1. Biotin
Biotin is one of the most talked-about ingredients when it comes to promoting thicker, healthier hair. Also known as vitamin B7, biotin plays a key role in the production of keratin, the protein that makes up your hair. It helps strengthen weak strands, reduce breakage, and support the growth of new hair by improving your body’s ability to metabolize nutrients essential for hair health. It’s not a miracle, though, and won’t regrow hair overnight.
2. Niacin
Niacin, or vitamin B3, is another powerful player in the world of haircare. It works by boosting blood circulation to the scalp, which helps deliver more oxygen and nutrients to hair follicles (which are two essentials for healthy hair growth). Improved scalp circulation can lead to a stronger foundation for growing new hair and maintaining the health of existing strands. Plus, niacin can help reduce inflammation and improve the appearance of dull, thinning hair, so it’s an all-around team player in the world of haircare.
3. Caffeine
Caffeine isn’t just for waking you up in the morning — it’s also a surprisingly effective ingredient in many hair-thickening shampoos and treatments. When applied topically, caffeine helps stimulate hair follicles and prolong the growth phase of the hair cycle. This means it can reduce shedding and encourage longer, stronger hair over time.
4. Castor Oil
Castor oil has long been a go-to natural remedy for promoting hair growth and thickness. Rich in ricinoleic acid and fatty acids, it helps nourish the scalp, reduce inflammation, and lock in moisture, creating a healthy environment for hair to thrive. Its thick, emollient texture coats strands and can make them feel instantly fuller and shinier.
5. Keratin
Keratin is the structural protein that makes up your hair, so it only makes sense that adding keratin to your routine can help fortify and protect your strands. Products infused with keratin can help rebuild the damaged areas of the hair shaft, smooth rough texture, and reduce frizz—all while making the hair appear thicker and healthier.
6. Copper Peptides
Copper peptides are lesser known but incredibly promising when it comes to hair regrowth and scalp health. These tiny protein fragments help stimulate blood flow to the scalp and extend the growth phase of hair follicles. They also support the production of collagen and elastin, which improves the overall condition of the scalp and hair. Copper peptides can aid in both preventing hair loss and encouraging new growth, especially when used consistently in serums or scalp treatments.