Does Vitamin B3 Help Hair Growth?

Imagine your hair follicles as tiny engines beneath your scalp, running day and night to produce new strands. Like any engine, they need the right fuel and maintenance to stay efficient. Vitamin B3, also known as niacin or its gentler form, niacinamide, has become a popular “fuel additive” in wellness circles. Search terms such as vitamin B3 hair growth or niacinamide for scalp health draw thousands of curious readers each month. But does topping up with B3 really help hair grow thicker or faster?

Let’s lift the hood and see what the science says about B3, scalp blood flow, and those hardworking follicle engines.

Vitamin B3: The Essential Fuel

Hair follicles are among the most metabolically active structures in the body. They require steady energy and oxygen to stay in the growth phase, known as anagen. Vitamin B3 is vital here: it helps build NAD⁺, a molecule every cell needs to convert nutrients into energy [1].

When this “fuel system” runs low, things start to misfire. Severe B3 deficiency (pellagra) can lead to widespread hair loss alongside skin and digestive symptoms [1]. Although true deficiency is rare today, it reminds us that niacin is essential for maintaining normal hair follicle function.

Beyond basic nutrition, niacin also acts as a vasodilator: it widens blood vessels, often causing a temporary warmth or “niacin flush.” That improved circulation could, in theory, deliver more oxygen and nutrients to the scalp [2]. Niacinamide, meanwhile, doesn’t flush but helps the skin barrier and reduces inflammation, important for a calm, healthy scalp. Together, these properties make vitamin B3 an intriguing candidate for supporting hair health.

The Evidence So Far

Early Promise

In a 2005 pilot trial, 60 women with female-pattern hair thinning applied a topical niacin derivative for six months. Those using the niacin formula reported increased hair fullness compared with placebo [2]. Although small, this study hinted that niacin might “tune up” follicle engines enough to improve density.

Mixed Results

More recent research has taken a broader look at vitamin B3 as part of nutrient combinations that nourish the scalp and hair from within. In 2024, a study in women with hair thinning evaluated a supplement containing several B-vitamins (including B3), zinc, and botanical extracts. After six months, the group taking the supplement showed noticeably fuller and denser hair compared with those taking a placebo [3]. Although the formula didn’t test B3 alone, the findings suggest that maintaining healthy levels of B-vitamins (niacin included) can help support hair density and overall follicle vitality as part of a balanced nutritional approach.

In 2020, Procter & Gamble scientists tested whether niacinamide could raise levels of VEGF, a growth factor that supports new blood vessel formation. Across a wide dose range, it failed to stimulate VEGF synthesis, leading the authors to conclude that niacinamide has no measurable effect on human hair growth when used alone [4].

So while the B3 story started with optimism, follow-up research suggested niacinamide might be a good team player, but not a star striker when it comes to growing hair.

A Supportive Role

Even if B3 isn’t a stand-alone solution, it may still help maintain scalp health. Niacinamide can reduce oxidative stress and oil imbalance, both of which can trigger scalp inflammation and hair shedding [5]. That’s why it frequently appears in multi-ingredient serums or shampoos marketed for “energizing” follicles or reducing B3 hair thinning. It’s the background maintenance oil rather than the turbocharger: important, but not transformative on its own.

The Next Generation: NMN and the NAD⁺ Boost

Enter nicotinamide mononucleotide (NMN), a newer form of B3 gaining attention for its anti-aging potential. If regular niacin is standard fuel, NMN is a high-octane version designed to boost NAD⁺ directly.

Recent research is shining a light on NMN, which is often described as an upgraded version of niacin. Think of it as a premium-grade fuel designed to recharge the follicle’s engine from within. In laboratory studies, scientists found that NMN helped stressed hair cells recover, restoring their rhythm and vitality. It seemed to calm inflammation, improve communication between growth signals, and enhance the cells’ ability to generate energy [6]. When tested in animal models of hair thinning, follicles treated with NMN began to grow thicker, healthier strands, even in areas affected by hormones linked to pattern hair loss, performing almost as well as established growth treatments [6].

Building on those discoveries, a 2025 study explored whether taking NMN orally could translate to visible hair benefits. After three months, women who supplemented with NMN reported stronger, shinier hair and less shedding. Microscopic analysis also showed subtle improvements in hair thickness and the number of actively growing hairs [7]. While it was a small, early-stage study, the results suggest that NMN may work by improving the quality of existing hair rather than dramatically increasing quantity, more like fine-tuning the engine than replacing it altogether.

How B3 Supports the Scalp

When niacin dilates blood vessels, it may temporarily enhance blood flow to the scalp, increasing the delivery of oxygen and nutrients to hair follicles. Niacinamide, although it doesn’t cause flushing, supports cellular repair and helps the scalp manage oxidative stress, one of the main factors that can weaken follicles over time [5].

At the microscopic level, vitamin B3 fuels the production of NAD⁺, which powers ATP creation: the energy that drives hair matrix cell division. Boosting NAD⁺ is like keeping the engine’s battery fully charged. This helps follicles resist “oxidative wear,” stay in the growth phase longer, and maintain thicker shafts [6].

These effects are subtle but meaningful: B3 doesn’t push follicles to overperform, but it ensures they don’t stall out due to poor fuel or stress overload.

Beyond the Mirror: What’s Really Behind Hair Loss?

Hair loss is rarely about a single missing nutrient; it’s usually a reflection of what’s happening beneath the surface. Hormonal changes, chronic stress, thyroid issues, nutrient gaps, poor sleep, and scalp inflammation can all play a part in how well your follicles perform [1,5].

Before looking for a quick fix, start by addressing the basics that nourish the whole system. A diet rich in vitamin B3 and other key nutrients found in poultry, fish, eggs, legumes, nuts, and whole grains helps keep both scalp and hair in balance [1]. If your meals are often rushed or repetitive, a simple multivitamin can fill in the blanks, though more isn’t necessarily better. High-dose niacin can cause flushing or, in rare cases, liver strain.

Topical niacinamide-based shampoos or serums can soothe irritation, rebalance oil, and support the scalp barrier [5]. Think of them as creating the right environment for growth rather than forcing instant results. Since hair cycles last months, consistency and patience matter more than quick transformations.

Something worth thinking about: how is your scalp feeling lately? Tight, dry, greasy, sensitive? Sometimes the scalp shows us what the body is trying to say: about stress, diet, hormones, or even sleep quality. Paying attention to those signals is often the first step toward real change.

For Health Professionals: Treating the Root, Not Just the Strand

For clinicians and trichologists, it’s worth viewing hair thinning as a multifactorial condition, not just a dermatological symptom. Alongside assessing vitamin B levels, evaluate possible endocrine imbalances (like thyroid disorders or polycystic ovary syndrome), iron or vitamin D deficiencies, autoimmune processes, and medication-related shedding [1,5]. Integrative care: balancing nutrition, hormonal regulation, and stress management often yields better outcomes than any single treatment.

Vitamin B3 and niacinamide can play supportive roles here, especially in combination with established therapies such as minoxidil, platelet-rich plasma, or low-level light therapy [3,5]. And as new studies explore NAD⁺ precursors like NMN, the idea of restoring hair vitality by improving cellular energy and reducing inflammation is gaining scientific ground [7].

The most sustainable approach is one that recognizes the interconnected ecosystem of the scalp, skin, and overall health. Hair loss rarely stems from a single trigger, and outcomes improve when treatment plans reflect that complexity. Integrating nutritional support, stress management, hormonal balance, and evidence-based topical or systemic therapies allows for a more comprehensive strategy, one that strengthens the hair by restoring overall physiological balance rather than treating symptoms in isolation.

The Takeaway: Start Where Growth Begins

Vitamin B3 plays a quiet but essential role in keeping hair vibrant: it fuels the microscopic engines that power follicle growth and renewal. While taking extra B3 won’t spark dramatic regrowth on its own, supporting your body’s ability to make and recycle cellular energy can help hair look stronger, shinier, and more resilient over time.

True hair vitality starts deeper than the scalp. By protecting your cells from oxidative stress, improving circulation, and sustaining mitochondrial health, nutrients like niacin and its advanced form NMN can help create the internal conditions for growth. It’s the same principle behind emerging cellular-health approaches, optimizing the system, not just the symptom.

If you're a practitioner interested in all things niacin, take a look at Tro+ Calm, our practitioner-only, extra-strength, and next-generation formulation designed to help patients relieve stress, reduce anxiousness, and quiet the mind when they need it most.

Read more on vitamin B3 below:

• Niacin vs. Niacinamide: Understanding Vitamin B3, Benefits, and Side Effects
• Does Vitamin B3 Increase Testosterone?
• The Difference Between “Flush” and “No-Flush” Niacin
• Does niacin cross the blood-brain barrier?

References

1. Guo, E. L., & Katta, R. (2017). Diet and hair loss: Effects of nutrient deficiency and supplement use. Dermatology Practical & Conceptual, 7(1), 1–10.

2. Draelos, Z. D., Jacobson, E. L., Kim, H., Kim, M., & Jacobson, M. K. (2005). A pilot study evaluating the efficacy of topically applied niacin derivatives for the treatment of female pattern alopecia. Journal of Cosmetic Dermatology, 4(4), 258–261.

3. Martin-Biggers J, Barbosa Bueno de Campos ME. A randomized, placebo-controlled clinical study evaluating a dietary supplement for hair growth. J Clin Aesthet Dermatol. 2024;17(11):34-38.

4. Oblong, J. E., Peplow, A. W., Hartman, S. M., & Davis, M. G. (2020). Topical niacinamide does not stimulate hair growth based on the existing body of evidence. International Journal of Cosmetic Science, 42(2), 217–219.

5. Pozo-Pérez, L., Tornero-Esteban, P., & López-Bran, E. (2024). Clinical and preclinical approach in AGA treatment: A review of current and new therapies in the regenerative field. Stem Cell Research & Therapy, 15, 260.

6. Xu, C., Dai, J., Ai, H., Du, W., & Ji, H. (2024). β-Nicotinamide mononucleotide promotes cell proliferation and hair growth by reducing oxidative stress. Molecules, 29(4), 798.

7. Fukumoto, S., Ito, M., Kunitomo, H., Hataoka, T., Chiba, T., Nureki, O., & Fujimoto, T. (2025). Oral Supplementation of Nicotinamide Mononucleotide (NMN) Improves Hair Quality and Subjective Perception of Hair Appearance in Middle-Aged Women. Cosmetics, 12(5), 204.