How does capsicum improve scalp circulation and boost growth?

Blood circulation is the system responsible for transporting oxygen-rich blood and nutrients throughout the body, including the scalp. When circulation is functioning well, hair follicles receive the essential fuel—oxygen, amino acids, vitamins—to maintain their active growth phase, known as the anagen phase. When circulation is poor, several problems arise. First, the follicles receive fewer nutrients and less oxygen, which weakens their cells. Second, cellular waste accumulates, making regeneration harder. Third, in conditions such as androgenetic alopecia, poor circulation allows dihydrotestosterone (DHT)—a hormone that damages follicles—to accumulate locally.

What does capsicum (capsaicin) do?

Capsicum, which contains the compound capsaicin, acts by activating the TRPV1 receptor (transient receptor potential vanilloid 1) in nerve endings. This triggers the release of a neuropeptide called CGRP (calcitonin gene-related peptide), which causes blood vessels to dilate—a process known as vasodilation. This widening increases blood flow to the scalp area. As a result, the delivery of oxygen and nutrients to the hair follicles improves, potentially supporting stronger and more sustained hair growth. A significant study by Harada et al. (2007) evaluated the effects of capsaicin combined with isoflavones in both humans and mice. The study was conducted over five months and involved 48 individuals with alopecia.

It used a randomized, double-blind, placebo-controlled design. Researchers measured levels of IGF-1 (Insulin-like Growth Factor 1), a protein that plays a crucial role in hair growth, and counted hairs per square centimeter. The results were promising: 64.5% of participants in the treated group experienced new hair growth compared to only 11.8% in the placebo group. In mice, IGF-1 levels in the skin increased within just 30–180 minutes of treatment. However, because the treatment involved both capsaicin and isoflavones, the specific contribution of capsicum alone remains unclear. Another study conducted in Shanghai in 2022 compared a topical mixture of capsaicin, piperine, and curcumin to minoxidil in patients with alopecia areata. The study included 60 participants treated over a three-month period. Hair regrowth was evaluated using the SALT scale and dermatoscopy. Results showed hair regrowth comparable to minoxidil, although, again, the combination of ingredients makes it difficult to isolate the effect of capsaicin.

Side effects and safety concerns

Though natural, capsicum is not entirely free of side effects. When applied topically, it may cause local irritation, redness, and mild burning sensations. In some individuals, especially those with sensitive skin, it can lead to contact dermatitis or mild burns. There are isolated cases of eczema reactions reported in response to capsaicin-based treatments. For safety, it's essential to avoid contact with eyes or mucous membranes.

What happens when circulation is poor?

When blood flow to the scalp is inadequate, several physical consequences may occur. Hair becomes thinner and weaker, and hair loss may accelerate. Follicles can become dormant, prolonging the resting (telogen) phase and reducing the number of active hairs. In addition, poor circulation can increase a follicle's sensitivity to DHT, making it more vulnerable to hormone-induced damage. Over time, local hypoxia (low oxygen levels) may occur, placing stress on follicular cells and hindering their regeneration.

User Experiences

Capsicum, commonly known as cayenne pepper, has emerged as a botanical of interest in hair loss research due to its active compound, capsaicin. While Tressless community discussions on capsicum are currently sparse, the scientific literature offers promising insights that users may not yet be widely aware of. Scientific studies consistently report that capsaicin can stimulate hair growth. It works primarily by promoting the expression of insulin-like growth factor 1 (IGF-1), which supports hair follicle health and may prolong the anagen (growth) phase of the hair cycle. A 2024 study formulated a 0.2% cayenne pepper microemulsion and found it significantly improved hair growth in animal models. Another study showed that a 20% capsicum leaf extract solution had comparable efficacy to 2% minoxidil in rabbits.

Additional findings revealed that shampoo formulations containing capsicum extracts were well-tolerated and perceived by volunteers to improve local oxygenation and circulation of the scalp. Furthermore, cayenne leaf extract in tonic formulations demonstrated measurable improvements in hair quantity and length in mice. Despite this growing body of evidence, the Tressless community has not yet extensively engaged with or documented real-world experiences using capsicum. This absence of user feedback might reflect either limited experimentation or underreporting of results. However, given the mounting research and the widespread use of natural products in topical treatments, it's likely that capsicum-based products will gain traction as users explore alternatives to conventional options like minoxidil and finasteride. For now, while anecdotal community insights are missing, users interested in trying capsicum may find reassurance in its safety profile and the consistent research backing its potential for stimulating scalp circulation and hair regrowth.

How to use capsicum safely

Dermatologically formulated products—such as shampoos or serums containing around 0.01% capsaicin—are recommended. Begin with small amounts applied infrequently to test skin tolerance. Massage the scalp during application to enhance circulation. If persistent irritation occurs, stop use immediately.mThanks to its active compound capsaicin, capsicum can stimulate circulation in the scalp, promote the release of growth factors like IGF-1, and support hair growth. These effects have been demonstrated in several real studies, though most involved ingredient combinations. The solo effect of capsicum remains an area for further research. Nonetheless, capsicum appears promising as a non-hormonal, natural aid for those concerned with hair thinning or loss, provided it is used with caution and awareness of possible side effects.

References

Harada, N., Okajima, K., Arai, M., Kurihara, H., & Nakagata, N. (2007). Administration of capsaicin and isoflavone promotes hair growth by increasing insulin-like growth factor-I production in mice and in humans with alopecia. Growth Hormone & IGF Research, 17(5), 408–415. Retrieved from https://pubmed.ncbi.nlm.nih.gov/17569567

Shanghai General Hospital & Shanghai Jiao Tong University School of Medicine. (2022, April 21). Efficacy of a mixed preparation containing capsaicin, piperine and curcumin in the treatment of alopecia areata. Journal of Cosmetic Dermatology. Retrieved from https://www.cosmeticsdesign-asia.com/Article/2022/04/21/Mix-of-peppers-and-turmeric-as-effective-as-minoxidil-in-treating-hair-loss-study

WebMD. (n.d.). Capsicum – Uses, Side Effects, and More. Retrieved from https://www.webmd.com/vitamins/ai/ingredientmono-945/capsicum

Mayo Clinic. (n.d.). Capsaicin (topical route). Retrieved from https://www.mayoclinic.org/drugs-supplements/capsaicin-topical-route/description/drg-20062561

Wimpole Clinic. (n.d.). Chili Oil For Hair Growth + 6 More Hair Growth Oils. Retrieved from https://wimpoleclinic.com/blog/go-natural-best-oils-use-stimulate-hair-growth/

MDPI. (2022). An Updated Etiology of Hair Loss and the New Cosmeceutical. Cosmetics, 10(4), 106. Retrieved from https://www.mdpi.com/2079-9284/10/4/106