Sulphur, an essential chemical element for life, can be found in cysteine, methionine, biotin and thiamine.  It is sulphur that gives strength and insolubility to keratin. Keratin is a fibrous protein produced by keratin cells during the keratinisation process that takes place during har growth.  The strength of hair is based sulphur-sulphur interactions called disulphide bonds.  Due to its tightly wound structure and disulphide bonding, keratin functions as one of the strongest biological materials in nature.

To obtain sulphur from the diet we must consume foods such as onions, beans, eggs or wholegrains.  Sulphur is also a component of the amino acid cysteine.   Sulphur is a highly reactive compound and sulphur to sulphur cross-linking limits digestibility and lowers absorption in heated foods.  Researchers have concluded this limited availability due to sulphur oxidation may be linked to hair loss.

When a keratin cell within the hair follicle attempts to produce keratin but finds a reduced availability of sulphur or cysteine, the production of keratin will slow down and eventually cease.  When keratin production is reduced, the hair fibre will emerge thinner and grow more slowly.  When keratin production is ceased all together, hair growth will stop, and the hair follicle will go into telogen (resting phase) early, and the cycle will start again.


Whilst sulphur is important for the formation of the hair fibre, there are many other roles for this chemical element that contribute to overall hair health:

The manufacture of proteins – Proteins are the biological workhorses of all cells.  First, they exist as unfolded polypeptides or amino acid chains derived from mRNA.  Proper protein folding is essential for the correct function of all proteins.  Sulphur can exert a protection action over potential protein misfolding by increasing hydration around a polypeptide for proper packing of the protein and stabilisation of the protein’s conformation. The high keratin content of the hair makes correct protein folding essential for the integrity of the hair fibre.

Increased blood flow – Sulphur moieties stimulate prostacyclin synthesis which increase the size of blood vessels, increasing blood flow all over the body when sulphur is consumed or supplemented.  Increasing blood flow increase the exchange of nutrients and waste from cells.  Cells of the hair follicle and hair fibre divide faster than most cells in the body.  They are nutritionally expensive and require a constant and high level of nutrient and waste exchange for optimal function and growth.

Maintains the integrity of the connective tissue housing the hair follicle – Sulphur is needed for the sulphation of proteoglycans.  Proteoglycans intersect the cell membrane and stabilise the hair follicle, assisting in transmembrane cell signalling and binding of growth factors.  Sulphur also helps maintain collagen levels, providing anchorage for the base of the hair follicle.

Reduces cell damage and inflammation – Sulphur reduces mRNA levels of inflammatory proteins such as IL-6 and IL-1A leading to reduced inflammation.  Sulphur also increases the cells ability to get rid of dysfunctional cellular components via a process called autophagy.  Correct autophagy ensures cell survival when nutrients are low via the recycling of amino acids and fatty acids.  Sulphur helps hair follicles maintain immune privilege, the loss of immune privilege is linked to hair loss conditions such as alopecia areata.

Can increase availability of sulphur containing amino acids – Elemental sulphur can be incorporated into polypeptides to form cysteine and methionine, the main building blocks of the hair fibre. Low availability of sulphur containing amino acids are linked to sudden hair shedding that can continue over an extended period of time (telogen effluvium).

Supports detoxification in the liver – The liver uses sulphur containing enzymes (sulphotransferases) to increase the water solubility of proteins, steroid hormones, lipids and other compounds to reduce biological activity and aid in excretion via the kidney or bile.  Proper liver function contributes to the normal growth of hair and the appropriate balancing of hormones such as estrogen and testosterone.

Essential for cell function – Taurine can be derived from sulphur to regulate intracellular levels of calcium, improve energy production and maintain cell integrity.  Sulphur is also responsible for ion exchange in the cell due to its oxygen sensing capabilities and cell membrane permeability.

Sulphur benefits for hair growth
Sulphur benefits for hair growth


Keratin, a mixture of keratin and keratin filament-associated proteins, is found in the skin and the hair fibre.  Keratin in the skin is relatively soft and pliable when compared to the relatively rigid and stiff keratin found in the hair fibre.  The different properties of keratins allow them to be separated in to two different groups: alpha-keratin and beta-keratin.

Sulphur can be incorporated into cysteine, increasing cysteine availability for the hair fibre. As cysteine contains sulphur, it can form disulphide bonds with other cysteines.  Coiled curl fibres high in cysteine will provide the strongest base for an interfilamentous protein.  Properly bound filaments build a thick and smooth hair fibre with high tensile strength resistant to breakage and damage.  Disulphide bonds between sulphur entities make up around 65-85% of the hair fibre strength.


To ensure we get enough sulphur from our diet we must consume sulphur rich foods.  High sulphur food includes onions and garlic and foods high in cysteine or methionine (sulphur containing amino acids).

Sulphur is a highly reactive compound and sulphur to sulphur cross linking in processed and cooked food limits digestibility and absorption of sulphur in the gut.  The boiling point for sulphur is 112˚C, this means that food cooked above this temperature is prone to strong disulphide linking before digestion can take place.

The effect on processing and cooking sulphur containing foods led researchers to investigate sulphur deficiencies in a normal population. They found that the World Health Organisation had underestimated the amount of sulphur and sulphur containing amino acids needed in the diet [1].


Sulphur is one of the more important chemical elements that contribute to the health of the growing hair fibre.

There are several ways to increase the amount of sulphur that gets delivered straight to your hair follicle:

  • Take a supplement containing sulphur.
  • Increase your intake of raw and sulphur rich food.

Sulphur has been proven to increase the length and thickness of the hair follicle and surrounding epidermis.

Follow these tips to increase your levels of circulating sulphur and achieve your hair growth goals.


  1. Dietary cysteine reduces the methionine requirement in men. The American Journal of Clinical Nutrition, 74(6), pp.761-766.