As the name implies, supplementation should only be used for additive effects – your primary fitness goals will be mostly achieved via diet and exercise. Still, with that in mind, there are three supplements that are frequently cited for general health and building muscle:
- Creatine
- One of the only truly effective legal supplements and completely safe. Helps improve performance during exercise. Get the cheapest Monohydrate you can find – the rest is just marketing – and take 5g a day, every day.
- Vitamin D
- Has numerous health benefits if you are deficient in it, which many people in modern society are due to decreased sun exposure.
- Omega-3 Supplement such as Fish Oil (note that flax/chia seeds are not sufficient)
- Good for general health if you aren’t already eating fish in your diet.
- Preworkouts
- Can be helpful with performance in a workout, but the majority of the effect comes from the very high caffeine content.
For more information on supplementation, see /r/supplements or Examine.com.