Dried He Shou Wu root slices beside unbranded supplement capsules
He Shou Wu’s reputation for restoring dark hair rests on a centuries-old story. The modern evidence is mostly from mice, and the safety record is concerning.

He Shou Wu, sold in the West as fo-ti, is the dried root of Polygonum multiflorum (also classified as Reynoutria multiflora). Its name is usually translated along the lines of “black-haired Mr. He,” after a legendary figure said to have regained his youth and dark hair by eating the root. That story is still doing the marketing: He Shou Wu capsules, teas, and tonics are sold to reverse greying, thicken hair, and restore vitality.

Grey hair is one of the few hair concerns with no approved treatment, which makes it fertile ground for supplements. The question is whether He Shou Wu has any human evidence behind it, and what the trade-off is.

The Claim

“A time-tested herbal tonic that restores your hair’s natural color and strength from within — nature’s answer to grey hair.”

(Composite representative claim drawn from supplement marketing.)

Why Hair Turns Grey

Hair gets its color from melanocytes in each follicle, which are replenished by a pool of melanocyte stem cells. With age, that pool is depleted and oxidative stress, including hydrogen peroxide build-up, impairs pigment production. A 2018 review of premature greying also links it to vitamin B12 deficiency, low copper, ferritin, or vitamin D, and thyroid disease. Those causes are worth testing for, because correcting a real deficiency is the one situation where some repigmentation is plausible.

Natural reversal does happen, but rarely. A 2021 study in eLife mapped pigment along 397 individual hairs and found repigmentation in 10 people aged 9 to 39. The authors concluded that reversal is limited to isolated follicles sitting just above a greying threshold. Once a follicle’s stem cells are gone, no supplement is known to bring them back. That is a useful backdrop for any product that promises to “restore” color.

What the Hair Studies Actually Show

We found no peer-reviewed, controlled human trials showing that He Shou Wu reverses grey hair or improves hair growth. The research behind the claims is in animals and cells:

These studies justify further research, not consumer claims. Mouse hair cycles and induced greying models differ from human age-related greying, and a melanin increase in cultured cells says nothing about whether an oral dose reaches human follicles.

The Liver Problem

The safety evidence is much stronger than the efficacy evidence. A 2015 systematic review collected 450 published cases of liver injury associated with Polygonum multiflorum. In the case reports where a reason for use was recorded, about 60% of people were taking it for grey hair or hair loss. The median time to injury was 30 days. The review recorded several deaths and two liver transplants, and found that injury occurred with both raw and processed root.

The U.S. National Institutes of Health’s LiverTox database maintains an entry on the herb. Anyone taking He Shou Wu who develops fatigue, nausea, dark urine, or yellowing skin or eyes should stop and see a doctor.

The Regulatory Picture

In the U.S., He Shou Wu is sold as a dietary supplement, so it does not need FDA approval before sale. In April 2026, the FDA issued a warning letter to Nature’s Elements, Inc., a seller of He Shou Wu products. The letter cited a cholesterol-lowering claim for He Shou Wu and a hair-loss claim for a separate “DHT Blocker” product, and it described manufacturing gaps, including no finished-product specifications or batch records for the He Shou Wu product. The letter did not address grey-hair claims, but it illustrates how loosely these products can be made and marketed.

QuestionWhat the evidence shows
Reverses grey hair in humans?No controlled human trials found
Promotes hair growth?Mouse studies only
Increases melanin?In mice and cultured cells
Safe because it’s traditional?450+ published liver-injury cases; regulators have issued warnings
Processed root is safe?Injury reported with both raw and processed forms

Better Options for Grey Hair

There is no proven way to reverse genetically driven greying. If greying is premature or sudden, it is worth checking B12, iron, vitamin D, and thyroid function with a doctor. Otherwise, hair dye remains the effective option. For hair thinning, our reviews of hair growth supplements and biotin cover the better-studied choices.

Verdict: Claim Unsupported

There is no controlled human evidence that He Shou Wu reverses grey hair or regrows hair; the support comes from a legend, a handful of mouse studies, and cell experiments. Meanwhile, hundreds of published cases link it to liver injury, many in people taking it for their hair. The risk is documented; the benefit is not.

References & Further Reading