Well, do you feel a flush of warmth and energy after drinking the mixture, and experimented with it as more concentrated, or more dilute?

I get a flush on cayenne extract (in whiskey), and have been passing liver flukes myself here and there.

It's not necessarily that you are not absorbing, but maybe just not digesting the spice particles. it depends upon what sort of enzymes your body is able to produce.

The better the enzymes, the tinier the food gets broken down, and the more that gets absorbed into the bloodstream.

Apple cider vinegar (dark caramel colored), 1-2 tablespoons in a 2-3 dl glass of water an hour before a meal provides a lot of the minerals needed for better stomach acid and breakdown of the spices, etc.

Also, tipping down the spices without first tasting skips the salivary glands (first-line of signalling from tongue to stomach and pancreas), to prompt the digestion process

From re-reading your story, It seems you may just be having a whole metric poopton of cayenne! Your intestines will choose themselves what to absorb and what not to absorb. ;) replenishing the stomach-acid vital nutrients with ACV may be called for.