I'm often asked about supplement use in my job. What works, what doesn't, should I take this or that?
The human body is an incredible machine. Believe it or not, millions of years of evolution have produced adaptations that are pretty damn near perfect. When we exercise, whether that be of the endurance variety, or the lifting-heavy-things type of flavour, we are primed to adapt. Most supplements are not going to make a huge difference. Good diet, adequate rest and quality sleep trump most of what a supplement can offer. However, once we have perfected our routines, there may be some additional interventions (supplement-wise) that can give some marginal gains.
I like to think of training as a cake. Consistent training with progressive overload provides the base of the cake; our concurrent daily habits pertaining to sleep, nutrition, hydration and stress management is the icing; all good cakes NEED icing btw; supplements are perhaps the sprinkles on top, but you know, most cakes taste pretty darn good without sprinkles.
Here's what has been shown to be beneficial (in certain situations):
Vitamin D - 600iu daily
Creatine Monohydrate 3-5g daily
Beetroot juice (or watermelon or pomegranate)
Caffeine 2-3mg/kg pre-exercsie
Tart Cherry Juice
Beta Hydroxy Betamethyl butyrate (HMB) - 3g/day
Omega-3 Fatty Acids 2g/day
Gelatin/Vitamin C/Collagen - 5-15g gelatin/50mg Vit C/Collagen 10g
Whey protein - 20-40g post resistance exercise
All kinds of other supplements have been advocated in certain situations. Most have little or very limited evidence for benefit. Perfect the basics before you drop a pay cheque on expensive supplements.