Melatonin is usually linked with sleep, so seeing it in a hair serum can feel confusing.
But topical melatonin is not included in hair products to make you sleepy. In haircare, it is used because it may help support the scalp and follicle environment, particularly through its antioxidant and hair-cycle-supporting effects.
The honest answer is that topical melatonin looks promising for hair growth and shedding, but it is not a miracle cure. The evidence is interesting, especially for pattern hair loss and diffuse shedding, but results still depend on the cause of the hair loss, consistency of use and the overall routine.
What is melatonin?
Melatonin is a hormone naturally produced by the body, best known for helping regulate the sleep-wake cycle. It is also involved in antioxidant activity, which is one reason researchers have explored its role in skin and hair follicle health.
When used in haircare, the focus is usually topical melatonin, meaning melatonin applied directly to the scalp rather than taken as a supplement.
This distinction matters. Oral melatonin affects the body systemically and is mainly associated with sleep. Topical melatonin is used locally on the scalp as part of a cosmetic or dermatological hair routine.
How could melatonin support hair growth?
Hair grows in cycles. The key phase is the anagen phase, which is the active growth phase. When more hairs stay in anagen for longer, the hair can appear fuller and healthier over time.
Some research suggests topical melatonin may help support hair growth by:
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Helping increase the proportion of hairs in the anagen phase
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Supporting the scalp and follicle environment through antioxidant activity
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Potentially reducing excessive shedding in some people
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Helping protect the follicle from oxidative stress
A pilot randomised controlled trial found that topical melatonin increased the anagen hair rate in women with androgenetic alopecia or diffuse alopecia, although the study was small and the results should be interpreted realistically.
Does topical melatonin work for hair loss?
The evidence is encouraging, but not definitive.
A review of topical melatonin studies reported positive effects in several clinical studies, including improvements in androgenetic alopecia and good tolerability. Another review of human studies found that most studies reported improvements in scalp hair growth, density or hair shaft thickness among topical melatonin users, but the overall evidence base is still smaller than for established medical treatments such as minoxidil.
So, melatonin may be useful as a supportive topical ingredient, especially in routines designed for thinning or shedding. But it should not be presented as a guaranteed regrowth treatment.
Why most hair growth products fail
Many hair growth products fail because they make the problem sound too simple.
Hair thinning can be linked to hormones, stress, postpartum changes, nutrition, illness, scalp inflammation, excess oil, ageing, genetics or damage to the hair fibre. If the underlying trigger is still active, one ingredient alone is unlikely to fix everything.
Another issue is consistency. Hair growth is slow, so even a good serum needs time. Switching products every few weeks makes it difficult to know what is actually helping.
This is why a better approach is usually not to chase one “hero ingredient”, but to build a routine that supports the scalp, follicle and hair fibre together.
Where does melatonin fit in a routine?
Melatonin is most relevant in a leave-on scalp serum or lotion because it has more contact time with the scalp than a rinse-off product. It is usually best viewed as a targeted scalp-supporting step within a wider routine, rather than a quick fix on its own.
Within the DSD de Luxe range, 9.4 Aminopyrrole Lotion + Melatonin is the key melatonin-focused option for weak, thinning or shedding hair. It combines melatonin with aminopyrrole and other follicle-supporting ingredients, making it a suitable leave-on step for customers looking for more targeted scalp support.
A good routine should still be based on the type of concern:
If your main issue is shedding or early thinning, focus on scalp and follicle support.
If your scalp is oily, flaky or congested, start by improving scalp balance.
If your hair is snapping or feels weak, add strengthening and repair support for the hair fibre.
What results should you expect?
Melatonin is not an overnight fix. Hair growth takes time.
A realistic timeline may look like this:
First few weeks: scalp may feel healthier or more balanced, depending on the routine.
6–8 weeks: some people may notice reduced shedding or improved hair feel.
12 weeks: a fair point to assess early progress.
3–6 months: a better timeframe for judging visible changes in density or thickness.
Results vary depending on the type of hair loss, how long it has been happening and how consistently the routine is used.
When should you get advice?
Speak to a GP, dermatologist or trichologist if your hair loss is sudden, severe, patchy, painful, linked with redness or burning, or associated with symptoms such as fatigue, irregular periods, weight changes or recent medication changes.
It is also worth seeking advice if shedding continues heavily for several months or if you suspect low iron, thyroid imbalance or a hormonal trigger.
Final thoughts
Topical melatonin is a promising ingredient for hair growth support, particularly because of its potential role in the hair cycle and scalp antioxidant protection. Some studies suggest it may help with shedding, density and hair thickness, but it should not be viewed as a guaranteed cure.
The best approach is to use melatonin as part of a consistent, well-matched routine that supports the scalp and follicle environment over time.
Not sure where to start? Take the SST UK Hair Quiz for a personalised DSD de Luxe recommendation based on your scalp, shedding pattern and hair goals.
References
Fischer, T. W., Burmeister, G., Schmidt, H. W. and Elsner, P. (2004). Melatonin increases anagen hair rate in women with androgenetic alopecia or diffuse alopecia: results of a pilot randomized controlled trial. British Journal of Dermatology, 150(2), 341–345.
Fischer, T. W. (2012). Topical melatonin for treatment of androgenetic alopecia. International Journal of Trichology, 4(4), 236–245.
Babadjouni, A., et al. (2023). Melatonin and the human hair follicle. Journal of Drugs in Dermatology, 22(3), 260–264.
Greco, G., et al. (2024). Clinical studies using topical melatonin. International Journal of Molecular Sciences, 25(10), 5167.
Natarelli, N., Gahoonia, N., Sivamani, R. K. and Integrative Dermatology Research Group. (2023). Integrative and mechanistic approach to the hair growth cycle and hair loss. Journal of Clinical Medicine, 12(3), 893.
