Milk Thistle for Hair: What the Research Shows

Milk thistle has some hair-related research, but it's early and mostly lab work. A 2024 study found that a shampoo containing milk thistle flower extract increased hair density and total hair count compared with placebo, and silibinin, a compound from the plant, activated hair-growth pathways in human dermal papilla cells.

Here's what the studies found, how the flower extract differs from the seed supplement, and what's known about safety.

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Key Takeaways

• In a clinical study, a shampoo containing Silybum marianum (milk thistle) flower extract significantly increased hair density and total hair count at 16 and 24 weeks compared with placebo.
• In human dermal papilla cells, the flower extract increased proliferation and VEGF production and suppressed cellular senescence.
• Silibinin, a milk thistle compound, increased viability and activated Wnt/β-catenin signalling in 3D human dermal papilla spheroids.
• The best-known milk thistle supplement, silymarin, has not been tested for hair growth in the studies we found.

What Is Milk Thistle?

Milk thistle (Silybum marianum) is a medicinal plant. Silymarin, a mixture of flavonolignans such as silybin, is the major constituent of its extract.

Flower Extract vs Silymarin

The hair study tested a flower extract in a shampoo. A silymarin supplement is a different preparation, so the shampoo results don't automatically apply to a capsule.

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What To Know Before Trying It

• Match the form to the evidence. The clinical hair study used a shampoo with flower extract.
• Be patient. Results appeared after 16 to 24 weeks.
• Check with your doctor if you take medication, especially drugs with a narrow therapeutic window.

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What The Research Shows

Flower Extract In Cells And A Clinical Study

Silybum marianum flower extract increased the proliferation and VEGF production of human hair follicle dermal papilla cells, and it suppressed cell senescence and IL-6 in senescence models. In a clinical study, hair density and total hair count at 16 and 24 weeks after using a shampoo with the extract were significantly higher than with placebo (You et al., 2024).

Silibinin In The Lab

Silibinin significantly increased viability through AKT activation in 3D spheroids of human dermal papilla cells, increased spheroid diameter and activated Wnt/β-catenin signalling, with higher expression of hair-induction genes. The authors suggested silibinin as a candidate for hair loss therapy; this was a cell study (Cheon et al., 2019).

Safety

Silymarin is safe in humans at therapeutic doses and well tolerated even at a high dose of 700 mg three times a day for 24 weeks. Some gastrointestinal discomfort, like nausea and diarrhea, occurred. Caution is advised in pregnancy and with narrow-therapeutic-window drugs (Soleimani et al., 2019).

See also: Centella Asiatica (Gotu Kola) for Hair: What the Research Shows · Phytoceramides for Hair: What They Are and What the Research Shows

Frequently Asked Questions

Does milk thistle help hair growth?

In one clinical study, a shampoo with milk thistle flower extract increased hair density and total hair count versus placebo, and lab studies show effects on dermal papilla cells. Silymarin supplements haven't been tested for hair.

Is milk thistle safe?

Silymarin was well tolerated in human studies, with some nausea and diarrhea reported. Talk to your doctor before taking it, especially if you're pregnant or take medication.

How long does it take to work?

In the clinical study, differences were measured at 16 and 24 weeks.

References

1. You J, Woo J, Roh KB, et al. Evaluation of efficacy of Silybum marianum flower extract on the mitigating hair loss in vitro and in vivo. J Cosmet Dermatol. 2024. PubMed
2. Cheon HI, Bae S, Ahn KJ. Flavonoid Silibinin Increases Hair-Inductive Property Via Akt and Wnt/β-Catenin Signaling Activation in 3-Dimensional-Spheroid Cultured Human Dermal Papilla Cells. J Microbiol Biotechnol. 2019. PubMed
3. Soleimani V, Delghandi PS, Moallem SA, et al. Safety and toxicity of silymarin, the major constituent of milk thistle extract: An updated review. Phytother Res. 2019. PubMed