But the claim is false. Experts told AAP FactCheck that the heart and most internal organs don't contain melanin. The difficulty of synthesising melanin from the skin, brain, adrenal glands and inner ear makes an alleged worldwide trade in the substance implausible.

An Instagram post (archived here) featuring a video of American herbal remedies retailer Alexander Hickman, who calls himself Yah'ki Awakened, suggests human bodies are valuable targets for alleged melanin traders.

"Melanin is more expensive than gold right now per gram, $463 a gram. You see what I'm saying? Check this out: you have 150 trillion cells in your body, each (sic) trillion cells in your body have melanin particles and melanin fragments in it. You are a walking gazillionaire," he says in the video.

"So now it makes sense why we coming up missing. We coming up missing and we missing the organs that have most of the melanin in it. You have more melanin in your heart and in your internal organs than you have in your skin, and they are taking it, man. 

"That's why you see, we are missing. Where is all the black men going? Have y'all ever googled the statistics of how many black women get abducted, and they never find them, a year?"

Melanin is a natural substance in the body that produces hair, eye and skin pigmentation.  

In humans, melanin exists in three forms: eumelanin, pheomelanin and neuromelanin. 

Eumelanin is found in the hair, skin and around the nipples, pheomelanin is found in the hair and skin, and neuromelanin is found in the brain.

People with more melanin generally have darker skin, eyes and hair than those with little melanin.

But Professor Pablo Fernández-Peñas, head of dermatology at Westmead Hospital, dismissed the claim that melanin could be harvested from the heart and other internal organs. 

"There is no melanin there," Prof Fernández-Peñas told AAP FactCheck.

Prof Fernández-Peñas said only microscopic amounts of melanin could possibly be extracted from human cells and other organs.

"I don’t think it that can be extracted. The yield would be very low. It is only very abundant on the skin but not much," he said.

Associate Professor Rick Sturm, a human pigmentation genetics expert at the University of Queensland, said the amount of melanin in the human body outside the skin and hair was very low.

"These are very few in number. The heart is not a major production site for melanin – I would say none," he told AAP FactCheck.

"The brain has another type of melanin called neuromelanin, which is the only other form of melanin of any note but also present at low amounts.

"I consider this video to be completely bogus," Prof Sturm said. 

The Instagram video features a short clip showing a black substance being scraped from someone's skin, implying that eumelanin was being removed.

However, the video actually shows a cosmetic hand exfoliation treatment (see, for example, similar treatments here, here and here). 

“The video is quite shocking and gives the impression that melanin can just be scrapped from the skin. This is by no means the case," Prof Sturm said.

"Melanin is predominantly present in the skin but requires special techniques to isolate this quite insoluble molecule, which is a very minor component (of the skin).”

The video also claims melanin is 15 times more expensive than gold.

Gold was around $US64 per gram ($US1984 per troy ounce) at the time of writing (July 20, 2023). 

The price of synthetic melanin starts at about $290 per gram, or 4.5 times the price of gold, though AAP FactCheck found chemical suppliers selling it for much higher prices (for example, here). 

Prof Sturm said melanin is not a particularly scarce or valuable substance, nor is it unique to the human body.

“It is dirt cheap," he said.

"If you really want to see melanin formed, just peel a banana and wait until it goes black.”