How Is Sulfur Used in Industry, Agriculture, and Medicine?

Sulfur ranks among the most versatile elements on Earth, touching virtually every sector of the modern economy. Its largest single use is as a feedstock for sulfuric acid, the world’s most produced industrial chemical, but it also cross-links the rubber in your tires, protects crops from fungal disease, and sits inside hundreds of FDA-approved pharmaceuticals. Much of today’s sulfur supply is itself a byproduct of cleaning fossil fuels, which means the element is cheap, abundant, and increasingly in search of new applications.

Where the Sulfur Comes From

Most of the sulfur used worldwide is not mined from elemental deposits the way it once was. Instead, it arrives as a byproduct of refining crude oil and processing natural gas. Petroleum and natural gas contain sulfur compounds that must be removed to meet fuel-quality and emissions standards. The recovered sulfur is then purified and sold, making oil and gas refineries the dominant suppliers. Because global refining capacity continues to grow, an oversupply of sulfur has been projected for the near-term future, prompting researchers and industry to look for new markets and uses for the element.¹

Sulfuric Acid and the Backbone of Industrial Chemistry

The single biggest destination for recovered sulfur is the production of sulfuric acid. This dense, corrosive liquid is sometimes called the bellwether of industrial activity because so many manufacturing processes depend on it. Sulfuric acid is essential in phosphate fertilizer production, petroleum refining, metal ore processing, and the manufacture of chemicals ranging from dyes to explosives. Its role in making superphosphate and other phosphate fertilizers alone accounts for a large share of global sulfuric acid demand. Because sulfur is a precursor to this acid, fluctuations in sulfur supply ripple through fertilizer prices and food costs worldwide.¹

Rubber Vulcanization

If you have ever wondered why a car tire can grip hot asphalt without melting or shatter in winter cold without cracking, sulfur is a big part of the answer. Vulcanization is the process of heating raw rubber with sulfur so that sulfur atoms form cross-links between the long, floppy polymer chains. Those bridges lock the chains into a three-dimensional network, giving the rubber elasticity, strength, and resistance to temperature extremes. The amount of sulfur added controls how stiff the final product becomes: a small dose yields a soft, stretchy material suitable for rubber bands, while a heavy dose produces hard rubber used in electrical insulation and industrial parts. Research using calorimetry has confirmed that the heat released during vulcanization scales directly with the amount of sulfur present in the compound.² Without sulfur-based vulcanization, modern tires, hoses, gaskets, and seals would not exist in their current form.

Detergents and Surfactants

Sulfur also plays a less visible but equally widespread role in household and industrial cleaning. Linear alkylbenzene sulfonic acid, often abbreviated LAS or ASA, is the main active ingredient in many commercial detergent formulations. It is produced by reacting linear alkylbenzene with sulfur trioxide, a process called sulfonation that takes place in specialized falling-film reactors.³ The resulting sulfonate molecule has one end that clings to grease and another that dissolves in water, which is what makes detergent work. Billions of kilograms of these sulfur-derived surfactants are manufactured each year for laundry soap, dishwashing liquid, and industrial degreasers.

Sulfur as a Plant Nutrient

Sulfur is one of the essential nutrients plants need to grow. It is a structural component of amino acids, proteins, vitamins, and enzyme cofactors, and plants that lack it develop yellowing leaves and stunted growth.⁴ Most of the sulfur that plants absorb ends up in two amino acids, cysteine and methionine, which together account for roughly ninety percent of the total sulfur in most plant tissues.⁵ These amino acids are also important for human and animal nutrition, so sulfur-deficient crops translate into lower-quality food and feed.

For decades, atmospheric sulfur deposited from industrial emissions provided an unintentional fertilizer subsidy. As air quality regulations have tightened and smokestack sulfur dioxide emissions have dropped, many soils that once received enough sulfur passively now need supplementation. Elemental sulfur has become an increasingly popular fertilizer choice, but it is not immediately plant-available. Soil microbes must first oxidize it to sulfate, the form roots can actually take up.⁶ The speed of that conversion depends on soil acidity, temperature, moisture, and the population of sulfur-oxidizing bacteria present.⁷ Farmers sometimes co-granulate elemental sulfur with other nutrients to deliver a slow-release sulfur source that feeds the crop over weeks rather than all at once.

The Oldest Fungicide Still in Use

Elemental sulfur holds a distinction that few chemicals can match: it is humanity’s oldest fungicide and is still used on farms today.⁸ Ancient Greek and Roman writers described dusting vines with sulfur to ward off mildew, and modern growers do essentially the same thing with more refined formulations. Sulfur is particularly effective against powdery mildew, a group of fungal diseases that attack everything from grapes to strawberries to peas.

Field trials on peas in India found that sulfur applied at moderate rates controlled powdery mildew effectively and produced better yields than several other treatments, with no plant damage observed even at double the effective dose.⁹ In strawberry production, weekly sulfur applications reduced both leaf and fruit disease as well as or better than standard synthetic fungicides, and yields jumped by 80 to 300 percent compared with untreated controls depending on growing conditions.¹⁰ Phytotoxicity was minimal and occurred only when temperatures climbed above 35°C for at least two hours, which means sulfur works well in most growing seasons. Because sulfur attacks fungi through multiple biochemical targets simultaneously, pathogens have a harder time developing resistance to it, which makes it a valuable rotation partner alongside single-site synthetic fungicides.

Sulfur-Containing Pharmaceuticals

Sulfur is woven deeply into the fabric of modern medicine. Out of all the heteroatoms that appear in approved drugs (apart from oxygen and nitrogen), sulfur is the most common, present in a set of over 360 FDA-approved pharmaceuticals.¹¹ What makes sulfur so attractive to drug designers is its chemical flexibility. Unlike oxygen, sulfur can sit at oxidation states ranging from −2 to +6, giving medicinal chemists the ability to fine-tune a molecule’s shape, polarity, and binding properties simply by adjusting the sulfur atom’s oxidation level.¹² The most common sulfur-containing drug scaffolds include sulfonamides, thioethers, sulfones, and penicillins.

Sulfonamide Antibiotics

Sulfonamide drugs, commonly called “sulfa drugs,” were among the first systemic antibiotics, introduced in the 1930s. They work by blocking an enzyme called dihydropteroate synthase, which bacteria need to make folate, a vitamin essential for DNA replication.¹³ Because humans get folate from food rather than synthesizing it, sulfa drugs can starve bacteria without harming the patient’s cells. Research has also shown that sulfonamides promote a “methylfolate trap” inside bacteria, which accelerates cell death even beyond simple folate starvation.¹⁴

Sulfonamides are no longer the front-line antibiotics they once were, since resistance has spread widely. But the sulfonamide chemical scaffold lives on far beyond infection treatment. Compounds with this backbone now serve as diuretics, anti-inflammatory agents, glaucoma medications, and blood-sugar-lowering drugs.¹⁵ Furosemide, a widely prescribed diuretic, and celecoxib, a common anti-inflammatory, both carry sulfonamide groups.

N-Acetylcysteine as an Antidote

One of the most dramatic medical uses of a sulfur compound is N-acetylcysteine, or NAC, the standard antidote for acetaminophen (paracetamol) overdose. When taken in excess, acetaminophen overwhelms the liver’s detoxification pathways and produces a reactive metabolite that destroys liver cells. NAC works by boosting the liver’s production of glutathione, the sulfur-containing molecule that normally neutralizes the dangerous metabolite.¹⁶ Given early enough, NAC is highly effective at preventing liver failure; delays in treatment dramatically worsen the prognosis, and without timely NAC, liver transplantation may become the only option.¹⁷

Sulfur in Dermatology

Topical sulfur preparations have been used to treat skin conditions for centuries, and they remain part of the modern dermatology toolkit. Sulfur has keratolytic properties, meaning it helps shed dead skin cells, and it also has mild antibacterial and antifungal activity. It is commonly found in over-the-counter acne treatments, dandruff shampoos, and lotions for seborrheic dermatitis.

One condition where sulfur shows particular promise is rosacea, a chronic inflammatory skin disorder. A study of Japanese patients with rosacea found that a topical sulfur preparation significantly improved clinical scores for burning sensation, flushing, and skin sensitivity. Among patients who tested positive for Demodex mites, which are implicated in some forms of rosacea, the positivity rate dropped from about 81 percent to roughly 29 percent after eight weeks of treatment.¹⁸ Contact dermatitis or discomfort was reported in about 41 percent of the sulfur-treated group, so topical sulfur is not irritation-free, but the symptom improvements were meaningful enough to support its use as an alternative to standard metronidazole therapy.

MSM and Joint Health Supplements

Methylsulfonylmethane, or MSM, is one of the most popular sulfur-based dietary supplements, marketed primarily for joint pain and osteoarthritis. It provides sulfur in a bioavailable organic form and is found naturally in small amounts in certain foods. A randomized controlled trial of patients with knee osteoarthritis found that 12 weeks of MSM supplementation produced statistically significant improvements in pain and physical function compared with placebo.¹⁹ The researchers noted, however, that the improvements were small and it remains unclear whether they are clinically meaningful.

A meta-analysis pooling data from MSM and the related compound DMSO found a reduction in pain that was neither statistically nor clinically significant overall.²⁰ The mixed findings and relatively short dosing periods in available trials make it hard to draw definitive conclusions. If you are considering MSM for joint pain, the evidence suggests any benefit is modest at best, and you should not expect it to replace proven treatments.

Wine, Dried Fruit, and Food Preservation

If you have ever read a wine label that says “contains sulfites,” you have encountered sulfur’s role in food science. Sulfur dioxide is the most widely used preservative in winemaking, valued for both its antimicrobial and antioxidant properties.²¹ It suppresses unwanted bacteria and wild yeasts, prevents oxidation that would turn a fresh white wine brown and flat, and helps stabilize color. Winemakers have added sulfur dioxide to wine since at least the Roman era, and despite ongoing research into alternatives, nothing has matched its combination of effectiveness and low cost.

Beyond wine, sulfites are used to preserve dried fruits, prevent browning in cut potatoes, and extend the shelf life of various processed foods. Some people are sensitive to sulfites, particularly those with asthma, and food labeling regulations in most countries require disclosure when sulfite levels exceed a threshold. The amounts used in food preservation are small and considered safe for the general population by regulatory agencies.

Cleaning the Air With Sulfur Chemistry

Sulfur’s environmental story has an ironic twist. While sulfur dioxide emissions from coal-burning power plants cause acid rain and respiratory problems, the cleanup technology itself produces a sulfur-containing product that turns out to be useful. The 1990 U.S. Clean Air Act Amendments required coal power plants to scrub sulfur dioxide from their exhaust. Most plants accomplish this through flue gas desulfurization, which captures SO₂ and converts it into a synthetic form of gypsum.²² This FGD gypsum is chemically similar to mined gypsum and is used in wallboard manufacturing, as a soil amendment to improve structure in heavy clay soils, and as a source of calcium and sulfur for crops. What was once a pollutant and a disposal headache became a construction material and a fertilizer ingredient.

Lithium-Sulfur Batteries

One of the most actively researched frontiers for sulfur is energy storage. Lithium-sulfur batteries pair a lithium metal anode with a sulfur cathode and offer a theoretical energy density of about 2,600 watt-hours per kilogram, several times higher than current lithium-ion technology.²³ Sulfur is also cheap and abundant compared with the cobalt and nickel used in conventional lithium-ion cathodes, which makes the chemistry attractive for electric vehicles and grid-scale storage.

The catch is that lithium-sulfur batteries still face practical hurdles. During charge and discharge, intermediate compounds called polysulfides dissolve into the electrolyte and migrate to the anode, degrading performance over repeated cycles. Researchers are designing cathode architectures that physically and chemically trap these polysulfides, such as carbon-cloth scaffolds embedded with metal-organic framework-derived materials that confine the sulfur and maintain high loading levels.²⁴ Commercialization is not imminent, but the pace of cathode innovation has accelerated over the past decade, and several companies are working toward early applications in drones and specialized electronics where weight is more important than cycle life.

Sulfur Concrete

Conventional concrete uses Portland cement as its binder, requires water to cure, and is one of the largest sources of industrial carbon dioxide emissions. Sulfur concrete offers an alternative by replacing cement and water entirely with molten sulfur as the binding agent. When it solidifies, sulfur concrete gains strength rapidly, shrinks less than Portland cement concrete, and shows superior resistance to acids and salt environments.²⁵ These properties make it appealing for infrastructure exposed to corrosive conditions, such as sewer pipes, chemical plant floors, and marine structures.

Researchers have also explored making sulfur concrete more sustainable by incorporating fly ash and recycled aggregates in place of virgin materials.²⁶ Interestingly, sulfur concrete can itself be recycled: investigations found that its mechanical strength actually improved by about 30 percent after being melted down and re-cast once, though a second recycling caused a significant drop in strength.²⁷ Given that global sulfur supply exceeds current demand, sulfur concrete could absorb some of that surplus while reducing the cement industry’s carbon footprint.

Hair Styling and Personal Care

Your hair owes its strength and shape to sulfur. Keratin, the protein that makes up hair, is held in its natural structure by disulfide bonds, which are chemical bridges between sulfur atoms on neighboring protein chains. Permanent waves and chemical straightening treatments work by first breaking those disulfide bonds with a reducing agent, typically a thioglycolate (itself a sulfur compound), which allows the protein chains to slide past one another and be reshaped around rods or combed flat. A second step then rebuilds the cross-links, locking the hair in its new configuration. Hydrogen peroxide is traditionally used for that re-bonding step.²⁸ Both the bonds being broken and the chemicals doing the breaking involve sulfur chemistry, making this one of the most direct consumer encounters with the element’s reactivity.

Sulfur also shows up in medicated shampoos for dandruff and scalp conditions, where its keratolytic and antifungal properties help control flaking. Combined with salicylic acid, sulfur-based shampoos remain a common recommendation for seborrheic dermatitis, carrying forward a tradition of topical sulfur use in skin and scalp care that stretches back thousands of years.