Are clinical trials using animal studies always valid for humans? Consider me a skeptic.

I frequently see advertisements and newsletters (even some written by physicians) that promote lab tests and treatments based entirely on studies done using rodents. These “experts” frequently draw conclusions from these studies that their lab test or product is a breakthrough of vital importance to humanity. While it may be true, all too often it’s not.

Let me give you a recent example of a study done in mice that could lead to the conclusion that every woman with breast cancer should be taking very robust doses of the adrenal hormone DHEA. This study should serve both as an encouragement and as a caution, an example of the care we must exercise when we use animal studies to draw conclusions about humans.

In this test, laboratory mice had their ovaries removed, and were given a large dose of estrogen each day.  Small pieces of human breast cancer were transferred under the skin of these laboratory mice, and permitted to grow for 9 1/2 months.  During that time, some mice received treatment with DHEA while others did not. At the end of the test period, in the non-DHEA mice the tumors had expanded to nearly ten times their original size.  By contrast, the mice that were given varied doses of DHEA had much smaller tumors.  How much smaller? Depending on the dosage, the tumors in the treated mice were anywhere from 50% to an amazing 80% smaller.  The optimum dose seemed to be about 1 milligram of DHEA daily.

Sounds compelling. But how does this translate into the DHEA dose for a human woman?  Well, let’s do some basic math:

The average laboratory mouse weighs about 20 grams.  I’ll use my wife (with her permission, of course) as a sample female human: she is a small woman, weighing about 50 kilograms (or 50,000 grams). I’m a relatively big guy at about 100 kilograms, or 100,000 grams.  This means that my small wife is about 2,500 times larger than a mouse – and I am about 5,000 times larger!

You can see the obvious problem. Just consider how much DHEA my wife would have to take to match the one milligram mouse dose – 2,500 milligrams of DHEA per day. If I were the patient I would need twice as much: 5,000 milligrams per day!  Since the average over-the-counter DHEA pill provides a 25 milligram dose, my wife would need 100 pills per day and I would have to take 200.

I’ve seen medical studies in which patients were given 100 milligrams per day of DHEA.  The negative side effects were almost nonexistent.  But no one knows what would happen if you gave a human being 2,500 milligrams of DHEA every day, and I frankly don’t know anybody crazy enough to find out. DHEA is a potent participant in the body’s intracrine system (the hormones that work inside our cells). DHEA is converted into a variety of sex hormones in virtually every tissue in the body and is also part of the neurotransmitters within the brain. No one has any idea of what would happen to a human being taking such massive doses.

Does research on rodents and other animals have value? I’m sure it does. But at Longevity Medical Clinic we strongly prefer to base our treatments on peer-reviewed studies done on human beings. That’s a sure way of making sure we’re prescribing just the right dose – for a person, not a mouse!