If the first thing that comes to mind when you hear sulfur is the smelly element you learned about in chem class, you're not wrong. Sulfur is a natural element that can be found in plants, foods, proteins (in the form of amino acids), and even water. And yes, it can often smell like rotten eggs.
So where does sulfur fit in the beauty world? When it comes to hair, our experts—board-certified dermatologist Marisa Garshick, MD, and chemist Joe Cincotta, Ph.D.—confirm that it does indeed have a purpose in your routine.
Meet the Expert
Read on to learn about the benefits of sulfur for hair.
Sulfur for Hair
Type of ingredient: Strengthener
Main benefits: Strengthens hair, improves hair elasticity and flexibility, hydrates the scalp, and reduces inflammation
Who should use it: In general, people with dry or brittle hair or hair susceptible to breakage may benefit from using sulfur.
How often can you use it?: There is no formal recommended amount of topical use, however, Garshick recommends using small amounts. Overuse (copious amounts at a time) can lead to irritation of the scalp. While it can be used any time of day, due to the odor, it's typically recommended to use sulfur products at night.
Works well with: "Typically, any strengthening and conditioning agents can work well in conjunction with sulfur," says Garshick. "In general, some ingredients can include argan oil and antioxidants."
Don’t use with: Cincotta notes that sulfur should not be used with very acidic mixtures or products, such as apple cider vinegar.
Benefits of Sulfur for Hair
There are multiple benefits to sulfur for hair, especially for those with dry, brittle hair. "It is thought that sulfur can help to strengthen hair and improve elasticity," says Garshick. "This is because keratin, a key protein in our hair, is made up of sulfur so it is thought that supplementing with sulfur may help to improve overall hair health, however, more research is needed. Sulfur is also found in certain amino acids which are important for hair health, such as cysteine and methionine."
Cincotta adds: "The sulfur in the hair is part of a very special amino acid found in hair called cystine. Cystine is the predominant amino acid found in both the cortex and cuticle of the hair. It is the major structural component of keratin protein. It makes the surface of hair (cuticle) tough and resistant."
- Strengthens hair: "Sulfur is a key component of keratin, so it helps to keep the hair strong and reduce the potential for hair breakage and brittleness," says Garshick.
- Reduces inflammation: Garshick notes that sulfur can help reduce inflammation in the scalp, which can help improve overall hair health. Similarly, studies saw positive results in the reduction of dandruff when testing shampoos that included sulfur in a controlled trial.
- Antibacterial benefits: "[Sulfur] has antibacterial benefits, which can also be helpful for overall scalp health and help promote a good environment for the hair," says Garshick.
- Improves elasticity: Both Cincotta and Garshick agree that by contributing to the key protein in hair—keratin—sulfur helps improve the overall elasticity of the hair.
- Promotes hair growth: Garshick notes that sulfur is thought to prolong the anagen or growth phase of the hair cycle, so it may have a benefit when it comes to hair growth. However, more research is needed to support this she adds.
Hair Type Considerations
Generally speaking, sulfur should work for all hair types. That being said, it may be especially beneficial to someone with damaged, brittle, or dry hair.
"Sulfur will exhibit best results on damaged hair," says Cincotta. "[Such as] hair that is color-treated, bleached, relaxed, and permed. Also, hair that has heat damage from flat irons, curling irons, or overexposure to the sun. Basically, any damaged hair. All the damaging effects listed above cause the hair to lose strength and elasticity. By infusing hair with sulfur-containing products that damage can be reversed to some extent."
Cincotta also notes that sulfur will not damage hair, so there is no need to avoid it. "If hair is healthy and undamaged the sulfur will not find damaged areas in the hair and will rinse out," he says. "While it can be used by all hair types, given the limited research into topical formulations of sulfur for the hair, it is important to note that the benefits may vary among individuals," Garshick adds. She also recommends doing a patch test before using any sulfur product, especially for those with sensitive skin.
How To Use Sulfur for Hair
Sulfur usage for hair often depends on the product, but first things first, it's important to note that you should not attempt to make a sulfur hair product on your own. "I only recommend that you purchase sulfur-containing products; I do not recommend DIY masks," says Cincotta.
So, how does one use sulfur products? "Sulfur-containing products should be used on wet hair after shampooing and either used in a rinse out or, better yet, in a leave-in conditioner or treatment," says Cincotta. "Blow-dry or air-dry afterward." When looking for a sulfur product, you'll typically find it in mask or shampoo form.
"When sulfur is combined with selenium to create the compound selenium sulfide, it can be used in the treatment of dandruff as it works as an antifungal agent," says Garshick. "The problem with sulfur-containing anti-dandruff shampoos is there is a malodor that many may find disagreeable," notes Cincotta. Trends may come and go, but we can almost guarantee that our hair smelling like rotten eggs will never be in.
So, while you may have passed on this odorous ingredient in the past, maybe it's time to think again. The experts confirm that sulfur can in fact have benefits on the scalp and hair, and we recommend testing it out on a night in.
The Best Hair Products With Sulfur
Curious about which sulfur products to pick up first? The experts recommend the following.
"This leave-in treatment incorporates blue sea kale which is rich in sulfur to help strengthen the hair bonds," says Garshick. "In doing so, it helps to strengthen the hair, in addition to working to boosting moisture and shine."
"In clinical testing we performed on hair swatches using the Color Wow Kale-Infused Dream Cocktail, results showed 50 percent less breakage after one treatment and no malodor," adds Cincotta.
This mask for glossy hair contains blue sea kale. "Blue sea kale is the highest vegetable source of elemental sulfur," explains Cincotta.
What protein does sulfur work best with for hair?
Why does sulfur smell?
Ironically, pure sulfur actually has no smell. Sulfur has an odor due to its compounds.
Do oils work well with sulfur for hair?
Typically, yes. Strengthening and conditioning agents can work well in conjunction with sulfur, including oils, according to Garshick.
Boone, C.; Bond, C.; Cross, A.; Jenkins, J. Sulfur General Fact Sheet; National Pesticide Information Center, Oregon State University Extension Services. 2017.
Leyden JJ, McGinley KJ, Mills OH, Kyriakopoulos AA, Kligman AM. Effects of sulfur and salicylic acid in a shampoo base in the treatment of dandruff: a double-blind study using corneocyte counts and clinical grading. Cutis. 1987;39(6):557-561.
Stewart D. Sulfer Element Facts. Chemicool. 2021.