B4 Review

Our Rating

Sometimes you need that extra kick when heading for a workout, particularly after a hard day in the office.

There is no surprise then that pre-workout supplements have become so popular with gym-goers – and from BPI Sports comes B4.

This one-a-day capsule can either be used as a pre-workout or a fat burner depending on your aims, with BPI claiming it is “the most exclusive high-end dual sports performance and weight loss supplement available”.

Ingredients and how they work

Niacin – Sometimes listed as vitamin B3, niacin can boost the levels of the hormone leptin which suppresses food intake. It can cause the skin to flush, though.

Pre-workout & Fat Burning Super Blend (Caffeine, Dendrobium, Sword bean, Psoralea, Japanese sophora, Red wine concentrate, Yohimbe)

Caffeine works by suppressing the inhibitory neurotransmitter adenosine which causes sleep and relaxation, while it also boosts energy levels.

There is limited research into the effectiveness of dendrobium, although it is believed to increase focus and energy.

Sword bean appears to have limited impact on the fat-loss process.

Psoralea appears to demonstrate anti-stress tendencies and is a re-uptake inhibitor for dopamine and noradrenaline.

Japanese sophora, popular in Chinese medicine, demonstrates antioxidant and anti-inflammatory activities.

Red wine concentrate contains the antioxidant resveratrol, which has the potential to be an anti-obesity agent.

Yohimbe is an effective fat burner – although it can cause anxiety, gastrointestinal distress and hypertension

Check out which ingredients work and which don’t in our
Fat burner ingredients guide

B4 pros and cons


  • One-a-day formula
  • Fat burner & a pre-workout


  • Side effects linked to yohimbe and niacin
  • Debate over effectiveness of ingredients
  • Proprietary blend

B4 review conclusions

B4 certainly looks and sounds the part, however it does fall a little short of the mark for us.

There is no arguing that the one-a-day regime is more preferable to taking half-a-dozen capsules, while we do like the fact you can use it as a pre-workout.

However more clinical research is needed into some of the ingredients within the proprietary blend to highlight their benefits in the thermogenic and fat-loss process. Dendrobium, sword bean, psoralea and Japanese sophora all sound impressive but the evidence is far from conclusive.

Caffeine is a mainstay of the majority of fat burners, but the dosage is unfortunately not listed, and although niacin and yobimbe are both effective, they do have side effects linked to them. It is worth shopping around for the “yohimbe-free” version if you are concerned over the side effects.

Our top-three fat burners

To find out which supplements we have rated as our top fat burners, check out our top-three guide.