The Exact Ingredients For Better Hair Growth, According To Experts

by | Mar 4, 2024 | Hair

Remember being six years old and dreaming that you’d wake up with astoundingly long locks ala Rapunzel? (Her haircare must’ve been truly incredible to enable that level of hair growth *and* have it be strong enough to hoist her evil witch mother up the building.)

Now, we’ve come to understand that growing long hair is much less about waiting for it to grow and more about nourishing your hair from root to tip to achieve glowing, strong strands. If achieving long, Pocahontas-esque locks of lustre is your goal, you’ve come to the exact right page. We’re about to dive deep into which ingredients actually penetrate the scalp to boost hair growth.

Meet the experts: Claire Shread is the Co-Founder at Umberto Giannini. Dr Tarryn Jacobs is a dermatologist based in Pretoria.

First, how does hair grow?

Allow yourself a brief science lesson. Below the scalp’s surface sits your hair bulb, where hair begins to grow. When the hair root is supplied with blood, hair grows. Typically, the hair on your head grows at a rate of about 1cm per month. Per a paper in the National Library of Medicine, hair continues to grow as long as there new hair cells in the hair bulb. Added to this, hair grows in a particular phase, called the anagen phase, which can last several years. When we think of hair growth, it can be likened to volume: thick, bouncy hair that’s growing densely.

READ MORE: How To Balance Your Haircare And Workouts, If You’re Black

What causes hair to grow ‘slowly’ or stop growing?

A healthy adult loses about 70 to 100 hairs on the head per day. as part of our normal hair cycle. If there is increased hair shedding, it’s referred to as a condition called telogen effluvium, explains Dr Jacobs. Here, there is an increase in the number of hairs shifting from the growing phase (anagen) to the shedding phase (telogen). Common triggers of this can be severe stress, childbirth, medications, extreme dieting or underlying medical conditions like thyroid disease.

Some factors could cause the root to become damaged, leading to less growth. This can happen with a health condition, such as alopecia. “A common hair loss disorder that we see in the clinic which is due to genetics, is also known as male or female pattern balding (androgenetic alopecia),” says dermatologist Dr Tarryn Jacobs. “In women, the first signs of this type of hair loss is thinning or a widening part.”

READ MORE: 2024’s Biggest Hair Trends Include Bows, Highlights And Pixie Cuts

Other reasons you could experience hair thinning:

  • Medications
  • Health problems and autoimmune conditions
  • Poor nutrition
  • Age
  • Chemical hair treatments
  • Treatments like chemotherapy or radiation

If you’re experiencing hair loss, it’s best to chat to a doctor or dermatologist who can recommend treatments. “Hair loss can have an immense impact on your emotional well-being and there are effective treatment options available,” says Dr Jacobs.

How to boost your hair growth

However, if you want to grow your hair longer than it is, you have options. “We think volume comes from three places: one, your diet, your lifestyle, your hormone balance and two, how you treat your scalp and then, three, what you’re putting your hair through,” says Claire Shread, co-founder at Umberto Giannini. Balancing your hormone levels, particularly your thyroid, is linked to better hair growth. Having enough vitamins and minerals in your diet can also support healthy hair growth and letting your hair rest is key. Avoid tight hairstyles that pull at the roots of the hair, causing them to fall out.

If you’re struggling with hair loss or thinning, Dr Jacobs’ go-to is minoxidil.

“[It] has proven efficacy and helps stimulate hair growth and improves hair thickness. It works by increasing the length of the anagen, the active growth phase,” she says.

Added to that, nourished hair is hair that grows well. That’s because hair growth can be stunted if it breaks off in the middle of the shaft, making it weaker. “So if you can protect your hair for longer, you’ll get longer hair,” explains Shread.

Your mission, should you choose to accept it, is to make sure your hair is as healthy as possible by fortifying it so that it grows longer and breakage is reduced.

READ MORE: How To Use Rosemary Oil To Grow Stronger, Healthier Hair, According to Experts

The ingredients that encourage hair growth

Having said all this, there are specific ingredients that anecdotally (and scientifically) boost hair growth. They typically work by stimulating the hair follicle, bringing fresh blood so that hair can grow.

Can caffeine help hair grow?

“Caffeine has a stimulating, blood circulation action to the scalp,” says Shread. Per one study in the International Journal Of Trichology, people with androgenetic alopecia were treated with caffeine. The study found that caffeine is a viable route to treating hair loss since it stimulates hair growth. In another study, scientists tested caffeine for hair growth alongside the popular treatment minoxidil, which is also used for hair growth. They found a difference in efficacy of just one percent, making it as efficient.

Can rosemary oil help hair grow?

Not many studies back up the popular claim that rosemary oil can boost hair growth. But this hasn’t stopped throngs of TikTokers, who swear by its efficacy. One randomised control trial found it to be effective when compared to minoxidil. Another study on rats found similar results.

It’s thought that rosemary works by improving circulation in the scalp. It’s also anti-inflammatory and has been linked to decreased greying and fighting dandruff. “What’s it’s important to note is that rosemary oil, in one study, is compared to a lower concentration of minoxidil (ie 2%) than what is indicated and used for androgenetic alopecia (male and female pattern balding), which is 5%,” says Dr Jacobs. “There is far more evidence supporting the efficacy of topical minoxidil. We need a lot more research before doctors can start recommending rosemary oil for hair loss.”

READ MORE: Here’s Everything You Need to Know About Getting a ‘Hair Botox’ Treatment

Can pea sprout extract help hair grow?

According to experts at Umberto Giannini, who use this extract in its Grow Tonic, pea sprout extract contains vitamins and minerals that help restore vitality and density of the hair, prolonging its life cycle. One German study found that it is effective at helping hair grow longer and reduces hair loss.

Can arginine help hair grow?

One study in rats found that arginine helped with hair growth. However, the effects on humans remain to be seen. Still, it’s thought that arginine works by fortifying the hair follicle and prolongs the growth cycle of hair.

Can castor oil grow your hair?

“Many believe that vitamin E and ricinoleic acid (a fatty acid) in castor oil may increase circulation in the scalp and decrease inflammation,” says Dr Jacobs. “Although it may be nourishing for hair, unfortunately, there are no clinical studies to support its ability to grow hair.”

Can onion juice help your hair grow?

Um, this one is a bit strange. The theory? “It’s suggested that it may give a skin allergic reaction that can induce an immune reaction that could stimulate hair growth in alopecia areata, a non-scarring form of hair loss,” explains Dr Jacobs. “A single study compared onion juice to tap water in alopecia areata. Although there were positive results for hair growth, it was small with only 38 participants so we don’t have conclusive research to support its use,” she explains.

READ MORE: 9 Ways To Repair Damaged Hair

Can peptides help grow hair?

According to studies, there is evidence that peptides can encourage hair growth. As the building blocks of protein, peptides “may work by supporting the metabolic needs of hair cells,” explains Dr Jacobs. They could also work by improving cuticle strength and decreasing shedding.

“What’s crucial to note is that the studies supporting the efficacy of the natural ingredients found in hair growth over-the-counter products are limited in treating hair loss disorders but may help support healthy hair growth as part of a good hair care routine,” explains Dr Jacobs.

Hair growth serums

If nourishing your healthy hair for longer hair growth is a priority, try these products.

standard beauty peptide miracle growth serum
Standard Beauty Peptide Miracle Growth Serum

Apply directly to the scalp to nourish hair at the root and enjoy longer locks.

umberto giannini grow tonic
Umberto Giannini Grow Tonic

Reviewers swear by this product for its ability to boost hair growth.

the ordinary multi-peptide serum
The Ordinary Multi-Peptide Serum

With rave reviews, people report denser, more voluminous hair after using this.

Hair growth products

Supplement your routine with fortifying products for longer, stronger hair.

mielle rose mint shampoo for hair growth
Mielle Rose Mint Shampoo

This viral product boasts stronger, longer hair growth.

hair growth umberto giannini grow mask
Umberto Giannini Grow Mask

Nourished hair grows better without breaking, dry ends. Repair and protect with a mask.

hair growth hairbrush
Wet Brush Speed Dry

For gentler detangling, look to a brush that won’t break your hair.


Michelle October

Michelle is the features editor at WH. She’s immensely curious about the world, passionate about health and wellness and enjoys a good surf when the waves are good. Find her on Instagram here.

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