that moves oxygen from lungs to muscles. Effect of iron supplements can be described, as it gives more energy, helps recover from workouts better, and makes you faster. I usually do two courses of 30 days each, twice a year. I take liquid iron with orange juice, which helps for better absorption.
Be careful, it can turn teeth grey if it comes in contact with tooth enamel.
In the evening 30 mins before bed
ZMA - it's a combination of three ingredients: zinc, magnesium, and vitamin B6. There is not enough confident research about performance improvement and some calls that supplement 'placebo'. But it may help increase testosterone levels, aid exercise recovery, improve sleep quality, and build muscle and strength.
Casein - it's tasty, like a milkshake and also useful after hard training sessions, as it helps to recover mussels.
Within 30 mins after hard training sessions
BCAA - it's amino acids: leucine, isoleucine and valine, which provide the essential components, important for protein synthesis. It can help you feel less tired and sore after a hard workout.
Berocca - It's a soluble vitamin with orange flavor, which contains B vitamins, vitamin C plus added magnesium, calcium and zinc. It's great for refreshing after a training session.
Note: this product contains about as much caffeine as a cup of coffee (90 mg)
I also use sometimes Vitamin D, especially in winter time, but definitely, prefer simple sunlight. Russian mineral water (salty water) is good as well for recovery.