Another quick medical post – a friend of mine mentioned he was getting nose bleeds during his workouts and suspected it was due to the pre-workout supplement he was taking (C4). I took a quick look through the body building forums and it doesn’t look like anybody knows why,with most people using anecdotal evidence like “well I’ve never had that problem, therefore it’s not the pre workout. I hope you guys know better than to take anecdotal evidence seriously – for a quick brush up on logical fallacies click here.

Anyway, since nobody knew the answer, I decided to take a look at the ingredients (which was actually surprisingly difficult to find). The product is advertised as mostly Creatine Nitrate, so I had a hard time finding the other ingredients. Interestingly though, Creatine Nitrate isn’t the most common ingredient of the product. It contains more Beta Alanine than Creatine Nitrate. That’s fine though, they’re both amino acids and there’s no big harm in amino acids.

One suspicion my friend had was the caffeine content. However, C4 has 100mg of caffeine whereas 1MR (another pre workout) contains 300mg. It’s unlikely that, with such a huge gap between products, caffeine is the problem – though it could contribute to the problem. The reason is, if caffeine was the sole cause of this issue, a product with 300% the caffeine would have a large amount of customers complaining about nose bleeds.

The nasal membrane is quite thin so even mild trauma or dryness can cause them to crack open and result in a nose bleed. In this regard, caffeine is a stimulant and thus raises your heart rate and blood flow. However, there was another ingredient in the C4 that I found: Xanthinol Nicotinate.

Xanthinol Nicotinate is a vasodilator – which means it expands blood vessels. When blood vessels dilate, it increases blood flow due to reduced vascular resistance. As mentioned above, this increased blood flow could make it much easier for you to end up with nose bleeds.

Now the purpose of having a vasodilator in your pre workout is mainly because by increasing blood flow you can pump more blood and thus nutrients to the tissues and organs that need them. I don’t want to get more technical or this’ll end up as a long post so I’ll just leave it at this: your nose bleeds are probably caused by the increased blood flow resulting from Xanthinol Nicotinate in addition to caffeine. It’s not necessarily a bad thing in the short run, though it is definitely annoying having nosebleeds when you’re trying to workout.