Here are supplements with some supporting evidence:
Biotin (Vitamin B7): Plays a role in keratin production, a key component of hair. However, deficiency is less common, and benefits of supplementation appear limited unless the users have a diagnosed deficiency.
Zinc: Deficiency can lead to hair loss. Ensuring adequate dietary intake through foods like meat, seafood, and pumpkin seeds is often sufficient.
Iron: Deficiency can also trigger hair loss. One may consider dietary sources like lentils, spinach, and beans.
Vitamin D: Plays a role in cell growth and cycling, impacting hair follicles. Deficiency is common, and supplementation may benefit hair growth, although more study is needed.
Vitamin C: An antioxidant essential for collagen production, crucial for hair structure. One may focus on dietary sources like citrus fruits and peppers.
Reference
1. Shaher Duchi et al, The formulation and in vitro evaluation of WS Biotin, a novel encapsulated form of D-Biotin with improved water solubility for hair and skin treatment applications, Int J Cosmet Sci. 2024 Feb;46(1):119-129.
2. Jovan Lalosevic et al, Serum Zinc Concentration in Patients with Alopecia Areata, Acta Derm Venereol. 2023 Oct 3:103:adv13358.
3. Chia-Shuen Lin et al, Diagnosis and treatment of female alopecia: Focusing on the iron deficiency-related alopecia, Tzu Chi Med J. 2023 Aug 22;35(4):322-328.
4. Kriteeka Saini et al, Role of vitamin D in hair loss: A short review, J Cosmet Dermatol. 2021 Nov;20(11):3407-3414.
5. Hind M Almohanna et al, The Role of Vitamins and Minerals in Hair Loss: A Review , Dermatol Ther (Heidelb). 2019 Mar;9(1):51-70.