Index
1st part: henna, natron and Ramesses II
2nd part: bog bodies and photo-oxidation
3rd part: Tarim and Paracas mummies
4th part: Egypt and Sudan
5th part: techniques for tracing the original colour of archaeological hair, hypotheses about the origin of red/blond archaeological hair
This 5th and last part is going to be a bit more technical than the previous ones, but I think it is important that we have a clear picture of the situation. That is, it is important we see that techniques for hair colour analysis do exist, while, on the contrary, we don’t have any evidence supporting the various hypotheses about the origin of red/blond archaeological hair.
TECHNIQUES FOR TRACING THE ORIGINAL COLOUR OF ARCHAEOLOGICAL HAIR
As you will see, only some of these techniques allow us to directly measure the amount of eumelanin and phaeomelanin in hair. The others too are important, however, because they allow us to determine if the hair contains dyes or other pigments, traces of minerals present in the soil or burial, degradation products, etc. Consequently, using three or four of these techniques in combination can achieve good results, although, obviously, we can't always be sure of a definitive answer as far as archaeological hair is concerned.
Furthermore, these techniques are either non-destructive or minimally destructive, which means they can also be used on important finds such as pharaonic mummies.
Without sampling
Raman spectroscopy
As of now, Raman spectroscopy is one of the few tools to detect and distinguish melanins, as you can read in these three studies by Ismael Galvàn and colleagues: Raman spectroscopy as a non-invasive technique for the quantification of melanins in feathers and hairs, Dispersive Raman spectroscopy allows the identification and quantification of melanin types and Vibrational characterization of pheomelanin and trichochrome F by Raman spectroscopy.
The laser interacts with the hair molecules and produces a spectrum containing information on keratin, disulfide bonds and even pigments. Experimentally, it has been demonstrated that Raman spectra can correlate with the amount of eumelanin and phaeomelanin present in hair.
Since it is non destructive, Raman has already been used for various analyses on historical hair (see here).
However, a Raman spectrum of mummified hair doesn't automatically equate to a photograph of its original colour, because the hair may have been altered by the environment, mummification, cosmetics, oils, resins or dyes. Therefore, it would be useful to combine Raman with other techniques.
Fourier-transform infrared spectroscopy
The Fourier transform infrared spectroscopy (FTIR), included micro-FTIR and synchroton FTIR, allows for the analysis of molecular composition without necessarily sampling material. It has been used directly on ancient hair to assess keratin preservation, protein degradation, chemical modifications and substances from the environment or mummification.
For example, as you can read in this study, this technique has already been used to analyse the state of the hair of two Egyptian mummies.
Another study analysed ancient hair from the Roman period, to characterise its state of conservation and the alterations of the organic elements (see here).
Besides, along with scanning-electron-microscopy (SEM) and X-ray-diffraction-analysis (XRD), it has been used to investigte the Egyptian mummy called Screaming Woman. On its hair, juniper and henna have been found.
Athough performed with sampling, I think this 2018 study is important too. By using nano-FTIR and scanning transmission electron microscopy (STEM), the authors analysed sheep hairs melanosomes. They were able to directly distinguish, in situ (i. e. in the single hair), the vibrational characteristics associated with eumelanin and phaeomelanin, without resorting to chemical extraction. Some of the hairs were white (without melanosomes) and others black. In white hairs, they were able to indentify keratin, while in black hairs they could associate specific vibrational bands with melanosomes of eumelanin and phaeomelanin, thus distinguishing the chemical fingerprint of the two melanosomes.
So, althought this technique can’t measure the amounts of melanins, it can give us important information about the modifications that hair has undergone over centuries and millennia and about melanosomes.
Hyperspectral and multispectral imaging
Hyperspectral imaging collects and processes information from across the electromagnetic spectrum. The goal of hyperspectral imaging is to obtain the spectrum for each pixel in the image of a scene, with the purpose of finding objects, identifying materials or detecting processes
When applied to hairs, it can help distinguish pigments, dye residues, foreign materials, areas of different composition and surface alterations. Basically, it can give an excellent and completely non-invasive preliminary mapping.
X-ray fluorescence
X-ray fluorescence is another non-destructive technique which detects chemical elements, like iron, copper, lead, arsenic, etc. Along with scanning electron microscopy and energy dispersive X-ray spectroscopy, it has been used on two Andean mummies.
With sampling
High-performance liquid chromatography
High-performance liquid chromatography (HPLC) is a chromatography technique in analytical chemistry used to separate, identify, and quantify specific components in mixtures. The mixtures can originate from food, chemicals, pharmaceuticals, biological, environmental, agriculture, etc., in which the sample analysed is either a liquid or has been dissolved into a liquid.
Melanin is an extremely complex polymer and difficult to analyse directly, but through a standardised chemical reaction it produces certain relatively simple and characteristic molecules, such as PTCA, PDCA, TTCA, etc., which can be separated by HPLC.
For example, eumelanin produces PTCA, PDCA and PteCA, while phaeomelanin produces TTCA and TDCA.
Therefore, we don't directly measure how much melanin there is: we measure how much marker product is formed from melanin. A higher amount of PTCA indicates a higher amount of certain eumelanin structures, while TTCA is an important marker of the benzothiazole component of phaeomelanin.
Obviously, the whole process may be more difficult with archaeological hair.
Here’s an article on the subject.
Mass spectrometry imaging
Mass spectrometry imaging (MSI) can be performed on a section of a single hair, obtaining a true chemical map. In modern hair, it has been possible to directly visualise the melanin granules and distinguish them from the cuticle, cortex, and medulla (see here).
It also allows mapping numerous chemical species along and through a single hair shaft (see here).
The problem is that the most powerful versions of MSI are microdestructive: the hair generally needs to be sectioned and/or subjected to surface preparation.
X-ray Absorption Near Edge Structure (XANES)
XANES measures how an element absorbs X-rays near its absorption threshold and can provide information about its chemical state and coordination environment.
It has already been used, along with EXAFS (extended X-ray absorption fine structure), in the study of Egyptian mummies' hair. In particular, experiments on zinc showed differences between ancient and modern hair, suggesting that some of the zinc was of exogenous origin or had a different chemical environment than biological zinc. (see here)
However, this technique can’t determine directly hair colour. Melanin is a complex organic system, and colour doesn't simply depend on an element that XANES can identify as "black" or "red." XANES can, though, tell us if the element (pigment) we see is the result of mummification or other port-mortme treatments.
Scanning electron microscopy and Transmission electron microscopy
The scanning electron microscope (SEM) allows us to observe the surface and microstructure of hair at very high magnifications. With it, we can analyse the state of preservation and alterations of the cuticle, the cortex and medulla, the distribution and morphology of melanosomes and any mineral deposits or contaminants that have penetrated the hair.
Combining SEM with EDX (energy-dispersive X-ray spectroscopy) we can distinguish organic material from mineral deposits, identify elements from the soil or burial environment, recognise any pigments or contaminants and understand whether a colour change is likely endogenous or due to mineralisation/contamination.
However, if our goal is to study melanosomes, the transmission electron microscopy (TEM) could be even more informative than SEM.
For example, in the 1993 study Detection of eumelanogenic and pheomelanogenic melanosomes in the same normal human melanocyte, by M. Inazu and Y. Mishima, melanosomes were analysed with high-voltage transmission electron microscopy (HV-TEM) and EDX. Melanosomes producing the two melanins are different: phaeomelanosomes are spherical, while eumelanosomes are ellipsoidal/lamellar. By using HV-TEM, the authors of this study confirmed this different morphology. By using EDX, they found sulfur in spherical melanosomes, but not in ellipsoidal ones, and sulfur is typical of phaeomelanin. Lastly, they treated melanosomes with sodium hydroxide (NaOH) and found that the internal structure of the spheroidal melanosomes was dissolved, while that of the ellipsoidal melanosomes was not altered. This provided a further physicochemical difference between the two melanosomes.
Liquid chromatography–mass spectrometry
Liquid chromatography, combined with mass spectrometry (LC-MS) can tell us which melanin products are chemically present in hair and in what ratio, and this can tell us, indirectly, which melanin was originally mostly present.
This review on colour reconstruction in fossil material emphasises that the chemical markers of eu- and phaeomelanin are well characterized by HPLC/MS, but that diagenetic transformations of melanin in ancient finds still constitute a major problem. However, the SEM/EDX and controls on archaeological hair of different ages and conservation conditions can solve in part this problem. Along with others, this technique has been used for several analyses on an Egyptian mummy.
Pyrolysis-gas chromatography–mass spectrometry (Py-GC-MS)
Pyrolysis–gas chromatography–mass spectrometry is a method of chemical analysis in which the sample is heated to decomposition to produce smaller molecules that are separated by gas chromatography and detected using mass spectrometry.
With archaeological hairs, the sample is rapidly heated in the absence or near-absence of oxygen. Melanin, being a polymer, breaks down into smaller molecules. These products are then separated by GC and identified by MS. The composition of the resulting products can provide information on the presence and state of melanin.
So, basically, GC-MS does not directly "see" the intact eumelanin or phaeomelanin molecule, but only identifies characteristic degradation products.
DNA phenotyping - HIrisPlex-S
DNA phenotyping is the process of predicting an organism's phenotype using only genetic information collected from genotyping or DNA sequencing. This term, also known as molecular photofitting, is primarily used to refer to the prediction of a person's physical appearance and/or biogeographic ancestry for forensic purposes.
With this technique, significant genetic variants associated with a particular trait are discovered using a genome-wide association study (GWAS) approach, in which hundreds of thousands or millions of single-nucleotide polymorphisms (SNP) are tested for their association with each trait of interest. Predictive modeling is then used to build a mathematical model for making trait predictions about new subjects.
One online tool available to the public and law enforcement is the HIrisPlex-S Webtool. This system uses SNPs that are linked to human pigmentation to predict an individual's phenotype.
In the case of ancient human remains, the main issue for analysis is not just how much DNA is left, but how much endogenous human DNA is recoverable compared to modern contamination.
As I said, this method was originally developed for modern/forensic DNA, while in ancient DNA we often find fragmented DNA, postmortem damage, low coverage and possible modern contamination. It's not enough to find a SNP: we must be sure that the observed allele is truly that of the ancient individual and not the result of postmortem damage or contamination.
In this 2013 study authors extracted the DNA from twenty-one teeth between 1 and approximately 800 years of age and from 5 contemporary bones, and then analysed them using the HIrisPlex system. I quote from the abstract:
Twenty-three out of 26 bone DNA extracts yielded the full 24 SNP HIrisPlex profile, therefore successfully allowing model-based eye and hair colour prediction. HIrisPlex analysis of a tooth from the Polish general Władysław Sikorski (1881 to 1943) revealed blue eye colour and blond hair colour, which was positively verified from reliable documentation. The partial profiles collected in the remaining three cases (two contemporary samples and a 14th century sample) were sufficient for eye colour prediction.
Besides, a paper published in February 2026 developed a missing data imputation method for HIrisPlex-S, demonstrating that under certain conditions, predictions can be obtained even from ancient genomes with extremely low coverage, on the order of 0.1–0.5×.
In 2025, the first high-quality genome of an individual from Nuwayrat (Old Kingdom of Egypt), was published. From the genetic analysis, the authors predicted brown eyes, brown hair and dark/black skin pigmentation (see here and here). DNA was extracted from seven teeth.
However, this very work underscores how anomalous the result is: authors explicitly write that, until then, poor DNA preservation had prevented whole-genome sequencing in Dynastic Egypt. There's also a very important detail: the find was exceptionally well preserved. The body was placed in a large pottery vessel inside a rock-cut tomb and authors believe that this particular burial may have favoured DNA preservation.
So, caution is warranted: another recent study (from 2025) shows that HIrisPlex-S predictions can become unstable when coverage drops too low. In particular, below about 8×, some approaches can produce large errors.
Here are a couple of articles discussing some of the techniques we have just seen:
- Research Techniques Made Simple: Cell Biology Methods for the Analysis of Pigmentation
- From Extraction to Advanced Analytical Methods: The Challenges of Melanin Analysis
HYPOTHES ABOUT THE ORIGIN OF RED/BLOND ARCHAEOLOGICAL HAIR
It is important to keep in mind that none of these hypotheses has ever been directly tested on red- and blond-haired mummies. For this reason, I’m not saying they are wrong: I’m just saying they are only educated guesses, and passing off mere educated guesses as proven facts is scientifically incorrect.
So, basically, we need to find a process that can 1) explain both red and blond hair and 2) occur in places as different as the Tarim Basin, Egypt and South America.
Photo-oxidation
see part 2
Melanin oxidation/degradation
As you have seen in the previous parts of this article, melanin (and specifically eumelanin) oxidation/degradation is one the preferred hypotheses to explain blond and red archaeological hair, although 1) there is no evidence that melanin oxidation turns archaeological hair red or blond, and 2) there is no evidence this red/blond archaeological hair is due to melanin oxidation.
(Please note that here "degradation" is a sort of umbrella word: it means that the chemical structure of melanin is altered or fragmented and this can occur through various mechanisms.)
As far as melanin oxidation is concerned, we know for certain it can occur in two situations (apart from photo-oxidation, obviously). One is the bleaching with hydrogen peroxide (which I have already mentioned in previous parts) and another one comes from this study with ozonated water, although authors write that “Changes in shine and colour were minimal.” There is also this study on Japanese swimmers’ hair, but authors conclude that “discoloration was mainly due to cuticle damage by friction with water”, and, although they write that hypochlorous acid in the swimming pool water can oxidise melanosomes, this is only a concurrent factor.
As you probably know, one of the main oxidising agents is oxigen (here’s a list of the most common oxidizing agents), which means that oxidation can occur underground as well, for example because of residual atmospheric oxygen in the pores of the soil, in the burial materials or in the cavity in which the body is laid, or because of water/humidity and microorganisms.
However, the mummies and skeletons we are talking about not only have been found in very dry environments (so, most likely, there was very little or no humidity at all), but many of the bodies were laid to rest wrapped in several layers of textiles, just like the so-called “mummy bundles” of Paracas, or the Gebelein Man. In such a situation, it is unlikely that melanin can oxidise, and in any case, if oxidation occurred, we should find some traces of it on textiles as well. On the contrary, the textiles found in Paracas burials were in excellent conditions, so excellent that many of them were stolen by tomb looters. Furthermore, if oxidation occurred and we assume this is the cause of red hair, all the mummies found in the same place should have red hair.
Some argue that oxidation could have occurred when the mummies were removed from their burial sites: contact with oxygen in the open air would have oxidised the melanin, causing the hair colour to change. If this were the case, however, archaeologists should have noticed it. Others argue that contact with oxygen (and therefore oxidation) could have occurred due to tomb looters. In this case, however, it would be necessary to demonstrate that all the mummies with red hair come from burials that were disturbed by tomb looters.
In some of the previous parts (for example in the 2nd part, speaking of bog bodies) we have seen that dark, brown and blond hair have very small amounts of phaeomelanin, so, even if all eumelanin should disappear (through oxidation or other forms of degradation), the remaining phaeomelanin wouldn’t be enough to turn hair red. Probably this is reason why some speak of “products of degradation”. That is, products are left as a result of eumelanin oxidation/degradation and this products could turn hair red.
Deposits of iron and other minerals oxides
Minerals in the soil (such as iron or copper) are sometimes implicated in explaining red or blond hair in mummies and skeletons, but here two aspects of the issue need to be distinguished.
The fact that iron oxide (or other minerals) can produce a visible and very intense colour on a keratin fiber, without altering the internal biological pigment, is now well documented. See, for example, the experiment with the bearded vultures:
The rufous colouring on the feathers of the under parts of adult bearded vultures Gypaetus barbatus, studied by scanning electron microscopy, energy-dispersive X-ray microanalysis and X-ray diffraction analysis, is caused by an external deposit of iron oxide in the ferrihydrite state. Unstained feathers, e.g. in captive birds, are pure white.
Subsequent studies have experimentally observed the behavior of bearded vultures in captivity: when baths containing red/ferruginous soil were provided, the animals willingly immersed themselves, and their feathers took on a rich orange hue (see one more study here).
However, we don’t have any evidence that the red and blond hair of mummies and skeletons is caused by minerals in the soil. We only have evidence that, in certain cases, minerals were found on archaeological hair.
For example, here we have a study on the hair of two Andean mummies.
The hair was analysed with some of the techniques we just saw (scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray fluorescence spectroscopy. Fourier transformed infra-red spectroscopy), but NOT to ascertain its original colour. Researchers found out that for one of the mummies (PLM7_T305) a 3,5% of iron was found on its reddish hair. After treatment with ultrapure water, dichloromethane/methanol and acetone, the iron levels dropped to approximately 100 ppm. EDS mapping also showed that the iron was distributed across the surface. From these observations, researchers deduced that the red coloration was due to the use of hematite, an iron-based red pigment. However, strangely enough, the study doesn’t say which colour the hair sample turned after the treatment with ultrapure water, acetone, etc. and, as I said, researchers didn’t attempt to assess the levels of melanins in hair.
Another interesting study is the one on the relics of “Mary Magdalene” (kept in Provence, France), which consist of a dry skull and a lock of hair of brown colour.
Researchers analysed the hair with optical microscope, scanning electron microscope and helium ion microscope in order to assess melanin concentration and aspect of melanosomeThey observed microscopic characteristics of pigments consistent with dark brown hair. Along with localised red pigmentation features in some portions. The meaning of this red pigmentation is not very clear, however, because researchers didn’t use any of the techniques for the chemical analysis of melanin. The techniques they used were aimed to find mineral deposits and, in fact, they found significant superficial diatomaceous deposit, probably used as a prevention method against lice.
On the same year, 2019, another study on the hair of “Mary Magdalene” was published. I quote from the abstract:
As a new contribution to the scientific knowledge of Holy Maria-Magdalena’s remains, we have studied by SEM-EDX some mineral particles and micro-organism debris adhering to her hair. We found on it mineral particles of gypsum, aragonite and salt, algae fragments, microorganism as diatoms, coccoliths and tintinnides, and micro-debris of Crustaceans. Such marine micro-remains indicate a past close contact of the hair with sea water.
Many mineral particles of barytine were also found on or near the surfaces of the hairs, which, according to researchers, originated from the ceiling of the Sainte-Baume cave. Not even this time a chemical analysis of melanin was performed.
However, since (as I said in the previous paragraph) many of the mummies we are talking about were found wrapped in layers of textiles, I doubt that in such a condition a contamination from minerals in the soil can occur.
Keratin/tyrosine degradation/oxidation
As I said before, "degradation" is a sort of umbrella word: it means that the chemical structure of keratin is altered or fragmented. This can occur through various mechanisms: oxidation, hydrolysis, photodegradation, enzymatic/microbial attack, reactions with acids or bases and other chemical reactions.
Keratin is one of the components of hair (but also of scales, nails, feathers, horns, etc.).
Tyrosine is one of the 20 standard amino acids that are used by cells to synthesize proteins and is also the precursor to melanin.
As we have seen in previous parts, the products of degradation and oxidation of these two elements are sometimes used to explain the fair-haired mummies, and not only fair-haired mummies, but even… red-haired mammoths!
This 2014 study by Silvana Tridico and colleagues is about the hairs of wolly mammoths and wollly rhinoceros. At one point, authors write "The majority of overhairs and thicker guard hairs from the woolly mammoths and woolly rhino were vivid red/orange colour or ‘fox red’ as described by Krefft (1969)” and argue this colour may be in part due to melanin oxidation. However, they find out that also some hairs lacking melanin granules (i. e. they were originally white) had the same red/orange coloration. One of the sources cited (Krefft 1969) attributes this colour to photo-oxidation, but then researchers find “red/orange debris” on some of these red (originally white) hairs, and conclude this is due to a fungal deposit. The techniques they used to analyse hairs samples are scanning electron microscopy (SEM) and confocal microscopy, which means they didn’t perform a chemical analysis of eumelanin and phaeomelanin to trace the original colour. They don’t even verify if melanin was really oxidated.
So, we have here the usual situation: they wonder why these animals’ hairs are red, they make hypotheses about the oxidation of this and that, but don’t do the only thing that could, maybe, give an answer.
Besides (as you can read here) in 2006 a mutation of MC1R was found on a 43,000-year-old woolly mammoth. The author writes “… the reduction in activity of the Arg67Cys variant would be sufficient to result in substantially lighter hair color…it is possible that mammoth populations were polymorphic with regard to hair color, harboring both dark- and light-haired individuals." So, it is perfectly possible that the red hairs Tridico and colleagues were analysing were naturally red (apart from the ones without pigment granules).
Conclusions
The conclusions we can draw seem very clear to me. Although scientists today possess all the tools to analyse archaeological hair in terms of colour, they do not seem interested in doing so, preferring instead to keep repeating hypotheses that have never been proven.
We have seen that it is not a matter of funding, since these same tools have been used to conduct other types of hair analyses.
It’s not even a matter of damaging important finds, since many of these tools are either non-destructive or minimally destructive, and in any case we have seen that, whenever necessary, samples are taken from mummies and skeletons.
At this point, all we can do is wait and hope that someone decides to do the only sensible thing to clear up the mystery.
