How long should one wait to do HIIT after taking EC stack? This is my dosage today:

  1. 8:30 AM: 12.5 mg E, 100 mg C
  2. 12:30 PM: 12.5 mg E, 100 mg C

Can I do HIIT cardio at 5 PM?

  • I will improve/edit my answer if you add your weight/height and athletic level to the question. Commented Feb 2, 2015 at 15:45

1 Answer 1


I think the best you're going to get on this is anecdotal broscience. No medical professional in their right mind would advise the use of EC/ECA and HIIT, or even just EC/ECA on their own I'd imagine. So what you should do is not use ephedra/caffeine off label.

In the anecdotal broscience world, I'd avoid combining EC/ECA ingestion with anything resembling HIIT. It might maximize fat loss, but it's also going to maximize your heart rate beyond safe limits. You can read up on bodybuilding forums about people doing all kinds of things to their body and getting killer aesthetics, but the science against ephedra and sports use is pretty clear.

The use of ephedrine carries a risk of development of life-threatening arrhythmias. ... Our experience with the reported patient shows that ephedrine alone, or in combination with substances that increase its effects on the cardiovascular system, may also trigger paroxysms of non-ischemic ventricular tachycardia. The use of ephedrine carries a risk of development of life-threatening arrhythmias and should be discouraged.

Taking two substances that increase your blood pressure and heart rate, only to engage in an activity that drastically increases those rates as well, is a bad formula.

Here's a case study that might even be very close to what you're doing:

A previously healthy 29-year-old man was admitted with palpitations, dizziness, and near-syncope after he had recently started taking weight loss pills purchased on the internet. The pills contained caffeine and ephedrine. ... with no family history of cardiovascular disease [the healthy 29 year old] was admitted to the emergency room due to palpitations, dizziness, and near-syncope during weightlifting.

The guy's heart rate was 147, just sitting there in a hospital bed. If you're going to do EC/ECA, do your heart a favor and don't push it further by pushing your physical limits.

  • +1 off label use is bad, dont do it. However, if you've posted the question here I doubt I can do or say much to dissuade you. Please seek the counsel of an individual with certifications (ASM, ISA, CPT) and experience using these for cutting weight. Do not use these without direct supervision, if you don't have access to anyone like this please talk to your doctor first. Commented Feb 2, 2015 at 15:51

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