I've just watched Breaking Bad Season 01 Episode 03. In that Walter gives the chemical composition of human body. The conversation is as follows

Walter White: Let's break it down. Hydrogen. What does that give us?

Gretchen Schwartz: We're looking at 63%.

Walter White: Sixty-three, that is a big bite. My next step's gotta be oxygen.

Gretchen Schwartz: Oxygen, 26%.

Walter White: Twenty-six. There you have your water.

Gretchen Schwartz: Carbon, 9%.

Walter White: Carbon, 9.

Gretchen Schwartz: For a total of 98%.

Walter White: Right.

Gretchen Schwartz: Nitrogen, 1.25%.

Walter White: One-point-two-five.

Gretchen Schwartz: That brings you to 99 and a quarter. Which only leaves you with the trace elements down where the magic happens.

Walter White: Oh, wait a minute. What about calcium? Calcium's not a trace. Got a whole skeleton to account for.

Gretchen Schwartz: You would think, right? Calcium's only 0.25%.

Walter White: What? That low? Seriously? Damn, I never would've thought that. Okay, so where does iron fit in.

Gretchen Schwartz: Iron. 0.00004%

Walter White: What? You can't have hemoglobin without iron.

Gretchen Schwartz: Apparently, it don't take take much. No doubt. Go figure.

Walter White: Sodium.

Gretchen Schwartz: Sodium, 0.04%. Phosphorus, 0.19%.

Walter White: Point-one-nine. There we go. So the whole thing adds up to... 99.888042%. We are 0.111958%. Shy.

Gretchen Schwartz: Supposedly that's everything.

Walter White: Yeah? I don't know, it just... it seems like something's missing, doesn't it? There's got to be more to a human being than that.

Gretchen Schwartz: What about the soul?

Walter White: The soul? There's nothing but chemistry here.

When I searched for it, Wikipedia has something different.

Which one is correct?

  • $\begingroup$ Not quite a dupe. $\endgroup$ Commented Nov 29, 2014 at 7:16
  • $\begingroup$ Neither are correct if you are looking for the "chemical" composition. Water, proteins, and fats are chemicals that make up most of the composition. Oxygen, hydrogen, carbon, and nitrogen are elements that make up those chemicals. $\endgroup$
    – IAmNaN
    Commented Jun 30, 2021 at 23:54

1 Answer 1


That conversation is strange. While different tables exist, the very first elements seem messed up. If the body is 60 (some sources say 70)% water, then oxygen has to be the most abundant element by weight (water - H2O - has a molecular weight of ~18 g/mol, with hydrogen contributing only 2g/mol of that weight).

The usual figures are roughly Oxygen (65%), Carbon (18%), Hydrogen (10%), Nitrogen: (3%), Calcium (1.5%), etc.

However, the writers of Breaking Bad weren't stupid. So, they weren't discussing percentages of the mass of each element, but rather the frequency of that atom in the body. The number of hydrogen atoms does indeed exceed the number of oxygen atoms.

So, by atomic percent, Oxygen is 25.6%, Carbon: 9.5%, Hydrogen: 63%, Nitrogen: 1.3%, Calcium: 0.24%, etc. So yes, the numbers are approximately correct for a normal, average, youthful (more water) 70 kg male.

So here is a table incorporating both percent by weight and percent by abundance. The writers were pretty well informed.


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