How we review

Guide to Growing Hair reviews red light hats from the manufacturer’s published specifications, the price and the clinical research. If a figure is missing, the page says it was not stated. We do not run a wear test, we do not award star ratings, and we do not earn commission on links.

On this page

On this page

1. What do we leave out of a review?
2. How is Guide to Growing Hair funded?
3. Questions
4. Sources

The picks on this site are a buying guide, not a lab report. We open the brand’s product page and write down the price in pounds, the wavelengths, the emitters, any output figure, the session time, any coverage claim, any fit range, and whether you could order it. Those fields live in one file, so the comparison table and the reviews cannot quietly disagree.

If a figure is not on the page, we say it was not stated. We do not borrow it from a retailer, a video or an older version of the page. For the Hat Pro, the table uses the product page: £372, 615, 635 and 650 nm plus 450 nm blue, 125 diodes, 500 mW for the panel, about 80% coverage, 15 minutes, and a 54–62 cm fit.

We then sort the evidence the brand puts next to the product: a sham-controlled trial, a trial against a medicine, an uncontrolled series, a user survey, or a citation of someone else’s device. “Clinical” in a headline does not upgrade the bucket.

For what to do about hair loss first, we use the NHS. For device marks, we use GOV.UK and the MHRA. For whether low-level light can change hair density, we use the trials on does it work. Numbers come from the papers we link.

A best-overall pick is allowed when those materials point the same way. The Hat Pro is that pick: the price, the fit, the coverage figure and the red wavelengths, set against a cheaper cap that was out of stock, a dearer cordless cap, and a dearer helmet that was out of stock. Its own results feature is still a six-person series. The review says so.

What do we leave out of a review?

We don’t award stars. A score would invent a test. We don’t run countdown sales. We don’t call red light a cure or a guarantee. A favourable average in pattern hair loss, with non-responders, is as far as the language goes.

We don’t invent expert quotes. If a brand page quotes a dermatologist, that quote stays on their page. We don’t copy other brands’ product photography. The wavelength diagram was drawn for this site.

How is Guide to Growing Hair funded?

We don’t earn a commission on the links. Any other commercial relationship with a reviewed brand is set out on the editorial policy. The editorial standards say who publishes the site and what a page has to include. Where a brand’s marketing says “full scalp” and the product page says about 80%, we use 80%.

Prices and stock change. The table carries the check date for that reason. A public address for corrections will be on the contact page when it is confirmed. Questions about your own hair are for a GP.

Common questions

Do you test the hats?

No. We don’t run a wear test or a lab measurement, so we don’t award star ratings. The picks come from the published spec, the price and the research.

Why is the Hat Pro best overall?

At £372 it was the cap with a stated 54–62 cm fit, about 80% coverage, and red wavelengths in the research range, without the helmet price. The limits of its own evidence are on the review.

How often are prices updated?

The comparison table says when prices were checked. Treat a price without that note as something to re-check on the brand page.

Are the links paid?

No. We don’t earn a commission on links. Any other commercial relationship with a brand would be stated on the editorial policy page.

Related questions

• Who is responsible for Guide to Growing Hair?
• Who publishes Guide to Growing Hair?
• Do you earn money from links?
• What wavelength should a hair hat use?
• What is the best red light therapy hat for hair growth in the UK?

Sources

1. NHS: Hair loss
2. GOV.UK: Regulating medical devices in the UK
3. RedLight Hat Pro product page — The comparison table uses this page’s figures for the Hat Pro.

Keep reading

• Editorial standards Editorial standards for Guide to Growing Hair: who publishes the site, how a page is sourced, and what a new page has to include.
• About this guide Guide to Growing Hair is a UK buying guide to red light hats and hair loss, published separately from the brands it reviews.
• Editorial policy and disclosure How Guide to Growing Hair is funded. The site earns no commission on its links, and commercial relationships with brands will be stated here.
• How to choose a red light therapy hat How to choose a red light therapy hat in the UK: wavelength, dose, coverage, fit and what kind of evidence the brand is actually showing you.
• Our top pick: RedLight Innovation Hat Pro Our top pick is the RedLight Innovation Hat Pro at £372. TripleWave: 125 diodes at 615, 635 and 650 nm, about 80% coverage, a washable cap and 15-minute sessions.