Caffeine Shampoo: Does It Reach the Follicle in Two Minutes?
Caffeine shampoos promise to "energize" the scalp. The most useful research on them answers a narrower question: does caffeine from a shampoo get into the scalp at all in the short time it is on your head?
The absorption study
In 2007, Otberg and colleagues published a study in Skin Pharmacology and Physiology. Volunteers had a caffeine shampoo applied for two minutes, and the researchers then measured caffeine in their blood.
The clever part was how they separated the routes in. On some test sites they blocked the openings of the hair follicles. Comparing blocked and unblocked sites showed how much caffeine came in through the follicles and how much through the surface of the skin.
Caffeine was absorbed both ways. The follicles were faster and delivered more, and for the first 20 minutes they were the only fast route.
What it does and doesn't tell you
This study shows that a two-minute shampoo contact is enough for caffeine to start reaching the scalp through the follicles. It does not show that a caffeine shampoo grows hair. Those are different questions, and it is worth being clear about which one the evidence answers.
The part you control: contact time
Whatever shampoo you use, the habit that matters most is leaving it on. Massage it into the scalp and wait at least two minutes, ideally three to five, before rinsing. A fast lather-and-rinse gives every ingredient in the bottle less time to work.
Which shampoos contain caffeine
Four shampoos in our comparison list caffeine:
- Regenepure DR, with ketoconazole, saw palmetto, emu oil and niacin, in a base with no sulfates. Our top pick.
- Alpecin C1, where caffeine is the headline, in a sulfate cleanser.
- DS Laboratories Revita, with biotin, in a sulfate-less base.
- Nioxin System 2, with biotin and niacin, as part of a three-step system.
If caffeine is on your list, look at what comes with it. Regenepure DR is the only one of the four that also contains ketoconazole.
Read more about caffeine, or compare Regenepure DR vs Alpecin C1.
Sources
- Otberg N, et al. Follicular penetration of topically applied caffeine via a shampoo formulation. Skin Pharmacology and Physiology, 2007.